for (uint8_t i = 0; i < bitLen; i++){
ans ^= ((bits >> i) & 1);
}
- //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+ if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
return (ans == pType);
}
{
uint32_t parityWd = 0;
size_t j = 0, bitCnt = 0;
- for (int word = 0; word < (bLen); word+=pLen){
- for (int bit=0; bit < pLen; bit++){
+ for (int word = 0; word < (bLen); word+=pLen) {
+ for (int bit=0; bit < pLen; bit++) {
parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
BitStream[j++] = (BitStream[startIdx+word+bit]);
}
+ if (word+pLen > bLen) break;
+
j--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
{
- uint8_t foundCnt=0;
- for (int idx=0; idx < *size - pLen; idx++){
- if (memcmp(BitStream+idx, preamble, pLen) == 0){
+ return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
+}
+
+// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
+// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
+bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
+ // Sanity check. If preamble length is bigger than bitstream length.
+ if ( *size <= pLen ) return false;
+
+ uint8_t foundCnt = 0;
+ for (size_t idx = 0; idx < *size - pLen; idx++) {
+ if (memcmp(BitStream+idx, preamble, pLen) == 0) {
//first index found
foundCnt++;
- if (foundCnt == 1){
+ if (foundCnt == 1) {
+ if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
*startIdx = idx;
- }
- if (foundCnt == 2){
+ if (findone) return true;
+ } else if (foundCnt == 2) {
*size = idx - *startIdx;
- return 1;
+ return true;
}
}
}
- return 0;
+ 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)
{
- //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
- // otherwise could be a void with no arguments
- //set defaults
- uint32_t i = 0;
+ //sanity checks
+ if (*size < 64) return 0;
if (BitStream[1]>1) return 0; //allow only 1s and 0s
// 111111111 bit pattern represent start of frame
// include 0 in front to help get start pos
uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
- uint32_t idx = 0;
- uint32_t parityBits = 0;
uint8_t errChk = 0;
- uint8_t FmtLen = 10;
+ uint8_t FmtLen = 10; // sets of 4 bits = end data
*startIdx = 0;
errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
- if (errChk == 0 || *size < 64) return 0;
- if (*size > 64) FmtLen = 22;
- *startIdx += 1; //get rid of 0 from preamble
- idx = *startIdx + 9;
- for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
- parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
- //check even parity - quit if failed
- if (parityTest(parityBits, 5, 0) == 0) return 0;
- //set uint64 with ID from BitStream
- for (uint8_t ii=0; ii<4; ii++){
- *hi = (*hi << 1) | (*lo >> 63);
- *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
- }
+ if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
+ if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
+
+ //skip last 4bit parity row for simplicity
+ *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
+ if (*size == 40) { // std em410x format
+ *hi = 0;
+ *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
+ } else if (*size == 88) { // long em format
+ *hi = (bytebits_to_byte(BitStream, 24));
+ *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
+ } else {
+ return 0;
}
- if (errChk != 0) return 1;
- //skip last 5 bit parity test for simplicity.
- // *size = 64 | 128;
- return 0;
+ return 1;
}
//by marshmellow
}
//by marshmellow
+//amplify based on ask edge detection
void askAmp(uint8_t *BitStream, size_t size)
{
uint8_t Last = 128;
}
return;
}
-
+
//by marshmellow
//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
if (*clk==0 || start < 0) return -3;
if (*invert != 1) *invert = 0;
if (amp==1) askAmp(BinStream, *size);
- if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d", *clk, start);
+ if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
uint8_t initLoopMax = 255;
if (initLoopMax > *size) initLoopMax = *size;
int lastBit; //set first clock check - can go negative
size_t i, bitnum = 0; //output counter
uint8_t midBit = 0;
- uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+ uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
if (*clk <= 32) tol = 1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
size_t MaxBits = 3072; //max bits to collect
lastBit = start - *clk;
{
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 preLastSample = 0;
size_t LastSample = 0;
size_t currSample = 0;
- // sync to first lo-hi transition, and threshold
+ if ( size < 1024 ) return 0; // not enough samples
+
+ //find start of modulating data in trace
+ idx = findModStart(dest, size, threshold_value, fchigh);
// Need to threshold first sample
- // skip 160 samples to allow antenna/samples to settle
- if(dest[160] < threshold_value) dest[0] = 0;
+ if(dest[idx] < threshold_value) dest[0] = 0;
else dest[0] = 1;
-
+ idx++;
+
size_t numBits = 0;
// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
// or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
// (could also be fc/5 && fc/7 for fsk1 = 4-9)
- for(idx = 161; idx < size-20; idx++) {
+ for(; idx < size-20; idx++) {
// threshold current value
if (dest[idx] < threshold_value) dest[idx] = 0;
//do nothing with extra garbage
} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
//correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
- if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){
+ if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
dest[numBits-1]=1;
}
dest[numBits++]=1;
- } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage
- //do nothing with beginning garbage
+ } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
+ //do nothing with beginning garbage and reset.. should be rare..
