X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/b7fc61f0c947da24d8283fec67a5910e224eb2d6..34ff898553f3392c66c50d1a524070882d237fb5:/common/lfdemod.c diff --git a/common/lfdemod.c b/common/lfdemod.c index fbed6a9a..406b0445 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -187,6 +187,32 @@ bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_ return false; } +// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup. +size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) { + size_t i = 0; + size_t waveSizeCnt = 0; + uint8_t thresholdCnt = 0; + bool isAboveThreshold = dest[i++] >= threshold_value; + for (; i < size-20; i++ ) { + if(dest[i] < threshold_value && isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = false; + waveSizeCnt = 0; + } else if (dest[i] >= threshold_value && !isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = true; + waveSizeCnt = 0; + } else { + waveSizeCnt++; + } + if (thresholdCnt > 10) break; + } + if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt); + return i; +} + //by marshmellow //takes 1s and 0s and searches for EM410x format - output EM ID uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) @@ -496,7 +522,6 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow { size_t last_transition = 0; size_t idx = 1; - //uint32_t maxVal=0; if (fchigh==0) fchigh=10; if (fclow==0) fclow=8; //set the threshold close to 0 (graph) or 128 std to avoid static @@ -506,28 +531,8 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow size_t currSample = 0; if ( size < 1024 ) return 0; // not enough samples - // jump to modulating data by finding the first 4 threshold crossings (or first 2 waves) - // in case you have junk or noise at the beginning of the trace... - uint8_t thresholdCnt = 0; - size_t waveSizeCnt = 0; - bool isAboveThreshold = dest[idx++] >= threshold_value; - for (; idx < size-20; idx++ ) { - if(dest[idx] < threshold_value && isAboveThreshold) { - thresholdCnt++; - if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break; - isAboveThreshold = false; - waveSizeCnt = 0; - } else if (dest[idx] >= threshold_value && !isAboveThreshold) { - thresholdCnt++; - if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break; - isAboveThreshold = true; - waveSizeCnt = 0; - } else { - waveSizeCnt++; - } - if (thresholdCnt > 10) break; - } - if (g_debugMode == 2) prnt("threshold Count reached at %u",idx); + //find start of modulating data in trace + idx = findModStart(dest, size, threshold_value, fchigh); // Need to threshold first sample if(dest[idx] < threshold_value) dest[0] = 0; @@ -1509,42 +1514,26 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) size_t numBits=0; uint8_t curPhase = *invert; size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; - uint8_t fc=0, fullWaveLen=0, tol=1; - uint16_t errCnt=0, waveLenCnt=0; - fc = countFC(dest, *size, 0); + uint16_t fc=0, fullWaveLen=0, tol=1; + uint16_t errCnt=0, waveLenCnt=0, errCnt2=0; + fc = countFC(dest, *size, 1); + uint8_t fc2 = fc >> 8; + if (fc2 == 10) return -1; //fsk found - quit + fc = fc & 0xFF; if (fc!=2 && fc!=4 && fc!=8) return -1; //PrintAndLog("DEBUG: FC: %d",fc); *clock = DetectPSKClock(dest, *size, *clock); if (*clock == 0) return -1; - // jump to modulating data by finding the first 2 threshold crossings (or first 1 waves) - // in case you have junk or noise at the beginning of the trace... - uint8_t thresholdCnt = 0; - size_t waveSizeCnt = 0; - uint8_t threshold_value = 123; //-5 - bool isAboveThreshold = dest[i++] >= threshold_value; - for (; i < *size-20; i++ ) { - if(dest[i] < threshold_value && isAboveThreshold) { - thresholdCnt++; - if (thresholdCnt > 2 && waveSizeCnt < fc+1) break; - isAboveThreshold = false; - waveSizeCnt = 0; - } else if (dest[i] >= threshold_value && !isAboveThreshold) { - thresholdCnt++; - if (thresholdCnt > 2 && waveSizeCnt < fc+1) break; - isAboveThreshold = true; - waveSizeCnt = 0; - } else { - waveSizeCnt++; - } - if (thresholdCnt > 10) break; - } - if (g_debugMode == 2) prnt("DEBUG PSK: threshold Count reached at %u, count: %u",i, thresholdCnt); + //find start of modulating data in trace + uint8_t threshold_value = 123; //-5 + i = findModStart(dest, *size, threshold_value, fc); - int avgWaveVal=0, lastAvgWaveVal=0; - waveStart = i+1; //find first phase shift - for (; i= dest[i+2]){ waveEnd = i+1; if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart); @@ -1553,8 +1542,8 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) lastAvgWaveVal = avgWaveVal/(waveLenCnt); firstFullWave = waveStart; fullWaveLen=waveLenCnt; - //if average wave value is > graph 0 then it is an up wave or a 1 - if (lastAvgWaveVal > threshold_value) curPhase ^= 1; //fudge graph 0 a little 123 vs 128 + //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting) + if (lastAvgWaveVal > threshold_value) curPhase ^= 1; break; } waveStart = i+1; @@ -1575,7 +1564,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) //set start of wave as clock align lastClkBit = firstFullWave; if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen); - if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); + if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); waveStart = 0; dest[numBits++] = curPhase; //set first read bit for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ @@ -1606,6 +1595,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) } else if (i+1 > lastClkBit + *clock + tol + fc){ lastClkBit += *clock; //no phase shift but clock bit dest[numBits++] = curPhase; + } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often) + errCnt2++; + if(errCnt2 > 101) return errCnt2; } avgWaveVal = 0; waveStart = i+1;