+ case STATE_READER_AWAIT_1ST_FALLING_EDGE_OF_SOF:
+ if (!bit) {
+ // we went low, so this could be the beginning of a SOF
+ DecodeReader->posCount = 1;
+ DecodeReader->state = STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF;
+ }
+ break;
+
+ case STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF:
+ DecodeReader->posCount++;
+ if (bit) { // detected rising edge
+ if (DecodeReader->posCount < 4) { // rising edge too early (nominally expected at 5)
+ DecodeReader->state = STATE_READER_AWAIT_1ST_FALLING_EDGE_OF_SOF;
+ } else { // SOF
+ DecodeReader->state = STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF;
+ }
+ } else {
+ if (DecodeReader->posCount > 5) { // stayed low for too long
+ DecodeReaderReset(DecodeReader);
+ } else {
+ // do nothing, keep waiting
+ }
+ }
+ break;
+
+ case STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF:
+ DecodeReader->posCount++;
+ if (!bit) { // detected a falling edge
+ if (DecodeReader->posCount < 20) { // falling edge too early (nominally expected at 21 earliest)
+ DecodeReaderReset(DecodeReader);
+ } else if (DecodeReader->posCount < 23) { // SOF for 1 out of 4 coding
+ DecodeReader->Coding = CODING_1_OUT_OF_4;
+ DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+ } else if (DecodeReader->posCount < 28) { // falling edge too early (nominally expected at 29 latest)
+ DecodeReaderReset(DecodeReader);
+ } else { // SOF for 1 out of 256 coding
+ DecodeReader->Coding = CODING_1_OUT_OF_256;
+ DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+ }
+ } else {
+ if (DecodeReader->posCount > 29) { // stayed high for too long
+ DecodeReader->state = STATE_READER_AWAIT_1ST_FALLING_EDGE_OF_SOF;
+ } else {
+ // do nothing, keep waiting
+ }
+ }
+ break;
+
+ case STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF:
+ DecodeReader->posCount++;
+ if (bit) { // detected rising edge
+ if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
+ if (DecodeReader->posCount < 32) { // rising edge too early (nominally expected at 33)
+ DecodeReader->state = STATE_READER_AWAIT_1ST_FALLING_EDGE_OF_SOF;
+ } else {
+ DecodeReader->posCount = 1;
+ DecodeReader->bitCount = 0;
+ DecodeReader->byteCount = 0;
+ DecodeReader->sum1 = 1;
+ DecodeReader->state = STATE_READER_RECEIVE_DATA_1_OUT_OF_256;
+ LED_B_ON();
+ }
+ } else { // CODING_1_OUT_OF_4
+ if (DecodeReader->posCount < 24) { // rising edge too early (nominally expected at 25)
+ DecodeReader->state = STATE_READER_AWAIT_1ST_FALLING_EDGE_OF_SOF;
+ } else {
+ DecodeReader->posCount = 1;
+ DecodeReader->state = STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4;
+ }
+ }
+ } else {
+ if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
+ if (DecodeReader->posCount > 34) { // signal stayed low for too long
+ DecodeReaderReset(DecodeReader);
+ } else {
+ // do nothing, keep waiting
+ }
+ } else { // CODING_1_OUT_OF_4
+ if (DecodeReader->posCount > 26) { // signal stayed low for too long
+ DecodeReaderReset(DecodeReader);
+ } else {
+ // do nothing, keep waiting
+ }