From d5051b981792695644f17f86cf4ed49bac2b5ff0 Mon Sep 17 00:00:00 2001 From: marshmellow42 Date: Sun, 12 Mar 2017 23:11:52 -0400 Subject: [PATCH] meant to put clock detection before demods ... fixing that. no code changed here... --- common/lfdemod.c | 1444 +++++++++++++++++++++++----------------------- 1 file changed, 726 insertions(+), 718 deletions(-) diff --git a/common/lfdemod.c b/common/lfdemod.c index 721c9d1c..fdcb475b 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -22,21 +22,23 @@ // There are 4 main sections of code below: // Utilities Section: // for general utilities used by multiple other functions -// Modulation Demods &/or Decoding Section: -// for main general modulation demodulating and encoding decoding code. // Clock / Bitrate Detection Section: // for clock detection functions for each modulation +// Modulation Demods &/or Decoding Section: +// for main general modulation demodulating and encoding decoding code. // Tag format detection section: // for detection of specific tag formats within demodulated data // // marshmellow //----------------------------------------------------------------------------- -#include -#include "lfdemod.h" -#include +#include // for memset, memcmp and size_t +#include // for uint_32+ +#include // for bool -//---------------------------------Utilities Section-------------------------------------------------- +//********************************************************************************************** +//---------------------------------Utilities Section-------------------------------------------- +//********************************************************************************************** //to allow debug print calls when used not on device void dummy(char *fmt, ...){} @@ -261,266 +263,6 @@ int ManchesterEncode(uint8_t *BitStream, size_t size) { return i; } -//------------------------------Modulation Demods &/or Decoding Section------------------------------------------------------ - -// look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index... -bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, int i) { - for (; i < buffSize - 4; ++i) { - *stStartIdx += lowToLowWaveLen[i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now... - if (lowToLowWaveLen[i] >= clk*1-tol && lowToLowWaveLen[i] <= (clk*2)+tol && highToLowWaveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior - if (lowToLowWaveLen[i+1] >= clk*2-tol && lowToLowWaveLen[i+1] <= clk*2+tol && highToLowWaveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 - if (lowToLowWaveLen[i+2] >= (clk*3)/2-tol && lowToLowWaveLen[i+2] <= clk*2+tol && highToLowWaveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave - if (lowToLowWaveLen[i+3] >= clk*1-tol && lowToLowWaveLen[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit - *stStopLoc = i + 3; - return true; - } - } - } - } - } - return false; -} -//by marshmellow -//attempt to identify a Sequence Terminator in ASK modulated raw wave -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 clk = 0; - int tol = 0; - int i, j, skip, start, end, low, high, minClk, waveStart; - //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow] - int tmpbuff[bufsize / 32]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured - int waveLen[bufsize / 32]; // high to low wave count //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; - memset(tmpbuff, 0, sizeof(tmpbuff)); - - if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) { - if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); - return false; //just noise - } - i = 0; - j = 0; - minClk = 255; - // get to first full low to prime loop and skip incomplete first pulse - while ((buffer[i] < high) && (i < bufsize)) - ++i; - while ((buffer[i] > low) && (i < bufsize)) - ++i; - skip = i; - - // populate tmpbuff buffer with pulse lengths - while (i < bufsize) { - // measure from low to low - while ((buffer[i] > low) && (i < bufsize)) - ++i; - start= i; - while ((buffer[i] < high) && (i < bufsize)) - ++i; - //first high point for this wave - waveStart = i; - while ((buffer[i] > low) && (i < bufsize)) - ++i; - if (j >= (bufsize/32)) { - break; - } - waveLen[j] = i - waveStart; //first high to first low - tmpbuff[j++] = i - start; - if (i-start < minClk && i < bufsize) { - minClk = i - start; - } - } - // set clock - might be able to get this externally and remove this work... - if (!clk) { - for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { - tol = fndClk[clkCnt]/8; - if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) { - clk=fndClk[clkCnt]; - break; - } - } - // clock not found - ERROR - if (!clk) { - if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); - return false; - } - } else tol = clk/8; - - *foundclock = clk; - i=0; - if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, i)) { - // first ST not found - ERROR - 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; - else - phaseoff = clk/2; - - // skip over the remainder of ST - skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point - - // now do it again to find the end - int dummy1 = 0; - end = skip; - if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, i+3)) { - //didn't