[uart] Share the fake UART, move the reader benchmarks to core and drive Modbus through loop()

[uart] Add frame parsing benchmarks
[cc1101] Add long packet support, plus a lambda packet_length for unknown-length packets (#17578 )
2026-11-15 09:36:04 +00:00 · 2026-11-15 03:03:44 -06:00 · 2026-11-15 02:48:18 -06:00 · 2026-11-14 21:43:21 -06:00 · 2026-11-15 13:17:23 +11:00 · 2026-11-15 02:11:09 +00:00
73 changed files with 4959 additions and 1076 deletions
@@ -149,6 +149,7 @@ esphome/components/cst226/* @clydebarrow
 esphome/components/cst328/* @latonita
 esphome/components/cst816/* @clydebarrow
 esphome/components/cst9220/* @clydebarrow
+esphome/components/cstxxx/* @clydebarrow @latonita
 esphome/components/ct_clamp/* @jesserockz
 esphome/components/current_based/* @djwmarcx
 esphome/components/cw2017/* @exciton
@@ -741,7 +742,7 @@ esphome/components/web_server_idf/* @dentra
 esphome/components/weikai/* @DrCoolZic
 esphome/components/weikai_i2c/* @DrCoolZic
 esphome/components/weikai_spi/* @DrCoolZic
-esphome/components/whirlpool/* @arpena @glmnet
+esphome/components/whirlpool/* @arpena @glmnet @Rodrigoah
 esphome/components/whynter/* @aeonsablaze
 esphome/components/wiegand/* @ssieb
 esphome/components/wireguard/* @droscy @lhoracek @thomas0bernard
@@ -1,3 +1,5 @@
+from typing import Any
+
 from esphome import automation, pins
 from esphome.automation import maybe_simple_id
 import esphome.codegen as cg
@@ -13,6 +15,7 @@ from esphome.const import (
    CONF_VALUE,
    CONF_WAIT_TIME,
 )
+from esphome.types import ConfigType

 CODEOWNERS = ["@lygris", "@gabest11"]
 DEPENDENCIES = ["spi"]
@@ -22,6 +25,8 @@ MULTI_CONF = True
 ns = cg.esphome_ns.namespace("cc1101")
 CC1101Component = ns.class_("CC1101Component", cg.Component, spi.SPIDevice)
 CC1101Listener = ns.class_("CC1101Listener")
+PACKET_TYPE = cg.std_vector.template(cg.uint8)
+RX_FIFO_SIZE = 64

 # Config keys
 CONF_RX_ATTENUATION = "rx_attenuation"
@@ -241,20 +246,34 @@ CONFIG_MAP = {
    cv.Optional(CONF_BS_POST_KI): cv.enum(BS_POST_KI, upper=False),
    cv.Optional(CONF_BS_POST_KP): cv.enum(BS_POST_KP, upper=False),
    cv.Optional(CONF_PACKET_MODE, default=False): cv.boolean,
-    cv.Optional(CONF_PACKET_LENGTH): cv.uint8_t,
    cv.Optional(CONF_CRC_ENABLE, default=False): cv.boolean,
    cv.Optional(CONF_WHITENING, default=False): cv.boolean,
 }


-def _validate_packet_mode(config):
-    if config.get(CONF_PACKET_MODE, False):
+def _is_long_packet(packet_length: Any) -> bool:
+    """A packet_length that does not fit the RX FIFO, or is a lambda."""
+    return cg.is_template(packet_length) or (packet_length or 0) > RX_FIFO_SIZE
+
+
+def _validate_packet_mode(config: ConfigType) -> ConfigType:
+    packet_mode = config.get(CONF_PACKET_MODE, False)
+    packet_length = config.get(CONF_PACKET_LENGTH)
+    if packet_mode:
        if CONF_GDO0_PIN not in config:
            raise cv.Invalid("gdo0_pin is required when packet_mode is enabled")
-        if CONF_PACKET_LENGTH not in config:
+        if packet_length is None:
            raise cv.Invalid("packet_length is required when packet_mode is enabled")
-        if config[CONF_PACKET_LENGTH] > 64:
-            raise cv.Invalid("packet_length must be <= 64 (FIFO size)")
+    elif cg.is_template(packet_length):
+        raise cv.Invalid("packet_mode is required when packet_length is a lambda")
+    if (
+        packet_mode
+        and _is_long_packet(packet_length)
+        and config.get(CONF_CRC_ENABLE, False)
+    ):
+        raise cv.Invalid(
+            "crc_enable is not supported with packet_length > 64 or a lambda"
+        )
    return config


@@ -263,6 +282,9 @@ CONFIG_SCHEMA = cv.All(
        {
            cv.GenerateID(): cv.declare_id(CC1101Component),
            cv.Optional(CONF_GDO0_PIN): pins.internal_gpio_input_pin_schema,
+            cv.Optional(CONF_PACKET_LENGTH): cv.templatable(
+                cv.int_range(min=0, max=1024)
+            ),
            cv.Optional(CONF_ON_PACKET): automation.validate_automation(single=True),
        }
    )
@@ -282,11 +304,24 @@ async def to_code(config):
            cg.add(getattr(var, f"set_{key}")(config[key]))

    await cg.add_pin(var.set_gdo0_pin, config.get(CONF_GDO0_PIN))
+    if (packet_length := config.get(CONF_PACKET_LENGTH)) is not None:
+        # packet_mode can also be switched on at run time, so this does not check it
+        if _is_long_packet(packet_length):
+            cg.add_define("USE_CC1101_LONG_PACKET")
+        if cg.is_template(packet_length):
+            lambda_ = await cg.process_lambda(
+                packet_length,
+                [(PACKET_TYPE.operator("ref").operator("const"), "x")],
+                return_type=cg.int32,
+            )
+            cg.add(var.set_packet_length_lambda(lambda_))
+        else:
+            cg.add(var.set_packet_length(packet_length))
    if CONF_ON_PACKET in config:
        await automation.build_automation(
            var.get_packet_trigger(),
            [
-                (cg.std_vector.template(cg.uint8), "x"),
+                (PACKET_TYPE, "x"),
                (cg.float_, "freq_offset"),
                (cg.float_, "rssi"),
                (cg.uint8, "lqi"),
@@ -1,8 +1,10 @@
 #include "cc1101.h"
 #include "cc1101pa.h"
+#include "esphome/core/application.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/progmem.h"
+#include <algorithm>
 #include <cmath>
 #include <cstring>

@@ -14,9 +16,15 @@ namespace esphome::cc1101 {

 ESPHOME_LOG_TAG(TAG, "cc1101");
 static constexpr size_t TX_FIFO_SIZE = 64;
+static constexpr size_t RX_FIFO_SIZE = 64;
+// RX FIFO threshold for FIFO_THR = 7 in long packet mode
+static constexpr uint8_t RX_FIFO_THRESHOLD = 32;
 // The crystal takes about 150 us to start after CSn goes low
 static constexpr uint32_t WAKEUP_DELAY_US = 200;

+static float freq_offset_hz(uint8_t freqest) { return static_cast<int8_t>(freqest) * (XTAL_FREQUENCY / (1 << 14)); }
+static float rssi_dbm(int8_t rssi) { return (rssi * RSSI_STEP) - RSSI_OFFSET; }
+
 // MDMCFG2 MOD_FORMAT values
 PROGMEM_STRING_TABLE(ModulationStrings, "2-FSK", "GFSK", "UNUSED", "ASK/OOK", "4-FSK", "UNUSED", "UNUSED", "MSK");

@@ -114,8 +122,6 @@ CC1101Component::CC1101Component() {
  memset(this->pa_table_, 0, sizeof(this->pa_table_));
 }

-void IRAM_ATTR CC1101Component::gpio_intr(CC1101Component *arg) { arg->enable_loop_soon_any_context(); }
-
 void CC1101Component::setup() {
  this->spi_setup();

@@ -193,7 +199,220 @@ void CC1101Component::call_listeners_(const std::vector<uint8_t> &packet, float
  this->packet_trigger_.trigger(packet, freq_offset, rssi, lqi);
 }

+float CC1101Component::symbol_rate_() const {
+  return (((256.0f + this->state_.DRATE_M) * (1 << this->state_.DRATE_E)) / (1 << 28)) * XTAL_FREQUENCY;
+}
+
+#ifdef USE_CC1101_LONG_PACKET
+bool CC1101Component::is_long_packet_mode_() const {
+  return this->packet_mode_ && (this->packet_length_ > RX_FIFO_SIZE || this->packet_length_func_ != nullptr);
+}
+
+void CC1101Component::arm_length_(uint16_t length) {
+  // Over 255 bytes or unknown starts in infinite mode (datasheet section 15.2.2). PKTLEN must not be 0, so a
+  // multiple of 256 stays in infinite mode and ends on the MCU byte count alone.
+  this->packet_expected_length_ = length;
+  this->state_.LENGTH_CONFIG = static_cast<uint8_t>(length > 0 && length < 256 ? LengthConfig::LENGTH_CONFIG_FIXED
+                                                                               : LengthConfig::LENGTH_CONFIG_INFINITE);
+  this->state_.PKTLEN = length % 256 == 0 ? 0xFF : static_cast<uint8_t>(length % 256);
+}
+
+void CC1101Component::reset_long_packet_rx_() {
+  this->packet_.clear();
+  this->packet_last_byte_ms_ = 0;
+  this->high_freq_.stop();
+  this->arm_length_(this->packet_length_func_ != nullptr ? 0 : this->packet_length_);
+}
+
+void CC1101Component::restart_long_packet_rx_() {
+  this->enter_idle_();
+  this->enter_rx_();
+  this->disable_loop();
+}
+
+void CC1101Component::maybe_switch_long_packet_to_fixed_() {
+  const uint16_t expected = this->packet_expected_length_;
+  if (this->state_.LENGTH_CONFIG == static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_FIXED) || expected == 0 ||
+      expected % 256 == 0) {
+    return;
+  }
+  const uint16_t received = this->packet_.size();
+  if (expected - received >= 256) {
+    return;
+  }
+  // PKTLEN keeps the (length % 256) set at the start, as in TI Design Note DN500 section 2.3
+  this->state_.LENGTH_CONFIG = static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_FIXED);
+  this->write_(Register::PKTCTRL0);
+  ESP_LOGVV(TAG, "Switched long packet RX to fixed mode: received=%u expected=%u pktlen=%u", received, expected,
+            this->state_.PKTLEN);
+}
+
+void CC1101Component::finish_long_packet_() {
+  this->packet_.resize(this->packet_expected_length_);
+  this->read_(Register::FREQEST);
+  this->read_(Register::LQI);
+  const float freq_offset = freq_offset_hz(this->state_.FREQEST);
+  const uint8_t lqi = this->state_.LQI & STATUS_LQI_MASK;
+  // No CRC check: crc_enable is rejected for long packets, CRC_OK is only set after the last payload byte.
+  // Restart RX before dispatching so a callback may change settings; swapping back keeps the reserved capacity
+  // unless a callback reserved a larger buffer.
+  std::vector<uint8_t> packet;
+  packet.swap(this->packet_);
+  this->restart_long_packet_rx_();
+  this->call_listeners_(packet, freq_offset, rssi_dbm(this->long_packet_rssi_), lqi);
+  if (packet.capacity() > this->packet_.capacity()) {
+    packet.clear();
+    this->packet_.swap(packet);
+  }
+}
+
+void CC1101Component::handle_long_packet_(uint8_t rx_bytes) {
+  // Leave one byte in the FIFO unless it holds the rest of the packet (datasheet section 20)
+  uint16_t to_read = rx_bytes > 0 ? rx_bytes - 1 : 0;
+  if (this->packet_expected_length_ > 0) {
+    const uint16_t remaining = this->packet_expected_length_ - this->packet_.size();
+    if (remaining <= rx_bytes) {
+      to_read = remaining;
+    }
+  }
+
+  if (to_read == 0) {
+    if (this->packet_.empty()) {
+      return;
+    }
+    // Discard a packet when no byte arrived for the air time of PACKET_IDLE_TIMEOUT_BYTES
+    const uint32_t timeout_ms =
+        std::max(static_cast<uint32_t>(std::ceil((8.0f * PACKET_IDLE_TIMEOUT_BYTES * 1000.0f) / this->symbol_rate_())),
+                 PACKET_IDLE_TIMEOUT_MIN_MS);
+    if (App.get_loop_component_start_time() - this->packet_last_byte_ms_ > timeout_ms) {
+      ESP_LOGW(TAG, "Packet receive timeout, discarding packet: received=%u expected=%u fifo=%u",
+               static_cast<uint16_t>(this->packet_.size()), this->packet_expected_length_, rx_bytes);
+      this->restart_long_packet_rx_();
+    }
+    return;
+  }
+
+  const size_t old_size = this->packet_.size();
+  if (old_size == 0) {
+    // The RSSI register follows the live signal; sample it while the packet is still on air
+    this->read_(Register::RSSI);
+    this->long_packet_rssi_ = this->state_.RSSI;
+    // The FIFO threshold signal does not fire for the bytes after the last threshold crossing; poll until done
+    this->high_freq_.start();
+  }
+  // Read through an aligned buffer: for an unaligned target the ESP32 SPI driver allocates a bounce buffer
+  alignas(4) uint8_t staged[RX_FIFO_SIZE];
+  this->read_(Register::FIFO, staged, to_read);
+  this->packet_.resize(old_size + to_read);
+  std::memcpy(this->packet_.data() + old_size, staged, to_read);
+  this->packet_last_byte_ms_ = App.get_loop_component_start_time();
+  ESP_LOGVV(TAG, "Drained RX FIFO: read=%u received=%u expected=%u fifo=%u", to_read,
+            static_cast<uint16_t>(this->packet_.size()), this->packet_expected_length_, rx_bytes);
+
+  if (this->packet_expected_length_ == 0 && this->packet_length_func_ != nullptr) {
+    const int32_t length = this->packet_length_func_(this->packet_);
+    if (length < 0) {
+      ESP_LOGVV(TAG, "Packet length lambda discarded packet: received=%u", static_cast<uint16_t>(this->packet_.size()));
+      this->restart_long_packet_rx_();
+      return;
+    }
+    if (length > MAX_PACKET_LENGTH) {
+      ESP_LOGW(TAG, "Packet length exceeds maximum, discarding packet: length=%" PRId32 " max=%u", length,
+               MAX_PACKET_LENGTH);
+      this->restart_long_packet_rx_();
+      return;
+    }
+    if (length > 0) {
+      this->arm_length_(static_cast<uint16_t>(length));
+      // A packet shorter than the first FIFO drain is already complete; finish_long_packet_() truncates it
+      if (this->packet_expected_length_ <= this->packet_.size()) {
+        this->finish_long_packet_();
+        return;
+      }
+      this->write_(Register::PKTLEN);
+      this->write_(Register::PKTCTRL0);
+      ESP_LOGVV(TAG, "Resolved packet length: received=%u expected=%u pktlen=%u",
+                static_cast<uint16_t>(this->packet_.size()), this->packet_expected_length_, this->state_.PKTLEN);
+    }
+  }
+
+  // Only reachable while the length is still unknown; a known length caps every read
+  if (this->packet_.size() > MAX_PACKET_LENGTH) {
+    ESP_LOGW(TAG, "Packet length exceeds maximum, discarding packet: length=%u max=%u",
+             static_cast<uint16_t>(this->packet_.size()), MAX_PACKET_LENGTH);
+    this->restart_long_packet_rx_();
+    return;
+  }
+
+  this->maybe_switch_long_packet_to_fixed_();
+
+  if (this->packet_expected_length_ > 0 && this->packet_.size() >= this->packet_expected_length_) {
+    this->finish_long_packet_();
+  }
+}
+
+void CC1101Component::loop_long_packet_() {
+  if (this->sleeping_ || this->state_.PKT_FORMAT != static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_FIFO) ||
+      this->gdo0_pin_ == nullptr) {
+    this->high_freq_.stop();
+    this->disable_loop();
+    return;
+  }
+  // While GDO0 (RX FIFO threshold) is high, the FIFO holds at least RX_FIFO_THRESHOLD bytes, so drain without
+  // reading RXBYTES. At high data rates RXBYTES changes between two reads, so waiting for two reads that agree
+  // and retrying on the next loop pass lets the FIFO overflow. MARCSTATE does not change during RX.
+  for (uint8_t i = 0; i < RX_FIFO_SIZE / RX_FIFO_THRESHOLD + 2 && this->gdo0_pin_->digital_read(); i++) {
+    this->read_(Register::MARCSTATE);
+    if (static_cast<State>(this->state_.MARC_STATE) == State::RXFIFO_OVERFLOW) {
+      ESP_LOGW(TAG, "RX FIFO overflow, discarding packet: received=%u expected=%u",
+               static_cast<uint16_t>(this->packet_.size()), this->packet_expected_length_);
+      this->restart_long_packet_rx_();
+      return;
+    }
+    this->handle_long_packet_(RX_FIFO_THRESHOLD);
+    if (this->packet_.empty()) {
+      return;  // finished or discarded
+    }
+  }
+  // Below the threshold the next crossing raises GDO0 again, and after the packet the count no longer changes,
+  // so retrying on the next loop pass is safe here. RXBYTES can be misread while bytes arrive (TI SWRZ020), so
+  // only trust two consecutive reads that agree.
+  this->read_(Register::RXBYTES);
+  uint8_t rx_bytes = this->state_.RXBYTES;
+  bool stable = false;
+  for (uint8_t retries = RXBYTES_STABLE_RETRIES; retries > 0 && !stable; retries--) {
+    const uint8_t previous = rx_bytes;
+    this->read_(Register::RXBYTES);
+    rx_bytes = this->state_.RXBYTES;
+    stable = rx_bytes == previous;
+  }
+  if (!stable) {
+    return;
+  }
+  rx_bytes = this->state_.NUM_RXBYTES;
+  // More than the FIFO holds can only be a misread; the staged drain buffer is FIFO sized
+  if (this->state_.RXFIFO_OVERFLOW || rx_bytes > RX_FIFO_SIZE) {
+    ESP_LOGW(TAG, "RX FIFO overflow, discarding packet: received=%u expected=%u fifo=%u",
+             static_cast<uint16_t>(this->packet_.size()), this->packet_expected_length_, rx_bytes);
+    this->restart_long_packet_rx_();
+    return;
+  }
+  if (rx_bytes == 0 && this->packet_.empty() && !this->gdo0_pin_->digital_read()) {
+    this->disable_loop();
+    return;
+  }
+  this->handle_long_packet_(rx_bytes);
+}
+#endif
+
 void CC1101Component::loop() {
+#ifdef USE_CC1101_LONG_PACKET
+  if (this->is_long_packet_mode_()) {
+    this->loop_long_packet_();
+    return;
+  }
+#endif
+
  this->disable_loop();
  if (this->sleeping_ || this->state_.PKT_FORMAT != static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_FIFO) ||
      this->gdo0_pin_ == nullptr || !this->gdo0_pin_->digital_read()) {
@@ -221,7 +440,7 @@ void CC1101Component::loop() {
    payload_length = this->state_.PKTLEN;
    expected_rx = payload_length;
  }
-  if (payload_length == 0 || payload_length > 64 || rx_bytes != expected_rx) {
+  if (payload_length == 0 || payload_length > RX_FIFO_SIZE || rx_bytes != expected_rx) {
    ESP_LOGW(TAG, "Invalid packet: rx_bytes %u, payload_length %u", rx_bytes, payload_length);
    this->enter_idle_();
    this->strobe_(Command::FRX);
@@ -235,8 +454,8 @@ void CC1101Component::loop() {
  this->read_(Register::FREQEST);
  this->read_(Register::RSSI);
  this->read_(Register::LQI);
-  float freq_offset = static_cast<int8_t>(this->state_.FREQEST) * (XTAL_FREQUENCY / (1 << 14));
-  float rssi = (this->state_.RSSI * RSSI_STEP) - RSSI_OFFSET;
+  float freq_offset = freq_offset_hz(this->state_.FREQEST);
+  float rssi = rssi_dbm(this->state_.RSSI);
  bool crc_ok = (this->state_.LQI & STATUS_CRC_OK_MASK) != 0;
  uint8_t lqi = this->state_.LQI & STATUS_LQI_MASK;
  if (this->state_.CRC_EN == 0 || crc_ok) {
@@ -256,7 +475,7 @@ void CC1101Component::loop() {
 void CC1101Component::dump_config() {
  int32_t freq = static_cast<int32_t>(this->state_.FREQ2 << 16 | this->state_.FREQ1 << 8 | this->state_.FREQ0) *
                 XTAL_FREQUENCY / (1 << 16);
-  float symbol_rate = (((256.0f + this->state_.DRATE_M) * (1 << this->state_.DRATE_E)) / (1 << 28)) * XTAL_FREQUENCY;
+  float symbol_rate = this->symbol_rate_();
  float bw = XTAL_FREQUENCY / (8.0f * (4 + this->state_.CHANBW_M) * (1 << this->state_.CHANBW_E));
  ESP_LOGCONFIG(TAG,
                "CC1101:\n"
@@ -271,6 +490,20 @@ void CC1101Component::dump_config() {
                LOG_STR_ARG(ModulationStrings::get_log_str(this->state_.MOD_FORMAT & 0x07, 0)), symbol_rate, bw,
                this->output_power_effective_);
  LOG_PIN("  CS Pin: ", this->cs_);
+  LOG_PIN("  GDO0 Pin: ", this->gdo0_pin_);
+
+  if (this->packet_mode_) {
+#ifdef USE_CC1101_LONG_PACKET
+    if (this->packet_length_func_ != nullptr) {
+      ESP_LOGCONFIG(TAG, "  Packet Length: lambda");
+    } else
+#endif
+        if (this->packet_length_ == 0) {
+      ESP_LOGCONFIG(TAG, "  Packet Length: variable");
+    } else {
+      ESP_LOGCONFIG(TAG, "  Packet Length: %u", this->packet_length_);
+    }
+  }
 }

 void CC1101Component::begin_tx() {
@@ -316,6 +549,14 @@ void CC1101Component::reset() {
 void CC1101Component::set_idle() {
  ESP_LOGV(TAG, "Setting IDLE state");
  this->enter_idle_();
+#ifdef USE_CC1101_LONG_PACKET
+  if (this->is_long_packet_mode_()) {
+    // Drop a partial packet so a pending loop pass cannot finish it and re-enter RX
+    this->strobe_(Command::FRX);
+    this->reset_long_packet_rx_();
+    this->disable_loop();
+  }
+#endif
 }

 void CC1101Component::power_down() {
@@ -393,7 +634,18 @@ void CC1101Component::enter_idle_() {
  }
 }

-bool CC1101Component::enter_rx_() { return this->enter_calibrated_(State::RX, Command::RX); }
+bool CC1101Component::enter_rx_() {
+#ifdef USE_CC1101_LONG_PACKET
+  if (this->is_long_packet_mode_()) {
+    // Every RX entry starts a fresh long packet; callers leave the chip in IDLE, where SFRX is allowed
+    this->strobe_(Command::FRX);
+    this->reset_long_packet_rx_();
+    this->write_(Register::PKTLEN);
+    this->write_(Register::PKTCTRL0);
+  }
+#endif
+  return this->enter_calibrated_(State::RX, Command::RX);
+}

 bool CC1101Component::enter_tx_() { return this->enter_calibrated_(State::TX, Command::TX); }

@@ -456,12 +708,22 @@ void CC1101Component::read_(Register reg, uint8_t *buffer, size_t length) {

 CC1101Error CC1101Component::transmit_packet(const uint8_t *data, size_t len) {
  if (this->state_.PKT_FORMAT != static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_FIFO)) {
+    ESP_LOGW(TAG, "Cannot transmit packet: packet mode is not FIFO");
    return CC1101Error::PARAMS;
  }
+#ifdef USE_CC1101_LONG_PACKET
+  // Long packet TX needs chunked FIFO refills and is not implemented
+  if (this->is_long_packet_mode_()) {
+    ESP_LOGW(TAG, "Cannot transmit packet: long packet mode is RX-only");
+    return CC1101Error::PARAMS;
+  }
+#endif
  const bool variable = this->state_.LENGTH_CONFIG == static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_VARIABLE);
  // In variable length mode the FIFO also holds the length byte
  if (len + (variable ? 1 : 0) > TX_FIFO_SIZE) {
-    ESP_LOGE(TAG, "Packet of %u bytes does not fit the TX FIFO", static_cast<unsigned>(len));
+    ESP_LOGW(TAG,
+             "Cannot transmit packet: long packet TX is not implemented, payload length %u exceeds TX FIFO limit %u",
+             static_cast<unsigned>(len), static_cast<unsigned>(TX_FIFO_SIZE));
    return CC1101Error::PARAMS;
  }

@@ -834,19 +1096,60 @@ void CC1101Component::set_bs_post_kp(BsPostKp value) {
  }
 }

-void CC1101Component::set_packet_mode(bool value) {
-  this->state_.PKT_FORMAT =
-      static_cast<uint8_t>(value ? PacketFormat::PACKET_FORMAT_FIFO : PacketFormat::PACKET_FORMAT_ASYNC_SERIAL);
-  if (value) {
-    // Configure GDO0 for FIFO status (asserts on RX FIFO threshold or end of packet)
-    this->state_.GDO0_CFG = 0x01;
-    // Set max RX FIFO threshold to ensure we only trigger on end-of-packet
-    this->state_.FIFO_THR = 15;
-    // Don't append status bytes to FIFO - we read from registers instead
-    this->state_.APPEND_STATUS = 0;
-  } else {
-    // Configure GDO0 for serial data (async serial mode)
+void CC1101Component::configure_packet_mode_() {
+#ifdef USE_CC1101_LONG_PACKET
+  // Ends a long reception in progress, also when switching to a short packet mode
+  this->high_freq_.stop();
+  this->packet_.clear();
+#endif
+  if (!this->packet_mode_) {
+    this->state_.PKT_FORMAT = static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_ASYNC_SERIAL);
    this->state_.GDO0_CFG = 0x0D;
+  } else {
+    this->state_.PKT_FORMAT = static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_FIFO);
+    this->state_.APPEND_STATUS = 0;
+#ifdef USE_CC1101_LONG_PACKET
+    if (this->is_long_packet_mode_()) {
+      // Threshold-only signal, reasserts after each partial FIFO drain
+      this->state_.GDO0_CFG = 0x00;
+      this->state_.FIFO_THR = 7;
+      // Reserve once so receiving never allocates; a lambda may read one FIFO drain past MAX_PACKET_LENGTH
+      this->packet_.reserve(this->packet_length_func_ != nullptr ? MAX_PACKET_LENGTH + RX_FIFO_SIZE
+                                                                 : this->packet_length_);
+      this->reset_long_packet_rx_();
+    } else
+#endif
+    {
+      this->state_.GDO0_CFG = 0x01;
+      this->state_.FIFO_THR = 15;
+      if (this->packet_length_ == 0) {
+        this->state_.LENGTH_CONFIG = static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_VARIABLE);
+      } else {
+        this->state_.LENGTH_CONFIG = static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_FIXED);
+        this->state_.PKTLEN = static_cast<uint8_t>(this->packet_length_);
+      }
+    }
+  }
+
+  if (this->initialized_) {
+    this->write_(Register::PKTCTRL0);
+    this->write_(Register::PKTCTRL1);
+    this->write_(Register::PKTLEN);
+    this->write_(Register::IOCFG0);
+    this->write_(Register::FIFOTHR);
+  }
+}
+
+void CC1101Component::set_packet_mode(bool value) {
+  this->packet_mode_ = value;
+#ifdef USE_CC1101_LONG_PACKET
+  // Long packet RX must drop the FIFO along with a partial packet, so go through IDLE and restart RX
+  if (this->initialized_ && this->is_long_packet_mode_()) {
+    this->reconfigure_packet_length_();
+  } else
+#endif
+  {
+    this->configure_packet_mode_();
  }
  if (this->initialized_) {
    if (this->gdo0_pin_ != nullptr) {
@@ -856,24 +1159,41 @@ void CC1101Component::set_packet_mode(bool value) {
        this->gdo0_pin_->detach_interrupt();
      }
    }
-    this->write_(Register::PKTCTRL0);
-    this->write_(Register::PKTCTRL1);
-    this->write_(Register::IOCFG0);
-    this->write_(Register::FIFOTHR);
  }
 }

-void CC1101Component::set_packet_length(uint8_t value) {
-  if (value == 0) {
-    this->state_.LENGTH_CONFIG = static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_VARIABLE);
-  } else {
-    this->state_.LENGTH_CONFIG = static_cast<uint8_t>(LengthConfig::LENGTH_CONFIG_FIXED);
-    this->state_.PKTLEN = value;
+void CC1101Component::set_packet_length(uint16_t value) {
+#ifndef USE_CC1101_LONG_PACKET
+  if (value > RX_FIFO_SIZE) {
+    ESP_LOGW(TAG, "Packet length %u needs a configured packet_length above %u", value,
+             static_cast<unsigned>(RX_FIFO_SIZE));
+    return;
  }
-  if (this->initialized_) {
-    this->write_(Register::PKTCTRL0);
-    this->write_(Register::PKTLEN);
+#else
+  this->packet_length_func_ = nullptr;
+#endif
+  this->packet_length_ = value;
+  this->reconfigure_packet_length_();
+}
+
+#ifdef USE_CC1101_LONG_PACKET
+void CC1101Component::set_packet_length_lambda(packet_length_func_t func) {
+  this->packet_length_func_ = func;
+  this->reconfigure_packet_length_();
+}
+#endif
+
+void CC1101Component::reconfigure_packet_length_() {
+  // While asleep the writes wait for wake_up() and the radio stays asleep, like set_frequency()
+  if (!this->initialized_ || this->sleeping_) {
+    this->configure_packet_mode_();
+    return;
  }
+  // Like the other runtime setters: go through IDLE, and flush bytes of a reception in progress
+  this->enter_idle_();
+  this->strobe_(Command::FRX);
+  this->configure_packet_mode_();
+  this->enter_rx_();
 }

 void CC1101Component::set_crc_enable(bool value) {
@@ -2,6 +2,7 @@

 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/spi/spi.h"
 #include "esphome/core/automation.h"
 #include "cc1101defs.h"
@@ -10,6 +11,7 @@
 namespace esphome::cc1101 {

 enum class CC1101Error { NONE = 0, TIMEOUT, PARAMS, CRC_ERROR, FIFO_OVERFLOW, PLL_LOCK };
+using packet_length_func_t = int32_t (*)(const std::vector<uint8_t> &);

 class CC1101Listener {
 public:
@@ -86,7 +88,10 @@ class CC1101Component final : public Component,

  // Packet mode settings
  void set_packet_mode(bool value);
-  void set_packet_length(uint8_t value);
+  void set_packet_length(uint16_t value);
+#ifdef USE_CC1101_LONG_PACKET
+  void set_packet_length_lambda(packet_length_func_t func);
+#endif
  void set_crc_enable(bool value);
  void set_whitening(bool value);

@@ -101,6 +106,7 @@ class CC1101Component final : public Component,
 protected:
  uint16_t chip_id_{0};
  bool initialized_{false};
+  bool packet_mode_{false};
  bool sleeping_{false};
  bool registers_dirty_{false};

@@ -112,13 +118,38 @@ class CC1101Component final : public Component,

  // GDO pin for packet reception
  InternalGPIOPin *gdo0_pin_{nullptr};
-  static void gpio_intr(CC1101Component *arg);
+  // Inline like App.get_loop_component_start_time(): on RP2040 an out-of-line IRAM_ATTR function in the same
+  // file as that inline one fails with a section type conflict
+  static void IRAM_ATTR gpio_intr(CC1101Component *arg) { arg->enable_loop_soon_any_context(); }

  // Packet handling
  void call_listeners_(const std::vector<uint8_t> &packet, float freq_offset, float rssi, uint8_t lqi);
+  void configure_packet_mode_();
+  void reconfigure_packet_length_();
+  float symbol_rate_() const;
+#ifdef USE_CC1101_LONG_PACKET
+  bool is_long_packet_mode_() const;
+  void arm_length_(uint16_t length);
+  void reset_long_packet_rx_();
+  void restart_long_packet_rx_();
+  void loop_long_packet_();
+  void handle_long_packet_(uint8_t rx_bytes);
+  void finish_long_packet_();
+  void maybe_switch_long_packet_to_fixed_();
+#endif
  Trigger<std::vector<uint8_t>, float, float, uint8_t> packet_trigger_;
  std::vector<uint8_t> packet_;
  std::vector<CC1101Listener *> listeners_;
+#ifdef USE_CC1101_LONG_PACKET
+  packet_length_func_t packet_length_func_{nullptr};
+  uint32_t packet_last_byte_ms_{0};
+#endif
+  uint16_t packet_length_{0};
+#ifdef USE_CC1101_LONG_PACKET
+  uint16_t packet_expected_length_{0};
+  int8_t long_packet_rssi_{0};  // raw RSSI register
+  HighFrequencyLoopRequester high_freq_;
+#endif

  // Low-level Helpers
  uint8_t strobe_(Command cmd);
@@ -15,6 +15,11 @@ static constexpr uint8_t PLL_LOCK_RETRIES = 3;
 static constexpr uint8_t STATUS_CRC_OK_MASK = 0x80;
 static constexpr uint8_t STATUS_LQI_MASK = 0x7F;

+static constexpr uint16_t MAX_PACKET_LENGTH = 1024;
+static constexpr uint16_t PACKET_IDLE_TIMEOUT_BYTES = 64;
+static constexpr uint32_t PACKET_IDLE_TIMEOUT_MIN_MS = 5;
+static constexpr uint8_t RXBYTES_STABLE_RETRIES = 4;
+
 static constexpr uint8_t BUS_BURST = 0x40;
 static constexpr uint8_t BUS_READ = 0x80;
 static constexpr uint8_t BUS_WRITE = 0x00;
@@ -1,36 +1,15 @@
-from esphome import pins
-import esphome.codegen as cg
-from esphome.components import i2c, touchscreen
-import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_INTERRUPT_PIN, CONF_RESET_PIN
+from esphome.components import cstxxx
 from esphome.types import ConfigType

 from .. import cst226_ns

-CST226Touchscreen = cst226_ns.class_(
-    "CST226Touchscreen",
-    touchscreen.Touchscreen,
-    i2c.I2CDevice,
-)
+AUTO_LOAD = ["cstxxx"]
+
+CST226Touchscreen = cst226_ns.class_("CST226Touchscreen", cstxxx.CSTTouchscreen)

 CST226ButtonListener = cst226_ns.class_("CST226ButtonListener")
-CONFIG_SCHEMA = (
-    touchscreen.touchscreen_schema("100ms")
-    .extend(
-        {
-            cv.GenerateID(): cv.declare_id(CST226Touchscreen),
-            cv.Optional(CONF_INTERRUPT_PIN): pins.internal_gpio_input_pin_schema,
-            cv.Optional(CONF_RESET_PIN): pins.gpio_output_pin_schema,
-        }
-    )
-    .extend(i2c.i2c_device_schema(0x5A))
-)
+CONFIG_SCHEMA = cstxxx.cst_touchscreen_schema(CST226Touchscreen, 0x5A)


 async def to_code(config: ConfigType) -> None:
-    var = cg.new_Pvariable(config[CONF_ID])
-    await touchscreen.register_touchscreen(var, config)
-    await i2c.register_i2c_device(var, config)
-
-    await cg.add_pin(var.set_interrupt_pin, config.get(CONF_INTERRUPT_PIN))
-    await cg.add_pin(var.set_reset_pin, config.get(CONF_RESET_PIN))
+    await cstxxx.new_cst_touchscreen(config)
@@ -14,6 +14,10 @@ void CST226Touchscreen::setup() {
 }

 void CST226Touchscreen::update_touches() {
+  if (!this->setup_complete_) {
+    this->skip_update_ = true;
+    return;
+  }
  uint8_t data[28];
  if (!this->status_comm_result(this->read_bytes(CST226_REG_STATUS, data, sizeof data))) {
    this->skip_update_ = true;
@@ -24,56 +28,39 @@ void CST226Touchscreen::update_touches() {
    return;
  }
  this->update_button_state_(false);
-  if (data[6] != 0xAB || data[0] == 0xAB || data[5] == 0x80) {
+  if (data[cstxxx::SYNC_IDX] != cstxxx::SYNC_BYTE || data[0] == cstxxx::SYNC_BYTE ||
+      data[cstxxx::FINGER_COUNT_IDX] == 0x80) {
    this->skip_update_ = true;
    return;
  }
-  uint8_t num_of_touches = data[5] & 0x7F;
+  uint8_t num_of_touches = data[cstxxx::FINGER_COUNT_IDX] & 0x7F;
  if (num_of_touches == 0 || num_of_touches > 5) {
-    this->write_byte(0, 0xAB);
+    this->write_byte(CST226_REG_STATUS, cstxxx::SYNC_BYTE);
    return;
  }

-  size_t index = 0;
  for (uint8_t i = 0; i != num_of_touches; i++) {
-    uint8_t id = data[index] >> 4;
-    int16_t x = (data[index + 1] << 4) | ((data[index + 3] >> 4) & 0x0F);
-    int16_t y = (data[index + 2] << 4) | (data[index + 3] & 0x0F);
-    int16_t z = data[index + 4];
-    this->add_raw_touch_position_(id, x, y, z);
-    ESP_LOGV(TAG, "Read touch %d: %d/%d", id, x, y);
-    index += 5;
-    if (i == 0)
-      index += 2;
+    auto touch = cstxxx::decode_touch(data, i);
+    this->add_raw_touch_position_(touch.id, touch.x, touch.y, touch.z);
+    ESP_LOGV(TAG, "Read touch %d: %d/%d", touch.id, touch.x, touch.y);
  }
 }

-bool CST226Touchscreen::read16_(uint16_t addr, uint8_t *data, size_t len) {
-  if (this->read_register16(addr, data, len) != i2c::ERROR_OK) {
-    ESP_LOGE(TAG, "Read data from 0x%04X failed", addr);
-    this->mark_failed();
-    return false;
-  }
-  return true;
-}
 void CST226Touchscreen::continue_setup_() {
-  uint8_t buffer[8];
-  if (this->interrupt_pin_ != nullptr) {
-    this->interrupt_pin_->setup();
-    this->attach_interrupt_(this->interrupt_pin_, gpio::INTERRUPT_FALLING_EDGE);
-  }
-  if (!this->setup_check(this->write_byte_reg16(0xD1, 0xD1), LOG_STR("Write byte to 0xD1 failed")))
+  this->setup_interrupt_pin_(gpio::INTERRUPT_FALLING_EDGE);
+  if (!this->enter_command_mode_())
    return;
  delay(10);
-  if (this->read16_(0xD204, buffer, 4)) {
-    uint16_t chip_id = buffer[2] + (buffer[3] << 8);
-    uint16_t project_id = buffer[0] + (buffer[1] << 8);
-    ESP_LOGCONFIG(TAG, "Chip ID %X, project ID %x", chip_id, project_id);
-  }
+  if (!this->check_firmware_())
+    return;
+  if (!this->setup_check(this->read_words_(cstxxx::REG_CHIP_INFO, this->project_id_, this->chip_id_),
+                         LOG_STR("Failed to read chip ID")))
+    return;
  if (this->x_raw_max_ == 0 || this->y_raw_max_ == 0) {
-    if (this->read16_(0xD1F8, buffer, 4)) {
-      this->x_raw_max_ = buffer[0] + (buffer[1] << 8);
-      this->y_raw_max_ = buffer[2] + (buffer[3] << 8);
+    uint16_t x_max, y_max;
+    if (this->read_words_(cstxxx::REG_RESOLUTION, x_max, y_max)) {
+      this->x_raw_max_ = x_max;
+      this->y_raw_max_ = y_max;
      if (this->swap_x_y_)
        std::swap(this->x_raw_max_, this->y_raw_max_);
    } else {
@@ -81,8 +68,10 @@ void CST226Touchscreen::continue_setup_() {
      this->y_raw_max_ = this->display_->get_native_height();
    }
  }
+  this->status_comm_check(this->write_register16(cstxxx::REG_NORMAL_MODE, nullptr, 0) == i2c::ERROR_OK);
  this->setup_complete_ = true;
 }
+
 void CST226Touchscreen::update_button_state_(bool state) {
  if (this->button_touched_ == state)
    return;
@@ -96,6 +85,10 @@ void CST226Touchscreen::dump_config() {
  LOG_I2C_DEVICE(this);
  LOG_PIN("  Interrupt Pin: ", this->interrupt_pin_);
  LOG_PIN("  Reset Pin: ", this->reset_pin_);
+  ESP_LOGCONFIG(TAG,
+                "  Chip ID: 0x%04X, Project ID: 0x%04X\n"
+                "  X/Y raw max: %d/%d",
+                this->chip_id_, this->project_id_, this->x_raw_max_, this->y_raw_max_);
 }