+ numBits = 0;
} else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
dest[numBits++]=1;
} else { //9+ = 10 sample waves (or 6+ = 7)
// by marshmellow
// to help detect clocks on heavily clipped samples
// based on count of low to low
-int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
-{
+int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock) {
uint8_t fndClk[] = {8,16,32,40,50,64,128};
size_t startwave;
size_t i = 100;
size_t minClk = 255;
+ int shortestWaveIdx = 0;
// get to first full low to prime loop and skip incomplete first pulse
while ((dest[i] < high) && (i < size))
++i;
// measure from low to low
while ((dest[i] > low) && (i < size))
++i;
- startwave= i;
+ startwave = i;
while ((dest[i] < high) && (i < size))
++i;
while ((dest[i] > low) && (i < size))
++i;
//get minimum measured distance
- if (i-startwave < minClk && i < size)
+ if (i-startwave < minClk && i < size) {
minClk = i - startwave;
+ shortestWaveIdx = startwave;
+ }
}
// set clock
if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
- if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
- return fndClk[clkCnt];
+ if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) {
+ *clock = fndClk[clkCnt];
+ return shortestWaveIdx;
+ }
}
return 0;
}
//test for large clean peaks
if (!clockFnd){
if (DetectCleanAskWave(dest, size, peak, low)==1){
- int ans = DetectStrongAskClock(dest, size, peak, low);
- if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
- for (i=clkEnd-1; i>0; i--){
- if (clk[i] == ans) {
- *clock = ans;
- //clockFnd = i;
- return 0; // for strong waves i don't use the 'best start position' yet...
- //break; //clock found but continue to find best startpos [not yet]
- }
+ int ans = DetectStrongAskClock(dest, size, peak, low, clock);
+ if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
+ if (ans > 0) {
+ return ans; //return shortest wave start position
}
}
}
return bestStart[best];
}
+
+int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
+ int firstPhaseShift = 0;
+ return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
+}
+
//by marshmellow
//detect psk clock by reading each phase shift
// a phase shift is determined by measuring the sample length of each wave
-int DetectPSKClock(uint8_t dest[], size_t size, int clock)
-{
+int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
uint16_t loopCnt = 4096; //don't need to loop through entire array...
if (size == 0) return 0;
}
}
}
+ *firstPhaseShift = firstFullWave;
if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
-
//test each valid clock from greatest to smallest to see which lines up
for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
lastClkBit = firstFullWave; //set end of wave as clock align
return lowestTransition;
}
+int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
+ size_t bestStart=0;
+ return DetectNRZClock_ext(dest, size, clock, &bestStart);
+}
+
+
//by marshmellow
//detect nrz clock by reading #peaks vs no peaks(or errors)
-int DetectNRZClock(uint8_t dest[], size_t size, int clock)
-{
+int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
size_t i=0;
uint8_t clk[]={8,16,32,40,50,64,100,128,255};
size_t loopCnt = 4096; //don't need to loop through entire array...
