+// by marshmellow
+// convert psk2 demod to psk1 demod
+// from only transition waves are 1s to phase shifts change bit
+void psk2TOpsk1(uint8_t *BitStream, size_t size)
+{
+ uint8_t phase=0;
+ for (size_t i=0; i<size; i++){
+ if (BitStream[i]==1){
+ phase ^=1;
+ }
+ BitStream[i]=phase;
+ }
+ return;
+}
+
+// redesigned by marshmellow adjusted from existing decode functions
+// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
+int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
+{
+ //26 bit 40134 format (don't know other formats)
+ int i;
+ int long_wait=29;//29 leading zeros in format
+ int start;
+ int first = 0;
+ int first2 = 0;
+ int bitCnt = 0;
+ int ii;
+ // Finding the start of a UID
+ for (start = 0; start <= *size - 250; start++) {
+ first = bitStream[start];
+ for (i = start; i < start + long_wait; i++) {
+ if (bitStream[i] != first) {
+ break;
+ }
+ }
+ if (i == (start + long_wait)) {
+ break;
+ }
+ }
+ if (start == *size - 250 + 1) {
+ // did not find start sequence
+ return -1;
+ }
+ // Inverting signal if needed
+ if (first == 1) {
+ for (i = start; i < *size; i++) {
+ bitStream[i] = !bitStream[i];
+ }
+ *invert = 1;
+ }else *invert=0;
+
+ int iii;
+ //found start once now test length by finding next one
+ for (ii=start+29; ii <= *size - 250; ii++) {
+ first2 = bitStream[ii];
+ for (iii = ii; iii < ii + long_wait; iii++) {
+ if (bitStream[iii] != first2) {
+ break;
+ }
+ }
+ if (iii == (ii + long_wait)) {
+ break;
+ }
+ }
+ if (ii== *size - 250 + 1){
+ // did not find second start sequence
+ return -2;
+ }
+ bitCnt=ii-start;
+
+ // Dumping UID
+ i = start;
+ for (ii = 0; ii < bitCnt; ii++) {
+ bitStream[ii] = bitStream[i++];
+ }
+ *size=bitCnt;
+ return 1;
+}
+
+// by marshmellow - demodulate NRZ wave (both similar enough)
+// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
+// there probably is a much simpler way to do this....
+int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
+{
+ if (justNoise(dest, *size)) return -1;
+ *clk = DetectNRZClock(dest, *size, *clk);
+ if (*clk==0) return -2;
+ size_t i, gLen = 4096;
+ if (gLen>*size) gLen = *size;
+ int high, low;
+ if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
+ int lastBit = 0; //set first clock check
+ size_t iii = 0, bitnum = 0; //bitnum counter
+ uint16_t errCnt = 0, MaxBits = 1000;
+ size_t bestErrCnt = maxErr+1;
+ size_t bestPeakCnt = 0, bestPeakStart = 0;
+ uint8_t bestFirstPeakHigh=0, firstPeakHigh=0, curBit=0, bitHigh=0, errBitHigh=0;
+ uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+ uint16_t peakCnt=0;
+ uint8_t ignoreWindow=4;
+ uint8_t ignoreCnt=ignoreWindow; //in case of noise near peak
+ //loop to find first wave that works - align to clock
+ for (iii=0; iii < gLen; ++iii){
+ if ((dest[iii]>=high) || (dest[iii]<=low)){
+ if (dest[iii]>=high) firstPeakHigh=1;
+ else firstPeakHigh=0;
+ lastBit=iii-*clk;
+ peakCnt=0;
+ errCnt=0;
+ //loop through to see if this start location works
+ for (i = iii; i < *size; ++i) {
+ // if we are at a clock bit
+ if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
+ //test high/low
+ if (dest[i] >= high || dest[i] <= low) {
+ bitHigh = 1;
+ peakCnt++;
+ errBitHigh = 0;
+ ignoreCnt = ignoreWindow;
+ lastBit += *clk;
+ } else if (i == lastBit + *clk + tol) {
+ lastBit += *clk;
+ }
+ //else if no bars found
+ } else if (dest[i] < high && dest[i] > low){
+ if (ignoreCnt==0){
+ bitHigh=0;
+ if (errBitHigh==1) errCnt++;
+ errBitHigh=0;
+ } else {
+ ignoreCnt--;
+ }
+ } else if ((dest[i]>=high || dest[i]<=low) && (bitHigh==0)) {
+ //error bar found no clock...