 }  // namespace esphome::cst226
@@ -1,11 +1,12 @@
 #pragma once

-#include "esphome/components/i2c/i2c.h"
-#include "esphome/components/touchscreen/touchscreen.h"
+#include "esphome/components/cstxxx/cstxxx.h"
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"

+#include <vector>
+
 namespace esphome::cst226 {

 static const uint8_t CST226_REG_STATUS = 0x00;
@@ -15,28 +16,23 @@ class CST226ButtonListener {
  virtual void update_button(bool state) = 0;
 };

-class CST226Touchscreen final : public touchscreen::Touchscreen, public i2c::I2CDevice {
+class CST226Touchscreen final : public cstxxx::CSTTouchscreen {
 public:
  void setup() override;
  void update_touches() override;
  void dump_config() override;

-  void set_interrupt_pin(InternalGPIOPin *pin) { this->interrupt_pin_ = pin; }
-  void set_reset_pin(GPIOPin *pin) { this->reset_pin_ = pin; }
  bool can_proceed() override { return this->setup_complete_ || this->is_failed(); }
  void register_button_listener(CST226ButtonListener *listener) { this->button_listeners_.push_back(listener); }

 protected:
-  bool read16_(uint16_t addr, uint8_t *data, size_t len);
  void continue_setup_();
  void update_button_state_(bool state);

-  InternalGPIOPin *interrupt_pin_{};
-  GPIOPin *reset_pin_{};
-  uint8_t chip_id_{};
-  bool setup_complete_{};
-  std::vector<CST226ButtonListener *> button_listeners_;
  bool button_touched_{};
+  uint16_t chip_id_{};
+  uint16_t project_id_{};
+  std::vector<CST226ButtonListener *> button_listeners_;
 };

 }  // namespace esphome::cst226
@@ -1,37 +1,15 @@
-from esphome import pins
-import esphome.codegen as cg
-from esphome.components import i2c, touchscreen
-import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_INTERRUPT_PIN, CONF_RESET_PIN
+from esphome.components import cstxxx
 from esphome.types import ConfigType

 from .. import cst328_ns

-CST328Touchscreen = cst328_ns.class_(
-    "CST328Touchscreen",
-    touchscreen.Touchscreen,
-    i2c.I2CDevice,
-)
+AUTO_LOAD = ["cstxxx"]
+
+CST328Touchscreen = cst328_ns.class_("CST328Touchscreen", cstxxx.CSTTouchscreen)

 CST328ButtonListener = cst328_ns.class_("CST328ButtonListener")
-
-CONFIG_SCHEMA = (
-    touchscreen.touchscreen_schema("100ms")
-    .extend(
-        {
-            cv.GenerateID(): cv.declare_id(CST328Touchscreen),
-            cv.Optional(CONF_INTERRUPT_PIN): pins.internal_gpio_input_pin_schema,
-            cv.Optional(CONF_RESET_PIN): pins.gpio_output_pin_schema,
-        }
-    )
-    .extend(i2c.i2c_device_schema(0x1A))
-)
+CONFIG_SCHEMA = cstxxx.cst_touchscreen_schema(CST328Touchscreen, 0x1A)


 async def to_code(config: ConfigType) -> None:
-    var = cg.new_Pvariable(config[CONF_ID])
-    await touchscreen.register_touchscreen(var, config)
-    await i2c.register_i2c_device(var, config)
-
-    await cg.add_pin(var.set_interrupt_pin, config.get(CONF_INTERRUPT_PIN))
-    await cg.add_pin(var.set_reset_pin, config.get(CONF_RESET_PIN))
+    await cstxxx.new_cst_touchscreen(config)
@@ -5,31 +5,8 @@ namespace esphome::cst328 {

 ESPHOME_LOG_TAG(TAG, "cst328.touchscreen");

-static const uint32_t CST328_BEFORE_RESET_TIMEOUT = 50;  // 50 ms from datasheet
-static const uint32_t CST328_TRANSITION_TIMEOUT = 300;   // 200 ms from datasheet, but typically much less
-static const uint16_t CST328_FW_CRC = 0xCACA;            // Expected firmware CRC value
-static const uint8_t CST328_SYNC_BYTE = 0xAB;            // Sync byte used in communication
-
-static const uint8_t ZERO_BYTE = 0;
-
-#define I2C_WARN_ON_ERROR(x, log_tag, format, ...) \
-  do { \
-    i2c::ErrorCode err_rc_ = (x); \
-    if (err_rc_ != i2c::ERROR_OK) { \
-      ESP_LOGW(log_tag, "%s(%d): [error %d] " format, __FUNCTION__, __LINE__, err_rc_, ##__VA_ARGS__); \
-      this->status_set_warning(format); \
-    } \
-  } while (0)
-
-#define I2C_FAIL_ON_ERROR(x, log_tag, format, ...) \
-  do { \
-    i2c::ErrorCode err_rc_ = (x); \
-    if (err_rc_ != i2c::ERROR_OK) { \
-      ESP_LOGE(log_tag, "%s(%d): [error %d] " format, __FUNCTION__, __LINE__, err_rc_, ##__VA_ARGS__); \
-      this->mark_failed(); \
-      return; \
-    } \
-  } while (0)
+static constexpr uint32_t CST328_BEFORE_RESET_TIMEOUT = 50;  // 50 ms from datasheet
+static constexpr uint32_t CST328_TRANSITION_TIMEOUT = 300;   // 200 ms from datasheet, but typically much less

 void CST328Touchscreen::setup() {
  ESP_LOGCONFIG(TAG, "Setting up CST328 Touchscreen...");
@@ -50,50 +27,36 @@ void CST328Touchscreen::reset_device_() {
 void CST328Touchscreen::continue_setup_() {
  ESP_LOGV(TAG, "Continuing CST328 setup...");

-  uint8_t data_byte{0};
-  uint8_t buf[24]{};
-
-  I2C_FAIL_ON_ERROR(this->write_register16(CST_WM_DEBUG_INFO, buf, 0), TAG, "Failed to enter debug/info mode");
-  I2C_FAIL_ON_ERROR(this->read_register16(CST_REG_FW_CRC_AND_BOOT_TIME, buf, 4), TAG,
-                    "Failed to read FW CRC and boot time");
-
-  uint16_t fw_crc = buf[2] + (buf[3] << 8);
-  if (fw_crc != CST328_FW_CRC) {
-    ESP_LOGE(TAG, "Error: Firmware CRC mismatch, expected 0x%04X but got 0x%04X", CST328_FW_CRC, fw_crc);
-    this->mark_failed();
+  if (!this->enter_command_mode_() || !this->check_firmware_())
+    return;
+  if (!this->setup_check(this->read_words_(cstxxx::REG_CHIP_INFO, this->project_id_, this->chip_id_),
+                         LOG_STR("Failed to read chip and project ID")))
    return;
-  }
-
-  I2C_FAIL_ON_ERROR(this->read_register16(CST_REG_CHIP_TYPE_AND_PROJECT_ID, buf, 4), TAG,
-                    "Failed to read chip and project ID");
-
-  this->chip_id_ = buf[2] + (buf[3] << 8);
-  this->project_id_ = buf[0] + (buf[1] << 8);
  ESP_LOGD(TAG, "Chip ID %X, project ID %X", this->chip_id_, this->project_id_);
-  I2C_FAIL_ON_ERROR(this->read_register16(CST_REG_FW_REVISION, buf, 4), TAG, "Failed to read FW version");
-
-  this->fw_ver_major_ = buf[3];
-  this->fw_ver_minor_ = buf[2];
-  this->fw_build_ = buf[0] + (buf[1] << 8);
+  uint16_t fw_version;
+  if (!this->setup_check(this->read_words_(cstxxx::REG_FW_VERSION, this->fw_build_, fw_version),
+                         LOG_STR("Failed to read FW version")))
+    return;
+  this->fw_ver_major_ = fw_version >> 8;
+  this->fw_ver_minor_ = fw_version & 0xFF;
  ESP_LOGV(TAG, "FW version %d.%d.%d", this->fw_ver_major_, this->fw_ver_minor_, this->fw_build_);

-  if (i2c::ERROR_OK == this->read_register16(CST_REG_X_Y_RESOLUTION, buf, 4)) {
-    this->x_raw_max_ = buf[0] + (buf[1] << 8);
-    this->y_raw_max_ = buf[2] + (buf[3] << 8);
+  uint16_t x_max, y_max;
+  if (this->read_words_(cstxxx::REG_RESOLUTION, x_max, y_max)) {
+    this->x_raw_max_ = x_max;
+    this->y_raw_max_ = y_max;
  } else {
    this->x_raw_max_ = this->display_->get_native_width();
    this->y_raw_max_ = this->display_->get_native_height();
  }

-  I2C_WARN_ON_ERROR(this->write_register16(CST_WM_NORMAL, buf, 0), TAG, "Failed to enter normal mode");
-  I2C_WARN_ON_ERROR(this->read_register16(CST_REG_TOUCH_INFORMATION, &data_byte, 1), TAG, "Failed to read sync");
-  I2C_WARN_ON_ERROR(this->write_register16(CST_REG_TOUCH_INFORMATION, &CST328_SYNC_BYTE, 1), TAG,
-                    "Failed to write sync");
+  uint8_t sync;
+  bool ok = this->write_register16(cstxxx::REG_NORMAL_MODE, nullptr, 0) == i2c::ERROR_OK;
+  ok &= this->read_byte_reg16(cstxxx::REG_TOUCH_DATA, &sync);
+  ok &= this->write_byte_reg16(cstxxx::REG_TOUCH_DATA, cstxxx::SYNC_BYTE);
+  this->status_comm_check(ok);

-  if (this->interrupt_pin_ != nullptr) {
-    this->interrupt_pin_->setup();
-    this->attach_interrupt_(this->interrupt_pin_, gpio::INTERRUPT_FALLING_EDGE);
-  }
+  this->setup_interrupt_pin_(gpio::INTERRUPT_FALLING_EDGE);

  this->setup_complete_ = true;
  ESP_LOGV(TAG, "CST328 setup complete");
@@ -142,21 +105,15 @@ void CST328Touchscreen::update_touches() {
  } else {
    this->update_button_state_(true);

-    uint8_t data_idx = 0;
    for (uint8_t i = 0; i < touch_cnt; i++) {
-      uint8_t id = touch_data[data_idx] >> 4;
-      int16_t x = (touch_data[data_idx + 1] << 4) | ((touch_data[data_idx + 3] >> 4) & 0x0F);
-      int16_t y = (touch_data[data_idx + 2] << 4) | (touch_data[data_idx + 3] & 0x0F);
-      int16_t z = touch_data[data_idx + 4];
-
-      this->add_raw_touch_position_(id, x, y, z);
-      data_idx += (i == 0) ? 7 : 5;
+      auto touch = cstxxx::decode_touch(touch_data, i);
+      this->add_raw_touch_position_(touch.id, touch.x, touch.y, touch.z);
    }
  }

  bool cleanup_error = false;
-  cleanup_error |= !this->write_byte_reg16(CST_REG_TOUCH_FINGER_NUMBER, ZERO_BYTE);
-  cleanup_error |= !this->write_byte_reg16(CST_REG_TOUCH_INFORMATION, CST328_SYNC_BYTE);
+  cleanup_error |= !this->write_byte_reg16(cstxxx::REG_FINGER_COUNT, 0);
+  cleanup_error |= !this->write_byte_reg16(cstxxx::REG_TOUCH_DATA, cstxxx::SYNC_BYTE);

  if (cleanup_error) {
    ESP_LOGW(TAG, "Failed to clean up touch registers");
@@ -1,61 +1,45 @@
 #pragma once

-#include "esphome/components/i2c/i2c.h"
-#include "esphome/components/touchscreen/touchscreen.h"
+#include "esphome/components/cstxxx/cstxxx.h"
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"

+#include <vector>
+
 namespace esphome::cst328 {

-static const uint8_t CST328_TOUCH_MAX_POINTS = 5;
-static const uint8_t CST328_TOUCH_DATA_SIZE = CST328_TOUCH_MAX_POINTS * 5 + 2;
+static constexpr uint8_t CST328_TOUCH_MAX_POINTS = 5;
+static constexpr uint8_t CST328_TOUCH_DATA_SIZE = cstxxx::report_size(CST328_TOUCH_MAX_POINTS);

-static const uint16_t CST_REG_TOUCH_INFORMATION = 0xD000;
-static const uint16_t CST_REG_TOUCH_FINGER_NUMBER = 0xD005;
-
-static const uint16_t CST_REG_FINGER_COUNT_IDX = CST_REG_TOUCH_FINGER_NUMBER - CST_REG_TOUCH_INFORMATION;
-
-static const uint16_t CST_REG_X_Y_RESOLUTION = 0xD1F8;
-static const uint16_t CST_REG_FW_CRC_AND_BOOT_TIME = 0xD1FC;
-static const uint16_t CST_REG_CHIP_TYPE_AND_PROJECT_ID = 0xD204;
-static const uint16_t CST_REG_FW_REVISION = 0xD208;
-
-static const uint16_t CST_WM_DEBUG_INFO = 0xD101;
-static const uint16_t CST_WM_NORMAL = 0xD109;
+static constexpr uint16_t CST_REG_TOUCH_INFORMATION = cstxxx::REG_TOUCH_DATA;
+static constexpr uint16_t CST_REG_FINGER_COUNT_IDX = cstxxx::FINGER_COUNT_IDX;
+static constexpr uint16_t CST_REG_X_Y_RESOLUTION = cstxxx::REG_RESOLUTION;
+static constexpr uint16_t CST_REG_FW_CRC_AND_BOOT_TIME = cstxxx::REG_FW_CHECK_CODE;

 class CST328ButtonListener {
 public:
  virtual void update_button(bool state) = 0;
 };

-class CST328Touchscreen : public touchscreen::Touchscreen, public i2c::I2CDevice {
+class CST328Touchscreen : public cstxxx::CSTTouchscreen {
 public:
  void setup() override;
  void register_button_listener(CST328ButtonListener *listener) { this->button_listeners_.push_back(listener); }
  void dump_config() override;

-  void set_interrupt_pin(InternalGPIOPin *pin) { this->interrupt_pin_ = pin; }
-  void set_reset_pin(GPIOPin *pin) { this->reset_pin_ = pin; }
-
 protected:
  void update_touches() override;
  void reset_device_();
  void continue_setup_();
  void update_button_state_(bool state);

-  InternalGPIOPin *interrupt_pin_{};
-  GPIOPin *reset_pin_{};
-
-  std::vector<CST328ButtonListener *> button_listeners_;
  bool button_touched_{};
-
-  uint16_t chip_id_{};
-  uint16_t project_id_{};
  uint8_t fw_ver_major_{};
  uint8_t fw_ver_minor_{};
+  std::vector<CST328ButtonListener *> button_listeners_;
+  uint16_t chip_id_{};
+  uint16_t project_id_{};
  uint16_t fw_build_{};
-
-  bool setup_complete_{};
 };

 }  // namespace esphome::cst328
@@ -1,35 +1,14 @@
-from esphome import pins
-import esphome.codegen as cg
-from esphome.components import i2c, touchscreen
-import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_INTERRUPT_PIN, CONF_RESET_PIN
+from esphome.components import cstxxx
 from esphome.types import ConfigType

 from .. import cst9220_ns

-CST9220Touchscreen = cst9220_ns.class_(
-    "CST9220Touchscreen",
-    touchscreen.Touchscreen,
-    i2c.I2CDevice,
-)
+AUTO_LOAD = ["cstxxx"]

-CONFIG_SCHEMA = (
-    touchscreen.touchscreen_schema("100ms")
-    .extend(
-        {
-            cv.GenerateID(): cv.declare_id(CST9220Touchscreen),
-            cv.Optional(CONF_INTERRUPT_PIN): pins.internal_gpio_input_pin_schema,
-            cv.Optional(CONF_RESET_PIN): pins.gpio_output_pin_schema,
-        }
-    )
-    .extend(i2c.i2c_device_schema(0x5A))
-)
+CST9220Touchscreen = cst9220_ns.class_("CST9220Touchscreen", cstxxx.CSTTouchscreen)
+
+CONFIG_SCHEMA = cstxxx.cst_touchscreen_schema(CST9220Touchscreen, 0x5A)


 async def to_code(config: ConfigType) -> None:
-    var = cg.new_Pvariable(config[CONF_ID])
-    await touchscreen.register_touchscreen(var, config)
-    await i2c.register_i2c_device(var, config)
-
-    await cg.add_pin(var.set_interrupt_pin, config.get(CONF_INTERRUPT_PIN))
-    await cg.add_pin(var.set_reset_pin, config.get(CONF_RESET_PIN))
+    await cstxxx.new_cst_touchscreen(config)
@@ -1,7 +1,4 @@
 #include "cst9220_touchscreen.h"
-#include "esphome/core/helpers.h"
-
-#include <cinttypes>

 namespace esphome::cst9220 {

@@ -16,55 +13,29 @@ void CST9220Touchscreen::setup() {
 }

 void CST9220Touchscreen::continue_setup_() {
-  uint8_t buffer[4];
+  this->setup_interrupt_pin_(gpio::INTERRUPT_FALLING_EDGE);

-  if (this->interrupt_pin_ != nullptr) {
-    this->interrupt_pin_->setup();
-    this->attach_interrupt_(this->interrupt_pin_, gpio::INTERRUPT_FALLING_EDGE);
-  }
-
-  // Enter command mode so the configuration registers can be read.
-  if (this->write_register16(REG_CMD_MODE, buffer, 0) != i2c::ERROR_OK) {
-    this->status_set_error(LOG_STR("Failed to enter command mode"));
-    this->mark_failed();
+  if (!this->enter_command_mode_())
    return;
-  }
  delay(10);
-
-  // The firmware check code confirms that valid firmware is loaded.
-  if (this->read_register16(REG_CHECKCODE, buffer, 4) != i2c::ERROR_OK) {
-    this->status_set_error(LOG_STR("Failed to read check code"));
-    this->mark_failed();
+  if (!this->check_firmware_())
    return;
-  }
-  uint32_t checkcode = encode_uint32(buffer[3], buffer[2], buffer[1], buffer[0]);
-  if ((checkcode & 0xFFFF0000) != 0xCACA0000) {
-    ESP_LOGE(TAG, "Invalid firmware check code: 0x%08" PRIX32, checkcode);
-    this->status_set_error(LOG_STR("Invalid firmware check code"));
-    this->mark_failed();
-    return;
-  }

  // Read the panel resolution unless the user supplied calibration values.
-  if (this->read_register16(REG_RESOLUTION, buffer, 4) == i2c::ERROR_OK) {
+  uint16_t x_max, y_max;
+  if (this->read_words_(cstxxx::REG_RESOLUTION, x_max, y_max)) {
    if (this->x_raw_max_ == this->x_raw_min_)
-      this->x_raw_max_ = encode_value_le<uint16_t>(buffer);
+      this->x_raw_max_ = x_max;
    if (this->y_raw_max_ == this->y_raw_min_)
-      this->y_raw_max_ = encode_value_le<uint16_t>(&buffer[2]);
+      this->y_raw_max_ = y_max;
  }

-  // Read the chip type and project id and validate the controller.
-  if (this->read_register16(REG_CHIP_INFO, buffer, 4) != i2c::ERROR_OK) {
-    this->status_set_error(LOG_STR("Failed to read chip ID"));
-    this->mark_failed();
+  if (!this->setup_check(this->read_words_(cstxxx::REG_CHIP_INFO, this->project_id_, this->chip_id_),
+                         LOG_STR("Failed to read chip ID")))
    return;
-  }
-  this->chip_id_ = encode_value_le<uint16_t>(&buffer[2]);
-  this->project_id_ = encode_value_le<uint16_t>(buffer);
  if (this->chip_id_ != CST9220_CHIP_ID && this->chip_id_ != CST9217_CHIP_ID) {
    ESP_LOGE(TAG, "Unknown chip ID: 0x%04X", this->chip_id_);
-    this->status_set_error(LOG_STR("Unknown chip ID"));
-    this->mark_failed();
+    this->mark_failed(LOG_STR("Unknown chip ID"));
    return;
  }

@@ -84,7 +55,7 @@ void CST9220Touchscreen::update_touches() {
  // Only an actual I2C failure should skip the update; a successful read with no
  // touches is a real "all fingers lifted" state that must flow through so the
  // base class can generate the release event.
-  if (!this->status_comm_result(this->read_register16(REG_TOUCH_DATA, data, sizeof(data)) == i2c::ERROR_OK)) {
+  if (!this->status_comm_result(this->read_register16(cstxxx::REG_TOUCH_DATA, data, sizeof(data)) == i2c::ERROR_OK)) {
    this->skip_update_ = true;
    return;
  }
@@ -92,30 +63,23 @@ void CST9220Touchscreen::update_touches() {
  // A valid report carries the marker at offset 6. Writing an acknowledge back makes the controller return
  // invalid frames during a long press, so none is written. An invalid frame keeps the previous points; while
  // a finger is down, read again shortly so a lost release frame does not leave the touch held.
-  if (data[6] != TOUCH_ACK) {
+  if (data[cstxxx::SYNC_IDX] != cstxxx::SYNC_BYTE) {
    this->skip_update_ = true;
    if (!this->touches_.empty())
      this->set_timeout(REREAD_TIMEOUT_ID, REREAD_DELAY_MS, [this] { this->store_.touched = true; });
    return;
  }

-  uint8_t num_touches = data[5] & 0x7F;
+  uint8_t num_touches = data[cstxxx::FINGER_COUNT_IDX] & 0x7F;
  if (num_touches > CST9220_MAX_TOUCHES)
    num_touches = CST9220_MAX_TOUCHES;

  for (uint8_t i = 0; i < num_touches; i++) {
-    // The first point starts at offset 0; subsequent points are offset by the
-    // two status bytes that follow it.
-    const uint8_t *p = data + i * 5 + (i == 0 ? 0 : 2);
-    uint8_t id = p[0] >> 4;
-    uint8_t event = p[0] & 0x0F;
-    if (event != TOUCH_EVENT_DOWN)
+    auto touch = cstxxx::decode_touch(data, i);
+    if (touch.event != TOUCH_EVENT_DOWN)
      continue;
-    // p[3] is shared: high nibble holds the X LSBs, low nibble the Y LSBs.
-    uint16_t x = (p[1] << 4) | (p[3] >> 4);
-    uint16_t y = (p[2] << 4) | (p[3] & 0x0F);
-    ESP_LOGV(TAG, "Read touch %d: %d/%d", id, x, y);
-    this->add_raw_touch_position_(id, x, y);
+    ESP_LOGV(TAG, "Read touch %d: %d/%d", touch.id, touch.x, touch.y);
+    this->add_raw_touch_position_(touch.id, touch.x, touch.y);
  }
 }

@@ -1,7 +1,6 @@
 #pragma once

-#include "esphome/components/i2c/i2c.h"
-#include "esphome/components/touchscreen/touchscreen.h"
+#include "esphome/components/cstxxx/cstxxx.h"
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
@@ -10,41 +9,26 @@ namespace esphome::cst9220 {

 ESPHOME_LOG_TAG(TAG, "cst9220.touchscreen");

-// The CST92xx family uses 16-bit (big-endian) register addresses.
-static const uint16_t REG_TOUCH_DATA = 0xD000;  // touch report
-static const uint16_t REG_CMD_MODE = 0xD101;    // enter command mode
-static const uint16_t REG_CHECKCODE = 0xD1FC;   // firmware check code
-static const uint16_t REG_RESOLUTION = 0xD1F8;  // panel resolution
-static const uint16_t REG_CHIP_INFO = 0xD204;   // chip type + project id
+static constexpr uint8_t TOUCH_EVENT_DOWN = 0x06;

-static const uint8_t TOUCH_ACK = 0xAB;
-static const uint8_t TOUCH_EVENT_DOWN = 0x06;
+static constexpr uint16_t CST9220_CHIP_ID = 0x9220;
+static constexpr uint16_t CST9217_CHIP_ID = 0x9217;

-static const uint16_t CST9220_CHIP_ID = 0x9220;
-static const uint16_t CST9217_CHIP_ID = 0x9217;
-
-// Maximum simultaneous touch points reported by the family.
-static const uint8_t CST9220_MAX_TOUCHES = 5;
+static constexpr uint8_t CST9220_MAX_TOUCHES = 5;
 // Report layout: 5 bytes per touch point plus 5 bytes of status/ack overhead.
-static const size_t CST9220_DATA_LENGTH = CST9220_MAX_TOUCHES * 5 + 5;
+static constexpr size_t CST9220_DATA_LENGTH = CST9220_MAX_TOUCHES * 5 + 5;

-class CST9220Touchscreen : public touchscreen::Touchscreen, public i2c::I2CDevice {
+class CST9220Touchscreen : public cstxxx::CSTTouchscreen {
 public:
  void setup() override;
  void dump_config() override;

-  void set_interrupt_pin(InternalGPIOPin *pin) { this->interrupt_pin_ = pin; }
-  void set_reset_pin(GPIOPin *pin) { this->reset_pin_ = pin; }
-
 protected:
  void update_touches() override;
  void continue_setup_();

-  InternalGPIOPin *interrupt_pin_{};
-  GPIOPin *reset_pin_{};
  uint16_t chip_id_{};
  uint16_t project_id_{};
-  bool setup_complete_{};
 };

 }  // namespace esphome::cst9220
@@ -0,0 +1,42 @@
+from esphome import pins
+import esphome.codegen as cg
+from esphome.components import i2c, touchscreen
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, CONF_INTERRUPT_PIN, CONF_RESET_PIN
+from esphome.cpp_generator import MockObj, MockObjClass
+from esphome.types import ConfigType
+
+CODEOWNERS = ["@clydebarrow", "@latonita"]
+DEPENDENCIES = ["i2c", "touchscreen"]
+DOMAIN = "cstxxx"
+
+cstxxx_ns = cg.esphome_ns.namespace("cstxxx")
+CSTTouchscreen = cstxxx_ns.class_(
+    "CSTTouchscreen", touchscreen.Touchscreen, i2c.I2CDevice
+)
+
+
+def cst_touchscreen_schema(touchscreen_class: MockObjClass, address: int) -> cv.Schema:
+    """Return the touchscreen schema of a Hynitron driver."""
+    return (
+        touchscreen.touchscreen_schema("100ms")
+        .extend(
+            {
+                cv.GenerateID(): cv.declare_id(touchscreen_class),
+                cv.Optional(CONF_INTERRUPT_PIN): pins.internal_gpio_input_pin_schema,
+                cv.Optional(CONF_RESET_PIN): pins.gpio_output_pin_schema,
+            }
+        )
+        .extend(i2c.i2c_device_schema(address))
+    )
+
+
+async def new_cst_touchscreen(config: ConfigType) -> MockObj:
+    """Create a Hynitron touchscreen and set its pins."""
+    var = cg.new_Pvariable(config[CONF_ID])
+    await touchscreen.register_touchscreen(var, config)
+    await i2c.register_i2c_device(var, config)
+
+    await cg.add_pin(var.set_interrupt_pin, config.get(CONF_INTERRUPT_PIN))
+    await cg.add_pin(var.set_reset_pin, config.get(CONF_RESET_PIN))
+    return var
@@ -0,0 +1,13 @@
+#include "cstxxx.h"
+#include "esphome/core/log.h"
+
+namespace esphome::cstxxx {
+
+ESPHOME_LOG_TAG(TAG, "cstxxx");
+
+void CSTTouchscreen::fail_check_code_(uint16_t check_code) {
+  ESP_LOGE(TAG, "Firmware check code 0x%04X", check_code);
+  this->mark_failed(LOG_STR("Invalid firmware check code"));
+}
+
+}  // namespace esphome::cstxxx
@@ -0,0 +1,92 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+#include "esphome/components/i2c/i2c.h"
+#include "esphome/components/touchscreen/touchscreen.h"
+#include "esphome/core/gpio.h"
+#include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
+
+namespace esphome::cstxxx {
+
+static constexpr uint16_t REG_TOUCH_DATA = 0xD000;
+static constexpr uint16_t REG_FINGER_COUNT = 0xD005;
+static constexpr uint16_t REG_COMMAND_MODE = 0xD101;
+static constexpr uint16_t REG_NORMAL_MODE = 0xD109;
+static constexpr uint16_t REG_RESOLUTION = 0xD1F8;
+static constexpr uint16_t REG_FW_CHECK_CODE = 0xD1FC;
+static constexpr uint16_t REG_CHIP_INFO = 0xD204;
+static constexpr uint16_t REG_FW_VERSION = 0xD208;
+
+static constexpr uint8_t FINGER_COUNT_IDX = REG_FINGER_COUNT - REG_TOUCH_DATA;
+static constexpr uint8_t SYNC_IDX = FINGER_COUNT_IDX + 1;
+static constexpr uint8_t SYNC_BYTE = 0xAB;
+static constexpr uint16_t FW_CHECK_CODE = 0xCACA;
+
+/// Bytes of a touch report holding `points` records; two status bytes follow the first record.
+constexpr size_t report_size(uint8_t points) { return points * 5 + 2; }
+
+struct TouchRecord {
+  uint8_t id;
+  uint8_t event;
+  uint16_t x;
+  uint16_t y;
+  uint8_t z;
+};
+
+/// Decodes record `index` of a touch report.
+inline TouchRecord decode_touch(const uint8_t *report, uint8_t index) {
+  const uint8_t *r = report + index * 5 + (index == 0 ? 0 : 2);
+  return {static_cast<uint8_t>(r[0] >> 4), static_cast<uint8_t>(r[0] & 0x0F),
+          static_cast<uint16_t>(r[1] << 4 | r[3] >> 4), static_cast<uint16_t>(r[2] << 4 | (r[3] & 0x0F)), r[4]};
+}
+
+class CSTTouchscreen : public touchscreen::Touchscreen, public i2c::I2CDevice {
+ public:
+  void set_interrupt_pin(InternalGPIOPin *pin) { this->interrupt_pin_ = pin; }
+  void set_reset_pin(GPIOPin *pin) { this->reset_pin_ = pin; }
+
+ protected:
+  /// Sets up the interrupt pin, if configured, to fire on `type`.
+  void setup_interrupt_pin_(gpio::InterruptType type) {
+    if (this->interrupt_pin_ == nullptr)
+      return;
+    this->interrupt_pin_->setup();
+    this->attach_interrupt_(this->interrupt_pin_, type);
+  }
+  /// Reads two little-endian words starting at `reg`.
+  bool ESPHOME_ALWAYS_INLINE read_words_(uint16_t reg, uint16_t &low, uint16_t &high) {
+    uint16_t words[2];
+    if (this->read_register16(reg, reinterpret_cast<uint8_t *>(words), sizeof(words)) != i2c::ERROR_OK)
+      return false;
+    low = convert_little_endian(words[0]);
+    high = convert_little_endian(words[1]);
+    return true;
+  }
+  /// Enters command mode, marking the component failed if the write fails.
+  bool enter_command_mode_() {
+    return this->setup_check(this->write_register16(REG_COMMAND_MODE, nullptr, 0) == i2c::ERROR_OK,
+                             LOG_STR("Failed to enter command mode"));
+  }
+  /// Checks the firmware check code, marking the component failed if it is unreadable or wrong.
+  bool check_firmware_() {
+    uint16_t boot_time, check_code;
+    if (!this->setup_check(this->read_words_(REG_FW_CHECK_CODE, boot_time, check_code)))
+      return false;
+    if (check_code == FW_CHECK_CODE)
+      return true;
+    this->fail_check_code_(check_code);
+    return false;
+  }
+  /// Logs a wrong firmware check code and marks the component failed.
+  void fail_check_code_(uint16_t check_code);
+
+  InternalGPIOPin *interrupt_pin_{};
+  GPIOPin *reset_pin_{};
+  bool setup_complete_{};
+};
+
+}  // namespace esphome::cstxxx
@@ -3126,9 +3126,6 @@ async def to_code(config):
            "_ZSt25__throw_bad_function_callv",
        ]:
            cg.add_build_flag(f"-Wl,--wrap={mangled}")
-        # Replace operator new so nothrow new returns nullptr. See operator_new.cpp.
-        # --undefined pulls it from libsrc.a before libstdc++ (_Znwj: 32 bit size_t on every ESP32).
-        cg.add_build_flag("-Wl,--undefined=_Znwj")

        # Wrap FILE*-based printf functions to eliminate newlib's _vfprintf_r
        # (~11 KB). See printf_stubs.cpp for implementation.
@@ -1,92 +0,0 @@
-/*
- * Replaces operator new for ESP-IDF builds without C++ exceptions. libstdc++'s nothrow forms call the
- * throwing form and catch std::bad_alloc, but the throw aborts here, so they abort instead of returning
- * nullptr. All forms stay in this file: --undefined=_Znwj pulls it in ahead of libstdc++.
- */
-
-#include "esphome/core/defines.h"
-
-#ifdef USE_ESP_IDF
-#include <sdkconfig.h>
-#ifndef CONFIG_COMPILER_CXX_EXCEPTIONS
-
-#include <cstdlib>
-#include <new>
-#include <type_traits>
-#include "esp_system.h"
-
-#ifdef __cpp_exceptions
-#error "CONFIG_COMPILER_CXX_EXCEPTIONS no longer matches -fexceptions"
-#endif
-
-// libstdc++'s aligned delete calls free() only when built with one of these
-#if !defined(_GLIBCXX_HAVE_ALIGNED_ALLOC) && !defined(_GLIBCXX_HAVE_POSIX_MEMALIGN) && !defined(_GLIBCXX_HAVE_MEMALIGN)
-#error "libstdc++'s aligned operator delete no longer frees with free()"
-#endif
-
-#ifndef CLANG_TIDY  // clang-tidy parses Xtensa with a 64 bit host target
-// --undefined=_Znwj in __init__.py relies on this mangling
-static_assert(std::is_same_v<std::size_t, unsigned int>, "update --undefined=_Znwj");
-#endif
-
-namespace esphome::esp32 {}  // namespace esphome::esp32
-
-namespace {
-
-// Standard new_handler retry loop; returns nullptr once no handler is installed
-template<typename Alloc> void *alloc_or_null(std::size_t size, Alloc alloc) {
-  // malloc(0) may return NULL, but operator new must return a unique pointer
-  if (size == 0)
-    size = 1;
-  for (;;) {
-    void *ptr = alloc(size);
-    if (ptr != nullptr)
-      return ptr;
-    std::new_handler handler = std::get_new_handler();
-    if (handler == nullptr)
-      return nullptr;
-    handler();
-  }
-}
-
-void *abort_if_null(void *ptr) {
-  if (ptr == nullptr)
-    esp_system_abort("std::bad_alloc");
-  return ptr;
-}
-
-void *plain_alloc(std::size_t size) {
-  return alloc_or_null(size, [](std::size_t n) { return std::malloc(n); });  // NOLINT(cppcoreguidelines-no-malloc)
-}
-
-// IDF's aligned_alloc accepts any size (no C11 multiple of alignment rule) and pairs with free(),
-// which libstdc++'s aligned delete uses (checked above)
-void *aligned_alloc_or_null(std::size_t size, std::align_val_t align) {
-  return alloc_or_null(size, [align](std::size_t n) { return ::aligned_alloc(static_cast<std::size_t>(align), n); });
-}
-
-}  // namespace
-
-// libstdc++'s operator delete (free) already matches these
-// NOLINTBEGIN(cert-dcl54-cpp,misc-new-delete-overloads)
-void *operator new(std::size_t size) { return abort_if_null(plain_alloc(size)); }
-void *operator new[](std::size_t size) { return abort_if_null(plain_alloc(size)); }
-void *operator new(std::size_t size, const std::nothrow_t & /*tag*/) noexcept { return plain_alloc(size); }
-void *operator new[](std::size_t size, const std::nothrow_t & /*tag*/) noexcept { return plain_alloc(size); }
-
-void *operator new(std::size_t size, std::align_val_t align) {
-  return abort_if_null(aligned_alloc_or_null(size, align));
-}
-void *operator new[](std::size_t size, std::align_val_t align) {
-  return abort_if_null(aligned_alloc_or_null(size, align));
-}
-void *operator new(std::size_t size, std::align_val_t align, const std::nothrow_t & /*tag*/) noexcept {
-  return aligned_alloc_or_null(size, align);
-}
-void *operator new[](std::size_t size, std::align_val_t align, const std::nothrow_t & /*tag*/) noexcept {
-  return aligned_alloc_or_null(size, align);
-}
-// NOLINTEND(cert-dcl54-cpp,misc-new-delete-overloads)
-
-#endif  // CONFIG_COMPILER_CXX_EXCEPTIONS
-#endif  // USE_ESP_IDF
@@ -7,6 +7,8 @@
 #include "esphome/core/automation.h"
 #include "esphome/components/network/ip_address.h"

+#include <atomic>
+
 #ifdef USE_ETHERNET

 #ifdef USE_ESP32
@@ -366,6 +368,9 @@ class EthernetComponent final : public Component {

 #ifdef USE_ETHERNET_IP_STATE_LISTENERS
  StaticVector<EthernetIPStateListener *, ESPHOME_ETHERNET_IP_STATE_LISTENERS> ip_state_listeners_;
+#ifdef USE_ESP32
+  std::atomic<uint8_t> ip_state_pending_{0};
+#endif
 #endif

 #ifdef USE_ETHERNET_CONNECT_TRIGGER
@@ -129,6 +129,14 @@ void EthernetComponent::log_error_and_mark_failed_(esp_err_t err, const char *me
 void EthernetComponent::loop() {
  const uint32_t now = App.get_loop_component_start_time();

+#ifdef USE_ETHERNET_IP_STATE_LISTENERS
+  // The IP events arrive on the event task; the listeners publish states, so notify them here
+  if (this->ip_state_pending_.load(std::memory_order_acquire) != 0) {
+    this->ip_state_pending_.store(0, std::memory_order_relaxed);
+    this->notify_ip_state_listeners_();
+  }
+#endif
+
  switch (this->state_) {
    case EthernetComponentState::STOPPED:
      if (this->started_) {
@@ -770,7 +778,8 @@ void EthernetComponent::eth_event_handler(void *arg, esp_event_base_t event_base
      event_name = "ETH connected";
      // For static IP configurations, GOT_IP event may not fire, so notify IP listeners here
 #if defined(USE_ETHERNET_IP_STATE_LISTENERS) && defined(USE_ETHERNET_MANUAL_IP)
-      global_eth_component->notify_ip_state_listeners_();
+      global_eth_component->ip_state_pending_.store(1, std::memory_order_release);
+      global_eth_component->enable_loop_soon_any_context();
 #endif
 #if USE_NETWORK_IPV6
      // Start SLAAC on link-up, not after the DHCPv4 lease. This also restores the
@@ -798,6 +807,9 @@ void EthernetComponent::got_ip_event_handler(void *arg, esp_event_base_t event_b
  const esp_netif_ip_info_t *ip_info = &event->ip_info;
  ESP_LOGV(TAG, "[Ethernet event] ETH Got IP " IPSTR, IP2STR(&ip_info->ip));
  global_eth_component->got_ipv4_address_ = true;
+#ifdef USE_ETHERNET_IP_STATE_LISTENERS
+  global_eth_component->ip_state_pending_.store(1, std::memory_order_release);
+#endif
 #if USE_NETWORK_IPV6 && (USE_NETWORK_MIN_IPV6_ADDR_COUNT > 0)
  global_eth_component->connected_ = global_eth_component->ipv6_count_ >= USE_NETWORK_MIN_IPV6_ADDR_COUNT;
  global_eth_component->enable_loop_soon_any_context();  // Enable loop when connection state changes
@@ -805,9 +817,6 @@ void EthernetComponent::got_ip_event_handler(void *arg, esp_event_base_t event_b
  global_eth_component->connected_ = true;
  global_eth_component->enable_loop_soon_any_context();  // Enable loop when connection state changes
 #endif /* USE_NETWORK_IPV6 */
-#ifdef USE_ETHERNET_IP_STATE_LISTENERS
-  global_eth_component->notify_ip_state_listeners_();
-#endif
 }

