[esp32_can] Add NO_ACK mode (#20706)

Co-authored-by: Cursor <cursoragent@cursor.com>

esphome/components/esp32_can/canbus.py

@@ -47,6 +47,7 @@ CanMode = esp32_can_ns.enum("CanMode")
 CAN_MODES = {
     "NORMAL": CanMode.CAN_MODE_NORMAL,
     "LISTENONLY": CanMode.CAN_MODE_LISTEN_ONLY,
+    "NO_ACK": CanMode.CAN_MODE_NO_ACK,
 }
 
 # Currently the driver only supports a subset of the bit rates defined in canbus

esphome/components/esp32_can/esp32_can.cpp

@@ -79,10 +79,13 @@ bool ESP32Can::setup_internal() {
   }
 
   // Select TWAI mode based on configuration
-  twai_mode_t twai_mode = (this->mode_ == CAN_MODE_LISTEN_ONLY) ? TWAI_MODE_LISTEN_ONLY : TWAI_MODE_NORMAL;
-
+  twai_mode_t twai_mode = TWAI_MODE_NORMAL;
   if (this->mode_ == CAN_MODE_LISTEN_ONLY) {
+    twai_mode = TWAI_MODE_LISTEN_ONLY;
     ESP_LOGI(TAG, "CAN bus configured in LISTEN_ONLY mode (passive, no ACKs)");
+  } else if (this->mode_ == CAN_MODE_NO_ACK) {
+    twai_mode = TWAI_MODE_NO_ACK;
+    ESP_LOGI(TAG, "CAN bus configured in NO_ACK mode (transmit without requiring ACK)");
   }
 
   twai_general_config_t g_config =

esphome/components/esp32_can/esp32_can.h

@@ -12,6 +12,7 @@ namespace esphome::esp32_can {
 enum CanMode : uint8_t {
   CAN_MODE_NORMAL = 0,
   CAN_MODE_LISTEN_ONLY = 1,
+  CAN_MODE_NO_ACK = 2,
 };
 
 class ESP32Can final : public canbus::Canbus {

tests/components/esp32_can/common.yaml

@@ -18,7 +18,7 @@ canbus:
     tx_pin: ${tx_pin}
     can_id: 4
     bit_rate: 50kbps
-    mode: NORMAL
+    mode: NO_ACK
     on_frame:
       - can_id: 500
         then: