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)
{
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
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;
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<loopCnt; i++){
+ int avgWaveVal=0, lastAvgWaveVal=0;
+ waveStart = i;
+ for (; i<loopCnt; i++) {
+ // find peak
if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
waveEnd = i+1;
if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
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;
//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++){
} 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;