 #if USE_NETWORK_IPV6
@@ -819,6 +828,9 @@ void EthernetComponent::got_ip6_event_handler(void *arg, esp_event_base_t event_
  // after a link flap fires another event for the same address.
  struct esp_ip6_addr if_ip6s[CONFIG_LWIP_IPV6_NUM_ADDRESSES];
  global_eth_component->ipv6_count_ = esp_netif_get_all_ip6(global_eth_component->eth_netif_, if_ip6s);
+#ifdef USE_ETHERNET_IP_STATE_LISTENERS
+  global_eth_component->ip_state_pending_.store(1, std::memory_order_release);
+#endif
 #if (USE_NETWORK_MIN_IPV6_ADDR_COUNT > 0)
  global_eth_component->connected_ =
      global_eth_component->got_ipv4_address_ && (global_eth_component->ipv6_count_ >= USE_NETWORK_MIN_IPV6_ADDR_COUNT);
@@ -827,9 +839,6 @@ void EthernetComponent::got_ip6_event_handler(void *arg, esp_event_base_t event_
  global_eth_component->connected_ = global_eth_component->got_ipv4_address_;
  global_eth_component->enable_loop_soon_any_context();  // Enable loop when connection state changes
 #endif
-#ifdef USE_ETHERNET_IP_STATE_LISTENERS
-  global_eth_component->notify_ip_state_listeners_();
-#endif
 }
 #endif /* USE_NETWORK_IPV6 */

@@ -48,7 +48,7 @@ CONF_WHITENING_ENABLE = "whitening_enable"
 CONF_WHITENING_INITIAL = "whitening_initial"

 sx126x_ns = cg.esphome_ns.namespace("sx126x")
-SX126x = sx126x_ns.class_("SX126x", cg.Component, spi.SPIDevice)
+SX126x = sx126x_ns.class_("SX126x", cg.Component)
 SX126xListener = sx126x_ns.class_("SX126xListener")
 SX126xBw = sx126x_ns.enum("SX126xBw")
 SX126xPacketType = sx126x_ns.enum("SX126xPacketType")
@@ -217,7 +217,9 @@ CONFIG_SCHEMA = (
            cv.Required(CONF_RF_SWITCH): cv.boolean,
            cv.Optional(CONF_SHAPING, default="NONE"): cv.enum(SHAPING),
            cv.Optional(CONF_SPREADING_FACTOR, default=7): cv.int_range(min=6, max=12),
-            cv.Optional(CONF_SYNC_VALUE, default=[]): cv.ensure_list(cv.hex_uint8_t),
+            cv.Optional(CONF_SYNC_VALUE, default=[]): cv.All(
+                cv.ensure_list(cv.hex_uint8_t), cv.Length(max=8)
+            ),
            cv.Optional(CONF_TCXO_VOLTAGE, default="NONE"): cv.enum(TCXO_VOLTAGE),
            cv.Optional(CONF_TCXO_DELAY, default="5ms"): cv.All(
                cv.positive_time_period_microseconds,
@@ -0,0 +1,97 @@
+#pragma once
+#include "sx126x_reg.h"
+#include <array>
+#include <span>
+#include <algorithm>
+
+namespace esphome::sx126x {
+enum SX126xBw : uint8_t {
+  // FSK
+  SX126X_BW_4800,
+  SX126X_BW_5800,
+  SX126X_BW_7300,
+  SX126X_BW_9700,
+  SX126X_BW_11700,
+  SX126X_BW_14600,
+  SX126X_BW_19500,
+  SX126X_BW_23400,
+  SX126X_BW_29300,
+  SX126X_BW_39000,
+  SX126X_BW_46900,
+  SX126X_BW_58600,
+  SX126X_BW_78200,
+  SX126X_BW_93800,
+  SX126X_BW_117300,
+  SX126X_BW_156200,
+  SX126X_BW_187200,
+  SX126X_BW_234300,
+  SX126X_BW_312000,
+  SX126X_BW_373600,
+  SX126X_BW_467000,
+  // LORA
+  SX126X_BW_7810,
+  SX126X_BW_10420,
+  SX126X_BW_15630,
+  SX126X_BW_20830,
+  SX126X_BW_31250,
+  SX126X_BW_41670,
+  SX126X_BW_62500,
+  SX126X_BW_125000,
+  SX126X_BW_250000,
+  SX126X_BW_500000,
+};
+
+// Requested settings are separate from the last successfully applied profile.
+// Bounded sync storage makes profile snapshots allocation-free.
+struct RadioProfile {
+  uint32_t bitrate{0};
+  uint32_t deviation{0};
+  uint32_t frequency{0};
+  uint32_t tcxo_delay{0};
+  uint16_t crc_polynomial{0};
+  uint16_t crc_initial{0};
+  uint16_t whitening_initial{0};
+  uint16_t preamble_detect{0};
+  uint16_t preamble_size{0};
+  SX126xBw bandwidth{SX126X_BW_125000};
+  uint8_t crc_size{0};
+  uint8_t tcxo_voltage{0};
+  uint8_t coding_rate{0};
+  uint8_t modulation{PACKET_TYPE_LORA};
+  uint8_t pa_ramp{0};
+  uint8_t shaping{0};
+  uint8_t spreading_factor{0};
+  int8_t pa_power{0};
+  uint8_t payload_length{0};
+  bool sx1261{false};
+  bool crc_enable{false};
+  bool crc_inverted{false};
+  bool whitening_enable{false};
+  bool rx_start{false};
+  bool rf_switch{false};
+  std::array<uint8_t, 8> sync_value{};
+  uint8_t sync_size{0};
+  bool sync_valid{true};
+  void set_sync_value(std::span<const uint8_t> bytes) {
+    this->sync_valid = bytes.size() <= this->sync_value.size();
+    if (!this->sync_valid) {
+      return;
+    }
+    std::copy(bytes.begin(), bytes.end(), this->sync_value.begin());
+    this->sync_size = bytes.size();
+  }
+  size_t max_packet_size() const { return this->payload_length > 0 ? this->payload_length : 255; }
+};
+
+// The parts of the last successfully applied profile that runtime operations read.
+// SetPacketParams is encoded once; sends only change its payload length byte.
+struct AppliedProfile {
+  uint32_t frequency{0};
+  std::array<uint8_t, 9> packet_params{};
+  uint8_t packet_params_size{0};
+  uint8_t payload_length{0};
+  uint8_t modulation{PACKET_TYPE_LORA};
+  bool rx_start{false};
+  size_t max_packet_size() const { return this->payload_length > 0 ? this->payload_length : 255; }
+};
+}  // namespace esphome::sx126x
@@ -2,534 +2,217 @@
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/progmem.h"

 namespace esphome::sx126x {

 ESPHOME_LOG_TAG(TAG, "sx126x");
-static constexpr uint16_t RAMP[8] PROGMEM = {10, 20, 40, 80, 200, 800, 1700, 3400};
-// Aligned 32 bit loads from flash are safe on ESP8266, so this table is read directly
-static constexpr uint32_t BW_HZ[31] PROGMEM = {4800,   5800,   7300,   9700,   11700,  14600,  19500,  23400,
-                                               29300,  39000,  46900,  58600,  78200,  93800,  117300, 156200,
-                                               187200, 234300, 312000, 373600, 467000, 7810,   10420,  15630,
-                                               20830,  31250,  41670,  62500,  125000, 250000, 500000};
-static constexpr uint8_t BW_LORA[10] PROGMEM = {LORA_BW_7810,   LORA_BW_10420, LORA_BW_15630, LORA_BW_20830,
-                                                LORA_BW_31250,  LORA_BW_41670, LORA_BW_62500, LORA_BW_125000,
-                                                LORA_BW_250000, LORA_BW_500000};
-static constexpr uint8_t BW_FSK[21] PROGMEM = {
-    FSK_BW_4800,   FSK_BW_5800,   FSK_BW_7300,   FSK_BW_9700,   FSK_BW_11700,  FSK_BW_14600,  FSK_BW_19500,
-    FSK_BW_23400,  FSK_BW_29300,  FSK_BW_39000,  FSK_BW_46900,  FSK_BW_58600,  FSK_BW_78200,  FSK_BW_93800,
-    FSK_BW_117300, FSK_BW_156200, FSK_BW_187200, FSK_BW_234300, FSK_BW_312000, FSK_BW_373600, FSK_BW_467000};
-
-static constexpr uint32_t RESET_DELAY_HIGH_US = 5000;
-static constexpr uint32_t RESET_DELAY_LOW_US = 2000;
-static constexpr uint32_t SWITCHING_DELAY_US = 1;
 static constexpr uint32_t TRANSMIT_TIMEOUT_MS = 4000;
-static constexpr uint32_t BUSY_TIMEOUT_MS = 20;
+static constexpr uint32_t MAX_TRANSMIT_TIMEOUT_MS = 262143;  // 24-bit SetTx timeout in 1/64 ms steps
+static constexpr uint32_t RECONFIGURE_INTERVAL_ID = 0;
+static constexpr uint32_t RECONFIGURE_INTERVAL_MS = 1000;

-// OCP (Over Current Protection) values
-static constexpr uint8_t OCP_80MA = 0x18;   // 80 mA max current
-static constexpr uint8_t OCP_140MA = 0x38;  // 140 mA max current
-
-// LoRa low data rate optimization threshold
-static constexpr float LOW_DATA_RATE_OPTIMIZE_THRESHOLD = 16.38f;  // 16.38 ms
-
-uint8_t SX126x::read_fifo_(uint8_t offset, std::vector<uint8_t> &packet) {
-  this->enable();
-  this->wait_busy_();
-  this->transfer_byte(RADIO_READ_BUFFER);
-  this->transfer_byte(offset);
-  uint8_t status = this->transfer_byte(0x00);
-  for (uint8_t &byte : packet) {
-    byte = this->transfer_byte(0x00);
-  }
-  this->disable();
-  return status;
-}
-
-void SX126x::write_fifo_(uint8_t offset, const uint8_t *data, size_t len) {
-  this->enable();
-  this->wait_busy_();
-  this->transfer_byte(RADIO_WRITE_BUFFER);
-  this->transfer_byte(offset);
-  for (size_t i = 0; i < len; i++) {
-    this->transfer_byte(data[i]);
-  }
-  this->disable();
-  delayMicroseconds(SWITCHING_DELAY_US);
-}
-
-uint8_t SX126x::read_opcode_(uint8_t opcode, uint8_t *data, uint8_t size) {
-  this->enable();
-  this->wait_busy_();
-  this->transfer_byte(opcode);
-  uint8_t status = this->transfer_byte(0x00);
-  for (int32_t i = 0; i < size; i++) {
-    data[i] = this->transfer_byte(0x00);
-  }
-  this->disable();
-  return status;
-}
-
-void SX126x::write_opcode_(uint8_t opcode, uint8_t *data, uint8_t size) {
-  this->enable();
-  this->wait_busy_();
-  this->transfer_byte(opcode);
-  for (int32_t i = 0; i < size; i++) {
-    this->transfer_byte(data[i]);
-  }
-  this->disable();
-  delayMicroseconds(SWITCHING_DELAY_US);
-}
-
-void SX126x::read_register_(uint16_t reg, uint8_t *data, uint8_t size) {
-  this->enable();
-  this->wait_busy_();
-  this->write_byte(RADIO_READ_REGISTER);
-  this->write_byte((reg >> 8) & 0xFF);
-  this->write_byte((reg >> 0) & 0xFF);
-  this->write_byte(0x00);
-  for (int32_t i = 0; i < size; i++) {
-    data[i] = this->transfer_byte(0x00);
-  }
-  this->disable();
-}
-
-void SX126x::write_register_(uint16_t reg, uint8_t *data, uint8_t size) {
-  this->enable();
-  this->wait_busy_();
-  this->write_byte(RADIO_WRITE_REGISTER);
-  this->write_byte((reg >> 8) & 0xFF);
-  this->write_byte((reg >> 0) & 0xFF);
-  for (int32_t i = 0; i < size; i++) {
-    this->transfer_byte(data[i]);
-  }
-  this->disable();
-  delayMicroseconds(SWITCHING_DELAY_US);
-}
-
-void IRAM_ATTR SX126x::gpio_intr(SX126x *arg) { arg->enable_loop_soon_any_context(); }
+// Indexed by SX126xError.
+PROGMEM_STRING_TABLE(SX126xErrorStrings, "none", "timeout", "invalid payload", "radio not ready", "bus timeout",
+                     "radio busy", "cancelled");

 void SX126x::setup() {
+  // Sized once so later packet reads never reallocate; read_packet() sets the length.
+  this->packet_.resize(SX126X_MAX_PACKET_SIZE);
  // setup pins
-  this->busy_pin_->setup();
-  this->rst_pin_->setup();
-  this->dio1_pin_->setup();
-  if (this->dio1_pin_->is_internal()) {
-    static_cast<InternalGPIOPin *>(this->dio1_pin_)
-        ->attach_interrupt(&SX126x::gpio_intr, this, gpio::INTERRUPT_RISING_EDGE);
+  GPIOPin *dio1 = this->radio_.get_dio1_pin();
+  this->radio_.bus().get_busy_pin()->setup();
+  this->radio_.get_rst_pin()->setup();
+  dio1->setup();
+  if (dio1->is_internal()) {
+    static_cast<InternalGPIOPin *>(dio1)->attach_interrupt(&SX126x::gpio_intr, this, gpio::INTERRUPT_RISING_EDGE);
  }

  // start spi
-  this->spi_setup();
+  this->radio_.bus().setup();

-  // configure rf
-  this->configure();
+  // configure rf; a failure is reported through mark_failed() only, with its own reason
+  const RadioEffects effects = this->radio_.configure(this->requested_profile_, this->version_);
+  if (effects.warning != nullptr) {
+    this->mark_failed(effects.warning);
+    return;
+  }
+  this->apply_(effects);
+}
+
+void SX126x::apply_(const RadioEffects &effects) {
+  // User code may only run once the radio has committed. A rejection during another
+  // operation's command sequence carries no status or callbacks.
+  ESPHOME_DEBUG_ASSERT(!this->radio_.busy() || (!effects.report && effects.listener == nullptr && !effects.received));
+  if (effects.sleep_loop) {
+    this->disable_loop();
+  } else if (this->radio_.state() != RadioState::RADIO_STATE_NEEDS_CONFIGURATION) {
+    this->enable_loop();
+  }
+  this->watch_configuration_();
+  // The packet buffer is borrowed from the status report until listeners return;
+  // loop() will not refill it meanwhile.
+  if (effects.received) {
+    this->rx_dispatching_ = true;
+  }
+  if (effects.report) {
+    this->status_comm_result(effects.warning == nullptr, effects.warning);
+  }
+  if (effects.listener != nullptr) {
+    effects.listener->on_transmit_complete(effects.result);
+  }
+  if (effects.received) {
+    for (auto *listener : this->listeners_) {
+      listener->on_packet(this->packet_, effects.rssi, effects.snr);
+    }
+    this->packet_trigger_.trigger(this->packet_, effects.rssi, effects.snr);
+    this->rx_dispatching_ = false;
+  }
 }

 void SX126x::configure() {
-  uint8_t buf[8];
-
-  // toggle chip reset
-  this->rst_pin_->digital_write(true);
-  delayMicroseconds(RESET_DELAY_HIGH_US);
-  this->rst_pin_->digital_write(false);
-  delayMicroseconds(RESET_DELAY_LOW_US);
-  this->rst_pin_->digital_write(true);
-  delayMicroseconds(RESET_DELAY_HIGH_US);
-
-  // wakeup
-  this->read_opcode_(RADIO_GET_STATUS, nullptr, 0);
-
-  // config tcxo
-  if (this->tcxo_voltage_ != TCXO_CTRL_NONE) {
-    uint32_t delay = this->tcxo_delay_ >> 6;
-    buf[0] = this->tcxo_voltage_;
-    buf[1] = (delay >> 16) & 0xFF;
-    buf[2] = (delay >> 8) & 0xFF;
-    buf[3] = (delay >> 0) & 0xFF;
-    this->write_opcode_(RADIO_SET_TCXOMODE, buf, 4);
-    buf[0] = 0x7F;
-    this->write_opcode_(RADIO_CALIBRATE, buf, 1);
-  }
-
-  // clear errors
-  buf[0] = 0x00;
-  buf[1] = 0x00;
-  this->write_opcode_(RADIO_CLR_ERROR, buf, 2);
-
-  // rf switch
-  if (this->rf_switch_) {
-    buf[0] = 0x01;
-    this->write_opcode_(RADIO_SET_RFSWITCHMODE, buf, 1);
-  }
-
-  // check silicon version to make sure hw is ok
-  this->read_register_(REG_VERSION_STRING, (uint8_t *) this->version_, sizeof(this->version_));
-  this->version_[sizeof(this->version_) - 1] = '\0';
-  if (strncmp(this->version_, "SX126", 5) != 0 && strncmp(this->version_, "LLCC68", 6) != 0) {
-    this->mark_failed(LOG_STR("Unsupported chip version"));
+  // Before setup() the bus is not set up, and after a failed setup the radio stays unused
+  if (!this->is_ready()) {
    return;
  }
-
-  // setup packet type
-  buf[0] = this->modulation_;
-  this->write_opcode_(RADIO_SET_PACKETTYPE, buf, 1);
-
-  // calibrate image
-  this->run_image_cal();
-
-  // set frequency
-  uint64_t freq = ((uint64_t) this->frequency_ << 25) / XTAL_FREQ;
-  buf[0] = (uint8_t) ((freq >> 24) & 0xFF);
-  buf[1] = (uint8_t) ((freq >> 16) & 0xFF);
-  buf[2] = (uint8_t) ((freq >> 8) & 0xFF);
-  buf[3] = (uint8_t) (freq & 0xFF);
-  this->write_opcode_(RADIO_SET_RFFREQUENCY, buf, 4);
-
-  // configure pa
-  int8_t pa_power = this->pa_power_;
-  if (this->sx1261_) {
-    // the following values were taken from section 13.1.14.1 table 13-21
-    // in rev 2.1 of the datasheet
-    if (pa_power == 15) {
-      uint8_t cfg[4] = {0x06, 0x00, 0x01, 0x01};
-      this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
-    } else {
-      uint8_t cfg[4] = {0x04, 0x00, 0x01, 0x01};
-      this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
-    }
-    pa_power = std::max(pa_power, (int8_t) -3);
-    pa_power = std::min(pa_power, (int8_t) 14);
-    buf[0] = OCP_80MA;
-    this->write_register_(REG_OCP, buf, 1);
-  } else {
-    // the following values were taken from section 13.1.14.1 table 13-21
-    // in rev 2.1 of the datasheet
-    uint8_t cfg[4] = {0x04, 0x07, 0x00, 0x01};
-    this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
-    pa_power = std::max(pa_power, (int8_t) -3);
-    pa_power = std::min(pa_power, (int8_t) 22);
-    buf[0] = OCP_140MA;
-    this->write_register_(REG_OCP, buf, 1);
+  if (!this->radio_.can_configure()) {
+    ESP_LOGW(TAG, "Radio operation in progress, configuration ignored");
+    return;
  }
-  buf[0] = pa_power;
-  buf[1] = this->pa_ramp_;
-  this->write_opcode_(RADIO_SET_TXPARAMS, buf, 2);
+  this->cold_sleep_ = false;
+  this->apply_(this->radio_.configure(this->requested_profile_, this->version_));
+}

-  // configure modem
-  if (this->modulation_ == PACKET_TYPE_LORA) {
-    // set modulation params
-    float duration = 1000.0f * (1UL << this->spreading_factor_) / BW_HZ[this->bandwidth_];
-    buf[0] = this->spreading_factor_;
-    buf[1] = progmem_read_byte(&BW_LORA[this->bandwidth_ - SX126X_BW_7810]);
-    buf[2] = this->coding_rate_;
-    buf[3] = (duration > LOW_DATA_RATE_OPTIMIZE_THRESHOLD) ? 0x01 : 0x00;
-    this->write_opcode_(RADIO_SET_MODULATIONPARAMS, buf, 4);
-
-    // set packet params and sync word
-    this->set_packet_params_(this->get_max_packet_size());
-    if (this->sync_value_.size() == 2) {
-      this->write_register_(REG_LORA_SYNCWORD, this->sync_value_.data(), this->sync_value_.size());
-    }
-  } else {
-    // set modulation params
-    uint32_t bitrate = ((uint64_t) XTAL_FREQ * 32) / this->bitrate_;
-    uint32_t fdev = ((uint64_t) this->deviation_ << 25) / XTAL_FREQ;
-    buf[0] = (bitrate >> 16) & 0xFF;
-    buf[1] = (bitrate >> 8) & 0xFF;
-    buf[2] = (bitrate >> 0) & 0xFF;
-    buf[3] = this->shaping_;
-    buf[4] = progmem_read_byte(&BW_FSK[this->bandwidth_ - SX126X_BW_4800]);
-    buf[5] = (fdev >> 16) & 0xFF;
-    buf[6] = (fdev >> 8) & 0xFF;
-    buf[7] = (fdev >> 0) & 0xFF;
-    this->write_opcode_(RADIO_SET_MODULATIONPARAMS, buf, 8);
-
-    // set crc params
-    if (this->crc_enable_) {
-      buf[0] = this->crc_initial_ >> 8;
-      buf[1] = this->crc_initial_ & 0xFF;
-      this->write_register_(REG_CRC_INITIAL, buf, 2);
-      buf[0] = this->crc_polynomial_ >> 8;
-      buf[1] = this->crc_polynomial_ & 0xFF;
-      this->write_register_(REG_CRC_POLYNOMIAL, buf, 2);
-    }
-
-    // set whitening params
-    if (this->whitening_enable_) {
-      // according to the datasheet, section 12 table 12-1 "The user should not
-      // change the value of the 7 MSB of this register"
-      this->read_register_(REG_WHITENING_INITIAL, buf, 1);
-      buf[0] = (buf[0] & 0xFE) | ((this->whitening_initial_ >> 8) & 0x01);
-      buf[1] = this->whitening_initial_ & 0xFF;
-      this->write_register_(REG_WHITENING_INITIAL, buf, 2);
-    }
-
-    // set packet params and sync word
-    this->set_packet_params_(this->get_max_packet_size());
-    if (!this->sync_value_.empty()) {
-      this->write_register_(REG_GFSK_SYNCWORD, this->sync_value_.data(), this->sync_value_.size());
-    }
+// A failed command leaves the radio needing configuration, which nothing else would do, so a node
+// that only uses YAML would stay deaf. Cold sleep is asked for, so it waits for a mode command.
+void SX126x::watch_configuration_() {
+  const bool needed = this->radio_.state() == RadioState::RADIO_STATE_NEEDS_CONFIGURATION && !this->cold_sleep_;
+  if (needed == this->reconfigure_pending_) {
+    return;
  }
-
-  // switch to rx or sleep
-  if (this->rx_start_) {
-    this->set_mode_rx();
+  this->reconfigure_pending_ = needed;
+  if (needed) {
+    this->set_interval(RECONFIGURE_INTERVAL_ID, RECONFIGURE_INTERVAL_MS, [this]() { this->configure(); });
  } else {
-    this->set_mode_sleep();
+    this->cancel_interval(RECONFIGURE_INTERVAL_ID);
  }
 }

-size_t SX126x::get_max_packet_size() {
-  if (this->payload_length_ > 0) {
-    return this->payload_length_;
+void SX126x::set_mode_rx() { this->change_mode_(ModeCommand::MODE_COMMAND_RX); }
+void SX126x::set_mode_tx() { this->change_mode_(ModeCommand::MODE_COMMAND_TX); }
+void SX126x::set_mode_standby(SX126xStandbyMode mode) { this->change_mode_(ModeCommand::MODE_COMMAND_STANDBY, mode); }
+void SX126x::set_mode_sleep(bool cold) {
+  this->change_mode_(cold ? ModeCommand::MODE_COMMAND_COLD_SLEEP : ModeCommand::MODE_COMMAND_SLEEP);
+}
+void SX126x::run_image_cal() { this->change_mode_(ModeCommand::MODE_COMMAND_IMAGE_CAL); }
+
+void SX126x::change_mode_(ModeCommand command, uint8_t arg) {
+  const bool sleep = command == ModeCommand::MODE_COMMAND_SLEEP || command == ModeCommand::MODE_COMMAND_COLD_SLEEP;
+  if (this->cold_sleep_) {
+    if (sleep) {
+      return;
+    }
+    // Cold sleep lost the configuration, so waking needs it applied again first
+    this->configure();
  }
-  return SX126X_MAX_PACKET_SIZE;
+  if (!this->radio_.can_change_mode()) {
+    ESP_LOGW(TAG, "Radio unavailable, mode change ignored");
+    return;
+  }
+  this->cold_sleep_ = command == ModeCommand::MODE_COMMAND_COLD_SLEEP;
+  this->apply_(this->radio_.change_mode(command, arg));
 }

-void SX126x::set_packet_params_(uint8_t payload_length) {
-  uint8_t buf[9];
-  if (this->modulation_ == PACKET_TYPE_LORA) {
-    buf[0] = (this->preamble_size_ >> 8) & 0xFF;
-    buf[1] = (this->preamble_size_ >> 0) & 0xFF;
-    buf[2] = (this->payload_length_ > 0) ? 0x01 : 0x00;
-    buf[3] = payload_length;
-    buf[4] = (this->crc_enable_) ? 0x01 : 0x00;
-    buf[5] = 0x00;
-    this->write_opcode_(RADIO_SET_PACKETPARAMS, buf, 6);
-  } else {
-    uint16_t preamble_size = this->preamble_size_ * 8;
-    buf[0] = (preamble_size >> 8) & 0xFF;
-    buf[1] = (preamble_size >> 0) & 0xFF;
-    buf[2] = (this->preamble_detect_ > 0) ? ((this->preamble_detect_ - 1) | 0x04) : 0x00;
-    buf[3] = this->sync_value_.size() * 8;
-    buf[4] = 0x00;
-    buf[5] = (this->payload_length_ > 0) ? 0x00 : 0x01;
-    buf[6] = payload_length;
-    if (this->crc_enable_) {
-      buf[7] = (this->crc_inverted_ ? 0x04 : 0x00) + (this->crc_size_ & 0x02);
-    } else {
-      buf[7] = 0x01;
-    }
-    buf[8] = (this->whitening_enable_) ? 0x01 : 0x00;
-    this->write_opcode_(RADIO_SET_PACKETPARAMS, buf, 9);
-  }
-}
+size_t SX126x::get_max_packet_size() { return this->radio_.max_packet_size(); }

 SX126xError SX126x::transmit_packet(const uint8_t *data, size_t len) {
-  // Callers such as a template number's on_value can run before setup() or after a failed setup
-  if (!this->is_ready()) {
-    ESP_LOGW(TAG, "Radio not ready, packet dropped");
-    return SX126xError::SX126X_ERROR_NOT_READY;
-  }
-  if (this->payload_length_ > 0 && this->payload_length_ != len) {
-    ESP_LOGE(TAG, "Packet size does not match config");
-    return SX126xError::INVALID_PARAMS;
-  }
-  if (len == 0 || len > this->get_max_packet_size()) {
-    ESP_LOGE(TAG, "Packet size out of range");
-    return SX126xError::INVALID_PARAMS;
-  }
-
-  SX126xError ret = SX126xError::NONE;
-  this->set_mode_standby(STDBY_XOSC);
-  if (this->payload_length_ == 0) {
-    this->set_packet_params_(len);
-  }
-  this->write_fifo_(0x00, data, len);
-  this->set_mode_tx();
-
-  // wait until transmit completes, typically the delay will be less than 100 ms
-  uint32_t start = millis();
-  while (!this->dio1_pin_->digital_read()) {
-    App.feed_wdt();
-    if (millis() - start > TRANSMIT_TIMEOUT_MS) {
-      ESP_LOGE(TAG, "Transmit packet failure");
-      ret = SX126xError::TIMEOUT;
-      break;
+  SX126xError result = this->start_transmit_(nullptr, data, len, TRANSMIT_TIMEOUT_MS);
+  if (result == SX126xError::SX126X_ERROR_NONE) {
+    // Wait for this send's own completion. A send without a listener cannot be cancelled,
+    // and no user code runs between these polls, so the send cannot be replaced.
+    result = SX126xError::SX126X_ERROR_NOT_READY;
+    while (this->radio_.is_transmitting()) {
+      const RadioEffects effects = this->radio_.poll_transmit(millis());
+      if (effects.finished) {
+        result = effects.result;
+        this->apply_(effects);
+        break;
+      }
+      App.feed_wdt();
    }
  }
-
-  uint8_t buf[2];
-  buf[0] = 0xFF;
-  buf[1] = 0xFF;
-  this->write_opcode_(RADIO_CLR_IRQSTATUS, buf, 2);
-  if (this->payload_length_ == 0) {
-    this->set_packet_params_(this->get_max_packet_size());
+  if (result != SX126xError::SX126X_ERROR_NONE) {
+    ESP_LOGW(
+        TAG, "Packet send failed: %s",
+        LOG_STR_ARG(SX126xErrorStrings::get_log_str(static_cast<uint8_t>(result), SX126xErrorStrings::LAST_INDEX)));
  }
-  if (this->rx_start_) {
-    this->set_mode_rx();
-  } else {
-    this->set_mode_sleep();
-  }
-  return ret;
+  return result;
 }

-void SX126x::call_listeners_(const std::vector<uint8_t> &packet, float rssi, float snr) {
-  for (auto &listener : this->listeners_) {
-    listener->on_packet(packet, rssi, snr);
+SX126xError SX126x::start_transmit_async(SX126xTransmitListener *listener, const uint8_t *data, size_t len,
+                                         uint32_t timeout_ms) {
+  if (listener == nullptr || timeout_ms == 0 || timeout_ms > MAX_TRANSMIT_TIMEOUT_MS) {
+    return SX126xError::SX126X_ERROR_INVALID_PARAMS;
  }
-  this->packet_trigger_.trigger(packet, rssi, snr);
+  return this->start_transmit_(listener, data, len, timeout_ms);
+}
+
+SX126xError SX126x::start_transmit_(SX126xTransmitListener *listener, const uint8_t *data, size_t len,
+                                    uint32_t timeout_ms) {
+  if (!this->is_ready()) {
+    return SX126xError::SX126X_ERROR_NOT_READY;
+  }
+  const RadioEffects effects = this->radio_.start_transmit(listener, data, len, timeout_ms);
+  this->apply_(effects);
+  return effects.result;
+}
+
+bool SX126x::cancel_transmit_async(SX126xTransmitListener *listener) {
+  const RadioEffects effects = this->radio_.cancel_transmit(listener);
+  if (!effects.finished) {
+    return false;
+  }
+  this->apply_(effects);
+  return true;
 }

 void SX126x::loop() {
-  if (this->dio1_pin_->is_internal()) {
-    this->disable_loop();
-  }
-  if (!this->dio1_pin_->digital_read()) {
+  if (this->rx_dispatching_ || this->is_failed()) {
    return;
  }
-
-  uint16_t status;
-  uint8_t buf[3];
-  uint8_t rssi;
-  int8_t snr;
-  this->read_opcode_(RADIO_GET_IRQSTATUS, buf, 2);
-  this->write_opcode_(RADIO_CLR_IRQSTATUS, buf, 2);
-  status = (buf[0] << 8) | buf[1];
-  if ((status & IRQ_RX_DONE) == IRQ_RX_DONE) {
-    if ((status & IRQ_CRC_ERROR) != IRQ_CRC_ERROR) {
-      this->read_opcode_(RADIO_GET_PACKETSTATUS, buf, 3);
-      if (this->modulation_ == PACKET_TYPE_LORA) {
-        rssi = buf[0];
-        snr = buf[1];
-      } else {
-        rssi = buf[2];
-        snr = 0;
-      }
-      this->read_opcode_(RADIO_GET_RXBUFFERSTATUS, buf, 2);
-      this->packet_.resize(buf[0]);
-      this->read_fifo_(buf[1], this->packet_);
-      this->call_listeners_(this->packet_, (float) rssi / -2.0f, (float) snr / 4.0f);
-    }
-  }
-}
-
-void SX126x::run_image_cal() {
-  // the following values were taken from section 9.2.1 table 9-2
-  // in rev 2.1 of the datasheet
-  uint8_t buf[2] = {0, 0};
-  if (this->frequency_ > 900000000) {
-    buf[0] = 0xE1;
-    buf[1] = 0xE9;
-  } else if (this->frequency_ > 850000000) {
-    buf[0] = 0xD7;
-    buf[1] = 0xDB;
-  } else if (this->frequency_ > 770000000) {
-    buf[0] = 0xC1;
-    buf[1] = 0xC5;
-  } else if (this->frequency_ > 460000000) {
-    buf[0] = 0x75;
-    buf[1] = 0x81;
-  } else if (this->frequency_ > 425000000) {
-    buf[0] = 0x6B;
-    buf[1] = 0x6F;
-  }
-  if (buf[0] > 0 && buf[1] > 0) {
-    this->write_opcode_(RADIO_CALIBRATEIMAGE, buf, 2);
-  }
-}
-
-void SX126x::set_mode_rx() {
-  uint8_t buf[8];
-
-  // configure irq params
-  uint16_t irq = IRQ_RX_DONE | IRQ_RX_TX_TIMEOUT | IRQ_CRC_ERROR;
-  buf[0] = (irq >> 8) & 0xFF;
-  buf[1] = (irq >> 0) & 0xFF;
-  buf[2] = (irq >> 8) & 0xFF;
-  buf[3] = (irq >> 0) & 0xFF;
-  buf[4] = (IRQ_RADIO_NONE >> 8) & 0xFF;
-  buf[5] = (IRQ_RADIO_NONE >> 0) & 0xFF;
-  buf[6] = (IRQ_RADIO_NONE >> 8) & 0xFF;
-  buf[7] = (IRQ_RADIO_NONE >> 0) & 0xFF;
-  this->write_opcode_(RADIO_SET_DIOIRQPARAMS, buf, 8);
-
-  // set timeout to 0
-  buf[0] = 0x00;
-  this->write_opcode_(RADIO_SET_LORASYMBTIMEOUT, buf, 1);
-
-  // switch to continuous mode rx
-  buf[0] = 0xFF;
-  buf[1] = 0xFF;
-  buf[2] = 0xFF;
-  this->write_opcode_(RADIO_SET_RX, buf, 3);
-}
-
-void SX126x::set_mode_tx() {
-  uint8_t buf[8];
-
-  // configure irq params
-  uint16_t irq = IRQ_TX_DONE | IRQ_RX_TX_TIMEOUT;
-  buf[0] = (irq >> 8) & 0xFF;
-  buf[1] = (irq >> 0) & 0xFF;
-  buf[2] = (irq >> 8) & 0xFF;
-  buf[3] = (irq >> 0) & 0xFF;
-  buf[4] = (IRQ_RADIO_NONE >> 8) & 0xFF;
-  buf[5] = (IRQ_RADIO_NONE >> 0) & 0xFF;
-  buf[6] = (IRQ_RADIO_NONE >> 8) & 0xFF;
-  buf[7] = (IRQ_RADIO_NONE >> 0) & 0xFF;
-  this->write_opcode_(RADIO_SET_DIOIRQPARAMS, buf, 8);
-
-  // switch to single mode tx
-  buf[0] = 0x00;
-  buf[1] = 0x00;
-  buf[2] = 0x00;
-  this->write_opcode_(RADIO_SET_TX, buf, 3);
-}
-
-void SX126x::set_mode_sleep(bool cold) {
-  // 0x04 = warm start (config retained), 0x00 = cold start (config lost, lowest power)
-  uint8_t buf[1];
-  buf[0] = cold ? 0x00 : 0x04;
-  this->write_opcode_(RADIO_SET_SLEEP, buf, 1);
-}
-
-void SX126x::set_mode_standby(SX126xStandbyMode mode) {
-  uint8_t buf[1];
-  buf[0] = mode;
-  this->write_opcode_(RADIO_SET_STANDBY, buf, 1);
-}
-
-void SX126x::wait_busy_() {
-  // wait if the device is busy, the maximum delay is only be a few ms
-  // with most commands taking only a few us
-  uint32_t start = millis();
-  while (this->busy_pin_->digital_read()) {
-    if (millis() - start > BUSY_TIMEOUT_MS) {
-      this->mark_failed(LOG_STR("Wait busy timeout"));
-      break;
-    }
-  }
+  this->apply_(this->radio_.poll(App.get_loop_component_start_time(), this->packet_));
 }

 void SX126x::dump_config() {
-  ESP_LOGCONFIG(TAG, "SX126x:");
-  LOG_PIN("  CS Pin: ", this->cs_);
-  LOG_PIN("  BUSY Pin: ", this->busy_pin_);
-  LOG_PIN("  RST Pin: ", this->rst_pin_);
-  LOG_PIN("  DIO1 Pin: ", this->dio1_pin_);
+  ESP_LOGCONFIG(TAG, "SX126x:\n  Ready for operation: %s",
+                YESNO(!this->is_failed() && this->radio_.state() == RadioState::RADIO_STATE_IDLE));
+  LOG_PIN("  CS Pin: ", this->radio_.bus().get_cs_pin());
+  LOG_PIN("  BUSY Pin: ", this->radio_.bus().get_busy_pin());
+  LOG_PIN("  RST Pin: ", this->radio_.get_rst_pin());
+  LOG_PIN("  DIO1 Pin: ", this->radio_.get_dio1_pin());
  ESP_LOGCONFIG(TAG,
                "  HW Version: %15s\n"
+                "  Requested configuration:\n"
                "  Frequency: %" PRIu32 " Hz\n"
                "  Bandwidth: %" PRIu32 " Hz\n"
                "  PA Power: %" PRId8 " dBm\n"
                "  PA Ramp: %" PRIu16 " us\n"
-                "  Payload Length: %" PRIu32 "\n"
+                "  Payload Length: %" PRIu8 "\n"
                "  CRC Enable: %s\n"
                "  Rx Start: %s",
-                this->version_, this->frequency_, BW_HZ[this->bandwidth_], this->pa_power_,
-                progmem_read_uint16(&RAMP[this->pa_ramp_]), this->payload_length_, TRUEFALSE(this->crc_enable_),
-                TRUEFALSE(this->rx_start_));
-  if (this->modulation_ == PACKET_TYPE_GFSK) {
+                this->version_, this->requested_profile_.frequency,
+                SX126xCommands::bandwidth_hz(this->requested_profile_.bandwidth), this->requested_profile_.pa_power,
+                SX126xCommands::ramp_us(this->requested_profile_.pa_ramp), this->requested_profile_.payload_length,
+                TRUEFALSE(this->requested_profile_.crc_enable), TRUEFALSE(this->requested_profile_.rx_start));
+  if (this->requested_profile_.modulation == PACKET_TYPE_GFSK) {
    const char *shaping = "NONE";
-    if (this->shaping_ == GAUSSIAN_BT_0_3) {
+    if (this->requested_profile_.shaping == GAUSSIAN_BT_0_3) {
      shaping = "GAUSSIAN_BT_0_3";
-    } else if (this->shaping_ == GAUSSIAN_BT_0_5) {
+    } else if (this->requested_profile_.shaping == GAUSSIAN_BT_0_5) {
      shaping = "GAUSSIAN_BT_0_5";
-    } else if (this->shaping_ == GAUSSIAN_BT_0_7) {
+    } else if (this->requested_profile_.shaping == GAUSSIAN_BT_0_7) {
      shaping = "GAUSSIAN_BT_0_7";
-    } else if (this->shaping_ == GAUSSIAN_BT_1_0) {
+    } else if (this->requested_profile_.shaping == GAUSSIAN_BT_1_0) {
      shaping = "GAUSSIAN_BT_1_0";
    }
    ESP_LOGCONFIG(TAG,
@@ -539,14 +222,15 @@ void SX126x::dump_config() {
                  "  Preamble Size: %" PRIu16 "\n"
                  "  Preamble Detect: %" PRIu16 "\n"
                  "  Bitrate: %" PRIu32 "b/s",
-                  this->deviation_, shaping, this->preamble_size_, this->preamble_detect_, this->bitrate_);
-  } else if (this->modulation_ == PACKET_TYPE_LORA) {
+                  this->requested_profile_.deviation, shaping, this->requested_profile_.preamble_size,
+                  this->requested_profile_.preamble_detect, this->requested_profile_.bitrate);
+  } else if (this->requested_profile_.modulation == PACKET_TYPE_LORA) {
    const char *cr = "4/8";
-    if (this->coding_rate_ == LORA_CR_4_5) {
+    if (this->requested_profile_.coding_rate == LORA_CR_4_5) {
      cr = "4/5";
-    } else if (this->coding_rate_ == LORA_CR_4_6) {
+    } else if (this->requested_profile_.coding_rate == LORA_CR_4_6) {
      cr = "4/6";
-    } else if (this->coding_rate_ == LORA_CR_4_7) {
+    } else if (this->requested_profile_.coding_rate == LORA_CR_4_7) {
      cr = "4/7";
    }
    ESP_LOGCONFIG(TAG,
@@ -554,16 +238,17 @@ void SX126x::dump_config() {
                  "  Spreading Factor: %" PRIu8 "\n"
                  "  Coding Rate: %s\n"
                  "  Preamble Size: %" PRIu16,
-                  this->spreading_factor_, cr, this->preamble_size_);
+                  this->requested_profile_.spreading_factor, cr, this->requested_profile_.preamble_size);
  }
-  if (!this->sync_value_.empty()) {
+  if (this->requested_profile_.sync_size != 0) {
    char hex_buf[17];  // 8 bytes max = 16 hex chars + null
-    ESP_LOGCONFIG(TAG, "  Sync Value: 0x%s",
-                  format_hex_to(hex_buf, this->sync_value_.data(), this->sync_value_.size()));
+    ESP_LOGCONFIG(
+        TAG, "  Sync Value: 0x%s",
+        format_hex_to(hex_buf, this->requested_profile_.sync_value.data(), this->requested_profile_.sync_size));
  }
-  ESP_LOGCONFIG(TAG, "  Whitening Enable: %s", TRUEFALSE(this->whitening_enable_));
-  if (this->whitening_enable_) {
-    ESP_LOGCONFIG(TAG, "  Whitening Initial: 0x%03x", this->whitening_initial_);
+  ESP_LOGCONFIG(TAG, "  Whitening Enable: %s", TRUEFALSE(this->requested_profile_.whitening_enable));
+  if (this->requested_profile_.whitening_enable) {
+    ESP_LOGCONFIG(TAG, "  Whitening Initial: 0x%03x", this->requested_profile_.whitening_initial);
  }
 }

@@ -1,157 +1,123 @@
 #pragma once

+#include "sx126x_radio.h"
 #include "esphome/components/spi/spi.h"
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
 #include "sx126x_reg.h"
-#include <utility>
 #include <vector>

 namespace esphome::sx126x {

 static constexpr size_t SX126X_MAX_PACKET_SIZE = 255;

-enum SX126xBw : uint8_t {
-  // FSK
-  SX126X_BW_4800,
-  SX126X_BW_5800,
-  SX126X_BW_7300,
-  SX126X_BW_9700,
-  SX126X_BW_11700,
-  SX126X_BW_14600,
-  SX126X_BW_19500,
-  SX126X_BW_23400,
-  SX126X_BW_29300,
-  SX126X_BW_39000,
-  SX126X_BW_46900,
-  SX126X_BW_58600,
-  SX126X_BW_78200,
-  SX126X_BW_93800,
-  SX126X_BW_117300,
-  SX126X_BW_156200,
-  SX126X_BW_187200,
-  SX126X_BW_234300,
-  SX126X_BW_312000,
-  SX126X_BW_373600,
-  SX126X_BW_467000,
-  // LORA
-  SX126X_BW_7810,
-  SX126X_BW_10420,
-  SX126X_BW_15630,
-  SX126X_BW_20830,
-  SX126X_BW_31250,
-  SX126X_BW_41670,
-  SX126X_BW_62500,
-  SX126X_BW_125000,
-  SX126X_BW_250000,
-  SX126X_BW_500000,
-};
-
-enum class SX126xError { NONE = 0, TIMEOUT, INVALID_PARAMS, SX126X_ERROR_NOT_READY };
-
 class SX126xListener {
 public:
+  // Called from loop(). The packet is borrowed until this returns; copy what you keep.
+  // Listeners may send, change mode or configure. A send returns BUSY if another packet
+  // is already waiting, which is then delivered by the next loop().
  virtual void on_packet(const std::vector<uint8_t> &packet, float rssi, float snr) = 0;
 };

-class SX126x final : public Component,
-                     public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW, spi::CLOCK_PHASE_LEADING,
-                                           spi::DATA_RATE_8MHZ> {
+class SX126x final : public Component {
 public:
+  void set_spi_parent(spi::SPIComponent *parent) { this->radio_.bus().set_spi_parent(parent); }
+  void set_cs_pin(GPIOPin *pin) { this->radio_.bus().set_cs_pin(pin); }
+  void set_data_rate(uint32_t rate) { this->radio_.bus().set_data_rate(rate); }
+  void set_mode(spi::SPIMode mode) { this->radio_.bus().set_mode(mode); }
+  void set_bit_order(spi::SPIBitOrder order) { this->radio_.bus().set_bit_order(order); }
+  void set_release_device(bool release) { this->radio_.bus().set_release_device(release); }
+  void set_write_only(bool write_only) { this->radio_.bus().set_write_only(write_only); }
+#ifdef USE_SPI_PSRAM_DMA
+  void set_psram_dma(bool enable) { this->radio_.bus().set_psram_dma(enable); }
+#endif
+  // Releases the SPI bus, as SPIDevice::spi_teardown() did before SX126x stopped being one
+  void spi_teardown() { this->radio_.bus().teardown(); }
  size_t get_max_packet_size();
  float get_setup_priority() const override { return setup_priority::PROCESSOR; }
  void setup() override;
  void loop() override;
  void dump_config() override;
-  void set_bandwidth(SX126xBw bandwidth) { this->bandwidth_ = bandwidth; }
-  void set_bitrate(uint32_t bitrate) { this->bitrate_ = bitrate; }
-  void set_busy_pin(GPIOPin *busy_pin) { this->busy_pin_ = busy_pin; }
-  void set_coding_rate(uint8_t coding_rate) { this->coding_rate_ = coding_rate; }
-  void set_crc_enable(bool crc_enable) { this->crc_enable_ = crc_enable; }
-  void set_crc_inverted(bool crc_inverted) { this->crc_inverted_ = crc_inverted; }
-  void set_crc_size(uint8_t crc_size) { this->crc_size_ = crc_size; }
-  void set_crc_polynomial(uint16_t crc_polynomial) { this->crc_polynomial_ = crc_polynomial; }
-  void set_crc_initial(uint16_t crc_initial) { this->crc_initial_ = crc_initial; }
-  void set_whitening_enable(bool whitening_enable) { this->whitening_enable_ = whitening_enable; }
-  void set_whitening_initial(uint16_t whitening_initial) { this->whitening_initial_ = whitening_initial; }
-  void set_deviation(uint32_t deviation) { this->deviation_ = deviation; }
-  void set_dio1_pin(GPIOPin *dio1_pin) { this->dio1_pin_ = dio1_pin; }
-  void set_frequency(uint32_t frequency) { this->frequency_ = frequency; }
-  void set_sx1261(bool sx1261) { this->sx1261_ = sx1261; }
+  void set_bandwidth(SX126xBw bandwidth) { this->requested_profile_.bandwidth = bandwidth; }
+  void set_bitrate(uint32_t bitrate) { this->requested_profile_.bitrate = bitrate; }
+  void set_busy_pin(GPIOPin *busy_pin) { this->radio_.bus().set_busy_pin(busy_pin); }
+  void set_coding_rate(uint8_t coding_rate) { this->requested_profile_.coding_rate = coding_rate; }
+  void set_crc_enable(bool crc_enable) { this->requested_profile_.crc_enable = crc_enable; }
+  void set_crc_inverted(bool crc_inverted) { this->requested_profile_.crc_inverted = crc_inverted; }
+  void set_crc_size(uint8_t crc_size) { this->requested_profile_.crc_size = crc_size; }
+  void set_crc_polynomial(uint16_t crc_polynomial) { this->requested_profile_.crc_polynomial = crc_polynomial; }
+  void set_crc_initial(uint16_t crc_initial) { this->requested_profile_.crc_initial = crc_initial; }
+  void set_whitening_enable(bool whitening_enable) { this->requested_profile_.whitening_enable = whitening_enable; }
+  void set_whitening_initial(uint16_t whitening_initial) {
+    this->requested_profile_.whitening_initial = whitening_initial;
+  }
+  void set_deviation(uint32_t deviation) { this->requested_profile_.deviation = deviation; }
+  void set_dio1_pin(GPIOPin *dio1_pin) { this->radio_.set_dio1_pin(dio1_pin); }
+  void set_frequency(uint32_t frequency) { this->requested_profile_.frequency = frequency; }
+  void set_sx1261(bool sx1261) { this->requested_profile_.sx1261 = sx1261; }
+  // Mode changes are ignored with a warning unless the radio is idle and configured.
  void set_mode_rx();
  void set_mode_tx();
  void set_mode_standby(SX126xStandbyMode mode);
  void set_mode_sleep(bool cold = false);
-  void set_modulation(uint8_t modulation) { this->modulation_ = modulation; }
-  void set_pa_power(int8_t power) { this->pa_power_ = power; }
-  void set_pa_ramp(uint8_t ramp) { this->pa_ramp_ = ramp; }
-  void set_payload_length(uint8_t payload_length) { this->payload_length_ = payload_length; }
-  void set_preamble_detect(uint16_t preamble_detect) { this->preamble_detect_ = preamble_detect; }
-  void set_preamble_size(uint16_t preamble_size) { this->preamble_size_ = preamble_size; }
-  void set_rst_pin(GPIOPin *rst_pin) { this->rst_pin_ = rst_pin; }
-  void set_rx_start(bool rx_start) { this->rx_start_ = rx_start; }
-  void set_rf_switch(bool rf_switch) { this->rf_switch_ = rf_switch; }
-  void set_shaping(uint8_t shaping) { this->shaping_ = shaping; }
-  void set_spreading_factor(uint8_t spreading_factor) { this->spreading_factor_ = spreading_factor; }
-  void set_sync_value(const std::vector<uint8_t> &sync_value) { this->sync_value_ = sync_value; }
-  void set_tcxo_voltage(uint8_t tcxo_voltage) { this->tcxo_voltage_ = tcxo_voltage; }
-  void set_tcxo_delay(uint32_t tcxo_delay) { this->tcxo_delay_ = tcxo_delay; }
+  void set_modulation(uint8_t modulation) { this->requested_profile_.modulation = modulation; }
+  void set_pa_power(int8_t power) { this->requested_profile_.pa_power = power; }
+  void set_pa_ramp(uint8_t ramp) { this->requested_profile_.pa_ramp = ramp; }
+  void set_payload_length(uint8_t payload_length) { this->requested_profile_.payload_length = payload_length; }
+  void set_preamble_detect(uint16_t preamble_detect) { this->requested_profile_.preamble_detect = preamble_detect; }
+  void set_preamble_size(uint16_t preamble_size) { this->requested_profile_.preamble_size = preamble_size; }
+  void set_rst_pin(GPIOPin *rst_pin) { this->radio_.set_rst_pin(rst_pin); }
+  void set_rx_start(bool rx_start) { this->requested_profile_.rx_start = rx_start; }
+  void set_rf_switch(bool rf_switch) { this->requested_profile_.rf_switch = rf_switch; }
+  void set_shaping(uint8_t shaping) { this->requested_profile_.shaping = shaping; }
+  void set_spreading_factor(uint8_t spreading_factor) { this->requested_profile_.spreading_factor = spreading_factor; }
+  void set_sync_value(const std::vector<uint8_t> &sync_value) { this->requested_profile_.set_sync_value(sync_value); }
+  void set_tcxo_voltage(uint8_t tcxo_voltage) { this->requested_profile_.tcxo_voltage = tcxo_voltage; }
+  void set_tcxo_delay(uint32_t tcxo_delay) { this->requested_profile_.tcxo_delay = tcxo_delay; }
  void run_image_cal();
+  // Mode changes and configuration are allowed during RX callbacks when the radio
+  // is available; they never modify the borrowed packet buffer.
  void configure();
  SX126xError transmit_packet(const uint8_t *data, size_t len);
  SX126xError transmit_packet(const std::vector<uint8_t> &packet) {
    return this->transmit_packet(packet.data(), packet.size());
  }
+  // Main-loop context only. SX126X_ERROR_NONE accepts one operation and promises one completion.
+  // Data is copied into the chip FIFO before return; listener must outlive completion.
+  // Pending RX rejects admission with BUSY and is delivered by a later loop().
+  // Timeout: 1..262143 ms. SPI/BUSY waits are synchronous; airtime is asynchronous.
+  [[nodiscard]] SX126xError start_transmit_async(SX126xTransmitListener *listener, const uint8_t *data, size_t len,
+                                                 uint32_t timeout_ms = 4000);
+  [[nodiscard]] SX126xError start_transmit_async(SX126xTransmitListener *listener, const std::vector<uint8_t> &packet,
+                                                 uint32_t timeout_ms = 4000) {
+    return this->start_transmit_async(listener, packet.data(), packet.size(), timeout_ms);
+  }
+  // Normal completion runs in loop(); cancellation completes synchronously in its caller.
+  // The radio is released before callbacks, which may start another operation if recovery
+  // succeeded. True accepts cancellation; the completion result reports cleanup failure.
+  bool cancel_transmit_async(SX126xTransmitListener *listener);
+  bool is_transmitting() const { return this->radio_.is_transmitting(); }
  void register_listener(SX126xListener *listener) { this->listeners_.push_back(listener); }
  Trigger<std::vector<uint8_t>, float, float> *get_packet_trigger() { return &this->packet_trigger_; }

- protected:
-  static void gpio_intr(SX126x *arg);
-  void configure_fsk_ook_();
-  void configure_lora_();
-  void set_packet_params_(uint8_t payload_length);
-  uint8_t read_fifo_(uint8_t offset, std::vector<uint8_t> &packet);
-  void write_fifo_(uint8_t offset, const uint8_t *data, size_t len);
-  void write_opcode_(uint8_t opcode, uint8_t *data, uint8_t size);
-  uint8_t read_opcode_(uint8_t opcode, uint8_t *data, uint8_t size);
-  void write_register_(uint16_t reg, uint8_t *data, uint8_t size);
-  void read_register_(uint16_t reg, uint8_t *data, uint8_t size);
-  void call_listeners_(const std::vector<uint8_t> &packet, float rssi, float snr);
-  void wait_busy_();
+ private:
+  static void IRAM_ATTR gpio_intr(SX126x *arg) { arg->enable_loop_soon_any_context(); }
+  void change_mode_(ModeCommand command, uint8_t arg = 0);
+  // The only place that runs user code for a radio operation: loop scheduling, then status,
+  // then the completion or packet listeners. SX126xRadio has already committed its state.
+  void apply_(const RadioEffects &effects);
+  void watch_configuration_();
+  SX126xError start_transmit_(SX126xTransmitListener *listener, const uint8_t *data, size_t len, uint32_t timeout_ms);
+  SX126xRadio radio_;
+  RadioProfile requested_profile_;
+  char version_[16]{};
  Trigger<std::vector<uint8_t>, float, float> packet_trigger_;
  std::vector<SX126xListener *> listeners_;
  std::vector<uint8_t> packet_;
-  std::vector<uint8_t> sync_value_;
-  GPIOPin *busy_pin_{nullptr};
-  GPIOPin *dio1_pin_{nullptr};
-  GPIOPin *rst_pin_{nullptr};
-  uint32_t bitrate_{0};
-  uint32_t deviation_{0};
-  uint32_t frequency_{0};
-  uint32_t payload_length_{0};
-  uint32_t tcxo_delay_{0};
-  uint16_t crc_polynomial_{0};
-  uint16_t crc_initial_{0};
-  uint16_t whitening_initial_{0};
-  uint16_t preamble_detect_{0};
-  uint16_t preamble_size_{0};
-  char version_[16];
-  SX126xBw bandwidth_{SX126X_BW_125000};
-  uint8_t crc_size_{0};
-  uint8_t tcxo_voltage_{0};
-  uint8_t coding_rate_{0};
-  uint8_t modulation_{PACKET_TYPE_LORA};
-  uint8_t pa_ramp_{0};
-  uint8_t shaping_{0};
-  uint8_t spreading_factor_{0};
-  int8_t pa_power_{0};
-  bool sx1261_{false};
-  bool crc_enable_{false};
-  bool crc_inverted_{false};
-  bool whitening_enable_{false};
-  bool rx_start_{false};
-  bool rf_switch_{false};
+  bool rx_dispatching_{false};
+  bool cold_sleep_{false};
+  bool reconfigure_pending_{false};
 };