uint8_t ignoreWindow = 4;
bool lastPeakHigh = 0;
int lastBit = 0;
+ size_t bestStart[]={0,0,0,0,0,0,0,0,0};
peakcnt=0;
//test each valid clock from smallest to greatest to see which lines up
for(clkCnt=0; clkCnt < 8; ++clkCnt){
}
}
if(peakcnt>peaksdet[clkCnt]) {
+ bestStart[clkCnt]=ii;
peaksdet[clkCnt]=peakcnt;
}
}
}
if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
}
-
+ *clockStartIdx = bestStart[best];
return clk[best];
}
return 0;
}
+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
+ int firstClockEdge = 0;
+ return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
+}
+
//by marshmellow
//detects the bit clock for FSK given the high and low Field Clocks
-uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
-{
+uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
continue;
// else new peak
// if we got less than the small fc + tolerance then set it to the small fc
- if (fcCounter < fcLow+fcTol)
+ // if it is inbetween set it to the last counter
+ if (fcCounter < fcHigh && fcCounter > fcLow)
+ fcCounter = lastFCcnt;
+ else if (fcCounter < fcLow+fcTol)
fcCounter = fcLow;
else //set it to the large fc
fcCounter = fcHigh;
rfLens[rfLensFnd++] = rfCounter;
}
} else {
+ *firstClockEdge = i;
firstBitFnd++;
}
rfCounter=0;
}
}
- if (ii<0) return 0; // oops we went too far
+ if (ii<2) return 0; // oops we went too far
return clk[ii];
}
uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t fcLensFnd = 0;
- uint8_t lastFCcnt=0;
+ uint8_t lastFCcnt = 0;
uint8_t fcCounter = 0;
size_t i;
- if (size == 0) return 0;
+ if (size < 180) return 0;
// prime i to first up transition
for (i = 160; i < size-20; i++)
size_t numBits=0;
uint8_t curPhase = *invert;
- size_t i, 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);
+ size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=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;
- int avgWaveVal=0, lastAvgWaveVal=0;
+
+ //find start of modulating data in trace
+ uint8_t threshold_value = 123; //-5
+ i = findModStart(dest, *size, threshold_value, fc);
+
//find first phase shift
- for (i=0; 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;
- //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
+ if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
waveLenCnt = waveEnd-waveStart;
- if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
+ if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
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 > 123) 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;
return errCnt;
}
+bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
+ size_t ststart = 0, stend = 0;
+ return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
+}
+
//by marshmellow
//attempt to identify a Sequence Terminator in ASK modulated raw wave
-bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
+bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
size_t bufsize = *size;
//need to loop through all samples and identify our clock, look for the ST pattern
uint8_t fndClk[] = {8,16,32,40,50,64,128};
int tol = 0;
int i, j, skip, start, end, low, high, minClk, waveStart;
bool complete = false;
- int tmpbuff[bufsize / 64];
- int waveLen[bufsize / 64];
+ int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
+ int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
size_t testsize = (bufsize < 512) ? bufsize : 512;
int phaseoff = 0;
high = low = 128;
waveStart = i;
while ((buffer[i] > low) && (i < bufsize))
++i;
- if (j >= (bufsize/64)) {
+ if (j >= (bufsize/32)) {
break;
}
waveLen[j] = i - waveStart; //first high to first low
if (start < 0) {
if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
return false;
+ } else {
+ if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
}
if (waveLen[i+2] > clk*1+tol)
phaseoff = 0;
end = skip;
for (i += 3; i < j - 4; ++i) {
end += tmpbuff[i];
- if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior
+ if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
start = skip;
size_t datalen = end - start;
// check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
- if (datalen % clk > clk/8) {
+ if ( clk - (datalen % clk) <= clk/8) {
+ // padd the amount off - could be problematic... but shouldn't happen often
+ datalen += clk - (datalen % clk);
+ } else if ( (datalen % clk) <= clk/8 ) {
+ // padd the amount off - could be problematic... but shouldn't happen often
+ datalen -= datalen % clk;
+ } else {
if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
return false;
- } else {
- // padd the amount off - could be problematic... but shouldn't happen often
- datalen += datalen % clk;
}
// if datalen is less than one t55xx block - ERROR
if (datalen/clk < 8*4) {
return false;
}
size_t dataloc = start;
+ if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
+ //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
+ for ( i=0; i <= (clk/8); ++i ) {
+ if ( buffer[dataloc - (clk*4) - i] <= low ) {
+ dataloc -= i;
+ break;
+ }
+ }
+ }
+
size_t newloc = 0;
i=0;
+ if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
+ bool firstrun = true;
// warning - overwriting buffer given with raw wave data with ST removed...
while ( dataloc < bufsize-(clk/2) ) {
//compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
for(i=0; i < clk/2-tol; ++i) {
buffer[dataloc+i] = high+5;
}
+ } //test for single sample outlier (high between two lows) in the case of very strong waves
+ if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
+ buffer[dataloc] = buffer[dataloc+2];
+ buffer[dataloc+1] = buffer[dataloc+2];
+ }
+ if (firstrun) {
+ *stend = dataloc;
+ *ststart = dataloc-(clk*4);
+ firstrun=false;
}
for (i=0; i<datalen; ++i) {
if (i+newloc < bufsize) {
if (i+newloc < dataloc)
buffer[i+newloc] = buffer[dataloc];
- dataloc++;
+ dataloc++;
}
}
newloc += i;
//skip next ST - we just assume it will be there from now on...
+ if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
dataloc += clk*4;
}
*size = newloc;
return true;
}
+
+// by iceman
+// find Visa2000 preamble in already demoded data
+int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
+ if (*size < 96) return -1; //make sure buffer has data
+ size_t startIdx = 0;
+ uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};
+ if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
+ return -2; //preamble not found
+ if (*size != 96) return -3; //wrong demoded size
+ //return start position
+ return (int)startIdx;
+}
projects / proxmark3-svn / blobdiff