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[remote_base] Fix RC5 decoding at either receive polarity (#16767)

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This commit is contained in:
Jonathan Swoboda
2026-06-03 17:45:56 -04:00
committed by Jesse Hills
parent 9c0ffee020
commit a5b4a7cd51
1 changed files with 51 additions and 39 deletions
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90
esphome/components/remote_base/rc5_protocol.cpp
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@@ -7,6 +7,7 @@ static const char *const TAG = "remote.rc5";
static constexpr uint32_t BIT_TIME_US = 889;
static constexpr uint8_t NBITS = 14;
static constexpr uint8_t NHALFBITS = NBITS * 2;
void RC5Protocol::encode(RemoteTransmitData *dst, const RC5Data &data) {
static bool toggle = false;
@@ -35,52 +36,63 @@ void RC5Protocol::encode(RemoteTransmitData *dst, const RC5Data &data) {
}
toggle = !toggle;
}
optional<RC5Data> RC5Protocol::decode(RemoteReceiveData src) {
RC5Data out{
.address = 0,
.command = 0,
};
uint8_t field_bit;
if (src.expect_space(BIT_TIME_US) && src.expect_mark(BIT_TIME_US)) {
field_bit = 1;
} else if (src.expect_space(2 * BIT_TIME_US)) {
field_bit = 0;
} else {
return {};
}
if (!(((src.expect_space(BIT_TIME_US) || src.peek_space(2 * BIT_TIME_US)) ||
(src.expect_mark(BIT_TIME_US) || src.peek_mark(2 * BIT_TIME_US))) &&
(((src.expect_mark(BIT_TIME_US) || src.expect_mark(2 * BIT_TIME_US)) &&
(src.expect_space(BIT_TIME_US) || src.peek_space(2 * BIT_TIME_US))) ||
((src.expect_space(BIT_TIME_US) || src.expect_space(2 * BIT_TIME_US)) &&
(src.expect_mark(BIT_TIME_US) || src.peek_mark(2 * BIT_TIME_US)))))) {
return {};
}
uint32_t out_data = 0;
for (int bit = NBITS - 4; bit >= 1; bit--) {
if ((src.expect_space(BIT_TIME_US) || src.expect_space(2 * BIT_TIME_US)) &&
(src.expect_mark(BIT_TIME_US) || src.peek_mark(2 * BIT_TIME_US))) {
out_data |= 0 << bit;
} else if ((src.expect_mark(BIT_TIME_US) || src.expect_mark(2 * BIT_TIME_US)) &&
(src.expect_space(BIT_TIME_US) || src.peek_space(2 * BIT_TIME_US))) {
out_data |= 1 << bit;
// Expand the runs into half-bit levels (true = mark). Each run is exactly one
// half-bit (BIT_TIME_US) or two (2 * BIT_TIME_US); stop at anything else.
//
// halfbits[0] is reserved for the leading half-bit, which is always dropped --
// S1 is 1, so its first half sits at the idle level (at either polarity) and
// merges into the pre-frame idle. Captured half-bits start at index 1.
bool halfbits[NHALFBITS + 2];
uint8_t n = 1;
for (uint32_t i = 0; n <= NHALFBITS && src.is_valid(i); i++) {
if (src.peek_mark(BIT_TIME_US, i)) {
halfbits[n++] = true;
} else if (src.peek_space(BIT_TIME_US, i)) {
halfbits[n++] = false;
} else if (src.peek_mark(2 * BIT_TIME_US, i)) {
halfbits[n++] = true;
halfbits[n++] = true;
} else if (src.peek_space(2 * BIT_TIME_US, i)) {
halfbits[n++] = false;
halfbits[n++] = false;
} else {
return {};
break;
}
}
if (src.expect_space(BIT_TIME_US) || src.expect_space(2 * BIT_TIME_US)) {
out_data |= 0;
} else if (src.expect_mark(BIT_TIME_US) || src.expect_mark(2 * BIT_TIME_US)) {
out_data |= 1;
// Expect a full frame once the leading half is restored: 27 captured halves
// (n == 28) or 26 when the final bit also ends on idle and its trailing half
// is dropped too (n == 27). A dropped edge half is the inverse of its partner
// (a Manchester bit always transitions mid-bit), so reconstruct the leading
// half (always) and the trailing half (only when it was dropped).
if (n != NHALFBITS && n != NHALFBITS - 1) {
return {};
}
halfbits[0] = !halfbits[1];
if (n == NHALFBITS - 1) {
halfbits[n] = !halfbits[n - 1];
}
out.command = (uint8_t) (out_data & 0x3F) + (1 - field_bit) * 64u;
out.address = (out_data >> 6) & 0x1F;
return out;
const bool carrier = halfbits[1];
uint16_t bits = 0;
for (uint8_t i = 0; i < NBITS; i++) {
const bool first = halfbits[2 * i];
const bool second = halfbits[2 * i + 1];
if (first == second) {
return {}; // no midpoint transition -> not a valid Manchester bit
}
bits = (bits << 1) | (second == carrier ? 1 : 0);
}
const bool field_bit = bits & (1 << 12); // S2: the inverted 7th command bit
return RC5Data{
.address = static_cast<uint8_t>((bits >> 6) & 0x1F),
.command = static_cast<uint8_t>((bits & 0x3F) | (field_bit ? 0 : 0x40)),
};
}
void RC5Protocol::dump(const RC5Data &data) {
ESP_LOGI(TAG, "Received RC5: address=0x%02X, command=0x%02X", data.address, data.command);
}