+// return start index of best starting position for that clock and return clock (by reference)
+int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
+{
+ size_t i=1;
+ uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
+ uint8_t clkEnd = 9;
+ uint8_t loopCnt = 255; //don't need to loop through entire array...
+ if (size <= loopCnt+60) return -1; //not enough samples
+ size -= 60; //sometimes there is a strange end wave - filter out this....
+ //if we already have a valid clock
+ uint8_t clockFnd=0;
+ for (;i<clkEnd;++i)
+ if (clk[i] == *clock) clockFnd = i;
+ //clock found but continue to find best startpos
+
+ //get high and low peak
+ int peak, low;
+ if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
+
+ //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]
+ }
+ }
+ }
+ }
+ uint8_t ii;
+ uint8_t clkCnt, tol = 0;
+ uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
+ uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
+ size_t errCnt = 0;
+ size_t arrLoc, loopEnd;
+
+ if (clockFnd>0) {
+ clkCnt = clockFnd;
+ clkEnd = clockFnd+1;
+ } else {
+ clkCnt=1;
+ }
+
+ //test each valid clock from smallest to greatest to see which lines up
+ for(; clkCnt < clkEnd; clkCnt++) {
+ if (clk[clkCnt] <= 32) {
+ tol=1;
+ } else {
+ tol=0;
+ }
+ //if no errors allowed - keep start within the first clock
+ if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
+ loopCnt = clk[clkCnt] * 2;
+
+ bestErr[clkCnt] = 1000;
+
+ //try lining up the peaks by moving starting point (try first few clocks)
+ for (ii=0; ii < loopCnt; ii++){
+ if (dest[ii] < peak && dest[ii] > low) continue;
+
+ errCnt = 0;
+ // now that we have the first one lined up test rest of wave array
+ loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
+ for (i=0; i < loopEnd; ++i){
+ arrLoc = ii + (i * clk[clkCnt]);
+ if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
+ }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
+ }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
+ }else{ //error no peak detected
+ errCnt++;
+ }
+ }
+ //if we found no errors then we can stop here and a low clock (common clocks)
+ // this is correct one - return this clock
+ if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
+ if (errCnt==0 && clkCnt<7) {
+ if (!clockFnd) *clock = clk[clkCnt];
+ return ii;
+ }
+ //if we found errors see if it is lowest so far and save it as best run
+ if (errCnt < bestErr[clkCnt]) {
+ bestErr[clkCnt] = errCnt;
+ bestStart[clkCnt] = ii;
+ }
+ }
+ }
+ uint8_t k;
+ uint8_t best = 0;
+ for (k=1; k < clkEnd; ++k){
+ if (bestErr[k] < bestErr[best]){
+ if (bestErr[k] == 0) bestErr[k]=1;
+ // current best bit to error ratio vs new bit to error ratio
+ if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
+ best = k;
+ }
+ }
+ if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d", clk[k], bestErr[k], clk[best], bestStart[best]);
+ }
+ if (!clockFnd) *clock = clk[best];
+ return bestStart[best];
+}
+
+//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)
+{
+ 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;
+ if (size<loopCnt) loopCnt = size-20;
+
+ //if we already have a valid clock quit
+ size_t i=1;
+ for (; i < 8; ++i)
+ if (clk[i] == clock) return clock;
+
+ size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
+ uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
+ uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
+ uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
+ uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
+ fc = countFC(dest, size, 0);
+ if (fc!=2 && fc!=4 && fc!=8) return -1;
+ if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
+
+ //find first full wave
+ for (i=160; i<loopCnt; i++){
+ if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
+ if (waveStart == 0) {
+ waveStart = i+1;
+ //prnt("DEBUG: waveStart: %d",waveStart);
+ } else {
+ waveEnd = i+1;