+ errBitHigh=1;
+ }
+ if (((i-iii) / *clk)>=MaxBits) break;
+ }
+ //we got more than 64 good bits and not all errors
+ if (((i-iii) / *clk) > 64 && (errCnt <= (maxErr))) {
+ //possible good read
+ if (!errCnt || peakCnt > bestPeakCnt){
+ bestFirstPeakHigh=firstPeakHigh;
+ bestErrCnt = errCnt;
+ bestPeakCnt = peakCnt;
+ bestPeakStart = iii;
+ if (!errCnt) break; //great read - finish
+ }
+ }
+ }
+ }
+ //PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart);
+ if (bestErrCnt > maxErr) return bestErrCnt;
+
+ //best run is good enough set to best run and set overwrite BinStream
+ lastBit = bestPeakStart - *clk;
+ memset(dest, bestFirstPeakHigh^1, bestPeakStart / *clk);
+ bitnum += (bestPeakStart / *clk);
+ for (i = bestPeakStart; i < *size; ++i) {
+ // if expecting a clock bit
+ if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
+ // test high/low
+ if (dest[i] >= high || dest[i] <= low) {
+ peakCnt++;
+ bitHigh = 1;
+ errBitHigh = 0;
+ ignoreCnt = ignoreWindow;
+ curBit = *invert;
+ if (dest[i] >= high) curBit ^= 1;
+ dest[bitnum++] = curBit;
+ lastBit += *clk;
+ //else no bars found in clock area
+ } else if (i == lastBit + *clk + tol) {
+ dest[bitnum++] = curBit;
+ lastBit += *clk;
+ }
+ //else if no bars found
+ } else if (dest[i] < high && dest[i] > low){
+ if (ignoreCnt == 0){
+ bitHigh = 0;
+ if (errBitHigh == 1){
+ dest[bitnum++] = 7;
+ errCnt++;
+ }
+ errBitHigh=0;
+ } else {
+ ignoreCnt--;
+ }
+ } else if ((dest[i] >= high || dest[i] <= low) && (bitHigh == 0)) {
+ //error bar found no clock...
+ errBitHigh=1;
+ }
+ if (bitnum >= MaxBits) break;
+ }
+ *size = bitnum;
+ return bestErrCnt;
+}
+
+//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 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};
+ uint8_t rfLensFnd = 0;
+ uint8_t lastFCcnt = 0;
+ uint16_t fcCounter = 0;
+ uint16_t rfCounter = 0;
+ uint8_t firstBitFnd = 0;
+ size_t i;
+ if (size == 0) return 0;
+
+ uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+ rfLensFnd=0;
+ fcCounter=0;
+ rfCounter=0;
+ firstBitFnd=0;
+ //PrintAndLog("DEBUG: fcTol: %d",fcTol);
+ // prime i to first up transition
+ for (i = 1; i < size-1; i++)
+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
+ break;
+
+ for (; i < size-1; i++){
+ fcCounter++;
+ rfCounter++;
+
+ if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
+ continue;
+ // else new peak
+ // if we got less than the small fc + tolerance then set it to the small fc
+ if (fcCounter < fcLow+fcTol)
+ fcCounter = fcLow;
+ else //set it to the large fc
+ fcCounter = fcHigh;
+
+ //look for bit clock (rf/xx)
+ if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
+ //not the same size as the last wave - start of new bit sequence
+ if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
+ for (int ii=0; ii<15; ii++){
+ if (rfLens[ii] == rfCounter){
+ rfCnts[ii]++;
+ rfCounter = 0;
+ break;
+ }
projects / proxmark3-svn / blobdiff