 }  // namespace esphome::sx126x
@@ -0,0 +1,355 @@
+#include "sx126x_commands.h"
+#include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
+
+#include <cmath>
+#include <cstring>
+
+namespace esphome::sx126x {
+static constexpr uint16_t RAMP[8] PROGMEM = {10, 20, 40, 80, 200, 800, 1700, 3400};
+// Aligned 32 bit loads from flash are safe on ESP8266, so this table is read directly
+static constexpr uint32_t BW_HZ[31] PROGMEM = {4800,   5800,   7300,   9700,   11700,  14600,  19500,  23400,
+                                               29300,  39000,  46900,  58600,  78200,  93800,  117300, 156200,
+                                               187200, 234300, 312000, 373600, 467000, 7810,   10420,  15630,
+                                               20830,  31250,  41670,  62500,  125000, 250000, 500000};
+static constexpr uint8_t BW_LORA[10] PROGMEM = {LORA_BW_7810,   LORA_BW_10420, LORA_BW_15630, LORA_BW_20830,
+                                                LORA_BW_31250,  LORA_BW_41670, LORA_BW_62500, LORA_BW_125000,
+                                                LORA_BW_250000, LORA_BW_500000};
+static constexpr uint8_t BW_FSK[21] PROGMEM = {
+    FSK_BW_4800,   FSK_BW_5800,   FSK_BW_7300,   FSK_BW_9700,   FSK_BW_11700,  FSK_BW_14600,  FSK_BW_19500,
+    FSK_BW_23400,  FSK_BW_29300,  FSK_BW_39000,  FSK_BW_46900,  FSK_BW_58600,  FSK_BW_78200,  FSK_BW_93800,
+    FSK_BW_117300, FSK_BW_156200, FSK_BW_187200, FSK_BW_234300, FSK_BW_312000, FSK_BW_373600, FSK_BW_467000};
+
+// OCP (Over Current Protection) values
+static constexpr uint8_t OCP_80MA = 0x18;   // 80 mA max current
+static constexpr uint8_t OCP_140MA = 0x38;  // 140 mA max current
+
+// LoRa low data rate optimization threshold
+static constexpr float LOW_DATA_RATE_OPTIMIZE_THRESHOLD = 16.38f;  // 16.38 ms
+
+void SX126xCommands::read_opcode_(uint8_t opcode, uint8_t *data, uint8_t size) {
+  const uint8_t header[] = {opcode, 0};
+  this->spi_device_.read(header, {data, size});
+}
+
+void SX126xCommands::write_opcode_(uint8_t opcode, const uint8_t *data, uint8_t size) {
+  this->spi_device_.write({&opcode, 1}, {data, size});
+}
+
+void SX126xCommands::read_register_(uint16_t reg, uint8_t *data, uint8_t size) {
+  const uint8_t header[] = {RADIO_READ_REGISTER, static_cast<uint8_t>(reg >> 8), static_cast<uint8_t>(reg), 0};
+  this->spi_device_.read(header, {data, size});
+}
+
+void SX126xCommands::write_register_(uint16_t reg, const uint8_t *data, uint8_t size) {
+  const uint8_t header[] = {RADIO_WRITE_REGISTER, static_cast<uint8_t>(reg >> 8), static_cast<uint8_t>(reg)};
+  this->spi_device_.write(header, {data, size});
+}
+
+ConfigurationResult SX126xCommands::configure(const RadioProfile &profile, std::span<char, 16> version,
+                                              AppliedProfile &applied) {
+  applied.frequency = profile.frequency;
+  applied.payload_length = profile.payload_length;
+  applied.modulation = profile.modulation;
+  applied.rx_start = profile.rx_start;
+  encode_packet_params(profile, applied);
+  uint8_t buf[8];
+  // wakeup
+  this->read_opcode_(RADIO_GET_STATUS, nullptr, 0);
+
+  // config tcxo
+  if (profile.tcxo_voltage != TCXO_CTRL_NONE) {
+    uint32_t delay = profile.tcxo_delay >> 6;
+    buf[0] = profile.tcxo_voltage;
+    buf[1] = (delay >> 16) & 0xFF;
+    buf[2] = (delay >> 8) & 0xFF;
+    buf[3] = (delay >> 0) & 0xFF;
+    this->write_opcode_(RADIO_SET_TCXOMODE, buf, 4);
+    buf[0] = 0x7F;
+    this->write_opcode_(RADIO_CALIBRATE, buf, 1);
+  }
+
+  // clear errors
+  buf[0] = 0x00;
+  buf[1] = 0x00;
+  this->write_opcode_(RADIO_CLR_ERROR, buf, 2);
+
+  // rf switch
+  if (profile.rf_switch) {
+    buf[0] = 0x01;
+    this->write_opcode_(RADIO_SET_RFSWITCHMODE, buf, 1);
+  }
+
+  // check silicon version to make sure hw is ok
+  this->read_register_(REG_VERSION_STRING, reinterpret_cast<uint8_t *>(version.data()), version.size());
+  if (!this->spi_device_.ok()) {
+    return ConfigurationResult::CONFIGURATION_RESULT_BUSY_TIMEOUT;
+  }
+  version[version.size() - 1] = '\0';
+  if (strncmp(version.data(), "SX126", 5) != 0 && strncmp(version.data(), "LLCC68", 6) != 0) {
+    return ConfigurationResult::CONFIGURATION_RESULT_UNSUPPORTED;
+  }
+
+  // setup packet type
+  buf[0] = profile.modulation;
+  this->write_opcode_(RADIO_SET_PACKETTYPE, buf, 1);
+
+  // calibrate image
+  this->calibrate_image(profile.frequency);
+
+  // set frequency
+  uint64_t freq = ((uint64_t) profile.frequency << 25) / XTAL_FREQ;
+  buf[0] = (uint8_t) ((freq >> 24) & 0xFF);
+  buf[1] = (uint8_t) ((freq >> 16) & 0xFF);
+  buf[2] = (uint8_t) ((freq >> 8) & 0xFF);
+  buf[3] = (uint8_t) (freq & 0xFF);
+  this->write_opcode_(RADIO_SET_RFFREQUENCY, buf, 4);
+
+  // configure pa
+  int8_t pa_power = profile.pa_power;
+  if (profile.sx1261) {
+    // the following values were taken from section 13.1.14.1 table 13-21
+    // in rev 2.1 of the datasheet
+    if (pa_power == 15) {
+      uint8_t cfg[4] = {0x06, 0x00, 0x01, 0x01};
+      this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
+    } else {
+      uint8_t cfg[4] = {0x04, 0x00, 0x01, 0x01};
+      this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
+    }
+    pa_power = clamp(pa_power, (int8_t) -3, (int8_t) 14);
+    buf[0] = OCP_80MA;
+    this->write_register_(REG_OCP, buf, 1);
+  } else {
+    // the following values were taken from section 13.1.14.1 table 13-21
+    // in rev 2.1 of the datasheet
+    uint8_t cfg[4] = {0x04, 0x07, 0x00, 0x01};
+    this->write_opcode_(RADIO_SET_PACONFIG, cfg, 4);
+    pa_power = clamp(pa_power, (int8_t) -3, (int8_t) 22);
+    buf[0] = OCP_140MA;
+    this->write_register_(REG_OCP, buf, 1);
+  }
+  buf[0] = pa_power;
+  buf[1] = profile.pa_ramp;
+  this->write_opcode_(RADIO_SET_TXPARAMS, buf, 2);
+
+  // configure modem
+  if (profile.modulation == PACKET_TYPE_LORA) {
+    // set modulation params
+    float duration = 1000.0f * (1UL << profile.spreading_factor) / BW_HZ[profile.bandwidth];
+    buf[0] = profile.spreading_factor;
+    buf[1] = progmem_read_byte(&BW_LORA[profile.bandwidth - SX126X_BW_7810]);
+    buf[2] = profile.coding_rate;
+    buf[3] = (duration > LOW_DATA_RATE_OPTIMIZE_THRESHOLD) ? 0x01 : 0x00;
+    this->write_opcode_(RADIO_SET_MODULATIONPARAMS, buf, 4);
+
+    // set packet params and sync word
+    this->write_opcode_(RADIO_SET_PACKETPARAMS, applied.packet_params.data(), applied.packet_params_size);
+    if (profile.sync_size == 2) {
+      this->write_register_(REG_LORA_SYNCWORD, profile.sync_value.data(), profile.sync_size);
+    }
+  } else {
+    // set modulation params
+    uint32_t bitrate = ((uint64_t) XTAL_FREQ * 32) / profile.bitrate;
+    uint32_t fdev = ((uint64_t) profile.deviation << 25) / XTAL_FREQ;
+    buf[0] = (bitrate >> 16) & 0xFF;
+    buf[1] = (bitrate >> 8) & 0xFF;
+    buf[2] = (bitrate >> 0) & 0xFF;
+    buf[3] = profile.shaping;
+    buf[4] = progmem_read_byte(&BW_FSK[profile.bandwidth - SX126X_BW_4800]);
+    buf[5] = (fdev >> 16) & 0xFF;
+    buf[6] = (fdev >> 8) & 0xFF;
+    buf[7] = (fdev >> 0) & 0xFF;
+    this->write_opcode_(RADIO_SET_MODULATIONPARAMS, buf, 8);
+
+    // set crc params
+    if (profile.crc_enable) {
+      buf[0] = profile.crc_initial >> 8;
+      buf[1] = profile.crc_initial & 0xFF;
+      this->write_register_(REG_CRC_INITIAL, buf, 2);
+      buf[0] = profile.crc_polynomial >> 8;
+      buf[1] = profile.crc_polynomial & 0xFF;
+      this->write_register_(REG_CRC_POLYNOMIAL, buf, 2);
+    }
+
+    // set whitening params
+    if (profile.whitening_enable) {
+      // according to the datasheet, section 12 table 12-1 "The user should not
+      // change the value of the 7 MSB of this register"
+      this->read_register_(REG_WHITENING_INITIAL, buf, 1);
+      buf[0] = (buf[0] & 0xFE) | ((profile.whitening_initial >> 8) & 0x01);
+      buf[1] = profile.whitening_initial & 0xFF;
+      this->write_register_(REG_WHITENING_INITIAL, buf, 2);
+    }
+
+    // set packet params and sync word
+    this->write_opcode_(RADIO_SET_PACKETPARAMS, applied.packet_params.data(), applied.packet_params_size);
+    if (profile.sync_size != 0) {
+      this->write_register_(REG_GFSK_SYNCWORD, profile.sync_value.data(), profile.sync_size);
+    }
+  }
+
+  // switch to rx or sleep
+  if (profile.rx_start) {
+    this->receive();
+  } else {
+    this->sleep();
+  }
+  return this->spi_device_.ok() ? ConfigurationResult::CONFIGURATION_RESULT_OK
+                                : ConfigurationResult::CONFIGURATION_RESULT_BUSY_TIMEOUT;
+}
+
+void SX126xCommands::encode_packet_params(const RadioProfile &profile, AppliedProfile &applied) {
+  auto &buf = applied.packet_params;
+  const uint8_t payload_length = profile.max_packet_size();
+  if (profile.modulation == PACKET_TYPE_LORA) {
+    buf[0] = (profile.preamble_size >> 8) & 0xFF;
+    buf[1] = (profile.preamble_size >> 0) & 0xFF;
+    buf[2] = (profile.payload_length > 0) ? 0x01 : 0x00;
+    buf[3] = payload_length;
+    buf[4] = (profile.crc_enable) ? 0x01 : 0x00;
+    buf[5] = 0x00;
+    applied.packet_params_size = 6;
+  } else {
+    uint16_t preamble_size = profile.preamble_size * 8;
+    buf[0] = (preamble_size >> 8) & 0xFF;
+    buf[1] = (preamble_size >> 0) & 0xFF;
+    buf[2] = (profile.preamble_detect > 0) ? ((profile.preamble_detect - 1) | 0x04) : 0x00;
+    buf[3] = profile.sync_size * 8;
+    buf[4] = 0x00;
+    buf[5] = (profile.payload_length > 0) ? 0x00 : 0x01;
+    buf[6] = payload_length;
+    if (profile.crc_enable) {
+      buf[7] = (profile.crc_inverted ? 0x04 : 0x00) + (profile.crc_size & 0x02);
+    } else {
+      buf[7] = 0x01;
+    }
+    buf[8] = (profile.whitening_enable) ? 0x01 : 0x00;
+    applied.packet_params_size = 9;
+  }
+}
+
+void SX126xCommands::set_packet_length(AppliedProfile &applied, uint8_t length) {
+  applied.packet_params[applied.modulation == PACKET_TYPE_LORA ? 3 : 6] = length;
+  this->write_opcode_(RADIO_SET_PACKETPARAMS, applied.packet_params.data(), applied.packet_params_size);
+}
+
+void SX126xCommands::calibrate_image(uint32_t frequency) {
+  // the following values were taken from section 9.2.1 table 9-2
+  // in rev 2.1 of the datasheet
+  uint8_t buf[2] = {0, 0};
+  if (frequency > 900000000) {
+    buf[0] = 0xE1;
+    buf[1] = 0xE9;
+  } else if (frequency > 850000000) {
+    buf[0] = 0xD7;
+    buf[1] = 0xDB;
+  } else if (frequency > 770000000) {
+    buf[0] = 0xC1;
+    buf[1] = 0xC5;
+  } else if (frequency > 460000000) {
+    buf[0] = 0x75;
+    buf[1] = 0x81;
+  } else if (frequency > 425000000) {
+    buf[0] = 0x6B;
+    buf[1] = 0x6F;
+  }
+  if (buf[0] > 0 && buf[1] > 0) {
+    this->write_opcode_(RADIO_CALIBRATEIMAGE, buf, 2);
+  }
+}
+
+void SX126xCommands::receive() {
+  uint8_t buf[8];
+
+  // configure irq params
+  uint16_t irq = IRQ_RX_DONE | IRQ_RX_TX_TIMEOUT | IRQ_CRC_ERROR;
+  buf[0] = (irq >> 8) & 0xFF;
+  buf[1] = (irq >> 0) & 0xFF;
+  buf[2] = (irq >> 8) & 0xFF;
+  buf[3] = (irq >> 0) & 0xFF;
+  buf[4] = (IRQ_RADIO_NONE >> 8) & 0xFF;
+  buf[5] = (IRQ_RADIO_NONE >> 0) & 0xFF;
+  buf[6] = (IRQ_RADIO_NONE >> 8) & 0xFF;
+  buf[7] = (IRQ_RADIO_NONE >> 0) & 0xFF;
+  this->write_opcode_(RADIO_SET_DIOIRQPARAMS, buf, 8);
+
+  // set timeout to 0
+  buf[0] = 0x00;
+  this->write_opcode_(RADIO_SET_LORASYMBTIMEOUT, buf, 1);
+
+  // switch to continuous mode rx
+  buf[0] = 0xFF;
+  buf[1] = 0xFF;
+  buf[2] = 0xFF;
+  this->write_opcode_(RADIO_SET_RX, buf, 3);
+}
+
+void SX126xCommands::transmit(uint32_t timeout_ms) {
+  uint8_t buf[8];
+
+  // configure irq params
+  uint16_t irq = IRQ_TX_DONE | IRQ_RX_TX_TIMEOUT;
+  buf[0] = (irq >> 8) & 0xFF;
+  buf[1] = (irq >> 0) & 0xFF;
+  buf[2] = (irq >> 8) & 0xFF;
+  buf[3] = (irq >> 0) & 0xFF;
+  buf[4] = (IRQ_RADIO_NONE >> 8) & 0xFF;
+  buf[5] = (IRQ_RADIO_NONE >> 0) & 0xFF;
+  buf[6] = (IRQ_RADIO_NONE >> 8) & 0xFF;
+  buf[7] = (IRQ_RADIO_NONE >> 0) & 0xFF;
+  this->write_opcode_(RADIO_SET_DIOIRQPARAMS, buf, 8);
+
+  const uint32_t ticks = timeout_ms * 64;
+  buf[0] = ticks >> 16;
+  buf[1] = ticks >> 8;
+  buf[2] = ticks;
+  this->write_opcode_(RADIO_SET_TX, buf, 3);
+}
+
+void SX126xCommands::sleep(bool cold) {
+  // 0x04 = warm start (config retained), 0x00 = cold start (config lost, lowest power)
+  const uint8_t mode = cold ? 0x00 : 0x04;
+  this->write_opcode_(RADIO_SET_SLEEP, &mode, 1);
+}
+
+void SX126xCommands::standby(SX126xStandbyMode mode) {
+  const uint8_t value = mode;
+  this->write_opcode_(RADIO_SET_STANDBY, &value, 1);
+}
+
+uint32_t SX126xCommands::bandwidth_hz(SX126xBw bw) { return BW_HZ[bw]; }
+uint16_t SX126xCommands::ramp_us(uint8_t ramp) { return progmem_read_uint16(&RAMP[ramp]); }
+
+void SX126xCommands::clear_irqs(uint16_t mask) {
+  const uint8_t data[] = {static_cast<uint8_t>(mask >> 8), static_cast<uint8_t>(mask)};
+  this->write_opcode_(RADIO_CLR_IRQSTATUS, data, 2);
+}
+
+uint16_t SX126xCommands::read_irq() {
+  uint8_t data[2]{};
+  this->read_opcode_(RADIO_GET_IRQSTATUS, data, 2);
+  return (uint16_t(data[0]) << 8) | data[1];
+}
+
+void SX126xCommands::write_fifo(const uint8_t *data, size_t size) {
+  const uint8_t header[] = {RADIO_WRITE_BUFFER, 0};
+  this->spi_device_.write(header, {data, size});
+}
+
+void SX126xCommands::read_packet(uint8_t modulation, std::vector<uint8_t> &packet, float &rssi, float &snr) {
+  uint8_t data[3]{};
+  this->read_opcode_(RADIO_GET_PACKETSTATUS, data, 3);
+  rssi = (modulation == PACKET_TYPE_LORA ? data[0] : data[2]) / -2.0f;
+  // FSK packets report no SNR
+  snr = modulation == PACKET_TYPE_LORA ? static_cast<int8_t>(data[1]) / 4.0f : NAN;
+  this->read_opcode_(RADIO_GET_RXBUFFERSTATUS, data, 2);
+  if (!this->spi_device_.ok()) {
+    return;  // The length and offset were not read.
+  }
+  packet.resize(data[0]);
+  const uint8_t header[] = {RADIO_READ_BUFFER, data[1], 0};
+  this->spi_device_.read(header, packet);
+}
+
+}  // namespace esphome::sx126x
@@ -0,0 +1,49 @@
+#pragma once
+#include "radio_profile.h"
+#include "sx126x_spi_device.h"
+#include <vector>
+
+namespace esphome::sx126x {
+enum class ConfigurationResult {
+  CONFIGURATION_RESULT_OK,
+  CONFIGURATION_RESULT_BUSY_TIMEOUT,
+  CONFIGURATION_RESULT_UNSUPPORTED
+};
+
+// Encodes chip commands. No ESPHome lifecycle, callbacks, or raw SPI access.
+// Commands record failure in the SPI device: callers start a sequence with begin()
+// and check ok() at its end, or before acting on a value that was read.
+class SX126xCommands {
+ public:
+  SX126xCommands() = default;
+  SX126xCommands(const SX126xCommands &) = delete;
+  SX126xCommands &operator=(const SX126xCommands &) = delete;
+  SX126xSpiDevice &bus() { return this->spi_device_; }
+  // Fills applied as it goes; only use it if the result is OK.
+  [[nodiscard]] ConfigurationResult configure(const RadioProfile &profile, std::span<char, 16> version,
+                                              AppliedProfile &applied);
+  // Sets the payload length in the applied packet parameters and writes them.
+  void set_packet_length(AppliedProfile &applied, uint8_t length);
+  void calibrate_image(uint32_t frequency);
+  void standby(SX126xStandbyMode mode);
+  void receive();
+  void transmit(uint32_t timeout_ms = 0);
+  void sleep(bool cold = false);
+  void clear_irqs(uint16_t mask = 0xFFFF);
+  // Returns 0 if the read was skipped or failed.
+  uint16_t read_irq();
+  void write_fifo(const uint8_t *data, size_t size);
+  // Leaves the packet unchanged if a read fails.
+  void read_packet(uint8_t modulation, std::vector<uint8_t> &packet, float &rssi, float &snr);
+  static uint32_t bandwidth_hz(SX126xBw bw);
+  static uint16_t ramp_us(uint8_t ramp);
+
+ private:
+  void read_opcode_(uint8_t opcode, uint8_t *data, uint8_t size);
+  void write_opcode_(uint8_t opcode, const uint8_t *data, uint8_t size);
+  void read_register_(uint16_t reg, uint8_t *data, uint8_t size);
+  void write_register_(uint16_t reg, const uint8_t *data, uint8_t size);
+  static void encode_packet_params(const RadioProfile &profile, AppliedProfile &applied);
+  SX126xSpiDevice spi_device_;
+};
+}  // namespace esphome::sx126x
@@ -0,0 +1,253 @@
+#include "sx126x_radio.h"
+#include "esphome/core/log.h"
+#include <utility>
+
+namespace esphome::sx126x {
+
+// No ESP_LOG calls in this file: log listeners are user code, see sx126x_radio.h.
+
+static constexpr uint32_t RESET_DELAY_HIGH_US = 5000;
+static constexpr uint32_t RESET_DELAY_LOW_US = 2000;
+static constexpr uint32_t RECEIVE_RETRY_INTERVAL_MS = 200;
+
+RadioEffects SX126xRadio::comm_report(bool ok) {
+  RadioEffects effects;
+  effects.report = true;
+  effects.warning = ok ? nullptr : LOG_STR("Wait busy timeout");
+  return effects;
+}
+
+RadioEffects SX126xRadio::configure(const RadioProfile &requested, std::span<char, 16> version) {
+  ESPHOME_DEBUG_ASSERT(this->can_configure());
+  this->busy_ = true;
+  this->rx_retry_pending_ = false;
+  this->pending_irq_ = 0;
+  RadioEffects effects;
+  effects.report = true;
+  effects.warning = this->apply_configuration_(requested, version);
+  this->commit_(effects.warning == nullptr ? RadioState::RADIO_STATE_IDLE
+                                           : RadioState::RADIO_STATE_NEEDS_CONFIGURATION);
+  return effects;
+}
+
+const LogString *SX126xRadio::apply_configuration_(const RadioProfile &requested, std::span<char, 16> version) {
+  if (!requested.sync_valid) {
+    return LOG_STR("Invalid sync value");
+  }
+  this->rst_pin_->digital_write(true);
+  delayMicroseconds(RESET_DELAY_HIGH_US);
+  this->rst_pin_->digital_write(false);
+  delayMicroseconds(RESET_DELAY_LOW_US);
+  this->rst_pin_->digital_write(true);
+  delayMicroseconds(RESET_DELAY_HIGH_US);
+  this->bus().begin();
+  AppliedProfile applied;
+  switch (this->commands_.configure(requested, version, applied)) {
+    case ConfigurationResult::CONFIGURATION_RESULT_OK:
+      this->applied_ = applied;
+      return nullptr;
+    case ConfigurationResult::CONFIGURATION_RESULT_UNSUPPORTED:
+      return LOG_STR("Unsupported chip version");
+    default:
+      return LOG_STR("Wait busy timeout");
+  }
+}
+
+RadioEffects SX126xRadio::change_mode(ModeCommand command, uint8_t arg) {
+  ESPHOME_DEBUG_ASSERT(this->can_change_mode());
+  this->busy_ = true;
+  this->bus().begin();
+  switch (command) {
+    case ModeCommand::MODE_COMMAND_RX:
+      this->commands_.receive();
+      break;
+    case ModeCommand::MODE_COMMAND_TX:
+      this->commands_.transmit();
+      break;
+    case ModeCommand::MODE_COMMAND_STANDBY:
+      this->commands_.standby(static_cast<SX126xStandbyMode>(arg));
+      break;
+    case ModeCommand::MODE_COMMAND_SLEEP:
+    case ModeCommand::MODE_COMMAND_COLD_SLEEP:
+      this->commands_.sleep(command == ModeCommand::MODE_COMMAND_COLD_SLEEP);
+      break;
+    case ModeCommand::MODE_COMMAND_IMAGE_CAL:
+      this->commands_.calibrate_image(this->applied_.frequency);
+      break;
+  }
+  const bool ok = this->bus().ok();
+  // Cold sleep loses the configuration, and a failed command leaves the chip state unknown.
+  this->commit_(ok && command != ModeCommand::MODE_COMMAND_COLD_SLEEP ? RadioState::RADIO_STATE_IDLE
+                                                                      : RadioState::RADIO_STATE_NEEDS_CONFIGURATION);
+  return comm_report(ok);
+}
+
+RadioEffects SX126xRadio::start_transmit(SX126xTransmitListener *listener, const uint8_t *data, size_t len,
+                                         uint32_t timeout_ms) {
+  RadioEffects effects;
+  if (this->state_ == RadioState::RADIO_STATE_NEEDS_CONFIGURATION) {
+    effects.result = SX126xError::SX126X_ERROR_NOT_READY;
+    return effects;
+  }
+  if (this->busy_ || this->state_ != RadioState::RADIO_STATE_IDLE) {
+    effects.result = SX126xError::SX126X_ERROR_BUSY;
+    return effects;
+  }
+  const uint8_t fixed_length = this->applied_.payload_length;
+  if (data == nullptr || len == 0 || len > this->max_packet_size() || (fixed_length != 0 && len != fixed_length)) {
+    effects.result = SX126xError::SX126X_ERROR_INVALID_PARAMS;
+    return effects;
+  }
+  this->busy_ = true;
+  this->bus().begin();
+  this->commands_.standby(STDBY_XOSC);
+  // RX cannot advance in standby. Keep a packet that completed before standby intact for
+  // poll(), before clearing IRQs or overwriting the shared FIFO. A failed read returns 0.
+  // A packet that failed its CRC is not delivered, so it does not hold up the send.
+  const uint16_t irq = this->commands_.read_irq() | this->pending_irq_;
+  if ((irq & IRQ_RX_DONE) && !(irq & IRQ_CRC_ERROR)) {
+    this->commit_(RadioState::RADIO_STATE_HOLDING_RX);
+    effects.result = SX126xError::SX126X_ERROR_BUSY;
+    return effects;
+  }
+  this->commands_.clear_irqs();
+  this->pending_irq_ = 0;
+  if (fixed_length == 0) {
+    this->commands_.set_packet_length(this->applied_, len);
+  }
+  this->commands_.write_fifo(data, len);
+  this->commands_.transmit(timeout_ms);
+  if (!this->bus().ok()) {
+    const bool restored = this->restore_();
+    this->commit_(restored ? RadioState::RADIO_STATE_IDLE : RadioState::RADIO_STATE_NEEDS_CONFIGURATION);
+    effects = comm_report(restored);
+    effects.result = SX126xError::SX126X_ERROR_BUSY_TIMEOUT;
+    return effects;
+  }
+  this->tx_ = {listener, millis(), timeout_ms};
+  this->commit_(RadioState::RADIO_STATE_TRANSMITTING);
+  // No status report on success, so no user code runs before the caller has the result.
+  // The completion reports status instead.
+  return effects;
+}
+
+RadioEffects SX126xRadio::poll_transmit(uint32_t now) {
+  if (this->busy_ || !this->is_transmitting()) {
+    return {};
+  }
+  bool done = false;
+  SX126xError outcome = SX126xError::SX126X_ERROR_NONE;
+  if (this->dio1_pin_->digital_read()) {
+    this->busy_ = true;
+    this->bus().begin();
+    const uint16_t status = this->commands_.read_irq();
+    this->commands_.clear_irqs(status);
+    this->busy_ = false;
+    if (!this->bus().ok()) {
+      outcome = SX126xError::SX126X_ERROR_BUSY_TIMEOUT;
+      done = true;
+    } else if (status & IRQ_RX_TX_TIMEOUT) {
+      outcome = SX126xError::SX126X_ERROR_TIMEOUT;
+      done = true;
+    } else if (status & IRQ_TX_DONE) {
+      done = true;
+    }
+  }
+  // A cached loop tick can precede admission; signed subtraction also handles wraparound.
+  if (!done && static_cast<int32_t>(now - this->tx_.started_ms) >= static_cast<int32_t>(this->tx_.timeout_ms)) {
+    outcome = SX126xError::SX126X_ERROR_TIMEOUT;
+    done = true;
+  }
+  return done ? this->finish_transmit_(outcome) : RadioEffects{};
+}
+
+RadioEffects SX126xRadio::cancel_transmit(SX126xTransmitListener *listener) {
+  if (this->busy_ || !this->is_transmitting() || listener == nullptr || listener != this->tx_.listener) {
+    return {};
+  }
+  return this->finish_transmit_(SX126xError::SX126X_ERROR_CANCELLED);
+}
+
+// The only place a send ends.
+RadioEffects SX126xRadio::finish_transmit_(SX126xError result) {
+  this->busy_ = true;
+  const bool restored = this->restore_();
+  this->commit_(restored ? RadioState::RADIO_STATE_IDLE : RadioState::RADIO_STATE_NEEDS_CONFIGURATION);
+  RadioEffects effects = comm_report(restored);
+  effects.result = restored ? result : SX126xError::SX126X_ERROR_BUSY_TIMEOUT;
+  effects.listener = std::exchange(this->tx_.listener, nullptr);
+  effects.finished = true;
+  return effects;
+}
+
+bool SX126xRadio::restore_() {
+  this->bus().begin();
+  this->commands_.standby(STDBY_XOSC);
+  this->commands_.clear_irqs();
+  if (this->applied_.payload_length == 0) {
+    this->commands_.set_packet_length(this->applied_, this->max_packet_size());
+  }
+  if (this->applied_.rx_start) {
+    this->commands_.receive();
+  } else {
+    this->commands_.sleep();
+  }
+  return this->bus().ok();
+}
+
+RadioEffects SX126xRadio::poll(uint32_t now, std::vector<uint8_t> &packet) {
+  if (this->busy_) {
+    return {};
+  }
+  if (this->is_transmitting()) {
+    return this->poll_transmit(now);
+  }
+  RadioEffects effects;
+  if (this->state_ == RadioState::RADIO_STATE_NEEDS_CONFIGURATION) {
+    effects.sleep_loop = true;  // Polling cannot recover the radio; configure() can.
+    return effects;
+  }
+  if (this->rx_retry_pending_ && now - this->rx_retry_started_ms_ < RECEIVE_RETRY_INTERVAL_MS) {
+    return effects;
+  }
+  const bool holding = this->state_ == RadioState::RADIO_STATE_HOLDING_RX;
+  if (!holding && this->pending_irq_ == 0 && !this->dio1_pin_->digital_read()) {
+    effects.sleep_loop = this->dio1_pin_->is_internal();  // Its interrupt wakes the loop.
+    return effects;
+  }
+  return this->receive_(holding, now, packet);
+}
+
+RadioEffects SX126xRadio::receive_(bool holding, uint32_t now, std::vector<uint8_t> &packet) {
+  this->busy_ = true;
+  this->bus().begin();
+  // A packet whose read failed has had its flags cleared, so they are kept until it is read.
+  const uint16_t status = this->commands_.read_irq() | this->pending_irq_;
+  const bool received = (status & IRQ_RX_DONE) && !(status & IRQ_CRC_ERROR);
+  if (!holding) {
+    // Cleared before the read, so a packet that completes during the read raises DIO1 again.
+    // A held packet keeps its IRQ until restoration.
+    this->commands_.clear_irqs(status);
+  }
+  float rssi = 0, snr = 0;
+  if (received) {
+    this->commands_.read_packet(this->applied_.modulation, packet, rssi, snr);
+  }
+  const bool read = this->bus().ok();
+  this->pending_irq_ = read ? 0 : status;
+  // Do not spend a BUSY timeout on every loop while a read keeps failing.
+  this->rx_retry_pending_ = !read;
+  this->rx_retry_started_ms_ = now;
+  RadioState next = this->state_;
+  if (read && holding) {
+    next = this->restore_() ? RadioState::RADIO_STATE_IDLE : RadioState::RADIO_STATE_NEEDS_CONFIGURATION;
+  }
+  this->commit_(next);
+  RadioEffects effects = comm_report(read && next != RadioState::RADIO_STATE_NEEDS_CONFIGURATION);
+  effects.received = read && received;
+  effects.rssi = rssi;
+  effects.snr = snr;
+  return effects;
+}
+
+}  // namespace esphome::sx126x
@@ -0,0 +1,149 @@
+#pragma once
+
+#include "radio_profile.h"
+#include "sx126x_commands.h"
+#include "esphome/core/hal.h"
+#include "esphome/core/log.h"
+#include <span>
+#include <vector>
+
+namespace esphome::sx126x {
+
+enum class SX126xError {
+  SX126X_ERROR_NONE = 0,
+  SX126X_ERROR_TIMEOUT,
+  SX126X_ERROR_INVALID_PARAMS,
+  SX126X_ERROR_NOT_READY,
+  SX126X_ERROR_BUSY_TIMEOUT,
+  SX126X_ERROR_BUSY,
+  SX126X_ERROR_CANCELLED
+};
+
+class SX126xTransmitListener {
+ public:
+  virtual void on_transmit_complete(SX126xError result) = 0;
+};
+
+// Who may use the radio between operations. This is driver state, not the chip's mode.
+enum class RadioState : uint8_t {
+  // Startup, cold sleep, or a failed configuration, mode command or restoration. Only
+  // configure() is accepted; sends return NOT_READY and the loop sleeps. SX126x configures
+  // again every second after a failure, and on the next mode command after cold sleep.
+  RADIO_STATE_NEEDS_CONFIGURATION,
+  // Available. The chip is receiving or sleeping, as configured, or after the TX mode command
+  // sending whatever the FIFO holds. That send is not tracked: a send or mode command may cut
+  // it short, and poll() clears its TX_DONE as a flag without a packet.
+  RADIO_STATE_IDLE,
+  // A send is on air. SPI is free between polls; only polling and cancellation are accepted.
+  RADIO_STATE_TRANSMITTING,
+  // Standby with a received packet left in the FIFO, found when a send entered standby.
+  // The send was rejected with BUSY; the next poll() delivers the packet and restores the
+  // radio. configure() may discard it to recover from repeated read failures.
+  RADIO_STATE_HOLDING_RX,
+};
+
+enum class ModeCommand : uint8_t {
+  MODE_COMMAND_RX,
+  MODE_COMMAND_TX,
+  MODE_COMMAND_STANDBY,
+  MODE_COMMAND_SLEEP,
+  MODE_COMMAND_COLD_SLEEP,
+  MODE_COMMAND_IMAGE_CAL,
+};
+
+// What a radio operation leaves for its caller to do. The radio has already committed its
+// state; the caller reports status first, then calls the listener or delivers the packet.
+struct RadioEffects {
+  SX126xError result{SX126xError::SX126X_ERROR_NONE};
+  // The completion to notify when finished is set; null for a blocking send.
+  SX126xTransmitListener *listener{nullptr};
+  // With report set: the warning to set, or null to clear it.
+  const LogString *warning{nullptr};
+  float rssi{0};
+  float snr{0};
+  bool report{false};
+  // A send ended, and result is its outcome.
+  bool finished{false};
+  // The packet buffer holds a packet to deliver.
+  bool received{false};
+  // Nothing to poll until the next DIO1 edge or configuration.
+  bool sleep_loop{false};
+};
+
+// Owns the radio state and every SPI command sequence.
+//
+// Status reports, completions and packet listeners can run user code, which may call back
+// into the driver. Every operation therefore does its SPI work with busy() set, commits the
+// next state, and returns RadioEffects; SX126x::apply_() then reports status and calls the
+// listeners. This class has no access to component status or listeners, so callbacks only
+// ever see a committed state. Do not log here either: log listeners are user code. busy()
+// covers re-entry during a sequence, for example from a GPIO pin that logs.
+//
+// Each sequence starts with bus().begin(); after a BUSY timeout the rest is skipped and
+// bus().ok() is false. A failed send preparation restores the radio in a new sequence. A
+// failed restoration needs configuration, and its result overrides the send result. A
+// successful send start reports nothing, so no user code runs before the caller has the
+// result. Every send ends in finish_transmit_(), exactly once.
+//
+// A failed receive read keeps the packet and retries after RECEIVE_RETRY_INTERVAL_MS, so a
+// stuck BUSY line does not cost a 20 ms wait on every loop.
+class SX126xRadio {
+ public:
+  SX126xRadio() = default;
+  SX126xRadio(const SX126xRadio &) = delete;
+  SX126xRadio &operator=(const SX126xRadio &) = delete;
+  SX126xSpiDevice &bus() { return this->commands_.bus(); }
+  void set_dio1_pin(GPIOPin *pin) { this->dio1_pin_ = pin; }
+  void set_rst_pin(GPIOPin *pin) { this->rst_pin_ = pin; }
+  GPIOPin *get_dio1_pin() const { return this->dio1_pin_; }
+  GPIOPin *get_rst_pin() const { return this->rst_pin_; }
+  RadioState state() const { return this->state_; }
+  bool busy() const { return this->busy_; }
+  bool is_transmitting() const { return this->state_ == RadioState::RADIO_STATE_TRANSMITTING; }
+  // A held packet may be discarded: explicit reconfiguration is the recovery path.
+  bool can_configure() const { return !this->busy_ && !this->is_transmitting(); }
+  bool can_change_mode() const { return !this->busy_ && this->state_ == RadioState::RADIO_STATE_IDLE; }
+  size_t max_packet_size() const { return this->applied_.max_packet_size(); }
+
+  // Requires can_configure(). Resets the chip and applies the requested profile.
+  RadioEffects configure(const RadioProfile &requested, std::span<char, 16> version);
+  // Requires can_change_mode(). Cold sleep and failed commands need configuration afterwards.
+  RadioEffects change_mode(ModeCommand command, uint8_t arg);
+  // Result SX126X_ERROR_NONE starts a send that finishes exactly once, through poll_transmit() or
+  // cancel_transmit(). Any other result owes no completion.
+  RadioEffects start_transmit(SX126xTransmitListener *listener, const uint8_t *data, size_t len, uint32_t timeout_ms);
+  // Sets finished only when it ended the current send.
+  RadioEffects poll_transmit(uint32_t now);
+  // Sets finished only if listener owns the current send.
+  RadioEffects cancel_transmit(SX126xTransmitListener *listener);
+  // One loop step: polls a send, or reads a received packet into packet.
+  RadioEffects poll(uint32_t now, std::vector<uint8_t> &packet);
+
+ private:
+  struct TxOperation {
+    SX126xTransmitListener *listener{nullptr};
+    uint32_t started_ms{0};
+    uint32_t timeout_ms{0};
+  };
+  void commit_(RadioState state) {
+    this->state_ = state;
+    this->busy_ = false;
+  }
+  static RadioEffects comm_report(bool ok);
+  const LogString *apply_configuration_(const RadioProfile &requested, std::span<char, 16> version);
+  bool restore_();
+  RadioEffects finish_transmit_(SX126xError result);
+  RadioEffects receive_(bool holding, uint32_t now, std::vector<uint8_t> &packet);
+  SX126xCommands commands_;
+  AppliedProfile applied_;
+  TxOperation tx_;
+  uint32_t rx_retry_started_ms_{0};
+  uint16_t pending_irq_{0};  // flags of a received packet whose read failed after they were cleared
+  GPIOPin *dio1_pin_{nullptr};
+  GPIOPin *rst_pin_{nullptr};
+  RadioState state_{RadioState::RADIO_STATE_NEEDS_CONFIGURATION};
+  bool busy_{false};
+  bool rx_retry_pending_{false};
+};
+
+}  // namespace esphome::sx126x
@@ -0,0 +1,45 @@
+#include "sx126x_spi_device.h"
+#include "esphome/core/hal.h"
+
+namespace esphome::sx126x {
+
+static constexpr uint32_t BUSY_TIMEOUT_MS = 20;
+static constexpr uint32_t SWITCHING_DELAY_US = 1;
+
+void SX126xSpiDevice::exchange_(std::span<const uint8_t> header, std::span<const uint8_t> tx, std::span<uint8_t> rx) {
+  if (!this->ok_) {
+    return;
+  }
+  // Selecting first wakes a sleeping radio. The guard releases CS even on timeout.
+  Selection selected(this->device_);
+  const uint32_t start = millis();
+  while (this->busy_pin_->digital_read()) {
+    if (millis() - start > BUSY_TIMEOUT_MS) {
+      this->ok_ = false;
+      return;
+    }
+  }
+  for (auto byte : header) {
+    this->device_.transfer_byte(byte);
+  }
+  for (auto byte : tx) {
+    this->device_.transfer_byte(byte);
+  }
+  for (auto &byte : rx) {
+    byte = this->device_.transfer_byte(0);
+  }
+}
+
+void SX126xSpiDevice::write(std::span<const uint8_t> header, std::span<const uint8_t> data) {
+  this->exchange_(header, data, {});
+  if (this->ok_) {
+    // This delay belongs after CS is released, not in the selected interval.
+    delayMicroseconds(SWITCHING_DELAY_US);
+  }
+}
+
+void SX126xSpiDevice::read(std::span<const uint8_t> header, std::span<uint8_t> data) {
+  this->exchange_(header, {}, data);
+}
+
+}  // namespace esphome::sx126x
@@ -0,0 +1,63 @@
+#pragma once
+
+#include "esphome/components/spi/spi.h"
+#include <span>
+
+namespace esphome::sx126x {
+
+// Persistent radio device. read()/write() use exchange_() for one complete selected interval.
+// No raw SPI access escapes. Call only from the main loop; spans are borrowed until return.
+// Failures stick: after a BUSY timeout every exchange is skipped until the next begin(),
+// so a command sequence checks ok() once instead of after every command.
+class SX126xSpiDevice {
+ public:
+  SX126xSpiDevice() = default;
+  SX126xSpiDevice(const SX126xSpiDevice &) = delete;
+  SX126xSpiDevice &operator=(const SX126xSpiDevice &) = delete;
+  void set_spi_parent(spi::SPIComponent *parent) { this->device_.set_spi_parent(parent); }
+  void set_cs_pin(GPIOPin *pin) { this->device_.set_cs_pin(pin); }
+  void set_data_rate(uint32_t rate) { this->device_.set_data_rate(rate); }
+  void set_mode(spi::SPIMode mode) { this->device_.set_mode(mode); }
+  void set_bit_order(spi::SPIBitOrder order) { this->device_.set_bit_order(order); }
+  void set_release_device(bool release) { this->device_.set_release_device(release); }
+  void set_write_only(bool write_only) { this->device_.set_write_only(write_only); }
+#ifdef USE_SPI_PSRAM_DMA
+  void set_psram_dma(bool enable) { this->device_.set_psram_dma(enable); }
+#endif
+
+  void set_busy_pin(GPIOPin *pin) { this->busy_pin_ = pin; }
+  GPIOPin *get_busy_pin() const { return this->busy_pin_; }
+  GPIOPin *get_cs_pin() const { return this->device_.get_cs_pin(); }
+  void setup() { this->device_.spi_setup(); }
+  void teardown() { this->device_.spi_teardown(); }
+  // Starts a command sequence with no recorded failure.
+  void begin() { this->ok_ = true; }
+  // False once any exchange since begin() timed out waiting for BUSY.
+  bool ok() const { return this->ok_; }
+  void write(std::span<const uint8_t> header, std::span<const uint8_t> data);
+  // Leaves data unchanged when the exchange is skipped or times out.
+  void read(std::span<const uint8_t> header, std::span<uint8_t> data);
+
+ private:
+  class Device final : public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW,
+                                             spi::CLOCK_PHASE_LEADING, spi::DATA_RATE_8MHZ> {
+   public:
+    GPIOPin *get_cs_pin() const { return this->cs_; }
+  };
+  class Selection {
+   public:
+    explicit Selection(Device &device) : device_(device) { this->device_.enable(); }
+    ~Selection() { this->device_.disable(); }
+    Selection(const Selection &) = delete;
+    Selection &operator=(const Selection &) = delete;
+
+   private:
+    Device &device_;
+  };
+  void exchange_(std::span<const uint8_t> header, std::span<const uint8_t> tx, std::span<uint8_t> rx);
+  Device device_;
+  GPIOPin *busy_pin_{nullptr};
+  bool ok_{true};
+};
+
+}  // namespace esphome::sx126x
@@ -5,13 +5,15 @@ from esphome.const import CONF_MODEL
 from esphome.types import ConfigType

 AUTO_LOAD = ["climate_ir"]
-CODEOWNERS = ["@glmnet", "@arpena"]
+CODEOWNERS = ["@glmnet", "@arpena", "@Rodrigoah"]

 whirlpool_ns = cg.esphome_ns.namespace("whirlpool")
 WhirlpoolClimate = whirlpool_ns.class_("WhirlpoolClimate", climate_ir.ClimateIR)

 Model = whirlpool_ns.enum("Model")
-MODELS = Model.options("DG11J1-3A", "DG11J1-91", "HISENSE_ARG", prefix="MODEL_")
+MODELS = Model.options(
+    "DG11J1-3A", "DG11J1-91", "HISENSE_ARG", "HITACHI_HCRA31NEWH", prefix="MODEL_"
+)

 CONFIG_SCHEMA = climate_ir.climate_ir_with_receiver_schema(WhirlpoolClimate).extend(
    {
@@ -26,3 +28,5 @@ async def to_code(config: ConfigType) -> None:
    # cv.enum keeps the YAML key as a str subclass; the MockObj value cannot be compared
    if config[CONF_MODEL] == "HISENSE_ARG":
        cg.add_define("USE_WHIRLPOOL_HISENSE_ARG")
+    elif config[CONF_MODEL] == "HITACHI_HCRA31NEWH":
+        cg.add_define("USE_WHIRLPOOL_HITACHI_HCRA31NEWH")
@@ -2,6 +2,8 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"

+#include <algorithm>
+
 namespace esphome::whirlpool {

 ESPHOME_LOG_TAG(TAG, "whirlpool.climate");
@@ -44,6 +46,17 @@ static constexpr uint8_t HISENSE_ARG_POWER_TOGGLE = 0x01;   // byte 15
 static constexpr uint8_t HISENSE_ARG_SETTINGS_ONLY = 0x02;  // byte 15
 static constexpr uint8_t HISENSE_ARG_FIXED_TEMP_STEP = 7;   // auto and fan-only send 23 C

+// Hitachi HCRA31NEWH model: power is a state in every frame
+static constexpr uint8_t HITACHI_BYTE10 = 0x20;      // byte 10
+static constexpr uint8_t HITACHI_COOL = 0x02;        // byte 15
+static constexpr uint8_t HITACHI_OFF = 0x01;         // byte 15
+static constexpr uint8_t HITACHI_BYTE18_ON = 0x38;   // byte 18
+static constexpr uint8_t HITACHI_BYTE18_OFF = 0x28;  // byte 18
+static constexpr uint8_t HITACHI_BYTE19 = 0x08;      // byte 19
+
+// Header, 21 bytes of 8 bits, two dividers and the footer mark
+static constexpr uint32_t WHIRLPOOL_FRAME_TIMINGS = 2 + WHIRLPOOL_STATE_LENGTH * 16 + 2 * 2 + 1;
+
 WhirlpoolClimate::WhirlpoolClimate()
    : climate_ir::ClimateIR(
          WHIRLPOOL_DG11J1_3A_TEMP_MIN, WHIRLPOOL_DG11J1_3A_TEMP_MAX, 1.0f, true, true,
@@ -55,19 +68,19 @@ void WhirlpoolClimate::transmit_state() {
  this->last_transmit_time_ = millis();  // setting the time of the last transmission.
  uint8_t remote_state[WHIRLPOOL_STATE_LENGTH];
  memset(remote_state, 0, sizeof(remote_state));
-  remote_state[0] = 0x83;
-  remote_state[1] = 0x06;
+  put_be16(remote_state, this->remote_id_());
  remote_state[6] = 0x80;
-  remote_state[18] = 0x08;  // the same on every supported model
+  remote_state[18] = 0x08;

-  auto powered_on = this->mode != climate::CLIMATE_MODE_OFF;
-  const bool power_toggle = powered_on != this->powered_on_assumed;
+  const bool powered_on = this->mode != climate::CLIMATE_MODE_OFF;
+  // Hitachi sends power as a state instead of a toggle
+  const bool power_toggle = !this->is_hitachi_hcra31newh_() && powered_on != this->powered_on_assumed;
  if (power_toggle) {
    // Set power toggle command
    remote_state[2] = 4;
    remote_state[15] = 1;
-    this->powered_on_assumed = powered_on;
  }
+  this->powered_on_assumed = powered_on;
  switch (this->mode) {
    case climate::CLIMATE_MODE_HEAT_COOL:
      // set fan auto
@@ -93,6 +106,10 @@ void WhirlpoolClimate::transmit_state() {
      remote_state[15] = 6;
      break;
    case climate::CLIMATE_MODE_OFF:
+      // These remotes keep the cool code in the power-off frame
+      if (this->is_hisense_arg_() || this->is_hitachi_hcra31newh_())
+        remote_state[3] = WHIRLPOOL_COOL;
+      break;
    default:
      break;
  }
@@ -102,6 +119,7 @@ void WhirlpoolClimate::transmit_state() {
  // Temperature
  auto temp = (uint8_t) roundf(clamp(this->target_temperature, this->temperature_min_(), this->temperature_max_()));
  const auto temp_step = (uint8_t) (temp - this->temperature_min_());
+  this->target_temperature = temp;  // publish what the unit was sent
  if (hisense_arg && this->fixed_temp_mode_()) {
    remote_state[3] |= HISENSE_ARG_FIXED_TEMP_STEP << 4;
  } else {
@@ -131,7 +149,6 @@ void WhirlpoolClimate::transmit_state() {
      remote_state[2] |= WHIRLPOOL_SWING_MASK;
      remote_state[8] = WHIRLPOOL_SWING_BYTE8;
    }
-    this->encode_hisense_arg_(remote_state, power_toggle, temp_step);
  } else if (this->send_swing_cmd_) {
    if (this->swing_mode == climate::CLIMATE_SWING_VERTICAL || this->swing_mode == climate::CLIMATE_SWING_OFF) {
      remote_state[2] |= WHIRLPOOL_SWING_MASK;
@@ -139,6 +156,11 @@ void WhirlpoolClimate::transmit_state() {
    }
  }

+  if (hisense_arg)
+    this->encode_hisense_arg_(remote_state, power_toggle, temp_step);
+  if (this->is_hitachi_hcra31newh_())
+    this->encode_hitachi_hcra31newh_(remote_state);
+
  // Checksum
  remote_state[13] = xor_bytes(&remote_state[2], 11, remote_state[13]);
  remote_state[20] = xor_bytes(&remote_state[14], 6, remote_state[20]);
@@ -148,6 +170,7 @@ void WhirlpoolClimate::transmit_state() {
  // Send code
  auto transmit = this->transmitter_->transmit();
  auto *data = transmit.get_data();
+  data->reserve(WHIRLPOOL_FRAME_TIMINGS);

  data->set_carrier_frequency(38000);

@@ -180,10 +203,6 @@ void WhirlpoolClimate::encode_hisense_arg_(uint8_t *remote_state, bool power_tog
  remote_state[15] = power_toggle ? HISENSE_ARG_POWER_TOGGLE : HISENSE_ARG_SETTINGS_ONLY;

  switch (this->mode) {
-    case climate::CLIMATE_MODE_OFF:
-      // The remote keeps the cool code in the power-off frame
-      remote_state[3] = (remote_state[3] & 0xF0) | WHIRLPOOL_COOL;
-      break;
    case climate::CLIMATE_MODE_DRY:
      // The unit runs these fan speeds itself; the user's choice is kept for the next mode change
      remote_state[2] &= ~WHIRLPOOL_FAN_MASK;
@@ -212,6 +231,27 @@ void WhirlpoolClimate::encode_hisense_arg_(uint8_t *remote_state, bool power_tog
 #endif
 }

+void WhirlpoolClimate::encode_hitachi_hcra31newh_(uint8_t *remote_state) const {
+#ifdef USE_WHIRLPOOL_HITACHI_HCRA31NEWH
+  remote_state[10] = HITACHI_BYTE10;
+  remote_state[18] = HITACHI_BYTE18_ON;
+  remote_state[19] = HITACHI_BYTE19;
+  // The unit takes the whole state from every frame: only the off frame carries the power bit
+  switch (this->mode) {
+    case climate::CLIMATE_MODE_COOL:
+      remote_state[15] = HITACHI_COOL;
+      break;
+    case climate::CLIMATE_MODE_OFF:
+      remote_state[2] |= WHIRLPOOL_POWER;
+      remote_state[15] = HITACHI_OFF;
+      remote_state[18] = HITACHI_BYTE18_OFF;
+      break;
+    default:
+      break;
+  }
+#endif
+}
+
 bool WhirlpoolClimate::on_receive(remote_base::RemoteReceiveData data) {
  // Check if the esp isn't currently transmitting.
  if (millis() - this->last_transmit_time_ < 500) {
@@ -234,7 +274,8 @@ bool WhirlpoolClimate::on_receive(remote_base::RemoteReceiveData data) {
      if (!data.expect_item(WHIRLPOOL_BIT_MARK, WHIRLPOOL_GAP))
        return false;
    }
-    if (i == WHIRLPOOL_SECOND_DIVIDER && !data.is_valid()) {
+    // The Hitachi remote always sends all 21 bytes; byte 18 holds its power state
+    if (i == WHIRLPOOL_SECOND_DIVIDER && !data.is_valid() && !this->is_hitachi_hcra31newh_()) {
      // Remote control only sent 14 bytes, nothing more to read, not even the footer
      ESP_LOGV(TAG, "Remote control only sent %d bytes", i);
      skip_footer = true;
@@ -261,13 +302,18 @@ bool WhirlpoolClimate::on_receive(remote_base::RemoteReceiveData data) {
  ESP_LOGV_HEX(TAG, remote_state, WHIRLPOOL_STATE_LENGTH, WHIRLPOOL_STATE_LENGTH, "Received: %s");

  // verify header remote code
-  if (remote_state[0] != 0x83 || remote_state[1] != 0x06)
+  if (encode_uint16(remote_state[0], remote_state[1]) != this->remote_id_())
    return false;

  // powr on/off button
  ESP_LOGV(TAG, "Power: %02X", (remote_state[2] & WHIRLPOOL_POWER));

-  if ((remote_state[2] & WHIRLPOOL_POWER) == WHIRLPOOL_POWER) {
+  if (this->is_hitachi_hcra31newh_()) {
+    // Power is a state: byte 18 says whether the unit is off
+    this->powered_on_assumed = remote_state[18] != HITACHI_BYTE18_OFF;
+    if (!this->powered_on_assumed)
+      this->mode = climate::CLIMATE_MODE_OFF;
+  } else if ((remote_state[2] & WHIRLPOOL_POWER) == WHIRLPOOL_POWER) {
    auto powered_on = this->mode != climate::CLIMATE_MODE_OFF;

    if (powered_on) {
@@ -309,7 +355,7 @@ bool WhirlpoolClimate::on_receive(remote_base::RemoteReceiveData data) {
    int temp = remote_state[3] & 0xF0;
    ESP_LOGVV(TAG, "Temperature Raw: %02X", temp);
    temp = (uint8_t) temp >> 4;
-    temp += static_cast<int>(this->temperature_min_());
+    temp = std::min(temp + static_cast<int>(this->temperature_min_()), static_cast<int>(this->temperature_max_()));
    ESP_LOGVV(TAG, "Temperature Climate: %u", temp);
    this->target_temperature = temp;
  }
@@ -6,9 +6,10 @@ namespace esphome::whirlpool {

 /// Simple enum to represent models.
 enum Model {
-  MODEL_DG11J1_3A = 0,    /// Temperature range is from 18 to 32
-  MODEL_DG11J1_91 = 1,    /// Temperature range is from 16 to 30
-  MODEL_HISENSE_ARG = 2,  /// Hisense/BGH (Argentina), 16 to 30
+  MODEL_DG11J1_3A = 0,           /// Temperature range is from 18 to 32
+  MODEL_DG11J1_91 = 1,           /// Temperature range is from 16 to 30
+  MODEL_HISENSE_ARG = 2,         /// Hisense/BGH (Argentina), 16 to 30
+  MODEL_HITACHI_HCRA31NEWH = 3,  /// Hitachi with the HCRA31NEWH remote, 16 to 30
 };

 // Temperature
@@ -29,7 +30,9 @@ class WhirlpoolClimate final : public climate_ir::ClimateIR {

  /// Override control to change settings of the climate device.
  void control(const climate::ClimateCall &call) override {
-    send_swing_cmd_ = call.get_swing_mode().has_value();
+    // The toggle remotes flip swing on every press, so only send one when the mode really changes
+    auto swing = call.get_swing_mode();
+    this->send_swing_cmd_ = swing.has_value() && *swing != this->swing_mode;
    climate_ir::ClimateIR::control(call);
  }

@@ -55,10 +58,22 @@ class WhirlpoolClimate final : public climate_ir::ClimateIR {
    return false;
 #endif
  }
+  /// False when the model is compiled out, so the compiler drops the Hitachi branches.
+  bool is_hitachi_hcra31newh_() const {
+#ifdef USE_WHIRLPOOL_HITACHI_HCRA31NEWH
+    return this->model_ == MODEL_HITACHI_HCRA31NEWH;
+#else
+    return false;
+#endif
+  }
+  /// The remote ID sent in bytes 0 and 1.
+  uint16_t remote_id_() const { return this->is_hitachi_hcra31newh_() ? 0xA959 : 0x8306; }
  /// Modes in which the Hisense ARG model sends a fixed temperature.
  bool fixed_temp_mode_() const;
  /// Add the Hisense ARG bytes on top of the common whirlpool frame.
  void encode_hisense_arg_(uint8_t *remote_state, bool power_toggle, uint8_t temp_step) const;
+  /// Add the Hitachi HCRA31NEWH bytes on top of the common whirlpool frame.
+  void encode_hitachi_hcra31newh_(uint8_t *remote_state) const;
  /// Set the time of the last transmission.
  uint32_t last_transmit_time_{};

@@ -563,7 +563,7 @@ class WiFiComponent final : public Component {
  // (In most use cases you won't need these)
  /// Setup WiFi interface.
  void setup() override;
-#if defined(USE_LN882X) || defined(USE_BK72XX)
+#if defined(USE_ESP32) || defined(USE_LN882X) || defined(USE_BK72XX)
  void on_powerdown() override;
 #endif
  void start();
@@ -1635,6 +1635,21 @@ bool WiFiComponent::wifi_dpp_start_listen_() {
 void WiFiComponent::wifi_dpp_stop_listen_() { esp_supp_dpp_stop_listen(); }
 #endif

+void WiFiComponent::on_powerdown() {
+  // Leave the AP before esp_restart() or deep sleep stops Wi-Fi. esp_wifi_stop() while associated
+  // makes the ESP32 retransmit its Disassociation up to the retry limit although the AP ACKs it
+  // (32 copies with protected management frames), which some APs handle badly.
+  // Upstream bug: https://github.com/espressif/esp-idf/issues/19443 - remove this once it is fixed
+  // in the ESP-IDF versions we support.
+  // Ask the driver: s_sta_connected lags until the main loop has handled the connect event.
+  wifi_ap_record_t ap_info;
+  if (esp_wifi_sta_get_ap_info(&ap_info) != ESP_OK)
+    return;
+  ESP_LOGD(TAG, "Disconnecting before powerdown");
+  esp_wifi_disconnect();
+  delay(100);  // NOLINT: once per reboot or deep sleep, lets the disassociation go out
+}
+
 bool WiFiComponent::wifi_disconnect_() { return esp_wifi_disconnect(); }

 bssid_t WiFiComponent::wifi_bssid() {
@@ -294,6 +294,8 @@ void Application::reboot() {
  for (auto &component : std::ranges::reverse_view(this->components_)) {
    component->on_shutdown();
  }
+  // No teardown on a forced reboot, but still power hardware down (Wi-Fi leaves the AP)
+  this->run_powerdown_hooks();
  arch_restart();
 }
 void Application::safe_reboot() {
@@ -185,10 +185,12 @@ class Component {
   */
  virtual bool teardown() { return true; }

-  /** Called after teardown is complete to power down hardware.
+  /** Called last before a reboot or deep sleep to power down hardware.
   *
-   * This is called after all components have finished their teardown process,
+   * On a safe shutdown this is called after all components have finished their teardown process,
   * making it safe to power down hardware like ethernet PHY.
+   * On a forced reboot (Application::reboot()) it is called right after on_shutdown() with no
+   * teardown, so implementations must not assume teardown() has run.
   */
  virtual void on_powerdown() {}

@@ -70,6 +70,7 @@
 #define USE_BUTTON
 #define USE_CAMERA
 #define USE_CANBUS_FD
+#define USE_CC1101_LONG_PACKET
 #define USE_CLIMATE
 #define USE_CLIMATE_VISUAL_OVERRIDES
 #define USE_CONTROLLER_REGISTRY
@@ -387,6 +388,7 @@
 #define USE_WATER_HEATER
 #define USE_WATER_HEATER_VISUAL_OVERRIDES
 #define USE_WHIRLPOOL_HISENSE_ARG
+#define USE_WHIRLPOOL_HITACHI_HCRA31NEWH
 #define USE_ZWAVE_PROXY