+ //prnt("DEBUG: waveEnd: %d",waveEnd);
+ waveLenCnt = waveEnd-waveStart;
+ if (waveLenCnt > fc){
+ firstFullWave = waveStart;
+ fullWaveLen=waveLenCnt;
+ break;
+ }
+ waveStart=0;
+ }
+ }
+ }
+ 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
+ waveStart = 0;
+ errCnt=0;
+ peakcnt=0;
+ if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
+
+ for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
+ //top edge of wave = start of new wave
+ if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
+ if (waveStart == 0) {
+ waveStart = i+1;
+ waveLenCnt=0;
+ } else { //waveEnd
+ waveEnd = i+1;
+ waveLenCnt = waveEnd-waveStart;
+ if (waveLenCnt > fc){
+ //if this wave is a phase shift
+ if (g_debugMode == 2) prnt("DEBUG PSK: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,i+1,fc);
+ if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
+ peakcnt++;
+ lastClkBit+=clk[clkCnt];
+ } else if (i<lastClkBit+8){
+ //noise after a phase shift - ignore
+ } else { //phase shift before supposed to based on clock
+ errCnt++;
+ }
+ } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
+ lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
+ }
+ waveStart=i+1;
+ }
+ }
+ }
+ if (errCnt == 0){
+ return clk[clkCnt];
+ }
+ if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
+ if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
+ }
+ //all tested with errors
+ //return the highest clk with the most peaks found
+ uint8_t best=7;
+ for (i=7; i>=1; i--){
+ if (peaksdet[i] > peaksdet[best]) {
+ best = i;
+ }
+ if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
+ }
+ return clk[best];
+}
+
+int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
+ //find shortest transition from high to low
+ size_t i = 0;
+ size_t transition1 = 0;
+ int lowestTransition = 255;
+ bool lastWasHigh = false;
+
+ //find first valid beginning of a high or low wave
+ while ((dest[i] >= peak || dest[i] <= low) && (i < size))
+ ++i;
+ while ((dest[i] < peak && dest[i] > low) && (i < size))
+ ++i;
+ lastWasHigh = (dest[i] >= peak);
+
+ if (i==size) return 0;
+ transition1 = i;
+
+ for (;i < size; i++) {
+ if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
+ lastWasHigh = (dest[i] >= peak);
+ if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
+ transition1 = i;
+ }
+ }
+ if (lowestTransition == 255) lowestTransition = 0;
+ if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
+ return lowestTransition;
+}
+
+//by marshmellow
+//detect nrz clock by reading #peaks vs no peaks(or errors)
+int DetectNRZClock(uint8_t dest[], size_t size, int clock)
+{
+ 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...
+ if (size == 0) return 0;
+ if (size<loopCnt) loopCnt = size-20;
+ //if we already have a valid clock quit
+ for (; i < 8; ++i)
+ if (clk[i] == clock) return clock;
+
+ //get high and low peak
+ int peak, low;
+ if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
+
+ int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
+ size_t ii;
+ uint8_t clkCnt;
+ uint8_t tol = 0;
+ uint16_t smplCnt = 0;
+ int16_t peakcnt = 0;
+ int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
+ uint16_t maxPeak = 255;
+ bool firstpeak = false;
+ //test for large clipped waves
+ for (i=0; i<loopCnt; i++){
+ if (dest[i] >= peak || dest[i] <= low){
+ if (!firstpeak) continue;
+ smplCnt++;
+ } else {
+ firstpeak=true;
+ if (smplCnt > 6 ){
+ if (maxPeak > smplCnt){
+ maxPeak = smplCnt;
+ //prnt("maxPk: %d",maxPeak);
+ }
+ peakcnt++;
+ //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
+ smplCnt=0;
+ }
+ }
+ }
+ bool errBitHigh = 0;
+ bool bitHigh = 0;
+ uint8_t ignoreCnt = 0;
+ uint8_t ignoreWindow = 4;
+ bool lastPeakHigh = 0;
+ int lastBit = 0;
+ peakcnt=0;
+ //test each valid clock from smallest to greatest to see which lines up
+ for(clkCnt=0; clkCnt < 8; ++clkCnt){
+ //ignore clocks smaller than smallest peak
