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fix ManchesterDecoding_Thinfilm (msb was always forced to 0)

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This commit is contained in:
Philippe Teuwen 2019-08-01 16:55:20 +02:00
commit 118c8478f0
2 changed files with 5 additions and 13 deletions
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9
armsrc/iso14443a.c
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@ -489,7 +489,8 @@ RAMFUNC int ManchesterDecoding_Thinfilm(uint8_t bit) {
if (Demod.syncBit != 0xFFFF) {
Demod.startTime = (GetCountSspClk() & 0xfffffff8);
Demod.startTime -= Demod.syncBit;
Demod.bitCount = 0; // number of decoded data bits
Demod.bitCount = 1; // number of decoded data bits
Demod.shiftReg = 1;
Demod.state = DEMOD_MANCHESTER_DATA;
}
}
@ -502,7 +503,7 @@ RAMFUNC int ManchesterDecoding_Thinfilm(uint8_t bit) {
}
} // modulation in first half only - Sequence D = 1
Demod.bitCount++;
Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100; // in both cases, add a 1 to the shiftreg
Demod.shiftReg = (Demod.shiftReg << 1) | 0x1; // in both cases, add a 1 to the shiftreg
if (Demod.bitCount == 8) { // if we decoded a full byte
Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
Demod.bitCount = 0;
@ -512,7 +513,7 @@ RAMFUNC int ManchesterDecoding_Thinfilm(uint8_t bit) {
} else { // no modulation in first half
if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0
Demod.bitCount++;
Demod.shiftReg = (Demod.shiftReg >> 1); // add a 0 to the shiftreg
Demod.shiftReg = (Demod.shiftReg << 1); // add a 0 to the shiftreg
if (Demod.bitCount >= 8) { // if we decoded a full byte
Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
Demod.bitCount = 0;
@ -521,7 +522,7 @@ RAMFUNC int ManchesterDecoding_Thinfilm(uint8_t bit) {
Demod.endTime = Demod.startTime + 8 * (8 * Demod.len + Demod.bitCount + 1);
} else { // no modulation in both halves - End of communication
if (Demod.bitCount > 0) { // there are some remaining data bits
Demod.shiftReg >>= (8 - Demod.bitCount); // right align the decoded bits
Demod.shiftReg <<= (8 - Demod.bitCount); // left align the decoded bits
Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output
return true;
}