 // Feature flags which do not work for zephyr
@@ -1428,8 +1428,9 @@ def lint_no_std_bind(fname, match):
 )
 def lint_no_std_nothrow(fname, match):
    return (
-        f"Use {highlight('RAMAllocator')} from esphome/core/helpers.h instead of {highlight('new (std::nothrow)')}; "
-        f"it returns nullptr on failure on every platform and can choose PSRAM or internal RAM.\n"
+        f"{highlight('new (std::nothrow)')} aborts on ESP-IDF when the allocation fails, exceptions are disabled "
+        f"there, so it never returns nullptr.\n"
+        f"Please use {highlight('RAMAllocator')} from esphome/core/helpers.h, which does.\n"
        f"  Before: {highlight('auto *buf = new (std::nothrow) uint8_t[n];')}\n"
        f"  After:  {highlight('auto buf = RAMAllocator<uint8_t>().make_unique_array_for_overwrite(n);')}\n"
        f"For one object use {highlight('RAMAllocator<T>().make_unique(args...)')}; both return empty on failure.\n"
@@ -25,6 +25,9 @@ CORE_BENCHMARKS_DIR: Path = Path(root_path) / "tests" / "benchmarks" / "core"
 # allow benchmarks to compile on the host platform.
 STUBS_DIR: Path = Path(root_path) / "tests" / "benchmarks" / "stubs"

+# Shared test doubles, reached by -I so only the benchmarks that include them pull in their headers
+HELPERS_DIR: Path = Path(root_path) / "tests" / "benchmarks" / "helpers"
+
 BUILD_FLAGS = [
    "-Os",  # match firmware optimization level (detects inlining regressions)
    "-g",  # debug symbols for profiling
@@ -32,6 +35,7 @@ BUILD_FLAGS = [
    "-fdata-sections",  # required for dead-code stripping with -Os
    "-DUSE_BENCHMARK",  # disable WarnIfComponentBlockingGuard in finish()
    f"-I{STUBS_DIR}",  # stub headers for ESP32-only components
+    f"-I{HELPERS_DIR}",  # shared test doubles such as fake_uart.h
 ]


@@ -0,0 +1,76 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/components/binary_sensor/binary_sensor.h"
+#include "esphome/components/ld2450/ld2450.h"
+#include "esphome/components/sensor/sensor.h"
+#include "fake_uart.h"
+
+namespace esphome::ld2450::benchmarks {
+
+using esphome::benchmarks::FakeUART;
+
+// Inner iteration count to amortize CodSpeed instrumentation overhead.
+static constexpr int kInnerIterations = 2000;
+static constexpr size_t FRAME_SIZE = 30;
+
+// Periodic frames with one moving target at two positions
+static constexpr uint8_t FRAME_A[FRAME_SIZE] = {0xAA, 0xFF, 0x03, 0x00, 0x0E, 0x03, 0xB1, 0x86, 0x10, 0x00,
+                                                0x40, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xCC};
+static constexpr uint8_t FRAME_B[FRAME_SIZE] = {0xAA, 0xFF, 0x03, 0x00, 0x2A, 0x03, 0xC8, 0x86, 0x10, 0x00,
+                                                0x40, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xCC};
+
+// --- loop() parsing one periodic frame, no entities attached ---
+
+static void LD2450_PeriodicFrame(benchmark::State &state) {
+  FakeUART uart;
+  LD2450Component radar;
+  radar.set_uart_parent(&uart);
+  radar.set_link_timeout(60000);
+  // Bring the link up outside the timed loop
+  uart.load(FRAME_A, FRAME_SIZE);
+  radar.loop();
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uart.load(FRAME_A, FRAME_SIZE);
+      radar.loop();
+    }
+    benchmark::DoNotOptimize(uart.available());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(LD2450_PeriodicFrame);
+
+// --- loop() parsing a moving target and publishing its sensors ---
+
+static void LD2450_PeriodicFrameSensors(benchmark::State &state) {
+  FakeUART uart;
+  LD2450Component radar;
+  radar.set_uart_parent(&uart);
+  radar.set_link_timeout(60000);
+  sensor::Sensor x, y, speed, distance, angle, count;
+  binary_sensor::BinarySensor presence;
+  radar.set_move_x_sensor(0, &x);
+  radar.set_move_y_sensor(0, &y);
+  radar.set_move_speed_sensor(0, &speed);
+  radar.set_move_distance_sensor(0, &distance);
+  radar.set_move_angle_sensor(0, &angle);
+  radar.set_target_count_sensor(&count);
+  radar.set_target_binary_sensor(&presence);
+  uart.load(FRAME_A, FRAME_SIZE);
+  radar.loop();
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uart.load((i & 1) ? FRAME_B : FRAME_A, FRAME_SIZE);
+      radar.loop();
+    }
+    benchmark::DoNotOptimize(x.state);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(LD2450_PeriodicFrameSensors);
+
+}  // namespace esphome::ld2450::benchmarks
@@ -0,0 +1,2 @@
+sensor:
+binary_sensor:
@@ -0,0 +1,67 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/components/modbus/modbus.h"
+#include "esphome/core/helpers.h"
+#include "fake_uart.h"
+
+namespace esphome::modbus::benchmarks {
+
+using esphome::benchmarks::FakeUART;
+
+// Inner iteration count to amortize CodSpeed instrumentation overhead.
+static constexpr int kInnerIterations = 2000;
+
+static constexpr uint8_t ADDRESS = 1;
+static constexpr uint8_t REGISTER_COUNT = 10;
+// Read 10 holding registers from address 0, as an energy meter poll does
+static constexpr uint8_t REQUEST_PDU[] = {0x03, 0x00, 0x00, 0x00, REGISTER_COUNT};
+// Address + function + byte count + 20 data bytes + CRC
+static constexpr size_t RESPONSE_SIZE = 3 + REGISTER_COUNT * 2 + 2;
+
+class SumDevice : public ModbusClientDevice {
+ public:
+  using ModbusClientDevice::ModbusClientDevice;
+  void on_read_holding_registers(uint16_t start_address, std::span<const uint16_t> registers,
+                                 ResponseStatus status) override {
+    for (uint16_t value : registers)
+      this->sum += value;
+  }
+  uint32_t sum{0};
+};
+
+class NoDelayHub : public ModbusClientHub {
+ protected:
+  // No wait before a send, so every loop() can send the next poll
+  int32_t tx_delay_remaining() override { return 0; }
+};
+
+// --- One continuous poll cycle per loop(): receive and CRC check the response, decode it, requeue and resend ---
+
+static void Modbus_ReadHoldingPollCycle(benchmark::State &state) {
+  // Address 1, function 3, byte count 20, 10 registers; the CRC goes in the last two bytes
+  uint8_t response[RESPONSE_SIZE] = {0x01, 0x03, 0x14, 0x09, 0x1F, 0x00, 0x00, 0x01, 0xF4, 0x00, 0x00, 0x13,
+                                     0x88, 0x00, 0x32, 0x03, 0xE8, 0x00, 0x00, 0x00, 0x64, 0x12, 0x34};
+  put_le16(&response[RESPONSE_SIZE - 2], crc16(response, RESPONSE_SIZE - 2));
+
+  FakeUART uart;
+  uart.set_baud_rate(9600);
+  NoDelayHub hub;
+  hub.set_uart_parent(&uart);
+  hub.setup();
+  SumDevice device(&hub, ADDRESS);
+  hub.queue_pdu(ADDRESS, REQUEST_PDU, &device, {.continuous = true});
+  // The first loop() sends the poll; every send rewinds the response, so the device answers each one
+  hub.loop();
+  uart.load(response, RESPONSE_SIZE);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      hub.loop();
+    }
+    benchmark::DoNotOptimize(device.sum);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(Modbus_ReadHoldingPollCycle);
+
+}  // namespace esphome::modbus::benchmarks
@@ -0,0 +1,57 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/components/uart/uart.h"
+#include "fake_uart.h"
+
+namespace esphome::uart::benchmarks {
+
+using esphome::benchmarks::FakeUART;
+
+// Inner iteration count to amortize CodSpeed instrumentation overhead.
+static constexpr int kInnerIterations = 2000;
+
+// One second of a GPS module's NMEA output
+static constexpr char NMEA_BURST[] = "$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47\r\n"
+                                     "$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A\r\n"
+                                     "$GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39\r\n"
+                                     "$GPGSV,2,1,08,01,40,083,46,02,17,308,41,12,07,344,39,14,22,228,45*75\r\n"
+                                     "$GPVTG,054.7,T,034.4,M,005.5,N,010.2,K*48\r\n";
+
+// --- read_available(): drain a whole NMEA burst through a byte-sum callback ---
+
+static void UART_ReadAvailable_NmeaBurst(benchmark::State &state) {
+  FakeUART uart;
+  UARTDevice dev(&uart);
+  uint32_t sum = 0;
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uart.load(reinterpret_cast<const uint8_t *>(NMEA_BURST), sizeof(NMEA_BURST) - 1);
+      dev.read_available([&](uint8_t b) { sum += b; });
+    }
+    benchmark::DoNotOptimize(sum);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(UART_ReadAvailable_NmeaBurst);
+
+// --- discard_available(): drop a 256 byte backlog ---
+
+// Two virtual calls per byte, available() and read_byte(): this measures that per-byte call overhead
+static void UART_DiscardAvailable(benchmark::State &state) {
+  uint8_t backlog[256]{};
+  FakeUART uart;
+  UARTDevice dev(&uart);
+
+  for (auto _ : state) {
+    for (int i = 0; i < kInnerIterations; i++) {
+      uart.load(backlog, sizeof(backlog));
+      dev.discard_available();
+    }
+    benchmark::DoNotOptimize(uart.available());
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(UART_DiscardAvailable);
+
+}  // namespace esphome::uart::benchmarks
@@ -0,0 +1,93 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/core/frame_reader.h"
+#include "esphome/core/line_reader.h"
+
+namespace esphome::benchmarks {
+
+// Inner iteration count to amortize CodSpeed instrumentation overhead.
+static constexpr int kInnerIterations = 2000;
+
+static constexpr char NMEA_GGA[] = "$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47\r\n";
+
+// A 30 byte frame with a 4 byte header and a 2 byte tail
+static constexpr uint8_t FRAME_30[30] = {0xAA, 0xFF, 0x03, 0x00, 0x0E, 0x03, 0xB1, 0x86, 0x10, 0x00,
+                                         0x40, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                                         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xCC};
+
+// Four A02YYUW distance frames among noise bytes; the doubled 0xFF fails the checksum and resyncs onto the
+// frame behind it. Ends on a whole frame, so every pass starts clean
+static constexpr uint8_t ULTRASONIC_NOISY[] = {0x12, 0xFF, 0x07, 0xA1, 0xA7, 0x34, 0xFF, 0xFF, 0x07, 0xA1, 0xA7,
+                                               0x00, 0xFF, 0x07, 0xA1, 0xA7, 0x56, 0xFF, 0x07, 0xA1, 0xA7};
+
+// --- LineReader: one GGA sentence fed byte by byte ---
+
+static void LineReader_NmeaLine(benchmark::State &state) {
+  LineReader<96> reader;
+  const auto *bytes = reinterpret_cast<const uint8_t *>(NMEA_GGA);
+  size_t total = 0;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(bytes);
+    for (int i = 0; i < kInnerIterations; i++) {
+      for (size_t j = 0; j < sizeof(NMEA_GGA) - 1; j++) {
+        size_t len;
+        if (reader.feed(bytes[j], len) != nullptr)
+          total += len;
+      }
+    }
+    benchmark::DoNotOptimize(total);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(LineReader_NmeaLine);
+
+// --- FrameReader: a 30 byte frame behind a 4 byte header ---
+
+static void FrameReader_30ByteFrame(benchmark::State &state) {
+  FrameReader<sizeof(FRAME_30), 0xAA, 0xFF, 0x03, 0x00> reader;
+  const uint8_t *bytes = FRAME_30;
+  uint32_t frames = 0;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(bytes);
+    for (int i = 0; i < kInnerIterations; i++) {
+      for (size_t j = 0; j < sizeof(FRAME_30); j++) {
+        if (reader.feed(bytes[j]) != nullptr)
+          frames++;
+      }
+    }
+    benchmark::DoNotOptimize(frames);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(FrameReader_30ByteFrame);
+
+// --- FrameReader: 4 byte checksummed frames, skipping noise and resyncing on a bad checksum ---
+
+static void FrameReader_UltrasonicNoisy(benchmark::State &state) {
+  FrameReader<4, 0xFF> reader;
+  const uint8_t *bytes = ULTRASONIC_NOISY;
+  uint32_t frames = 0;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(bytes);
+    for (int i = 0; i < kInnerIterations; i++) {
+      for (size_t j = 0; j < sizeof(ULTRASONIC_NOISY); j++) {
+        const uint8_t *frame = reader.feed(bytes[j]);
+        if (frame == nullptr)
+          continue;
+        if (frame[3] == static_cast<uint8_t>(frame[0] + frame[1] + frame[2])) {
+          frames++;
+        } else {
+          reader.resync();
+        }
+      }
+    }
+    benchmark::DoNotOptimize(frames);
+  }
+  state.SetItemsProcessed(state.iterations() * kInnerIterations);
+}
+BENCHMARK(FrameReader_UltrasonicNoisy);
+
+}  // namespace esphome::benchmarks
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <cstdint>
+#include <cstring>
+
+#include "esphome/components/uart/uart_component.h"
+
+namespace esphome::benchmarks {
+
+// Serves a fixed byte stream as received data. Every write rewinds it, so the stream answers each request.
+class FakeUART : public uart::UARTComponent {
+ public:
+  void load(const uint8_t *data, size_t len) {
+    this->data_ = data;
+    this->len_ = len;
+    this->pos_ = 0;
+  }
+  void rewind() { this->pos_ = 0; }
+
+  void write_array(const uint8_t *data, size_t len) override { this->rewind(); }
+  bool peek_byte(uint8_t *data) override {
+    if (this->pos_ >= this->len_)
+      return false;
+    *data = this->data_[this->pos_];
+    return true;
+  }
+  bool read_array(uint8_t *data, size_t len) override {
+    if (len > this->len_ - this->pos_)
+      return false;
+    std::memcpy(data, this->data_ + this->pos_, len);
+    this->pos_ += len;
+    return true;
+  }
+  size_t available() override { return this->len_ - this->pos_; }
+  uart::UARTFlushResult flush() override { return uart::UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS; }
+  void check_logger_conflict() override {}
+
+ protected:
+  const uint8_t *data_{nullptr};
+  size_t len_{0};
+  size_t pos_{0};
+};
+
+}  // namespace esphome::benchmarks
@@ -0,0 +1,62 @@
+"""Tests for cc1101 packet_length validation."""
+
+from typing import Any
+
+import pytest
+
+from esphome.components.cc1101 import _validate_packet_mode
+import esphome.config_validation as cv
+from esphome.core import Lambda
+
+LENGTH_LAMBDA = Lambda("return x.size() < 3 ? 0 : x[2] + 12;")
+
+
+@pytest.mark.parametrize(
+    "config",
+    [
+        {"packet_mode": True, "gdo0_pin": 2, "packet_length": LENGTH_LAMBDA},
+        {"packet_mode": True, "gdo0_pin": 2, "packet_length": 1024},
+        {"packet_mode": True, "gdo0_pin": 2, "packet_length": 64, "crc_enable": True},
+        {"packet_mode": False, "packet_length": 200, "crc_enable": True},
+    ],
+)
+def test_packet_length_valid(config: dict[str, Any]) -> None:
+    """Fixed lengths, a lambda, and CRC on packets that fit the FIFO are accepted."""
+    assert _validate_packet_mode(config) is config
+
+
+@pytest.mark.parametrize(
+    ("config", "message"),
+    [
+        (
+            {"packet_mode": False, "packet_length": LENGTH_LAMBDA},
+            "packet_mode is required when packet_length is a lambda",
+        ),
+        (
+            {"packet_mode": True, "gdo0_pin": 2},
+            "packet_length is required when packet_mode is enabled",
+        ),
+        (
+            {
+                "packet_mode": True,
+                "gdo0_pin": 2,
+                "packet_length": 65,
+                "crc_enable": True,
+            },
+            "crc_enable is not supported",
+        ),
+        (
+            {
+                "packet_mode": True,
+                "gdo0_pin": 2,
+                "packet_length": LENGTH_LAMBDA,
+                "crc_enable": True,
+            },
+            "crc_enable is not supported",
+        ),
+    ],
+)
+def test_packet_length_invalid(config: dict[str, Any], message: str) -> None:
+    """Invalid packet_length combinations are rejected with a clear message."""
+    with pytest.raises(cv.Invalid, match=message):
+        _validate_packet_mode(config)
@@ -0,0 +1,18 @@
+"""Validate the sync-word limit before firmware generation."""
+
+import pytest
+
+from esphome.components.sx126x import CONF_SYNC_VALUE, CONFIG_SCHEMA
+import esphome.config_validation as cv
+
+
+@pytest.mark.parametrize("size", [0, 1, 2, 8])
+def test_supported_sync_lengths(size: int) -> None:
+    value = [0x14] * size
+    assert CONFIG_SCHEMA.schema[CONF_SYNC_VALUE](value) == value
+
+
+@pytest.mark.parametrize("size", [9, 256])
+def test_oversized_sync_word(size: int) -> None:
+    with pytest.raises(cv.Invalid, match="at most 8"):
+        CONFIG_SCHEMA.schema[CONF_SYNC_VALUE]([0x14] * size)
@@ -0,0 +1,26 @@
+packages:
+  spi: !include ../../test_build_components/common/spi/esp32-idf.yaml
+
+cc1101:
+  # Above 255 bytes: infinite length mode, then fixed for the remainder
+  - id: transceiver_long_fixed
+    cs_pin: GPIO5
+    gdo0_pin: GPIO4
+    packet_mode: true
+    packet_length: 1024
+    on_packet:
+      then:
+        - lambda: 'ESP_LOGD("cc1101", "long packet %u bytes", x.size());'
+
+  # Length taken from the packet header
+  - id: transceiver_long_lambda
+    cs_pin: GPIO15
+    gdo0_pin: GPIO2
+    packet_mode: true
+    packet_length: !lambda |-
+      if (x.size() < 3) return 0;
+      if (x[0] != 0x54) return -1;
+      return x[2] + 12;
+    on_packet:
+      then:
+        - lambda: 'ESP_LOGD("cc1101", "lambda packet %u bytes rssi %.1f", x.size(), rssi);'
@@ -0,0 +1,24 @@
+packages:
+  spi: !include ../../test_build_components/common/spi/rp2040-ard.yaml
+
+cc1101:
+  - id: transceiver_long_fixed
+    cs_pin: GPIO5
+    gdo0_pin: GPIO4
+    packet_mode: true
+    packet_length: 1024
+    on_packet:
+      then:
+        - lambda: 'ESP_LOGD("cc1101", "long packet %u bytes", x.size());'
+
+  - id: transceiver_long_lambda
+    cs_pin: GPIO15
+    gdo0_pin: GPIO2
+    packet_mode: true
+    packet_length: !lambda |-
+      if (x.size() < 3) return 0;
+      if (x[0] != 0x54) return -1;
+      return x[2] + 12;
+    on_packet:
+      then:
+        - lambda: 'ESP_LOGD("cc1101", "lambda packet %u bytes rssi %.1f", x.size(), rssi);'
@@ -0,0 +1,7 @@
+substitutions:
+  cs_pin: GPIO5
+  gdo0_pin: GPIO4
+
+packages:
+  spi: !include ../../test_build_components/common/spi/rp2040-ard.yaml
+  cc1101: !include common.yaml
@@ -20,7 +20,14 @@ class FakePin final : public GPIOPin {
  bool level{false};
 };

-// Answers the 8-bit status read with a set report and 16-bit setup reads with zeros.
+// Fills a 16-bit register read: the firmware check code read gets a valid code, other registers zeros.
+inline void answer_setup_read(const uint8_t *data, size_t size, uint8_t *out, size_t out_size) {
+  std::memset(out, 0, out_size);
+  if (size == 2 && encode_uint16(data[0], data[1]) == cstxxx::REG_FW_CHECK_CODE && out_size == 4)
+    out[2] = out[3] = 0xCA;
+}
+
+// Answers the 8-bit status read with a set report and 16-bit setup reads through answer_setup_read().
 class StatusBus final : public i2c::I2CBus {
 public:
  std::array<uint8_t, 28> status{};
@@ -35,7 +42,7 @@ class StatusBus final : public i2c::I2CBus {
    if (size == 1 && data[0] == CST226_REG_STATUS) {
      std::memcpy(out, this->status.data(), std::min(out_size, this->status.size()));
    } else {
-      std::memset(out, 0, out_size);
+      answer_setup_read(data, size, out, out_size);
    }
    return i2c::ERROR_OK;
  }
@@ -1,5 +1,8 @@
 #include <gtest/gtest.h>

+#include <cstring>
+#include <vector>
+
 #include "esphome/components/cst226/touchscreen/cst226_touchscreen.h"
 #include "../common.h"

@@ -14,6 +17,45 @@ TEST(CST226TouchscreenTest, SetupCompletes) {
  EXPECT_FALSE(hub.is_failed());
 }

+// Records the writes that carry no read, and answers reads through answer_setup_read().
+class WriteLogBus final : public i2c::I2CBus {
+ public:
+  std::vector<std::vector<uint8_t>> writes;
+  bool bad_check_code{false};
+
+  i2c::ErrorCode write_readv(uint8_t address, const uint8_t *data, size_t size, uint8_t *out,
+                             size_t out_size) override {
+    if (out_size == 0) {
+      this->writes.emplace_back(data, data + size);
+    } else {
+      answer_setup_read(data, size, out, out_size);
+      if (this->bad_check_code)
+        std::memset(out, 0, out_size);
+    }
+    return i2c::ERROR_OK;
+  }
+};
+
+TEST(CST226TouchscreenTest, SetupEntersCommandModeAndLeavesIt) {
+  WriteLogBus bus;
+  CST226Touchscreen hub;
+  hub.set_i2c_bus(&bus);
+  hub.setup();
+  ASSERT_GE(bus.writes.size(), 2u);
+  EXPECT_EQ(bus.writes.front(), (std::vector<uint8_t>{0xD1, 0x01}));
+  EXPECT_EQ(bus.writes.back(), (std::vector<uint8_t>{0xD1, 0x09}));
+  EXPECT_FALSE(hub.is_failed());
+}
+
+TEST(CST226TouchscreenTest, SetupFailsOnAWrongCheckCode) {
+  WriteLogBus bus;
+  bus.bad_check_code = true;
+  CST226Touchscreen hub;
+  hub.set_i2c_bus(&bus);
+  hub.setup();
+  EXPECT_TRUE(hub.is_failed());
+}
+
 TEST(CST226TouchscreenTest, SetupFailsWithoutTheChip) {
  StatusBus bus;
  bus.fail = true;
@@ -0,0 +1,32 @@
+#include <gtest/gtest.h>
+
+#include <algorithm>
+
+#include "esphome/components/cstxxx/cstxxx.h"
+
+namespace esphome::cstxxx::testing {
+
+TEST(CSTxxxDecodeTouch, FirstRecordStartsTheReport) {
+  const uint8_t report[report_size(1)] = {0x16, 0x12, 0x34, 0x56, 0x78, 0x01, SYNC_BYTE};
+  auto touch = decode_touch(report, 0);
+  EXPECT_EQ(touch.id, 1);
+  EXPECT_EQ(touch.event, 0x06);
+  EXPECT_EQ(touch.x, 0x125);
+  EXPECT_EQ(touch.y, 0x346);
+  EXPECT_EQ(touch.z, 0x78);
+}
+
+TEST(CSTxxxDecodeTouch, LaterRecordsSkipTheStatusBytes) {
+  uint8_t report[report_size(3)]{};
+  report[FINGER_COUNT_IDX] = 3;
+  report[SYNC_IDX] = SYNC_BYTE;
+  const uint8_t third[5] = {0x26, 0xFF, 0x00, 0xF0, 0x05};
+  std::copy(third, third + 5, report + 12);
+  auto touch = decode_touch(report, 2);
+  EXPECT_EQ(touch.id, 2);
+  EXPECT_EQ(touch.x, 0xFFF);
+  EXPECT_EQ(touch.y, 0x000);
+  EXPECT_EQ(touch.z, 5);
+}
+
+}  // namespace esphome::cstxxx::testing
@@ -2,3 +2,7 @@ packages:
  i2c: !include ../../test_build_components/common/i2c/esp32-idf.yaml