+ if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
+ //try lining up the peaks by moving starting point (try first 256)
+ for (ii=20; ii < loopCnt; ++ii){
+ if ((dest[ii] >= peak) || (dest[ii] <= low)){
+ peakcnt=0;
+ bitHigh = false;
+ ignoreCnt = 0;
+ lastBit = ii-clk[clkCnt];
+ //loop through to see if this start location works
+ for (i = ii; i < size-20; ++i) {
+ //if we are at a clock bit
+ if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
+ //test high/low
+ if (dest[i] >= peak || dest[i] <= low) {
+ //if same peak don't count it
+ if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
+ peakcnt++;
+ }
+ lastPeakHigh = (dest[i] >= peak);
+ bitHigh = true;
+ errBitHigh = false;
+ ignoreCnt = ignoreWindow;
+ lastBit += clk[clkCnt];
+ } else if (i == lastBit + clk[clkCnt] + tol) {
+ lastBit += clk[clkCnt];
+ }
+ //else if not a clock bit and no peaks
+ } else if (dest[i] < peak && dest[i] > low){
+ if (ignoreCnt==0){
+ bitHigh=false;
+ if (errBitHigh==true) peakcnt--;
+ errBitHigh=false;
+ } else {
+ ignoreCnt--;
+ }
+ // else if not a clock bit but we have a peak
+ } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
+ //error bar found no clock...
+ errBitHigh=true;
+ }
+ }
+ if(peakcnt>peaksdet[clkCnt]) {
+ peaksdet[clkCnt]=peakcnt;
+ }
+ }
+ }
+ }
+ int iii=7;
+ uint8_t best=0;
+ for (iii=7; iii > 0; iii--){
+ if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
+ if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
+ best = iii;
+ }
+ } else if (peaksdet[iii] > peaksdet[best]){
+ best = iii;
+ }
+ 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);
+ }
+
+ return clk[best];
+}
+
+// by marshmellow
+// convert psk1 demod to psk2 demod
+// only transition waves are 1s
+void psk1TOpsk2(uint8_t *bits, size_t size) {
+ uint8_t lastBit = bits[0];
+ for (size_t i = 1; i < size; i++){
+ //ignore errors
+ if (bits[i] == 7) continue;
+
+ if (lastBit != bits[i]){
+ lastBit = bits[i];
+ bits[i] = 1;
+ } else {
+ bits[i] = 0;
+ }
+ }
+}
+
+// by marshmellow
+// convert psk2 demod to psk1 demod
+// from only transition waves are 1s to phase shifts change bit
+void psk2TOpsk1(uint8_t *bits, size_t size) {
+ uint8_t phase = 0;
+ for (size_t i = 0; i < size; i++){
+ if (bits[i] == 1){
+ phase ^= 1;
+ }
+ bits[i] = phase;
+ }
+}
+
+// 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)
+ uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+ uint8_t preamble_i[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
+ size_t startidx = 0;
+ if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
+ // if didn't find preamble try again inverting
+ if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
+ *invert ^= 1;
+ }
+ if (*size != 64 && *size != 224) return -2;
+ if (*invert==1)
+ for (size_t i = startidx; i < *size; i++)
+ bitStream[i] ^= 1;
+
+ return (int) startidx;
+}
+
+// by marshmellow - demodulate NRZ wave - requires a read with strong signal
+// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
+int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
+ 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-20;
+ int high, low;
+ if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
+
+ uint8_t bit=0;
+ //convert wave samples to 1's and 0's
+ for(i=20; i < *size-20; i++){
+ if (dest[i] >= high) bit = 1;
+ if (dest[i] <= low) bit = 0;
+ dest[i] = bit;
+ }
+ //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
+ size_t lastBit = 0;
+ size_t numBits = 0;
+ for(i=21; i < *size-20; i++) {
+ //if transition detected or large number of same bits - store the passed bits
+ if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
+ memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
+ numBits += (i - lastBit + (*clk/4)) / *clk;
+ lastBit = i-1;
+ }
+ }
+ *size = numBits;
+ return 0;
+}
+
+//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)
projects / proxmark3-svn / blobdiff