 <<: !include common.yaml
+
+# IPv6 with an IP sensor: compiles the IPv6 event handler's listener notification
+network:
+  enable_ipv6: true
@@ -0,0 +1,16 @@
+"""Enable real logger callbacks for radio reentrancy regression tests."""
+
+import esphome.codegen as cg
+from esphome.components.logger import request_log_listener
+from esphome.types import ConfigType
+from tests.testing_helpers import ComponentManifestOverride
+
+
+def override_manifest(manifest: ComponentManifestOverride) -> None:
+    async def to_code(config: ConfigType) -> None:
+        request_log_listener()
+        # The tests build a software SPI bus in C++, which no configured bus asks for
+        cg.add_define("USE_SPI_SOFTWARE")
+
+    manifest.multi_conf = False
+    manifest.to_code = to_code
@@ -7,3 +7,22 @@ button:
          cold: true
      - sx126x.set_mode_sleep:
          cold: !lambda return id(sx126x_my_number).state > 1;
+
+  - platform: template
+    name: "SX126x Async Send or Cancel"
+    on_press:
+      - lambda: |-
+          class Listener : public sx126x::SX126xTransmitListener {
+           public:
+            void on_transmit_complete(sx126x::SX126xError result) override {
+              ESP_LOGD("sx126x_test", "Async completion: %d", static_cast<int>(result));
+            }
+          };
+          static Listener listener;
+          if (id(sx126x_radio).is_transmitting()) {
+            id(sx126x_radio).cancel_transmit_async(&listener);
+          } else {
+            const uint8_t data[] = {0x11, 0x22, 0x33};
+            auto result = id(sx126x_radio).start_transmit_async(&listener, data, sizeof(data), 4000);
+            ESP_LOGD("sx126x_test", "Async admission: %d", static_cast<int>(result));
+          }
@@ -1,4 +1,5 @@
 sx126x:
+  id: sx126x_radio
  dio1_pin: ${dio1_pin}
  cs_pin: ${cs_pin}
  busy_pin: ${busy_pin}
@@ -0,0 +1,643 @@
+#include "sx126x_test_helpers.h"
+#include "esphome/core/application.h"
+#include <tuple>
+
+namespace esphome::sx126x::testing {
+
+class TransmitListener : public SX126xTransmitListener {
+ public:
+  void on_transmit_complete(SX126xError result) override {
+    this->results.push_back(result);
+    if (this->on_complete) {
+      this->on_complete(result);
+    }
+  }
+  std::vector<SX126xError> results;
+  std::function<void(SX126xError)> on_complete;
+};
+
+class ReceiveCallback : public SX126xListener {
+ public:
+  void on_packet(const std::vector<uint8_t> &packet, float rssi, float snr) override { this->on_packet_callback(); }
+  std::function<void()> on_packet_callback;
+};
+
+class SX126xAsyncModes : public ::testing::TestWithParam<std::tuple<bool, bool, bool>> {};
+
+TEST_P(SX126xAsyncModes, ReturnsBeforeCompletionAndRestoresMode) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(lora, rx, fixed);
+  hw.auto_complete = false;
+  hw.clear_trace();
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 1234), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_TRUE(listener.results.empty());
+  EXPECT_EQ(hw.sends, 1u);
+  const auto &tx = hw.transactions.back();
+  EXPECT_EQ(tx, (std::vector<uint8_t>{RADIO_SET_TX, 0x01, 0x34, 0x80}));
+  const auto fifo = std::find_if(hw.transactions.begin(), hw.transactions.end(),
+                                 [](const auto &cmd) { return cmd[0] == RADIO_WRITE_BUFFER; });
+  ASSERT_NE(fifo, hw.transactions.end());
+  EXPECT_EQ(*fifo, (std::vector<uint8_t>{RADIO_WRITE_BUFFER, 0, 0x11, 0x22, 0x33}));
+  hw.packet.assign(3, 0x99);  // The driver must not retain the caller's payload.
+  hw.irq = IRQ_TX_DONE;
+  listener.on_complete = [&](SX126xError result) {
+    EXPECT_FALSE(hw.radio.is_transmitting());
+    EXPECT_EQ(hw.receiving, rx);
+    EXPECT_TRUE(hw.cs.level);
+  };
+  hw.radio.loop();
+  hw.radio.loop();
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST_P(SX126xAsyncModes, RejectsEveryFailedStartWithoutCallbackAndCanRetry) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware reference;
+  TransmitListener listener;
+  reference.configure(lora, rx, fixed);
+  reference.clear_trace();
+  ASSERT_EQ(reference.radio.start_transmit_async(&listener, reference.packet), SX126xError::SX126X_ERROR_NONE);
+  const size_t count = reference.transactions.size();
+  reference.radio.cancel_transmit_async(&listener);
+  for (size_t fault = 1; fault <= count; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hw;
+    TransmitListener result;
+    hw.configure(lora, rx, fixed);
+    hw.clear_trace();
+    hw.fail_at = fault;
+    EXPECT_EQ(hw.radio.start_transmit_async(&result, hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+    EXPECT_TRUE(result.results.empty());
+    EXPECT_FALSE(hw.radio.is_transmitting());
+    EXPECT_TRUE(hw.cs.level);
+    EXPECT_TRUE(hw.transactions[fault - 1].empty());
+    EXPECT_EQ(hw.sends, 0u);
+    EXPECT_EQ(hw.receiving, rx);  // One-shot fault permits failed-start cleanup.
+    hw.clear_trace();
+    hw.radio.configure();
+    ASSERT_EQ(hw.radio.start_transmit_async(&result, hw.packet), SX126xError::SX126X_ERROR_NONE);
+    hw.radio.loop();
+    EXPECT_EQ(result.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+  }
+}
+
+TEST_P(SX126xAsyncModes, ReportsEveryCompletionAndCleanupFailureOnce) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware reference;
+  TransmitListener listener;
+  reference.configure(lora, rx, fixed);
+  ASSERT_EQ(reference.radio.start_transmit_async(&listener, reference.packet), SX126xError::SX126X_ERROR_NONE);
+  reference.clear_trace();
+  reference.radio.loop();
+  const size_t count = reference.transactions.size();
+  for (size_t fault = 1; fault <= count; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hw;
+    TransmitListener result;
+    hw.configure(lora, rx, fixed);
+    ASSERT_EQ(hw.radio.start_transmit_async(&result, hw.packet), SX126xError::SX126X_ERROR_NONE);
+    hw.clear_trace();
+    hw.fail_at = fault;
+    hw.radio.loop();
+    EXPECT_EQ(result.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_BUSY_TIMEOUT}));
+    EXPECT_TRUE(hw.transactions[fault - 1].empty());
+    EXPECT_TRUE(hw.cs.level);
+    EXPECT_FALSE(hw.radio.is_transmitting());
+    hw.radio.loop();
+    EXPECT_EQ(result.results.size(), 1u);
+    hw.clear_trace();
+    hw.radio.configure();
+    ASSERT_EQ(hw.radio.start_transmit_async(&result, hw.packet), SX126xError::SX126X_ERROR_NONE);
+    hw.radio.loop();
+    ASSERT_EQ(result.results.size(), 2u);
+    EXPECT_EQ(result.results.back(), SX126xError::SX126X_ERROR_NONE);
+    EXPECT_EQ(hw.receiving, rx);
+  }
+}
+
+TEST_P(SX126xAsyncModes, BlockingAndAsyncUseTheSameCommandSequence) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware blocking, async;
+  TransmitListener listener;
+  blocking.configure(lora, rx, fixed);
+  async.configure(lora, rx, fixed);
+  blocking.clear_trace();
+  async.clear_trace();
+  ASSERT_EQ(blocking.radio.transmit_packet(blocking.packet), SX126xError::SX126X_ERROR_NONE);
+  ASSERT_EQ(async.radio.start_transmit_async(&listener, async.packet), SX126xError::SX126X_ERROR_NONE);
+  async.radio.loop();
+  EXPECT_EQ(blocking.transactions, async.transactions);
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+  EXPECT_EQ(blocking.receiving, async.receiving);
+}
+
+INSTANTIATE_TEST_SUITE_P(LoRaAndFSKWithRxOrSleepAndFixedOrVariablePayload, SX126xAsyncModes,
+                         ::testing::Combine(::testing::Bool(), ::testing::Bool(), ::testing::Bool()));
+
+TEST(SX126xAsync, SoftwareDeadlineWithoutDioAndCachedTickBeforeStart) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  hw.dio.internal = true;
+  const uint32_t before = millis();
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 50), SX126xError::SX126X_ERROR_NONE);
+  const uint32_t after = millis();
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, before - 1};
+    hw.radio.call();
+    EXPECT_TRUE(listener.results.empty());  // No unsigned underflow on the admitting loop tick.
+  }
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, after + 51};
+    hw.radio.call();  // Still enabled despite no IRQ or ISR edge.
+  }
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_TIMEOUT}));
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_FALSE(hw.radio.is_transmitting());
+}
+
+TEST(SX126xAsync, UnrelatedIrqIsNotSuccessAndTimeoutWinsOverTxDone) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.irq = IRQ_RX_DONE;
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, millis()};
+    hw.radio.loop();
+  }
+  EXPECT_TRUE(listener.results.empty());
+  hw.irq = IRQ_TX_DONE | IRQ_RX_TX_TIMEOUT;
+  hw.radio.loop();
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_TIMEOUT}));
+}
+
+TEST(SX126xAsync, CancelRequiresOwnerAndCompletesSynchronouslyOnce) {
+  RadioHardware hw;
+  TransmitListener listener, other;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(&listener));
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(nullptr));
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(&other));
+  EXPECT_TRUE(hw.radio.cancel_transmit_async(&listener));
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_CANCELLED}));
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(&listener));
+  hw.irq = IRQ_TX_DONE;  // A late IRQ cannot deliver a second completion.
+  hw.radio.loop();
+  EXPECT_EQ(listener.results.size(), 1u);
+  EXPECT_TRUE(hw.receiving);
+  hw.irq = IRQ_TX_DONE;  // Also cleared before a new send starts.
+  ASSERT_EQ(hw.radio.start_transmit_async(&other, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, millis()};
+    hw.radio.loop();
+  }
+  EXPECT_TRUE(other.results.empty());
+  EXPECT_TRUE(hw.radio.cancel_transmit_async(&other));
+}
+
+TEST(SX126xAsync, CompletionCallbackCanStartNextSend) {
+  RadioHardware hw;
+  TransmitListener first, second;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  first.on_complete = [&](SX126xError result) {
+    EXPECT_EQ(hw.radio.start_transmit_async(&second, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  };
+  ASSERT_EQ(hw.radio.start_transmit_async(&first, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(first.results.size(), 1u);
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_TRUE(second.results.empty());
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(second.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+static void expect_conflicting_calls_rejected(RadioHardware &hw, TransmitListener &listener) {
+  const size_t count = hw.transactions.size();
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  hw.radio.set_mode_rx();
+  hw.radio.set_mode_tx();
+  hw.radio.set_mode_standby(STDBY_XOSC);
+  hw.radio.set_mode_sleep(true);
+  hw.radio.configure();
+  hw.radio.run_image_cal();
+  EXPECT_EQ(hw.transactions.size(), count);
+}
+
+TEST(SX126xAsync, PendingReceiveRejectsAdmissionWithoutDispatchOrAcknowledgment) {
+  RadioHardware hw;
+  TransmitListener listener;
+  PacketListener receiver;
+  hw.configure(true, true);
+  hw.radio.register_listener(&receiver);
+  hw.irq = IRQ_RX_DONE;
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  EXPECT_TRUE(receiver.packets.empty());
+  EXPECT_TRUE(listener.results.empty());
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  hw.radio.loop();
+  EXPECT_EQ(receiver.packets.size(), 1u);
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  expect_conflicting_calls_rejected(hw, listener);
+  hw.radio.loop();
+  EXPECT_EQ(listener.results.size(), 1u);
+}
+
+TEST(SX126xAsync, ValidatesReadinessPayloadAndTimeoutWithoutSpi) {
+  RadioHardware hw;
+  TransmitListener listener;
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hw.transactions.empty());
+  hw.configure(true, true, true);
+  hw.clear_trace();
+  EXPECT_EQ(hw.radio.start_transmit_async(nullptr, hw.packet), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, nullptr, 3), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet.data(), 0), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet.data(), 2), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet.data(), 256), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 0), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 262144), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_TRUE(listener.results.empty());
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 262143), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_EQ(hw.transactions.back(), (std::vector<uint8_t>{RADIO_SET_TX, 0xFF, 0xFF, 0xC0}));
+  hw.radio.loop();
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet, 1), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_EQ(hw.transactions.back(), (std::vector<uint8_t>{RADIO_SET_TX, 0, 0, 64}));
+  hw.radio.loop();
+}
+
+TEST(SX126xAsync, PersistentBusyReportsFailedCleanupAndAllowsLaterRecovery) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.busy.on_read = []() { return true; };
+  ASSERT_TRUE(hw.radio.cancel_transmit_async(&listener));
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_BUSY_TIMEOUT}));
+  EXPECT_FALSE(hw.radio.is_transmitting());
+  EXPECT_TRUE(hw.radio.status_has_warning());
+  EXPECT_TRUE(hw.cs.level);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_EQ(listener.results.size(), 1u);  // Failed admission never invokes completion.
+  hw.busy.on_read = []() { return false; };
+  hw.radio.configure();
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  ASSERT_EQ(listener.results.size(), 2u);
+  EXPECT_EQ(listener.results.back(), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_FALSE(hw.radio.status_has_warning());
+}
+
+TEST(SX126xAsync, CancellationCallbackMayStartAnotherSend) {
+  RadioHardware hw;
+  TransmitListener first, second;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  first.on_complete = [&](SX126xError result) {
+    EXPECT_EQ(result, SX126xError::SX126X_ERROR_CANCELLED);
+    EXPECT_EQ(hw.radio.start_transmit_async(&second, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  };
+  ASSERT_EQ(hw.radio.start_transmit_async(&first, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_TRUE(hw.radio.cancel_transmit_async(&first));
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(&first));
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(second.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST(SX126xAsync, RejectsAfterFailedSetupWithoutBusAccess) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.fail_at = 1;
+  hw.configure(true, true);
+  ASSERT_TRUE(hw.radio.is_failed());
+  hw.clear_trace();
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_TRUE(listener.results.empty());
+}
+
+TEST(SX126xAsync, TwoRadiosHaveIndependentOwnersAndCompletion) {
+  RadioHardware a, b;
+  TransmitListener first, second;
+  a.configure(true, true);
+  b.configure(false, false);
+  a.auto_complete = b.auto_complete = false;
+  ASSERT_EQ(a.radio.start_transmit_async(&first, a.packet), SX126xError::SX126X_ERROR_NONE);
+  ASSERT_EQ(b.radio.start_transmit_async(&second, b.packet), SX126xError::SX126X_ERROR_NONE);
+  a.radio.cancel_transmit_async(&first);
+  EXPECT_TRUE(b.radio.is_transmitting());
+  EXPECT_TRUE(second.results.empty());
+  b.irq = IRQ_TX_DONE;
+  b.radio.loop();
+  EXPECT_EQ(first.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_CANCELLED}));
+  EXPECT_EQ(second.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST(SX126xAsync, BackToBackReceiveEchoPreservesBorrowedPacketForAllListeners) {
+  class EchoListener : public SX126xListener {
+   public:
+    std::function<void(const std::vector<uint8_t> &)> callback;
+    void on_packet(const std::vector<uint8_t> &packet, float rssi, float snr) override { callback(packet); }
+  } echo;
+  RadioHardware hw;
+  TransmitListener tx;
+  PacketListener observer;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  hw.radio.register_listener(&echo);
+  hw.radio.register_listener(&observer);
+  const auto first = hw.packet;
+  const std::vector<uint8_t> second(200, 0xA5);
+  unsigned calls = 0;
+  echo.callback = [&](const std::vector<uint8_t> &packet) {
+    if (++calls == 1) {
+      hw.packet = second;  // Larger back-to-back RX could reallocate the driver's packet_.
+      hw.irq = IRQ_RX_DONE;
+      const auto count = hw.transactions.size();
+      hw.radio.loop();  // Explicit loop reentry must not overwrite the borrowed RX buffer either.
+      // The send stops in standby and holds the new packet instead of overwriting the FIFO.
+      EXPECT_EQ(hw.radio.start_transmit_async(&tx, packet), SX126xError::SX126X_ERROR_BUSY);
+      ASSERT_EQ(hw.transactions.size(), count + 2);
+      EXPECT_EQ(hw.transactions[count][0], RADIO_SET_STANDBY);
+      EXPECT_EQ(hw.transactions.back()[0], RADIO_GET_IRQSTATUS);
+      EXPECT_EQ(packet, first);
+    } else {
+      EXPECT_EQ(packet, second);
+      EXPECT_EQ(hw.radio.start_transmit_async(&tx, packet), SX126xError::SX126X_ERROR_NONE);
+    }
+  };
+  hw.irq = IRQ_RX_DONE;
+  hw.radio.loop();
+  ASSERT_EQ(observer.packets.size(), 1u);
+  EXPECT_EQ(observer.packets[0], first);
+  EXPECT_TRUE(tx.results.empty());
+  EXPECT_FALSE(hw.radio.is_transmitting());
+  hw.radio.loop();
+  ASSERT_EQ(observer.packets.size(), 2u);
+  EXPECT_EQ(observer.packets[1], second);
+  ASSERT_EQ(calls, 2u);
+  auto fifo = std::find_if(hw.transactions.rbegin(), hw.transactions.rend(),
+                           [](const auto &cmd) { return !cmd.empty() && cmd[0] == RADIO_WRITE_BUFFER; });
+  ASSERT_NE(fifo, hw.transactions.rend());
+  EXPECT_EQ(std::vector<uint8_t>(fifo->begin() + 2, fifo->end()), second);
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(tx.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST(SX126xAsync, FailedReconfigurationRejectsAsyncUntilReconfigured) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(true, true);
+  hw.clear_trace();
+  hw.fail_at = 3;
+  hw.radio.configure();
+  hw.clear_trace();
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_TRUE(listener.results.empty());
+  hw.radio.configure();
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.loop();
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST(SX126xAsync, BlockingSendUsesIrqResultInsteadOfTreatingAnyDioAsSuccess) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  auto write = hw.cs.on_write;
+  hw.cs.on_write = [&](bool high) {
+    write(high);
+    if (high && !hw.transactions.back().empty() && hw.transactions.back()[0] == RADIO_SET_TX) {
+      hw.irq = IRQ_RX_TX_TIMEOUT;
+    }
+  };
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_TIMEOUT);
+  EXPECT_TRUE(hw.receiving);
+}
+
+TEST(SX126xAsync, FailedAdmissionRestoresReceivePollingWithoutAnotherTransmission) {
+  RadioHardware hw;
+  PacketListener rx;
+  TransmitListener tx;
+  hw.configure(true, true);
+  hw.radio.register_listener(&rx);
+  const auto configured_params = hw.packet_params;
+  hw.dio.internal = true;
+  hw.radio.call();
+  ASSERT_TRUE(hw.radio.is_idle());
+  hw.clear_trace();
+  hw.fail_at = 3;
+  EXPECT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+  EXPECT_TRUE(tx.results.empty());
+  EXPECT_TRUE(hw.radio.is_in_loop_state());
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.packet_params, configured_params);
+  hw.clear_trace();
+  hw.irq = IRQ_RX_DONE;  // No simulated ISR edge: restoration must re-enable polling.
+  hw.radio.call();
+  ASSERT_EQ(rx.packets.size(), 1u);
+  EXPECT_EQ(rx.packets[0], hw.packet);
+  EXPECT_EQ(hw.sends, 0u);
+}
+
+TEST_P(SX126xAsyncModes, ReceiveAtStandbyRejectsSendAndSurvivesReadFailure) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware hw;
+  PacketListener received;
+  TransmitListener tx;
+  hw.configure(lora, rx, fixed);
+  hw.radio.call();  // Advance from setup into ESPHome loop scheduling.
+  hw.radio.register_listener(&received);
+  hw.clear_trace();
+  auto write = hw.cs.on_write;
+  bool inject = true;
+  hw.cs.on_write = [&](bool high) {
+    write(high);
+    if (high && inject && !hw.transactions.back().empty() && hw.transactions.back()[0] == RADIO_SET_STANDBY) {
+      inject = false;
+      hw.irq = IRQ_RX_DONE;
+    }
+  };
+  EXPECT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  EXPECT_TRUE(tx.results.empty());
+  EXPECT_TRUE(received.packets.empty());
+  EXPECT_FALSE(hw.receiving);
+  EXPECT_FALSE(hw.radio.is_transmitting());
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  ASSERT_EQ(hw.transactions.size(), 2u);
+  EXPECT_EQ(hw.transactions[0][0], RADIO_SET_STANDBY);
+  EXPECT_EQ(hw.transactions[1][0], RADIO_GET_IRQSTATUS);
+  const auto resets = hw.rst.writes;
+  hw.radio.set_mode_rx();
+  EXPECT_EQ(hw.rst.writes, resets);
+  EXPECT_EQ(hw.transactions.size(), 2u);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  EXPECT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  EXPECT_FALSE(hw.radio.cancel_transmit_async(&tx));
+
+  hw.clear_trace();
+  hw.fail_at = 2;  // Packet metadata read fails after the held IRQ is read.
+  hw.radio.loop();
+  EXPECT_TRUE(hw.radio.is_in_loop_state());
+  EXPECT_TRUE(received.packets.empty());
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  EXPECT_FALSE(hw.receiving);
+  hw.clear_trace();
+  LoopBlockingGuard retry{nullptr, nullptr, App.get_loop_component_start_time() + 200};
+  hw.radio.loop();
+  hw.radio.loop();
+  ASSERT_EQ(received.packets.size(), 1u);
+  EXPECT_EQ(received.packets[0], hw.packet);
+  EXPECT_EQ(hw.receiving, rx);
+  EXPECT_EQ(hw.sends, 0u);
+  EXPECT_TRUE(tx.results.empty());
+  ASSERT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.loop();
+  EXPECT_EQ(tx.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST_P(SX126xAsyncModes, FailedPreparationAndRestorationRequireSuccessfulConfiguration) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(lora, rx, fixed);
+  hw.clear_trace();
+  const auto busy = hw.busy.on_read;
+  hw.busy.on_read = [&]() { return hw.transactions.size() >= 3 || busy(); };
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+  EXPECT_TRUE(listener.results.empty());
+  EXPECT_EQ(hw.sends, 0u);
+  EXPECT_FALSE(hw.radio.is_transmitting());
+  EXPECT_TRUE(hw.cs.level);
+  ASSERT_EQ(hw.transactions.size(), 4u);
+  EXPECT_TRUE(hw.transactions[2].empty());  // Failed preparation.
+  EXPECT_TRUE(hw.transactions[3].empty());  // Failed restoration.
+  hw.clear_trace();
+  hw.busy.on_read = busy;
+  hw.radio.set_mode_rx();
+  hw.radio.loop();
+  EXPECT_TRUE(hw.radio.is_idle());
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hw.transactions.empty());
+  hw.fail_at = 1;
+  hw.radio.configure();
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  hw.clear_trace();
+  hw.radio.configure();
+  EXPECT_TRUE(hw.radio.is_in_loop_state());
+  EXPECT_EQ(hw.receiving, rx);
+  EXPECT_TRUE(listener.results.empty());
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.loop();
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+TEST(SX126xAsync, ExplicitConfigurationCanRecoverAnUnreadableHeldPacket) {
+  RadioHardware hw;
+  TransmitListener listener;
+  hw.configure(true, true);
+  auto write = hw.cs.on_write;
+  hw.cs.on_write = [&](bool high) {
+    write(high);
+    if (high && !hw.transactions.back().empty() && hw.transactions.back()[0] == RADIO_SET_STANDBY) {
+      hw.irq = IRQ_RX_DONE;
+    }
+  };
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  hw.cs.on_write = write;
+  hw.busy.on_read = []() { return true; };
+  hw.radio.loop();
+  const auto resets = hw.rst.writes;
+  hw.radio.configure();
+  EXPECT_GT(hw.rst.writes, resets);
+  EXPECT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  hw.busy.on_read = []() { return false; };
+  hw.radio.configure();
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_TRUE(listener.results.empty());
+  ASSERT_EQ(hw.radio.start_transmit_async(&listener, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.loop();
+  EXPECT_EQ(listener.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+}
+
+class SX126xReceiveActions : public ::testing::TestWithParam<unsigned> {};
+
+TEST_P(SX126xReceiveActions, ModeAndConfigurationPreserveBorrowedPacket) {
+  RadioHardware hw;
+  ReceiveCallback action;
+  PacketListener observer;
+  hw.configure(true, true);
+  hw.radio.register_listener(&action);
+  hw.radio.register_listener(&observer);
+  const auto original = hw.packet;
+  const unsigned selected_action = GetParam();
+  unsigned callbacks = 0;
+  action.on_packet_callback = [&]() {
+    callbacks++;
+    hw.clear_trace();
+    switch (selected_action) {
+      case 0:
+        hw.radio.set_mode_sleep();
+        break;
+      case 1:
+        hw.radio.set_mode_sleep(true);
+        break;
+      case 2:
+        hw.radio.set_rx_start(false);
+        hw.radio.configure();
+        break;
+      case 3:
+        hw.radio.set_mode_standby(STDBY_XOSC);
+        break;
+      case 4:
+        hw.radio.set_mode_rx();
+        break;
+      case 5:
+        hw.radio.run_image_cal();
+        break;
+      default:
+        FAIL() << "Unknown action " << selected_action;
+    }
+    EXPECT_FALSE(hw.transactions.empty());  // The requested operation must actually reach the chip.
+    EXPECT_EQ(hw.receiving, selected_action >= 4);
+    const auto commands = hw.transactions.size();
+    hw.packet.assign(19, 0x99);
+    hw.irq = IRQ_RX_DONE;
+    hw.radio.loop();  // Recursive packet delivery is still forbidden, including after configure().
+    EXPECT_EQ(hw.transactions.size(), commands);
+  };
+  hw.irq = IRQ_RX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(callbacks, 1u);
+  ASSERT_EQ(observer.packets.size(), 1u);
+  EXPECT_EQ(observer.packets.front(), original);
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);  // The next packet is left for a later loop.
+  if (selected_action == 1) {
+    TransmitListener tx;
+    EXPECT_EQ(hw.radio.start_transmit_async(&tx, original), SX126xError::SX126X_ERROR_NOT_READY);
+  }
+}
+
+INSTANTIATE_TEST_SUITE_P(SleepColdSleepConfigureStandbyRxAndCalibration, SX126xReceiveActions,
+                         ::testing::Range(0u, 6u));
+
+}  // namespace esphome::sx126x::testing
@@ -0,0 +1,788 @@
+#include "sx126x_test_helpers.h"
+#include <cmath>
+#include "esphome/core/application.h"
+#include <tuple>
+#include <type_traits>
+#ifdef USE_HOST
+#include <string>
+#include "esphome/components/logger/logger.h"
+#endif
+namespace esphome::sx126x::testing {
+class SX126xBusySetup : public ::testing::TestWithParam<std::tuple<bool, bool>> {};
+
+TEST_P(SX126xBusySetup, StopsAtEveryConfigurationCommand) {
+  const auto [lora, rx] = GetParam();
+  RadioHardware reference;
+  reference.configure(lora, rx);
+  ASSERT_FALSE(reference.radio.is_failed());
+  ASSERT_FALSE(reference.radio.status_has_warning());
+  const size_t count = reference.transactions.size();
+  ASSERT_GT(count, 10u);
+  for (size_t fault = 1; fault <= count; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hardware;
+    hardware.fail_at = fault;
+    hardware.configure(lora, rx);
+    hardware.expect_aborted(fault);
+    EXPECT_TRUE(hardware.radio.is_failed());
+    hardware.radio.dump_config();  // Also safe if the version read never happened.
+    hardware.clear_trace();
+    hardware.radio.configure();
+    hardware.radio.set_mode_rx();
+    hardware.radio.set_mode_tx();
+    hardware.radio.set_mode_sleep();
+    hardware.radio.set_mode_standby(STDBY_XOSC);
+    hardware.radio.run_image_cal();
+    hardware.radio.loop();
+    EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    EXPECT_TRUE(hardware.transactions.empty());
+  }
+}
+
+INSTANTIATE_TEST_SUITE_P(LoRaAndFSKWithRxOrSleep, SX126xBusySetup,
+                         ::testing::Combine(::testing::Bool(), ::testing::Bool()));
+
+class SX126xBusyTransmit : public ::testing::TestWithParam<std::tuple<bool, bool, bool>> {};
+
+TEST_P(SX126xBusyTransmit, StopsAtEverySendAndCleanupCommandAndCanRetry) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware reference;
+  reference.configure(lora, rx, fixed);
+  reference.clear_trace();
+  ASSERT_EQ(reference.radio.transmit_packet(reference.packet), SX126xError::SX126X_ERROR_NONE);
+  const size_t count = reference.transactions.size();
+  for (size_t fault = 1; fault <= count; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hardware;
+    hardware.configure(lora, rx, fixed);
+    hardware.clear_trace();
+    hardware.fail_at = fault;
+    EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet.data(), hardware.packet.size()),
+              SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+    EXPECT_TRUE(hardware.transactions[fault - 1].empty());
+    EXPECT_TRUE(hardware.cs.level);
+    EXPECT_FALSE(hardware.radio.is_failed());
+    hardware.clear_trace();
+    hardware.radio.configure();
+    EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NONE);
+    EXPECT_FALSE(hardware.radio.status_has_warning());
+    EXPECT_EQ(hardware.receiving, rx);
+  }
+}
+
+TEST_P(SX126xBusyTransmit, RestoresEveryPreparationFailureWithoutAnotherTransmission) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware reference;
+  reference.configure(lora, rx, fixed);
+  reference.clear_trace();
+  ASSERT_EQ(reference.radio.transmit_packet(reference.packet), SX126xError::SX126X_ERROR_NONE);
+  size_t tx_command = 0;
+  for (size_t i = 0; i < reference.transactions.size(); i++) {
+    if (reference.transactions[i][0] == RADIO_SET_TX) {
+      tx_command = i + 1;
+      break;
+    }
+  }
+  ASSERT_NE(tx_command, 0u);
+  for (size_t fault = 1; fault <= tx_command; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hw;
+    PacketListener listener;
+    hw.configure(lora, rx, fixed);
+    hw.radio.register_listener(&listener);
+    const auto configured_params = hw.packet_params;
+    hw.clear_trace();
+    hw.fail_at = fault;
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+    EXPECT_TRUE(hw.transactions[fault - 1].empty());
+    EXPECT_TRUE(hw.cs.level);
+    EXPECT_EQ(hw.ends, hw.transactions.size());
+    EXPECT_EQ(hw.receiving, rx);
+    EXPECT_EQ(hw.packet_params, configured_params);
+    EXPECT_EQ(hw.irq, 0u);
+    EXPECT_FALSE(hw.radio.status_has_warning());
+    EXPECT_FALSE(hw.radio.is_failed());
+    const auto sends = hw.sends;
+    hw.clear_trace();
+    if (rx) {
+      if (!fixed) {
+        hw.packet.resize(9, 0x55);  // RX must accept a different length than the attempted TX.
+      }
+      hw.irq = IRQ_RX_DONE;
+      hw.radio.loop();
+      ASSERT_EQ(listener.packets.size(), 1u);
+      EXPECT_EQ(listener.packets[0], hw.packet);
+    }
+    EXPECT_EQ(hw.sends, sends);
+  }
+}
+
+TEST_P(SX126xBusyTransmit, FailedRestorationRequiresConfigureBeforeReceiveRecovery) {
+  const auto [lora, rx, fixed] = GetParam();
+  RadioHardware reference;
+  reference.configure(lora, rx, fixed);
+  reference.clear_trace();
+  ASSERT_EQ(reference.radio.transmit_packet(reference.packet), SX126xError::SX126X_ERROR_NONE);
+  size_t restoration = 0;
+  bool sent = false;
+  for (size_t i = 0; i < reference.transactions.size(); i++) {
+    if (reference.transactions[i][0] == RADIO_SET_TX) {
+      sent = true;
+    }
+    if (sent && reference.transactions[i][0] == RADIO_SET_STANDBY) {
+      restoration = i + 1;
+      break;
+    }
+  }
+  ASSERT_NE(restoration, 0u);
+  for (size_t fault = restoration; fault <= reference.transactions.size(); fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hw;
+    PacketListener listener;
+    hw.configure(lora, rx, fixed);
+    hw.radio.register_listener(&listener);
+    const auto configured_params = hw.packet_params;
+    hw.clear_trace();
+    hw.fail_at = fault;
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+    EXPECT_TRUE(hw.cs.level);
+    EXPECT_TRUE(hw.radio.status_has_warning());
+    EXPECT_FALSE(hw.radio.is_failed());
+    const auto sends = hw.sends;
+    hw.clear_trace();  // Clearing BUSY alone must not re-admit partial configuration.
+    hw.irq = IRQ_RX_DONE;
+    hw.radio.loop();
+    hw.radio.set_mode_rx();
+    hw.radio.set_mode_tx();
+    hw.radio.set_mode_standby(STDBY_XOSC);
+    hw.radio.set_mode_sleep();
+    hw.radio.run_image_cal();
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    EXPECT_TRUE(hw.transactions.empty());
+    EXPECT_TRUE(listener.packets.empty());
+    EXPECT_TRUE(hw.radio.status_has_warning());
+    hw.irq = 0;  // Hardware reset clears IRQs; the GPIO fake does not model reset.
+    hw.radio.configure();
+    EXPECT_FALSE(hw.radio.status_has_warning());
+    EXPECT_EQ(hw.packet_params, configured_params);
+    EXPECT_EQ(hw.receiving, rx);
+    if (rx) {
+      hw.irq = IRQ_RX_DONE;
+      hw.radio.loop();
+      ASSERT_EQ(listener.packets.size(), 1u);
+      EXPECT_EQ(listener.packets[0], hw.packet);
+    }
+    EXPECT_EQ(hw.sends, sends);  // Recovery must not depend on sending another packet.
+  }
+}
+
+TEST(SX126xBusy, PersistentBusyDuringPreparationAndRestorationRequiresConfigure) {
+  RadioHardware hw;
+  PacketListener listener;
+  hw.configure(true, true);
+  hw.radio.register_listener(&listener);
+  const auto configured_params = hw.packet_params;
+  hw.clear_trace();
+  auto normal_busy = hw.busy.on_read;
+  hw.busy.on_read = [&]() { return hw.transactions.size() >= 3 || normal_busy(); };
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+  EXPECT_FALSE(hw.receiving);
+  EXPECT_TRUE(hw.radio.status_has_warning());
+  EXPECT_EQ(hw.sends, 0u);
+  hw.busy.on_read = normal_busy;
+  hw.clear_trace();
+  hw.radio.set_mode_rx();
+  hw.radio.run_image_cal();
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_TRUE(hw.radio.status_has_warning());
+  hw.radio.configure();
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.packet_params, configured_params);
+  hw.irq = IRQ_RX_DONE;
+  hw.radio.loop();
+  ASSERT_EQ(listener.packets.size(), 1u);
+  EXPECT_EQ(listener.packets[0], hw.packet);
+  EXPECT_EQ(hw.sends, 0u);
+}
+
+INSTANTIATE_TEST_SUITE_P(LoRaAndFSKWithRxOrSleepAndFixedOrVariablePayload, SX126xBusyTransmit,
+                         ::testing::Combine(::testing::Bool(), ::testing::Bool(), ::testing::Bool()));
+
+class SX126xBusyReceive : public ::testing::TestWithParam<bool> {};
+
+TEST_P(SX126xBusyReceive, KeepsAPacketWhoseReadFailedAndRetries) {
+  const bool lora = GetParam();
+  for (size_t fault = 1; fault <= 5; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hardware;
+    PacketListener listener;
+    hardware.configure(lora, true);
+    hardware.radio.register_listener(&listener);
+    hardware.clear_trace();
+    hardware.irq = IRQ_RX_DONE;
+    hardware.fail_at = fault;
+    hardware.radio.loop();
+    hardware.expect_aborted(fault);
+    EXPECT_TRUE(listener.packets.empty());
+    EXPECT_TRUE(hardware.radio.status_has_warning());
+    EXPECT_FALSE(hardware.radio.is_failed());
+    // The flags may already be cleared; the packet is still read on the retry.
+    hardware.clear_trace();
+    LoopBlockingGuard retry{nullptr, nullptr, App.get_loop_component_start_time() + 200};
+    hardware.radio.loop();
+    ASSERT_EQ(listener.packets.size(), 1u);
+    EXPECT_EQ(listener.packets[0], hardware.packet);
+    EXPECT_FLOAT_EQ(listener.rssi, lora ? -40 : -42);
+    if (lora) {
+      EXPECT_FLOAT_EQ(listener.snr, 10);
+    } else {
+      EXPECT_TRUE(std::isnan(listener.snr));
+    }
+    EXPECT_FALSE(hardware.radio.status_has_warning());
+  }
+}
+
+INSTANTIATE_TEST_SUITE_P(LoRaAndFSK, SX126xBusyReceive, ::testing::Bool());
+
+// A packet whose flags were cleared before its read failed, then held by a send, survives a
+// second failed read
+TEST(SX126xBusy, HeldPacketSurvivesASecondFailedRead) {
+  RadioHardware hw;
+  PacketListener listener;
+  hw.configure(true, true);
+  hw.radio.register_listener(&listener);
+  hw.clear_trace();
+  hw.irq = IRQ_RX_DONE;
+  hw.fail_at = 3;  // the first read after the flags were cleared
+  hw.radio.loop();
+  ASSERT_EQ(hw.irq, 0);
+  ASSERT_TRUE(listener.packets.empty());
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  hw.clear_trace();
+  hw.fail_at = 2;  // the held packet's read
+  LoopBlockingGuard first{nullptr, nullptr, App.get_loop_component_start_time() + 200};
+  hw.radio.loop();
+  ASSERT_TRUE(listener.packets.empty());
+  hw.clear_trace();
+  LoopBlockingGuard second{nullptr, nullptr, App.get_loop_component_start_time() + 200};
+  hw.radio.loop();
+  ASSERT_EQ(listener.packets.size(), 1u);
+  EXPECT_EQ(listener.packets[0], hw.packet);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+TEST(SX126xBusy, KeepsPollingAnUnclearedInterruptAfterBusyTimeout) {
+  RadioHardware hardware;
+  PacketListener listener;
+  hardware.configure(true, true);
+  hardware.radio.register_listener(&listener);
+  hardware.dio.internal = true;  // No new ISR edge while the pending IRQ stays high.
+  hardware.clear_trace();
+  hardware.fail_at = 1;
+  hardware.irq = IRQ_RX_DONE;
+  hardware.radio.call();
+  EXPECT_TRUE(listener.packets.empty());
+  hardware.clear_trace();
+  LoopBlockingGuard retry{nullptr, nullptr, App.get_loop_component_start_time() + 200};
+  hardware.radio.call();
+  EXPECT_EQ(listener.packets.size(), 1u);
+}
+
+TEST(SX126xBusy, AssertsChipSelectBeforeWaitingForWakeup) {
+  RadioHardware hardware;
+  hardware.configure(true, true);
+  hardware.clear_trace();
+  hardware.busy.level = true;  // The CS callback releases BUSY only after selecting the chip.
+  EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_TRUE(hardware.cs.level);
+  EXPECT_EQ(hardware.ends, hardware.transactions.size());
+}
+
+TEST(SX126xBusy, RejectsSendBeforeSetupWithoutTouchingPins) {
+  RadioHardware hardware;
+  EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hardware.transactions.empty());
+  EXPECT_EQ(hardware.busy.reads, 0u);
+  EXPECT_EQ(hardware.dio.reads, 0u);
+}
+
+TEST(SX126xBusy, UnsupportedVersionFailsSetup) {
+  RadioHardware hardware;
+  hardware.supported_version = false;
+  hardware.configure(true, true);
+  EXPECT_TRUE(hardware.radio.is_failed());
+}
+
+TEST(SX126xBusy, RuntimeVersionFailureRequiresConfigureWithoutPermanentlyFailing) {
+  RadioHardware hardware;
+  hardware.configure(true, true);
+  hardware.supported_version = false;
+  hardware.radio.configure();
+  EXPECT_FALSE(hardware.radio.is_failed());
+  EXPECT_TRUE(hardware.radio.status_has_warning());
+  hardware.clear_trace();
+  EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  EXPECT_TRUE(hardware.transactions.empty());
+  hardware.supported_version = true;
+  hardware.radio.configure();
+  EXPECT_FALSE(hardware.radio.status_has_warning());
+  EXPECT_EQ(hardware.radio.transmit_packet(hardware.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+TEST(SX126xBusy, FailedReconfigurationRequiresSuccessfulConfigureBeforeOperations) {
+  RadioHardware reference;
+  reference.configure(true, true);
+  const size_t count = reference.transactions.size();
+  for (size_t fault = 1; fault <= count; fault++) {
+    SCOPED_TRACE(fault);
+    RadioHardware hw;
+    PacketListener listener;
+    hw.configure(true, true);
+    hw.radio.register_listener(&listener);
+    hw.clear_trace();
+    hw.fail_at = fault;
+    hw.radio.configure();
+    EXPECT_FALSE(hw.radio.is_failed());
+    hw.clear_trace();
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    hw.irq = IRQ_RX_DONE;
+    hw.radio.loop();
+    hw.radio.set_mode_rx();
+    hw.radio.set_mode_tx();
+    hw.radio.set_mode_standby(STDBY_XOSC);
+    hw.radio.set_mode_sleep();
+    hw.radio.run_image_cal();
+    EXPECT_TRUE(hw.transactions.empty());
+    EXPECT_TRUE(listener.packets.empty());
+    hw.radio.configure();
+    hw.irq = 0;
+    EXPECT_FALSE(hw.radio.status_has_warning());
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  }
+}
+
+TEST(SX126xBusy, RetryClearsStaleTxDoneBeforeWaitingForDelayedCompletion) {
+  RadioHardware reference;
+  reference.configure(true, true);
+  reference.clear_trace();
+  reference.radio.transmit_packet(reference.packet);
+  size_t cleanup = 0;
+  bool sent = false;
+  for (size_t i = 0; i < reference.transactions.size(); i++) {
+    if (reference.transactions[i][0] == RADIO_SET_TX) {
+      sent = true;
+    }
+    if (sent && reference.transactions[i][0] == RADIO_CLR_IRQSTATUS) {
+      cleanup = i + 1;
+      break;
+    }
+  }
+  ASSERT_NE(cleanup, 0u);
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.clear_trace();
+  hw.fail_at = cleanup;
+  ASSERT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+  EXPECT_EQ(hw.irq & IRQ_TX_DONE, 0);  // Shared restoration retries the failed IRQ clear.
+  hw.irq = IRQ_TX_DONE;                // A stale flag must still not finish the next TX.
+  hw.clear_trace();
+  hw.auto_complete = false;
+  unsigned polls = 0;
+  hw.dio.on_read = [&]() {
+    if (++polls == 5) {
+      hw.irq |= IRQ_TX_DONE;
+    }
+    return hw.irq != 0;
+  };
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_EQ(polls, 5u);
+  EXPECT_TRUE(hw.receiving);
+}
+
+}  // namespace esphome::sx126x::testing
+
+namespace esphome::sx126x::testing {
+template<typename T>
+concept RawSpiAccessible = requires(T &device) { device.transfer_byte(0); };
+template<typename T>
+concept ManualSelectionAccessible = requires(T &device) {
+  device.enable();
+  device.disable();
+};
+static_assert(!RawSpiAccessible<SX126x>);
+static_assert(!RawSpiAccessible<SX126xSpiDevice>);
+static_assert(!ManualSelectionAccessible<SX126x>);
+static_assert(!ManualSelectionAccessible<SX126xSpiDevice>);
+// The radio runs every command sequence and state change. Without component status or
+// listeners it cannot run user code mid-operation; SX126x::apply_() does that afterwards.
+static_assert(!std::is_base_of_v<Component, SX126xRadio>);
+}  // namespace esphome::sx126x::testing
+
+namespace esphome::sx126x::testing {
+TEST(SX126xBusy, FailedModeChangeCannotBeClearedByAnotherModeCommand) {
+  for (size_t fault = 1; fault <= 3; fault++) {
+    RadioHardware hw;
+    hw.configure(true, true);
+    hw.clear_trace();
+    hw.fail_at = fault;
+    hw.radio.set_mode_rx();
+    EXPECT_TRUE(hw.radio.status_has_warning());
+    hw.clear_trace();
+    hw.radio.set_mode_standby(STDBY_XOSC);
+    hw.radio.run_image_cal();
+    EXPECT_TRUE(hw.transactions.empty());
+    EXPECT_TRUE(hw.radio.status_has_warning());
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    hw.radio.configure();
+    EXPECT_FALSE(hw.radio.status_has_warning());
+    EXPECT_TRUE(hw.receiving);
+  }
+}
+
+TEST(SX126xBusy, ConfigurationCannotReenterSendPreparationOrRestoration) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.radio.call();  // Advance from setup into ESPHome loop scheduling.
+  hw.clear_trace();
+  auto write = hw.cs.on_write;
+  unsigned guarded = 0;
+  hw.cs.on_write = [&](bool high) {
+    write(high);
+    if (!high || hw.transactions.back().empty() || hw.transactions.back()[0] != RADIO_SET_STANDBY) {
+      return;
+    }
+    guarded++;
+    const auto commands = hw.transactions.size();
+    hw.radio.configure();
+    hw.radio.set_mode_rx();
+    hw.radio.loop();
+    EXPECT_TRUE(hw.radio.is_in_loop_state());
+    EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY);
+    EXPECT_EQ(hw.transactions.size(), commands);
+  };
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_EQ(guarded, 2u);
+  EXPECT_TRUE(hw.radio.is_in_loop_state());
+  EXPECT_TRUE(hw.receiving);
+}
+}  // namespace esphome::sx126x::testing
+
+namespace esphome::sx126x::testing {
+TEST(SX126xBusy, InvalidPayloadDoesNotEnterAnOperation) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.clear_trace();
+  EXPECT_EQ(hw.radio.transmit_packet(nullptr, 3), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet.data(), 0), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+TEST(SX126xBusy, ColdSleepIsWokenByAModeCommandAndWarmSleepRetainsIt) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.radio.set_mode_sleep(false);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.set_mode_sleep(true);
+  hw.clear_trace();
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  // Sleeping again leaves it asleep
+  hw.radio.set_mode_sleep(false);
+  EXPECT_TRUE(hw.transactions.empty());
+  // Any other mode command applies the lost configuration first
+  hw.radio.set_mode_rx();
+  EXPECT_FALSE(hw.transactions.empty());
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+// Runs the scheduler for ms milliseconds of real time, as the main loop would
+static void run_scheduler(uint32_t ms) {
+  const uint32_t start = millis();
+  while (millis() - start < ms) {
+    App.scheduler.call(millis());
+    delay(5);
+  }
+}
+
+TEST(SX126xBusy, FailedModeChangeIsReconfiguredWithoutBeingAsked) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.clear_trace();
+  hw.fail_at = 1;
+  hw.radio.set_mode_rx();
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  run_scheduler(1100);
+  EXPECT_FALSE(hw.radio.status_has_warning());
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  // Once configured, the retry stops
+  hw.clear_trace();
+  run_scheduler(1100);
+  EXPECT_TRUE(hw.transactions.empty());
+}
+
+TEST(SX126xBusy, ColdSleepIsNotReconfiguredWithoutBeingAsked) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.radio.set_mode_sleep(true);
+  hw.clear_trace();
+  run_scheduler(1100);
+  EXPECT_TRUE(hw.transactions.empty());
+}
+
+TEST(SX126xBusy, ConfigureBeforeSetupDoesNothing) {
+  RadioHardware hw;
+  hw.radio.configure();
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_EQ(hw.rst.writes, 0u);
+  hw.configure(true, true);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+// The TX mode command sends whatever the FIFO holds without tracking it; its TX_DONE is
+// cleared as a flag without a packet, and a send still works afterwards
+TEST(SX126xBusy, RawTxModeLeavesTheRadioUsable) {
+  RadioHardware hw;
+  PacketListener listener;
+  hw.configure(true, true);
+  hw.radio.register_listener(&listener);
+  hw.radio.set_mode_tx();
+  ASSERT_EQ(hw.irq & IRQ_TX_DONE, IRQ_TX_DONE);
+  hw.radio.loop();
+  EXPECT_EQ(hw.irq, 0);
+  EXPECT_TRUE(listener.packets.empty());
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+TEST(SX126xBusy, PacketThatFailedItsCrcDoesNotHoldUpASend) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.irq = IRQ_RX_DONE | IRQ_CRC_ERROR;
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+
+TEST(SX126xBusy, PacketCompletingDuringAReadIsReadNext) {
+  RadioHardware hw;
+  PacketListener listener;
+  hw.configure(true, true);
+  hw.radio.register_listener(&listener);
+  bool second = false;
+  hw.on_command = [&](uint8_t opcode) {
+    if (opcode == RADIO_READ_BUFFER && !second) {
+      second = true;
+      hw.irq |= IRQ_RX_DONE;
+    }
+  };
+  hw.irq = IRQ_RX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(listener.packets.size(), 1u);
+  EXPECT_EQ(hw.irq & IRQ_RX_DONE, IRQ_RX_DONE);  // DIO1 stays high for the second packet
+  hw.radio.loop();
+  EXPECT_EQ(listener.packets.size(), 2u);
+}
+
+TEST(SX126xBusy, UnavailableLoopStopsAndConfigurationResumesReceiveWithoutAnInterrupt) {
+  for (bool internal : {false, true}) {
+    for (unsigned cause = 0; cause < 3; cause++) {
+      SCOPED_TRACE(internal);
+      SCOPED_TRACE(cause);
+      RadioHardware hw;
+      PacketListener received;
+      hw.configure(true, true);
+      hw.radio.register_listener(&received);
+      // Set after setup: the fake pin cannot attach a hardware interrupt.
+      hw.dio.internal = internal;
+      hw.clear_trace();
+      if (cause == 0) {
+        hw.radio.set_mode_sleep(true);
+      } else if (cause == 1) {
+        hw.fail_at = 1;
+        hw.radio.configure();
+      } else {
+        hw.fail_at = 1;
+        hw.radio.set_mode_rx();
+      }
+      hw.clear_trace();
+      hw.radio.call();
+      ASSERT_TRUE(hw.radio.is_idle());
+      EXPECT_TRUE(hw.transactions.empty());
+      EXPECT_EQ(hw.dio.reads, 0u);
+      hw.radio.configure();
+      ASSERT_TRUE(hw.radio.is_in_loop_state());
+      hw.irq = IRQ_RX_DONE;  // No ISR edge: configure() must resume polling itself.
+      hw.radio.call();
+      ASSERT_EQ(received.packets.size(), 1u);
+      EXPECT_EQ(received.packets[0], hw.packet);
+    }
+  }
+}
+}  // namespace esphome::sx126x::testing
+
+namespace esphome::sx126x::testing {
+TEST(SX126xProfile, SettersDoNotChangeAppliedPacketOrRestorationPolicy) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.radio.set_payload_length(2);
+  hw.radio.set_rx_start(false);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_TRUE(hw.receiving);
+  hw.radio.configure();
+  EXPECT_EQ(hw.radio.get_max_packet_size(), 2u);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_INVALID_PARAMS);
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet.data(), 2), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_FALSE(hw.receiving);
+}
+
+TEST(SX126xProfile, RejectsOversizedSyncValueBeforeResetOrSpi) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.radio.set_sync_value(std::vector<uint8_t>(9, 1));
+  hw.clear_trace();
+  const auto reset_writes = hw.rst.writes;
+  hw.radio.configure();
+  EXPECT_EQ(hw.rst.writes, reset_writes);
+  EXPECT_TRUE(hw.transactions.empty());
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+  hw.radio.set_sync_value({0x14, 0x24});
+  hw.radio.configure();
+  EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NONE);
+}
+}  // namespace esphome::sx126x::testing
+
+#ifdef USE_HOST
+namespace esphome::sx126x::testing {
+template<typename F> static std::string capture_radio_logs(F action) {
+  const auto previous_baud_rate = logger::global_logger->get_baud_rate();
+  ::testing::internal::CaptureStdout();
+  logger::global_logger->set_baud_rate(115200);
+  action();
+  logger::global_logger->set_baud_rate(previous_baud_rate);
+  return ::testing::internal::GetCapturedStdout();
+}
+
+TEST(SX126xDiagnostics, BlockingRejectionsExplainWhyNoPacketWasSent) {
+  RadioHardware hw;
+  auto output = capture_radio_logs(
+      [&]() { EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_NOT_READY); });
+  EXPECT_NE(output.find("Packet send failed: radio not ready"), std::string::npos);
+  hw.configure(true, true, true);
+  hw.clear_trace();
+  output = capture_radio_logs(
+      [&]() { EXPECT_EQ(hw.radio.transmit_packet(hw.packet.data(), 2), SX126xError::SX126X_ERROR_INVALID_PARAMS); });
+  EXPECT_NE(output.find("Packet send failed: invalid payload"), std::string::npos);
+  EXPECT_TRUE(hw.transactions.empty());
+  hw.irq = IRQ_RX_DONE;
+  output =
+      capture_radio_logs([&]() { EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY); });
+  EXPECT_NE(output.find("Packet send failed: radio busy"), std::string::npos);
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  EXPECT_EQ(hw.sends, 0u);
+  hw.radio.loop();  // Deliver the held packet, which also clears its IRQ.
+  EXPECT_EQ(hw.irq, 0u);
+  hw.clear_trace();
+  hw.fail_at = 1;
+  output = capture_radio_logs(
+      [&]() { EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT); });
+  EXPECT_NE(output.find("Packet send failed: bus timeout"), std::string::npos);
+  EXPECT_EQ(hw.sends, 0u);
+}
+
+TEST(SX126xDiagnostics, AsyncAdmissionLeavesRejectionReportingToItsCaller) {
+  class Completion final : public SX126xTransmitListener {
+   public:
+    void on_transmit_complete(SX126xError result) override { ADD_FAILURE() << "Rejected send completed"; }
+  } completion;
+  RadioHardware hw;
+  const auto output = capture_radio_logs([&]() {
+    EXPECT_EQ(hw.radio.start_transmit_async(&completion, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    hw.configure(true, true, true);
+    EXPECT_EQ(hw.radio.start_transmit_async(&completion, hw.packet.data(), 2),
+              SX126xError::SX126X_ERROR_INVALID_PARAMS);
+    hw.irq = IRQ_RX_DONE;
+    EXPECT_EQ(hw.radio.start_transmit_async(&completion, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+  });
+  EXPECT_EQ(output.find("Packet send failed"), std::string::npos);
+  EXPECT_EQ(hw.sends, 0u);
+}
+
+TEST(SX126xDiagnostics, FailedSetupPrintsRequestedConfiguration) {
+  RadioHardware hw;
+  hw.fail_at = 1;
+  hw.radio.set_pa_power(10);
+  hw.configure(true, true, true);
+  ASSERT_TRUE(hw.radio.is_failed());
+  const auto output = capture_radio_logs([&]() { hw.radio.dump_config(); });
+  EXPECT_NE(output.find("Ready for operation: NO"), std::string::npos);
+  EXPECT_NE(output.find("Requested configuration:"), std::string::npos);
+  EXPECT_NE(output.find("Frequency: 915000000 Hz"), std::string::npos);
+  EXPECT_NE(output.find("PA Power: 10 dBm"), std::string::npos);
+  EXPECT_NE(output.find("Payload Length: 3"), std::string::npos);
+  EXPECT_NE(output.find("Sync Value: 0x1424"), std::string::npos);
+}
+
+TEST(SX126xDiagnostics, StagedConfigurationIsLabelledAndDoesNotAlterAppliedSettings) {
+  RadioHardware hw;
+  hw.configure(true, true, true);
+  hw.radio.set_frequency(868000000);
+  hw.radio.set_payload_length(2);
+  auto output = capture_radio_logs([&]() { hw.radio.dump_config(); });
+  EXPECT_NE(output.find("Ready for operation: YES"), std::string::npos);
+  EXPECT_NE(output.find("Requested configuration:"), std::string::npos);
+  EXPECT_NE(output.find("Frequency: 868000000 Hz"), std::string::npos);
+  EXPECT_NE(output.find("Payload Length: 2"), std::string::npos);
+  EXPECT_EQ(hw.radio.get_max_packet_size(), 3u);
+  hw.clear_trace();
+  hw.fail_at = 1;
+  hw.radio.configure();
+  output = capture_radio_logs([&]() { hw.radio.dump_config(); });
+  EXPECT_NE(output.find("Ready for operation: NO"), std::string::npos);
+  EXPECT_NE(output.find("Frequency: 868000000 Hz"), std::string::npos);
+  EXPECT_EQ(hw.radio.get_max_packet_size(), 3u);
+}
+class SX126xTimeoutDiagnostics : public ::testing::TestWithParam<bool> {};
+
+TEST_P(SX126xTimeoutDiagnostics, BlockingTimeoutLogsFailureAfterRestoration) {
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  if (GetParam()) {
+    hw.dio.on_read = [&]() {
+      if (hw.sends > 0) {
+        hw.irq = IRQ_RX_TX_TIMEOUT;
+      }
+      return hw.irq != 0;
+    };
+  }
+  const auto output =
+      capture_radio_logs([&]() { EXPECT_EQ(hw.radio.transmit_packet(hw.packet), SX126xError::SX126X_ERROR_TIMEOUT); });
+  EXPECT_NE(output.find("Packet send failed: timeout"), std::string::npos);
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_FALSE(hw.radio.is_transmitting());
+  EXPECT_FALSE(hw.radio.status_has_warning());  // Restoration itself succeeded.
+}
+
+INSTANTIATE_TEST_SUITE_P(SoftwareDeadlineAndRadioTimeout, SX126xTimeoutDiagnostics, ::testing::Bool());
+
+TEST(SX126xDiagnostics, AsyncTimeoutLeavesCompletionReportingToItsCaller) {
+  struct Completion final : SX126xTransmitListener {
+    void on_transmit_complete(SX126xError result) override {
+      this->count++;
+      EXPECT_EQ(result, SX126xError::SX126X_ERROR_TIMEOUT);
+    }
+    unsigned count{0};
+  } completion;
+  RadioHardware hw;
+  hw.configure(true, true);
+  const auto output = capture_radio_logs([&]() {
+    ASSERT_EQ(hw.radio.start_transmit_async(&completion, hw.packet), SX126xError::SX126X_ERROR_NONE);
+    hw.irq = IRQ_RX_TX_TIMEOUT;
+    hw.radio.loop();
+  });
+  EXPECT_EQ(completion.count, 1u);
+  EXPECT_EQ(output.find("Packet send failed"), std::string::npos);
+}
+
+}  // namespace esphome::sx126x::testing
+#endif
@@ -0,0 +1,182 @@
+#include "sx126x_test_helpers.h"
+#include "esphome/components/logger/logger.h"
+#include "esphome/core/application.h"
+#include <string>
+#include <tuple>
+
+namespace esphome::sx126x::testing {
+
+class RadioLogCallback {
+ public:
+  RadioLogCallback() : previous_(logger::global_logger) {
+    this->logger_.pre_setup();
+    this->logger_.set_log_level(ESPHOME_LOG_LEVEL_WARN);
+    this->logger_.add_log_callback(this,
+                                   [](void *instance, uint8_t level, const char *tag, const char *message, size_t len) {
+                                     auto *self = static_cast<RadioLogCallback *>(instance);
+                                     if (self->callback_) {
+                                       self->callback_(std::string(message, len));
+                                     }
+                                   });
+  }
+  ~RadioLogCallback() { logger::global_logger = this->previous_; }
+  void set_callback(std::function<void(const std::string &)> callback) { this->callback_ = std::move(callback); }
+
+ private:
+  std::function<void(const std::string &)> callback_;
+  logger::Logger *previous_;
+  logger::Logger logger_{0};
+};
+
+struct ReentryCompletion final : SX126xTransmitListener {
+  void on_transmit_complete(SX126xError result) override { this->results.push_back(result); }
+  std::vector<SX126xError> results;
+};
+
+// Setup reports why it failed, not a generic reason
+TEST(SX126xReentry, FailedSetupKeepsItsReason) {
+  RadioLogCallback log;
+  std::vector<std::string> messages;
+  log.set_callback([&](const std::string &message) { messages.push_back(message); });
+  RadioHardware hw;
+  hw.supported_version = false;
+  hw.configure(true, true);
+  ASSERT_TRUE(hw.radio.is_failed());
+  bool found = false;
+  for (const auto &message : messages)
+    found |= message.find("set Error flag: Unsupported chip version") != std::string::npos;
+  EXPECT_TRUE(found);
+}
+
+// Status logging is the only user code that can run inside a radio operation. It runs only
+// after the operation has committed its state, so a callback sees either a running send or a
+// released radio, and the interrupted operation touches nothing after the callback returns.
+
+TEST(SX126xReentry, SuccessfulStartRunsNoUserCode) {
+  RadioHardware hw;
+  RadioLogCallback log;
+  ReentryCompletion outer, nested;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  hw.radio.status_set_warning(LOG_STR("Previous communication failure"));
+  hw.irq = IRQ_TX_DONE;  // A stale IRQ must not complete the new send either.
+  unsigned callbacks = 0;
+  log.set_callback([&](const std::string &message) {
+    if (message.find("cleared Warning flag") != std::string::npos) {
+      callbacks++;
+      EXPECT_FALSE(hw.radio.is_transmitting());  // Only the completion clears the warning.
+      EXPECT_EQ(hw.radio.start_transmit_async(&nested, hw.packet), SX126xError::SX126X_ERROR_NONE);
+    }
+  });
+  ASSERT_EQ(hw.radio.start_transmit_async(&outer, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_EQ(callbacks, 0u);
+  EXPECT_TRUE(outer.results.empty());
+  LoopBlockingGuard clock{nullptr, nullptr, millis()};
+  hw.radio.loop();
+  EXPECT_TRUE(outer.results.empty());  // The stale IRQ was cleared before the send.
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  ASSERT_EQ(callbacks, 1u);
+  EXPECT_EQ(outer.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+  EXPECT_TRUE(nested.results.empty());
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_EQ(hw.sends, 2u);
+  ASSERT_TRUE(hw.radio.cancel_transmit_async(&nested));
+  EXPECT_EQ(nested.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_CANCELLED}));
+  EXPECT_EQ(outer.results.size(), 1u);
+}
+
+class SX126xStartReentry : public ::testing::TestWithParam<bool> {};
+
+TEST_P(SX126xStartReentry, WarningCallbackAfterFailedStartSeesReleasedRadio) {
+  const bool cold_sleep = GetParam();
+  RadioHardware hw;
+  RadioLogCallback log;
+  ReentryCompletion outer, nested;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  hw.radio.status_set_warning(LOG_STR("Previous communication failure"));
+  hw.clear_trace();
+  hw.fail_at = 3;  // Preparation fails; restoration succeeds and clears the warning.
+  unsigned callbacks = 0;
+  size_t commands_after_callback = 0;
+  log.set_callback([&](const std::string &message) {
+    if (message.find("cleared Warning flag") != std::string::npos) {
+      callbacks++;
+      EXPECT_FALSE(hw.radio.is_transmitting());
+      EXPECT_EQ(hw.receiving, true);  // Restoration finished before the callback.
+      if (cold_sleep) {
+        hw.radio.set_mode_sleep(true);
+      } else {
+        EXPECT_EQ(hw.radio.start_transmit_async(&nested, hw.packet), SX126xError::SX126X_ERROR_NONE);
+      }
+      commands_after_callback = hw.transactions.size();
+    }
+  });
+  EXPECT_EQ(hw.radio.start_transmit_async(&outer, hw.packet), SX126xError::SX126X_ERROR_BUSY_TIMEOUT);
+  ASSERT_EQ(callbacks, 1u);
+  EXPECT_EQ(hw.transactions.size(), commands_after_callback);  // The failed start touched nothing after it.
+  EXPECT_TRUE(outer.results.empty());                          // A rejected start never completes.
+  if (cold_sleep) {
+    EXPECT_FALSE(hw.radio.is_transmitting());
+    EXPECT_EQ(hw.radio.start_transmit_async(&outer, hw.packet), SX126xError::SX126X_ERROR_NOT_READY);
+    EXPECT_EQ(hw.sends, 0u);
+    return;
+  }
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_EQ(hw.sends, 1u);
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  EXPECT_EQ(nested.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+  EXPECT_TRUE(outer.results.empty());
+}
+
+INSTANTIATE_TEST_SUITE_P(NestedSendOrColdSleep, SX126xStartReentry, ::testing::Bool());
+
+class SX126xPollingReentry : public ::testing::TestWithParam<std::tuple<unsigned, bool>> {};
+
+TEST_P(SX126xPollingReentry, WarningCallbackCannotCancelOrDisturbAFinishedSend) {
+  const auto [failed_command, reuse_listener] = GetParam();
+  RadioHardware hw;
+  RadioLogCallback log;
+  ReentryCompletion first, second;
+  auto *replacement = reuse_listener ? &first : &second;
+  hw.configure(true, true);
+  hw.auto_complete = false;
+  ASSERT_EQ(hw.radio.start_transmit_async(&first, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.clear_trace();
+  hw.fail_at = failed_command;  // 0: success, 1: IRQ read fails, 2: IRQ clear fails.
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.status_set_warning(LOG_STR("Previous communication failure"));
+  unsigned callbacks = 0;
+  size_t commands_after_replacement = 0;
+  log.set_callback([&](const std::string &message) {
+    if (callbacks == 0 && message.find("cleared Warning flag") != std::string::npos) {
+      callbacks++;
+      EXPECT_TRUE(first.results.empty());                    // Status is reported before the completion.
+      EXPECT_FALSE(hw.radio.cancel_transmit_async(&first));  // Already finished: no second completion.
+      EXPECT_EQ(hw.radio.start_transmit_async(replacement, hw.packet), SX126xError::SX126X_ERROR_NONE);
+      commands_after_replacement = hw.transactions.size();
+    }
+  });
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, millis()};
+    hw.radio.loop();
+  }
+  ASSERT_EQ(callbacks, 1u);
+  const auto expected = failed_command == 0 ? SX126xError::SX126X_ERROR_NONE : SX126xError::SX126X_ERROR_BUSY_TIMEOUT;
+  EXPECT_EQ(first.results, (std::vector<SX126xError>{expected}));
+  EXPECT_TRUE(second.results.empty());
+  EXPECT_TRUE(hw.radio.is_transmitting());
+  EXPECT_EQ(hw.transactions.size(), commands_after_replacement);  // No stale IRQ clear or restoration.
+  hw.irq = IRQ_TX_DONE;
+  hw.radio.loop();
+  ASSERT_EQ(replacement->results.size(), reuse_listener ? 2u : 1u);
+  EXPECT_EQ(replacement->results.back(), SX126xError::SX126X_ERROR_NONE);
+  EXPECT_FALSE(hw.radio.is_transmitting());
+}
+
+INSTANTIATE_TEST_SUITE_P(ReadSuccessReadFailureAndClearFailure, SX126xPollingReentry,
+                         ::testing::Combine(::testing::Values(0u, 1u, 2u), ::testing::Bool()));
+
+}  // namespace esphome::sx126x::testing
@@ -0,0 +1,127 @@
+#include "sx126x_test_helpers.h"
+#include "esphome/core/application.h"
+#include <tuple>
+
+namespace esphome::sx126x::testing {
+
+struct RejectedCompletion final : SX126xTransmitListener {
+  void on_transmit_complete(SX126xError result) override { ADD_FAILURE() << "Rejected transmission completed"; }
+};
+
+class SX126xReceiveRetry : public ::testing::TestWithParam<std::tuple<bool, unsigned, bool>> {};
+
+TEST_P(SX126xReceiveRetry, PersistentBusyIsRateLimitedAndRecoversWithoutNewEdge) {
+  const auto [held_receive, failed_command, rollover] = GetParam();
+  RadioHardware hw;
+  PacketListener listener;
+  RejectedCompletion tx;
+  hw.configure(true, true);
+  hw.radio.register_listener(&listener);
+  hw.radio.call();
+  hw.dio.internal = true;
+  if (held_receive) {
+    auto write = hw.cs.on_write;
+    hw.cs.on_write = [&](bool high) {
+      write(high);
+      if (high && !hw.transactions.back().empty() && hw.transactions.back()[0] == RADIO_SET_STANDBY) {
+        hw.irq = IRQ_RX_DONE;
+      }
+    };
+    EXPECT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_BUSY);
+    hw.cs.on_write = write;
+  }
+  hw.clear_trace();
+  hw.irq = IRQ_RX_DONE;
+  hw.fail_at = failed_command;
+  const uint32_t start = rollover ? 0xFFFFFFF0u : 1000;
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, start};
+    hw.radio.call();
+  }
+  hw.expect_aborted(failed_command);
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  const auto normal_busy = hw.busy.on_read;
+  hw.busy.on_read = []() { return true; };
+  for (uint32_t elapsed = 1; elapsed < 200; elapsed++) {
+    LoopBlockingGuard clock{nullptr, nullptr, start + elapsed};
+    hw.radio.call();
+  }
+  EXPECT_EQ(hw.transactions.size(), failed_command);  // No SPI/BUSY waits inside the retry interval.
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, start + 200};
+    hw.radio.call();
+  }
+  ASSERT_EQ(hw.transactions.size(), failed_command + 1);
+  EXPECT_TRUE(hw.transactions.back().empty());
+  EXPECT_TRUE(hw.radio.is_in_loop_state());
+  EXPECT_TRUE(hw.cs.level);
+  EXPECT_EQ(hw.irq, IRQ_RX_DONE);
+  EXPECT_TRUE(listener.packets.empty());
+  hw.busy.on_read = normal_busy;
+  hw.fail_at = 0;
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, start + 399};
+    hw.radio.call();
+    EXPECT_EQ(hw.transactions.size(), failed_command + 1);
+  }
+  {
+    LoopBlockingGuard clock{nullptr, nullptr, start + 400};
+    hw.radio.call();
+  }
+  ASSERT_EQ(listener.packets.size(), 1u);
+  EXPECT_EQ(listener.packets.front(), hw.packet);
+  EXPECT_FALSE(hw.radio.status_has_warning());
+  EXPECT_TRUE(hw.receiving);
+  EXPECT_EQ(hw.sends, 0u);
+  hw.radio.call();
+  EXPECT_EQ(listener.packets.size(), 1u);
+}
+
+INSTANTIATE_TEST_SUITE_P(IdleAndHeldRxWithIrqAndPacketFailuresAcrossRollover, SX126xReceiveRetry,
+                         ::testing::Combine(::testing::Bool(), ::testing::Values(1u, 2u), ::testing::Bool()));
+
+TEST(SX126xReceiveRetry, SuccessfulConfigurationClearsBackoffAndOtherRadiosRemainIndependent) {
+  RadioHardware failed, other;
+  PacketListener recovered, unaffected;
+  failed.configure(true, true);
+  other.configure(true, true);
+  failed.radio.register_listener(&recovered);
+  other.radio.register_listener(&unaffected);
+  failed.clear_trace();
+  failed.fail_at = 1;
+  failed.irq = IRQ_RX_DONE;
+  LoopBlockingGuard clock{nullptr, nullptr, 1000};
+  failed.radio.loop();
+  other.irq = IRQ_RX_DONE;
+  other.radio.loop();
+  ASSERT_EQ(unaffected.packets.size(), 1u);
+  EXPECT_TRUE(recovered.packets.empty());
+  failed.clear_trace();
+  failed.radio.configure();
+  failed.irq = IRQ_RX_DONE;
+  failed.radio.loop();
+  ASSERT_EQ(recovered.packets.size(), 1u);  // Explicit recovery does not wait for the old retry deadline.
+}
+
+TEST(SX126xReceiveRetry, ReceiveBackoffDoesNotDelayTransmitCompletion) {
+  struct Completion final : SX126xTransmitListener {
+    void on_transmit_complete(SX126xError result) override { this->results.push_back(result); }
+    std::vector<SX126xError> results;
+  } tx;
+  RadioHardware hw;
+  hw.configure(true, true);
+  hw.clear_trace();
+  hw.fail_at = 1;
+  hw.irq = IRQ_TX_DONE;  // Failed read of an unrelated stale IRQ starts the RX retry gate.
+  LoopBlockingGuard clock{nullptr, nullptr, millis()};
+  hw.radio.loop();
+  EXPECT_TRUE(hw.radio.status_has_warning());
+  hw.clear_trace();
+  hw.irq = 0;
+  ASSERT_EQ(hw.radio.start_transmit_async(&tx, hw.packet), SX126xError::SX126X_ERROR_NONE);
+  hw.radio.loop();  // Same cached tick, before the RX retry gate opens.
+  EXPECT_EQ(tx.results, (std::vector<SX126xError>{SX126xError::SX126X_ERROR_NONE}));
+  EXPECT_TRUE(hw.receiving);
+}
+
+}  // namespace esphome::sx126x::testing
@@ -0,0 +1,237 @@
+#pragma once
+#include <gtest/gtest.h>
+#include <functional>
+#include <vector>
+#include "esphome/components/sx126x/sx126x.h"
+namespace esphome::sx126x::testing {
+class TestPin : public GPIOPin {
+ public:
+  void setup() override {}
+  void pin_mode(gpio::Flags flags) override {}
+  gpio::Flags get_flags() const override { return gpio::FLAG_NONE; }
+  size_t dump_summary(char *buffer, size_t len) const override { return snprintf(buffer, len, "test"); }
+  bool digital_read() override {
+    this->reads++;
+    return this->on_read ? this->on_read() : this->level;
+  }
+  void digital_write(bool level) override {
+    this->writes++;
+    this->level = level;
+    if (this->on_write) {
+      this->on_write(level);
+    }
+  }
+  bool is_internal() override { return this->internal; }
+
+  bool level{false};
+  bool internal{false};
+  unsigned reads{0};
+  unsigned writes{0};
+  std::function<bool()> on_read;
+  std::function<void(bool)> on_write;
+};
+
+// Exercise the real software SPI adapter and driver through GPIO pins. Each CS
+// assertion starts a command; BUSY can reject any one of those commands.
+class RadioHardware {
+ public:
+  RadioHardware() {
+    this->cs.level = true;
+    this->cs.on_write = [this](bool high) {
+      if (!high) {
+        EXPECT_FALSE(this->selected_);
+        this->selected_ = true;
+        this->transactions.emplace_back();
+        this->bit_ = 0;
+        this->byte_ = 0;
+        this->busy.level = this->transactions.size() == this->fail_at;
+      } else if (this->selected_) {
+        this->selected_ = false;
+        this->ends++;
+        const auto &command = this->transactions.back();
+        if (command.empty()) {
+          return;
+        }
+        switch (command[0]) {
+          case RADIO_SET_PACKETPARAMS:
+            this->packet_params = command;
+            break;
+          case RADIO_CLR_IRQSTATUS:
+            this->irq &= ~((uint16_t(command[1]) << 8) | command[2]);
+            break;
+          case RADIO_SET_TX:
+            this->sends++;
+            if (this->auto_complete) {
+              this->irq |= IRQ_TX_DONE;
+            }
+            break;
+          case RADIO_SET_RX:
+            this->receiving = true;
+            break;
+          case RADIO_SET_SLEEP:
+          case RADIO_SET_STANDBY:
+            this->receiving = false;
+            break;
+          default:
+            break;
+        }
+        if (this->on_command) {
+          this->on_command(command[0]);
+        }
+      }
+    };
+    this->busy.on_read = [this]() {
+      EXPECT_TRUE(this->selected_);  // NSS must wake the chip before waiting.
+      return this->busy.level;
+    };
+    this->miso.on_read = [this]() {
+      EXPECT_TRUE(this->selected_);
+      EXPECT_FALSE(this->busy.level);  // No clocks/data may follow a BUSY timeout.
+      auto &command = this->transactions.back();
+      const bool bit = (this->reply_byte_(command) >> (7 - this->bit_)) & 1;
+      this->byte_ = (this->byte_ << 1) | this->mosi.level;
+      if (++this->bit_ == 8) {
+        command.push_back(this->byte_);
+        this->byte_ = 0;
+        this->bit_ = 0;
+      }
+      return bit;
+    };
+    this->dio.on_read = [this]() { return this->irq != 0; };
+    this->rst.on_write = [this](bool high) {
+      if (!high) {
+        this->irq = 0;
+      }
+    };
+    this->spi.set_clk(&this->clk);
+    this->spi.set_mosi(&this->mosi);
+    this->spi.set_miso(&this->miso);
+    // call() runs setup() and marks the bus set up, so it accepts devices
+    this->spi.call();
+    this->radio.set_spi_parent(&this->spi);
+    this->radio.set_cs_pin(&this->cs);
+    this->radio.set_busy_pin(&this->busy);
+    this->radio.set_dio1_pin(&this->dio);
+    this->radio.set_rst_pin(&this->rst);
+    this->radio.set_frequency(915000000);
+    this->radio.set_tcxo_voltage(TCXO_CTRL_1_8V);
+    this->radio.set_rf_switch(true);
+    this->radio.set_crc_enable(true);
+    this->radio.set_sync_value({0x14, 0x24});
+  }
+  ~RadioHardware() {
+    // The configuration retry interval (id 0) must not outlive the radio
+    App.scheduler.cancel_interval(&this->radio, uint32_t{0});
+    this->radio.spi_teardown();
+  }
+
+  void configure(bool lora, bool rx, bool fixed = false) {
+    this->radio.set_modulation(lora ? PACKET_TYPE_LORA : PACKET_TYPE_GFSK);
+    this->radio.set_bandwidth(lora ? SX126X_BW_125000 : SX126X_BW_4800);
+    this->radio.set_bitrate(4800);
+    this->radio.set_rx_start(rx);
+    this->radio.set_payload_length(fixed ? 3 : 0);
+    this->radio.call();  // The normal component lifecycle runs setup().
+  }
+
+  void clear_trace() {
+    this->transactions.clear();
+    this->ends = 0;
+    this->fail_at = 0;
+    this->busy.level = false;
+    this->dio.reads = 0;
+  }
+
+  void expect_aborted(size_t command) {
+    ASSERT_EQ(this->transactions.size(), command);
+    EXPECT_TRUE(this->transactions.back().empty());
+    EXPECT_EQ(this->ends, command);
+    EXPECT_TRUE(this->cs.level);
+  }
+
+  SX126x radio;
+  spi::SPIComponent spi;
+  TestPin cs, busy, dio, rst, clk, mosi, miso;
+  std::vector<std::vector<uint8_t>> transactions;
+  std::vector<uint8_t> packet{0x11, 0x22, 0x33};
+  std::vector<uint8_t> packet_params;
+  size_t fail_at{0};
+  size_t ends{0};
+  unsigned sends{0};
+  uint16_t irq{0};
+  // Called as each command ends, with its opcode
+  std::function<void(uint8_t)> on_command;
+  bool receiving{false};
+  bool auto_complete{true};
+  bool supported_version{true};
+
+ protected:
+  uint8_t reply_byte_(const std::vector<uint8_t> &command) {
+    if (command.empty()) {
+      return 0;
+    }
+    const size_t pos = command.size();
+    switch (command[0]) {
+      case RADIO_READ_REGISTER:
+        if (pos >= 4) {
+          static constexpr char VERSION[16] = "SX1262";
+          return this->supported_version ? VERSION[pos - 4] : 0;
+        }
+        break;
+      case RADIO_GET_IRQSTATUS:
+        if (pos == 2) {
+          return this->irq >> 8;
+        }
+        if (pos == 3) {
+          return this->irq & 0xFF;
+        }
+        break;
+      case RADIO_GET_PACKETSTATUS:
+        if (pos == 2) {
+          return 80;
+        }
+        if (pos == 3) {
+          return 40;
+        }
+        if (pos == 4) {
+          return 84;
+        }
+        break;
+      case RADIO_GET_RXBUFFERSTATUS:
+        if (pos == 2) {
+          return this->packet.size();
+        }
+        if (pos == 3) {
+          return 7;
+        }
+        break;
+      case RADIO_READ_BUFFER:
+        if (pos >= 3) {
+          EXPECT_EQ(command[1], 7);
+          return this->packet[pos - 3];
+        }
+        break;
+      default:
+        break;
+    }
+    return 0;
+  }
+
+  bool selected_{false};
+  uint8_t bit_{0};
+  uint8_t byte_{0};
+};
+
+class PacketListener : public SX126xListener {
+ public:
+  void on_packet(const std::vector<uint8_t> &packet, float rssi, float snr) override {
+    this->packets.push_back(packet);
+    this->rssi = rssi;
+    this->snr = snr;
+  }
+  std::vector<std::vector<uint8_t>> packets;
+  float rssi{};
+  float snr{};
+};
+
+}  // namespace esphome::sx126x::testing
@@ -10,7 +10,8 @@ def override_manifest(manifest: ComponentManifestOverride) -> None:
    manifest.auto_load = ["climate_ir", "climate"]

    async def to_code_testing(config: ConfigType) -> None:
-        # Compiles in the Hisense ARG model, which climate.py adds only when it is configured
+        # Compiles in the Hisense ARG and Hitachi models, which climate.py adds only when configured
        cg.add_define("USE_WHIRLPOOL_HISENSE_ARG")
+        cg.add_define("USE_WHIRLPOOL_HITACHI_HCRA31NEWH")

    manifest.to_code = to_code_testing
@@ -8,3 +8,8 @@ climate:
    model: HISENSE_ARG
    transmitter_id: xmitr
    receiver_id: rcvr
+  - platform: whirlpool
+    name: Whirlpool Hitachi HCRA31NEWH Climate
+    model: HITACHI_HCRA31NEWH
+    transmitter_id: xmitr
+    receiver_id: rcvr
@@ -252,6 +252,9 @@ TEST(WhirlpoolHisenseArg, SwingIsSentOnEveryTransmit) {

 TEST(WhirlpoolDG11J13A, SwingIsSentOnlyWhenItChanges) {
  Fixture f(MODEL_DG11J1_3A);
+  f.command(climate::CLIMATE_MODE_COOL, 24, climate::CLIMATE_FAN_LOW, climate::CLIMATE_SWING_OFF);
+  EXPECT_EQ(f.last_frame()[2] & 0x80, 0) << "swing is already off";
+
  f.command(climate::CLIMATE_MODE_COOL, 24, climate::CLIMATE_FAN_LOW, climate::CLIMATE_SWING_VERTICAL);
  Frame frame = f.last_frame();
  EXPECT_EQ(frame[2] & 0x80, 0x80);
@@ -261,6 +264,9 @@ TEST(WhirlpoolDG11J13A, SwingIsSentOnlyWhenItChanges) {
  frame = f.last_frame();
  EXPECT_EQ(frame[2] & 0x80, 0);
  EXPECT_EQ(frame[8], 0x00);
+
+  f.command(climate::CLIMATE_MODE_COOL, 25, climate::CLIMATE_FAN_LOW, climate::CLIMATE_SWING_VERTICAL);
+  EXPECT_EQ(f.last_frame()[2] & 0x80, 0) << "swing is already vertical";
 }

 // Cool 24 C (step 8), fan low, powered on assumed
@@ -385,4 +391,90 @@ TEST(WhirlpoolHisenseArg, EveryTransmitHasValidChecksums) {
  }
 }

+// Cool 24 C (step 8), fan low, unit on
+static Frame hitachi_cool_frame() {
+  return with_checksums({0xA9, 0x59, 0x03, 0x82, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x20,
+                         0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x38, 0x08, 0x00});
+}
+
+// The off frame: power bit, cool code, byte 15 0x01 and byte 18 0x28
+static Frame hitachi_off_frame() {
+  return with_checksums({0xA9, 0x59, 0x07, 0x82, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x20,
+                         0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x28, 0x08, 0x00});
+}
+
+TEST(WhirlpoolHitachiHCRA31NEWH, CoolAndOffMatchKnownFrames) {
+  Fixture f(MODEL_HITACHI_HCRA31NEWH);
+  f.command(climate::CLIMATE_MODE_COOL, 24, climate::CLIMATE_FAN_LOW);
+  // Turning on sends the full state with no power bit
+  expect_frame(f.last_frame(), hitachi_cool_frame());
+
+  f.command(climate::CLIMATE_MODE_OFF, 24, climate::CLIMATE_FAN_LOW);
+  expect_frame(f.last_frame(), hitachi_off_frame());
+
+  // A second off command still sends the power bit
+  f.command(climate::CLIMATE_MODE_OFF, 24, climate::CLIMATE_FAN_LOW);
+  EXPECT_EQ(f.last_frame()[2] & 0x04, 0x04);
+
+  f.command(climate::CLIMATE_MODE_HEAT, 24, climate::CLIMATE_FAN_LOW);
+  const Frame frame = f.last_frame();
+  EXPECT_EQ(frame[2] & 0x04, 0);
+  EXPECT_EQ(frame[3], 0x80);
+  EXPECT_EQ(frame[15], 0x06);
+  EXPECT_EQ(frame[18], 0x38);
+}
+
+TEST(WhirlpoolHitachiHCRA31NEWH, ReceivePowerIsAState) {
+  Fixture f(MODEL_HITACHI_HCRA31NEWH);
+  ASSERT_EQ(f.climate.mode, climate::CLIMATE_MODE_OFF);
+
+  // An on frame restores the mode even though it has no power bit
+  EXPECT_TRUE(receive(f.climate, hitachi_cool_frame()));
+  EXPECT_EQ(f.climate.mode, climate::CLIMATE_MODE_COOL);
+  EXPECT_FLOAT_EQ(f.climate.target_temperature, 24);
+  EXPECT_EQ(f.climate.fan_mode, climate::CLIMATE_FAN_LOW);
+  // The same frame again keeps it on
+  EXPECT_TRUE(receive(f.climate, hitachi_cool_frame()));
+  EXPECT_EQ(f.climate.mode, climate::CLIMATE_MODE_COOL);
+
+  EXPECT_TRUE(receive(f.climate, hitachi_off_frame()));
+  EXPECT_EQ(f.climate.mode, climate::CLIMATE_MODE_OFF);
+  // A repeated off frame does not toggle
+  EXPECT_TRUE(receive(f.climate, hitachi_off_frame()));
+  EXPECT_EQ(f.climate.mode, climate::CLIMATE_MODE_OFF);
+}
+
+TEST(WhirlpoolHitachiHCRA31NEWH, ReceiveChecksRemoteId) {
+  Fixture hitachi(MODEL_HITACHI_HCRA31NEWH);
+  EXPECT_FALSE(receive(hitachi.climate, hisense_cool_frame()));
+  Fixture whirlpool(MODEL_DG11J1_91);
+  EXPECT_FALSE(receive(whirlpool.climate, hitachi_cool_frame()));
+}
+
+TEST(WhirlpoolHitachiHCRA31NEWH, ReceivedTemperatureIsClamped) {
+  Fixture f(MODEL_HITACHI_HCRA31NEWH);
+  Frame frame = hitachi_cool_frame();
+  frame[3] = 0xF2;  // step 15 would be 31 C
+  EXPECT_TRUE(receive(f.climate, with_checksums(frame)));
+  EXPECT_FLOAT_EQ(f.climate.target_temperature, 30);
+}
+
+TEST(WhirlpoolDG11J13A, TargetIsClampedAndRoundedToWhatWasSent) {
+  Fixture f(MODEL_DG11J1_3A);
+  f.command(climate::CLIMATE_MODE_COOL, 35, climate::CLIMATE_FAN_LOW);
+  EXPECT_FLOAT_EQ(f.climate.target_temperature, 32);
+  f.command(climate::CLIMATE_MODE_COOL, 24.4f, climate::CLIMATE_FAN_LOW);
+  EXPECT_FLOAT_EQ(f.climate.target_temperature, 24);
+}
+
+TEST(WhirlpoolHitachiHCRA31NEWH, ReceiveRejectsShortFrame) {
+  Fixture f(MODEL_HITACHI_HCRA31NEWH);
+  remote_base::RawTimings raw = waveform(hitachi_cool_frame());
+  // Cut after the second divider: 14 bytes, no footer
+  raw.resize(2 + 14 * 16 + 2 * 2);
+  remote_base::RemoteReceiveData data(raw, 25, remote_base::TOLERANCE_MODE_PERCENTAGE);
+  EXPECT_FALSE(static_cast<remote_base::RemoteReceiverListener &>(f.climate).on_receive(data));
+  EXPECT_EQ(f.climate.mode, climate::CLIMATE_MODE_OFF);
+}
+
 }  // namespace esphome::whirlpool::testing
@@ -0,0 +1,23 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, CONF_NAME
+from esphome.types import ConfigType
+
+CODEOWNERS = ["@esphome/tests"]
+MULTI_CONF = True
+
+reboot_hook_recorder_ns = cg.esphome_ns.namespace("reboot_hook_recorder")
+RebootHookRecorder = reboot_hook_recorder_ns.class_("RebootHookRecorder", cg.Component)
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.declare_id(RebootHookRecorder),
+        cv.Required(CONF_NAME): cv.string,
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+async def to_code(config: ConfigType) -> None:
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    cg.add(var.set_name(config[CONF_NAME]))
@@ -0,0 +1,10 @@
+#include "reboot_hook_recorder.h"
+#include "esphome/core/log.h"
+
+namespace esphome::reboot_hook_recorder {
+
+ESPHOME_LOG_TAG(TAG, "reboot_hook_recorder");
+
+void RebootHookRecorder::record_(const char *hook) { ESP_LOGI(TAG, "HOOK %s %s", this->name_, hook); }
+
+}  // namespace esphome::reboot_hook_recorder
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "esphome/core/component.h"
+
+namespace esphome::reboot_hook_recorder {
+
+/// Logs every shutdown lifecycle hook it receives, so a test can check their order.
+class RebootHookRecorder : public Component {
+ public:
+  void set_name(const char *name) { this->name_ = name; }
+
+  void on_safe_shutdown() override { this->record_("on_safe_shutdown"); }
+  void on_shutdown() override { this->record_("on_shutdown"); }
+  // Needs a second call to finish, like a component waiting for a connection to close
+  bool teardown() override {
+    if (++this->teardown_calls_ < 2) {
+      this->record_("teardown_pending");
+      return false;
+    }
+    if (this->teardown_calls_ == 2)
+      this->record_("teardown_done");
+    return true;
+  }
+  void on_powerdown() override { this->record_("on_powerdown"); }
+
+ protected:
+  void record_(const char *hook);
+
+  const char *name_{""};
+  uint8_t teardown_calls_{0};
+};
+
+}  // namespace esphome::reboot_hook_recorder
@@ -0,0 +1,19 @@
+esphome:
+  name: reboot-hooks-forced
+host:
+logger:
+  level: DEBUG
+api:
+  # Reboot once the test has connected, so that it sees every hook
+  on_client_connected:
+    - delay: 100ms
+    - lambda: App.reboot();
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+reboot_hook_recorder:
+  - name: first
+  - name: second
@@ -0,0 +1,19 @@
+esphome:
+  name: reboot-hooks-safe
+host:
+logger:
+  level: DEBUG
+api:
+  # Reboot once the test has connected, so that it sees every hook
+  on_client_connected:
+    - delay: 100ms
+    - lambda: App.safe_reboot();
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+
+reboot_hook_recorder:
+  - name: first
+  - name: second
@@ -0,0 +1,80 @@
+"""Test the order of the shutdown lifecycle hooks on a forced and on a safe reboot."""
+
+import re
+
+import pytest
+
+from .log_utils import LineWaiter
+from .types import APIClientConnectedFactory, RunCompiledFunction
+from .wait_utils import wait_or_fail
+
+HOOK_PATTERN = re.compile(r"HOOK (\w+) (\w+)")
+# Hooks run in reverse component order, so "first" gets each hook last.
+LAST_HOOK = "HOOK first on_powerdown"
+
+
+async def _record_reboot_hooks(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> list[tuple[str, str]]:
+    """Connect, which makes the device reboot, and return its (component, hook) calls in order."""
+    waiter = LineWaiter()
+    hooks: list[tuple[str, str]] = []
+
+    def on_line(line: str) -> None:
+        if match := HOOK_PATTERN.search(line):
+            hooks.append((match[1], match[2]))
+        waiter.callback(line)
+
+    async with (
+        run_compiled(yaml_config, line_callback=on_line),
+        api_client_connected(),
+    ):
+        await wait_or_fail(
+            waiter.wait_for(LAST_HOOK),
+            5.0,
+            "Device did not run the powerdown hooks",
+            hooks=hooks,
+        )
+    return hooks
+
+
+@pytest.mark.asyncio
+async def test_reboot_hook_order_forced(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """A forced reboot runs on_shutdown then on_powerdown, with no safe shutdown or teardown."""
+    hooks = await _record_reboot_hooks(yaml_config, run_compiled, api_client_connected)
+
+    assert hooks == [
+        ("second", "on_shutdown"),
+        ("first", "on_shutdown"),
+        ("second", "on_powerdown"),
+        ("first", "on_powerdown"),
+    ]
+
+
+@pytest.mark.asyncio
+async def test_reboot_hook_order_safe(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """A safe reboot powers down only after every component has finished its teardown."""
+    hooks = await _record_reboot_hooks(yaml_config, run_compiled, api_client_connected)
+
+    assert hooks == [
+        ("second", "on_safe_shutdown"),
+        ("first", "on_safe_shutdown"),
+        ("second", "on_shutdown"),
+        ("first", "on_shutdown"),
+        ("second", "teardown_pending"),
+        ("first", "teardown_pending"),
+        ("second", "teardown_done"),
+        ("first", "teardown_done"),
+        ("second", "on_powerdown"),
+        ("first", "on_powerdown"),
+    ]
Author	SHA1	Message	Date
J. Nick Koston	13dcacfc33	[uart] Share the fake UART, move the reader benchmarks to core and drive Modbus through loop()	2026-11-15 03:03:44 -06:00
J. Nick Koston	76ad7a838e	[uart] Add frame parsing benchmarks	2026-11-15 02:48:18 -06:00
Hajo Noerenberg	1dff22f578	[cc1101] Add long packet support, plus a lambda packet_length for unknown-length packets (#17578 )	2026-11-14 21:43:21 -06:00
Vinicius FortunaandClyde Stubbs	c2eb540b37	[sx126x] Refactor/sx126x radio lifecycle (#22197 ) Co-authored-by: Clyde Stubbs <2366188+clydebarrow@users.noreply.github.com>	2026-11-15 13:17:23 +11:00
J. Nick Kostonandclydebarrow	fad21e3f14	[cstxxx] Share the Hynitron 16-bit register touchscreen code (#22718 ) Co-authored-by: clydebarrow <2366188+clydebarrow@users.noreply.github.com>	2026-11-15 02:11:09 +00:00
Rodrigoah	904f0df920	[whirlpool] Add the Hitachi HCRA31NEWH model (#22704 )	2026-11-14 14:23:51 -06:00
Chris	7128d22f07	[ethernet] Notify IP state listeners from the main loop (#22657 )	2026-11-14 13:22:11 -06:00
Miguel Angel Nubla	825e2c3dd0	[wifi] Leave the AP before restarting on ESP32 (#22715 )	2026-11-14 18:05:42 +00:00