find second ST - ERROR - if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting"); - return false; - } - end -= phaseoff; - if (g_debugMode==2) prnt("DEBUG STT: start of data: %d end of data: %d, datalen: %d, clk: %d, bits: %d, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff); - //now begin to trim out ST so we can use normal demod cmds - 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 ( 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; - } - // if datalen is less than one t55xx block - ERROR - if (datalen/clk < 8*4) { - if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting"); - 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) - if (buffer[dataloc]low && buffer[dataloc+3]low) { - 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; iMaxBits) break; - } - *size=bitnum; - return errCnt; -} - -//by marshmellow -//take 10 and 01 and manchester decode -//run through 2 times and take least errCnt -int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) { - uint16_t bitnum=0, MaxBits = 512, errCnt = 0; - size_t i, ii; - uint16_t bestErr = 1000, bestRun = 0; - if (*size < 16) return -1; - //find correct start position [alignment] - for (ii=0;ii<2;++ii){ - for (i=ii; i<*size-3; i+=2) - if (BitStream[i]==BitStream[i+1]) - errCnt++; - - if (bestErr>errCnt){ - bestErr=errCnt; - bestRun=ii; - } - errCnt=0; - } - *alignPos=bestRun; - //decode - for (i=bestRun; i < *size-3; i+=2){ - if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ - BitStream[bitnum++]=invert; - } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ - BitStream[bitnum++]=invert^1; - } else { - BitStream[bitnum++]=7; - } - if(bitnum>MaxBits) break; - } - *size=bitnum; - return bestErr; -} - // by marshmellow // to detect a wave that has heavily clipped (clean) samples uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) { @@ -540,457 +282,9 @@ uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t lo return allArePeaks; } -//by marshmellow -//demodulates strong heavily clipped samples -int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx) -{ - *startIdx=0; - size_t bitCnt=0, smplCnt=1, errCnt=0; - bool waveHigh = (BinStream[0] >= high); - for (size_t i=1; i < *size; i++){ - if (BinStream[i] >= high && waveHigh){ - smplCnt++; - } else if (BinStream[i] <= low && !waveHigh){ - smplCnt++; - } else { //transition - if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ - if (smplCnt > clk-(clk/4)-1) { //full clock - if (smplCnt > clk + (clk/4)+1) { //too many samples - errCnt++; - if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); - BinStream[bitCnt++] = 7; - } else if (waveHigh) { - BinStream[bitCnt++] = invert; - BinStream[bitCnt++] = invert; - } else if (!waveHigh) { - BinStream[bitCnt++] = invert ^ 1; - BinStream[bitCnt++] = invert ^ 1; - } - if (*startIdx==0) *startIdx = i-clk; - waveHigh = !waveHigh; - smplCnt = 0; - } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock - if (waveHigh) { - BinStream[bitCnt++] = invert; - } else if (!waveHigh) { - BinStream[bitCnt++] = invert ^ 1; - } - if (*startIdx==0) *startIdx = i-(clk/2); - waveHigh = !waveHigh; - smplCnt = 0; - } else { - smplCnt++; - //transition bit oops - } - } else { //haven't hit new high or new low yet - smplCnt++; - } - } - } - *size = bitCnt; - return errCnt; -} - -//by marshmellow -//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester -int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) { - if (*size==0) return -1; - int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default - 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, amp %d", *clk, start, amp); - - //start pos from detect ask clock is 1/2 clock offset - // NOTE: can be negative (demod assumes rest of wave was there) - *startIdx = start - (*clk/2); - uint8_t initLoopMax = 255; - if (initLoopMax > *size) initLoopMax = *size; - // Detect high and lows - //25% clip in case highs and lows aren't clipped [marshmellow] - int high, low; - if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) - return -2; //just noise - - size_t errCnt = 0; - // if clean clipped waves detected run alternate demod - if (DetectCleanAskWave(BinStream, *size, high, low)) { - if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod"); - errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx); - if (askType) { //askman - uint8_t alignPos = 0; - errCnt = manrawdecode(BinStream, size, 0, &alignPos); - *startIdx += *clk/2 * alignPos; - if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos); - return errCnt; - } else { //askraw - return errCnt; - } - } - if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx); - if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); - - 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 - 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; - - for (i = start; i < *size; ++i) { - if (i-lastBit >= *clk-tol){ - if (BinStream[i] >= high) { - BinStream[bitnum++] = *invert; - } else if (BinStream[i] <= low) { - BinStream[bitnum++] = *invert ^ 1; - } else if (i-lastBit >= *clk+tol) { - if (bitnum > 0) { - if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); - BinStream[bitnum++]=7; - errCnt++; - } - } else { //in tolerance - looking for peak - continue; - } - midBit = 0; - lastBit += *clk; - } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ - if (BinStream[i] >= high) { - BinStream[bitnum++] = *invert; - } else if (BinStream[i] <= low) { - BinStream[bitnum++] = *invert ^ 1; - } else if (i-lastBit >= *clk/2+tol) { - BinStream[bitnum] = BinStream[bitnum-1]; - bitnum++; - } else { //in tolerance - looking for peak - continue; - } - midBit = 1; - } - if (bitnum >= MaxBits) break; - } - *size = bitnum; - return errCnt; -} - -int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) { - int start = 0; - return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start); -} - -// 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_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) { - 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; - if (lastBit == 0) { - *startIdx = i - (numBits * *clk); - if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx); - } - lastBit = i-1; - } - } - *size = numBits; - return 0; -} -int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) { - int startIdx = 0; - return nrzRawDemod_ext(dest, size, clk, invert, &startIdx); -} - -//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq]) -size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) { - size_t last_transition = 0; - size_t idx = 1; - if (fchigh==0) fchigh=10; - if (fclow==0) fclow=8; - //set the threshold close to 0 (graph) or 128 std to avoid static - uint8_t threshold_value = 123; - size_t preLastSample = 0; - size_t LastSample = 0; - size_t currSample = 0; - 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 - if(dest[idx] < threshold_value) dest[0] = 0; - else dest[0] = 1; - - last_transition = idx; - 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 < size; idx++) { - // threshold current value - if (dest[idx] < threshold_value) dest[idx] = 0; - else dest[idx] = 1; - - // Check for 0->1 transition - if (dest[idx-1] < dest[idx]) { - preLastSample = LastSample; - LastSample = currSample; - currSample = idx-last_transition; - if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3) - //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 (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){ - dest[numBits-1]=1; - } - dest[numBits++]=1; - if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; - } 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; - if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; - } else { //9+ = 10 sample waves (or 6+ = 7) - dest[numBits++]=0; - if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh; - } - last_transition = idx; - } - } - return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 -} - -//translate 11111100000 to 10 -//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock -size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) { - uint8_t lastval=dest[0]; - size_t idx=0; - size_t numBits=0; - uint32_t n=1; - for( idx=1; idx < size; idx++) { - n++; - if (dest[idx]==lastval) continue; //skip until we hit a transition - - //find out how many bits (n) we collected (use 1/2 clk tolerance) - //if lastval was 1, we have a 1->0 crossing - if (dest[idx-1]==1) { - n = (n * fclow + rfLen/2) / rfLen; - } else {// 0->1 crossing - n = (n * fchigh + rfLen/2) / rfLen; - } - if (n == 0) n = 1; - - //first transition - save startidx - if (numBits == 0) { - if (lastval == 1) { //high to low - *startIdx += (fclow * idx) - (n*rfLen); - if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen); - } else { - *startIdx += (fchigh * idx) - (n*rfLen); - if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen); - } - } - - //add to our destination the bits we collected - memset(dest+numBits, dest[idx-1]^invert , n); - numBits += n; - n=0; - lastval=dest[idx]; - }//end for - // if valid extra bits at the end were all the same frequency - add them in - if (n > rfLen/fchigh) { - if (dest[idx-2]==1) { - n = (n * fclow + rfLen/2) / rfLen; - } else { - n = (n * fchigh + rfLen/2) / rfLen; - } - memset(dest+numBits, dest[idx-1]^invert , n); - numBits += n; - } - return numBits; -} - -//by marshmellow (from holiman's base) -// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) -int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) { - // FSK demodulator - size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx); - size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx); - return size; -} - -int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) { - int startIdx=0; - return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx); -} - -// by marshmellow -// convert psk1 demod to psk2 demod -// only transition waves are 1s -void psk1TOpsk2(uint8_t *BitStream, size_t size) { - size_t i=1; - uint8_t lastBit=BitStream[0]; - for (; i> 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; - - //find start of modulating data in trace - uint8_t threshold_value = 123; //-5 - i = findModStart(dest, *size, threshold_value, fc); - - //find first phase shift - int avgWaveVal=0, lastAvgWaveVal=0; - waveStart = i; - for (; i= dest[i+2]){ - waveEnd = i+1; - if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart); - waveLenCnt = waveEnd-waveStart; - 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 (could cause inverting) - if (lastAvgWaveVal > threshold_value) curPhase ^= 1; - break; - } - - waveStart = i+1; - avgWaveVal = 0; - } - avgWaveVal += dest[i+2]; - } - if (firstFullWave == 0) { - // no phase shift detected - could be all 1's or 0's - doesn't matter where we start - // so skip a little to ensure we are past any Start Signal - firstFullWave = 160; - memset(dest, curPhase, firstFullWave / *clock); - } else { - memset(dest, curPhase^1, firstFullWave / *clock); - } - //advance bits - numBits += (firstFullWave / *clock); - *startIdx = firstFullWave - (*clock * numBits)+2; - //set start of wave as clock align - lastClkBit = firstFullWave; - if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx); - 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++){ - //top edge of wave = start of new wave - if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ - if (waveStart == 0) { - waveStart = i+1; - waveLenCnt = 0; - avgWaveVal = dest[i+1]; - } else { //waveEnd - waveEnd = i+1; - waveLenCnt = waveEnd-waveStart; - lastAvgWaveVal = avgWaveVal/waveLenCnt; - if (waveLenCnt > fc){ - //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); - //this wave is a phase shift - //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc); - if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit - curPhase ^= 1; - dest[numBits++] = curPhase; - lastClkBit += *clock; - } else if (i < lastClkBit+10+fc){ - //noise after a phase shift - ignore - } else { //phase shift before supposed to based on clock - errCnt++; - dest[numBits++] = 7; - } - } 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; - } - } - avgWaveVal += dest[i+1]; - } - *size = numBits; - return errCnt; -} - -int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) { - int startIdx = 0; - return pskRawDemod_ext(dest, size, clock, invert, &startIdx); -} - -//-------------------Clock / Bitrate Detection Section------------------------------------------------------------------------------------ +//********************************************************************************************** +//-------------------Clock / Bitrate Detection Section------------------------------------------ +//********************************************************************************************** // by marshmellow // to help detect clocks on heavily clipped samples @@ -1589,7 +883,721 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge); } -//-----------------Tag format detection section-------------------------------------------------------------- +//********************************************************************************************** +//--------------------Modulation Demods &/or Decoding Section----------------------------------- +//********************************************************************************************** + +// look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index... +bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, int i) { + for (; i < buffSize - 4; ++i) { + *stStartIdx += lowToLowWaveLen[i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now... + if (lowToLowWaveLen[i] >= clk*1-tol && lowToLowWaveLen[i] <= (clk*2)+tol && highToLowWaveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior + if (lowToLowWaveLen[i+1] >= clk*2-tol && lowToLowWaveLen[i+1] <= clk*2+tol && highToLowWaveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 + if (lowToLowWaveLen[i+2] >= (clk*3)/2-tol && lowToLowWaveLen[i+2] <= clk*2+tol && highToLowWaveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave + if (lowToLowWaveLen[i+3] >= clk*1-tol && lowToLowWaveLen[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit + *stStopLoc = i + 3; + return true; + } + } + } + } + } + return false; +} +//by marshmellow +//attempt to identify a Sequence Terminator in ASK modulated raw wave +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 clk = 0; + int tol = 0; + int i, j, skip, start, end, low, high, minClk, waveStart; + //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow] + int tmpbuff[bufsize / 32]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured + int waveLen[bufsize / 32]; // high to low wave count //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; + memset(tmpbuff, 0, sizeof(tmpbuff)); + + if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) { + if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); + return false; //just noise + } + i = 0; + j = 0; + minClk = 255; + // get to first full low to prime loop and skip incomplete first pulse + while ((buffer[i] < high) && (i < bufsize)) + ++i; + while ((buffer[i] > low) && (i < bufsize)) + ++i; + skip = i; + + // populate tmpbuff buffer with pulse lengths + while (i < bufsize) { + // measure from low to low + while ((buffer[i] > low) && (i < bufsize)) + ++i; + start= i; + while ((buffer[i] < high) && (i < bufsize)) + ++i; + //first high point for this wave + waveStart = i; + while ((buffer[i] > low) && (i < bufsize)) + ++i; + if (j >= (bufsize/32)) { + break; + } + waveLen[j] = i - waveStart; //first high to first low + tmpbuff[j++] = i - start; + if (i-start < minClk && i < bufsize) { + minClk = i - start; + } + } + // set clock - might be able to get this externally and remove this work... + if (!clk) { + for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { + tol = fndClk[clkCnt]/8; + if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) { + clk=fndClk[clkCnt]; + break; + } + } + // clock not found - ERROR + if (!clk) { + if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); + return false; + } + } else tol = clk/8; + + *foundclock = clk; + i=0; + if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, i)) { + // first ST not found - ERROR + 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; + else + phaseoff = clk/2; + + // skip over the remainder of ST + skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point + + // now do it again to find the end + int dummy1 = 0; + end = skip; + if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, i+3)) { + //didn't find second ST - ERROR + if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting"); + return false; + } + end -= phaseoff; + if (g_debugMode==2) prnt("DEBUG STT: start of data: %d end of data: %d, datalen: %d, clk: %d, bits: %d, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff); + //now begin to trim out ST so we can use normal demod cmds + 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 ( 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; + } + // if datalen is less than one t55xx block - ERROR + if (datalen/clk < 8*4) { + if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting"); + 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) + if (buffer[dataloc]low && buffer[dataloc+3]low) { + 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; iMaxBits) break; + } + *size=bitnum; + return errCnt; +} + +//by marshmellow +//take 10 and 01 and manchester decode +//run through 2 times and take least errCnt +int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) { + uint16_t bitnum=0, MaxBits = 512, errCnt = 0; + size_t i, ii; + uint16_t bestErr = 1000, bestRun = 0; + if (*size < 16) return -1; + //find correct start position [alignment] + for (ii=0;ii<2;++ii){ + for (i=ii; i<*size-3; i+=2) + if (BitStream[i]==BitStream[i+1]) + errCnt++; + + if (bestErr>errCnt){ + bestErr=errCnt; + bestRun=ii; + } + errCnt=0; + } + *alignPos=bestRun; + //decode + for (i=bestRun; i < *size-3; i+=2){ + if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ + BitStream[bitnum++]=invert; + } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ + BitStream[bitnum++]=invert^1; + } else { + BitStream[bitnum++]=7; + } + if(bitnum>MaxBits) break; + } + *size=bitnum; + return bestErr; +} + +//by marshmellow +//demodulates strong heavily clipped samples +int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx) +{ + *startIdx=0; + size_t bitCnt=0, smplCnt=1, errCnt=0; + bool waveHigh = (BinStream[0] >= high); + for (size_t i=1; i < *size; i++){ + if (BinStream[i] >= high && waveHigh){ + smplCnt++; + } else if (BinStream[i] <= low && !waveHigh){ + smplCnt++; + } else { //transition + if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ + if (smplCnt > clk-(clk/4)-1) { //full clock + if (smplCnt > clk + (clk/4)+1) { //too many samples + errCnt++; + if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); + BinStream[bitCnt++] = 7; + } else if (waveHigh) { + BinStream[bitCnt++] = invert; + BinStream[bitCnt++] = invert; + } else if (!waveHigh) { + BinStream[bitCnt++] = invert ^ 1; + BinStream[bitCnt++] = invert ^ 1; + } + if (*startIdx==0) *startIdx = i-clk; + waveHigh = !waveHigh; + smplCnt = 0; + } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock + if (waveHigh) { + BinStream[bitCnt++] = invert; + } else if (!waveHigh) { + BinStream[bitCnt++] = invert ^ 1; + } + if (*startIdx==0) *startIdx = i-(clk/2); + waveHigh = !waveHigh; + smplCnt = 0; + } else { + smplCnt++; + //transition bit oops + } + } else { //haven't hit new high or new low yet + smplCnt++; + } + } + } + *size = bitCnt; + return errCnt; +} + +//by marshmellow +//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester +int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) { + if (*size==0) return -1; + int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default + 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, amp %d", *clk, start, amp); + + //start pos from detect ask clock is 1/2 clock offset + // NOTE: can be negative (demod assumes rest of wave was there) + *startIdx = start - (*clk/2); + uint8_t initLoopMax = 255; + if (initLoopMax > *size) initLoopMax = *size; + // Detect high and lows + //25% clip in case highs and lows aren't clipped [marshmellow] + int high, low; + if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) + return -2; //just noise + + size_t errCnt = 0; + // if clean clipped waves detected run alternate demod + if (DetectCleanAskWave(BinStream, *size, high, low)) { + if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod"); + errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx); + if (askType) { //askman + uint8_t alignPos = 0; + errCnt = manrawdecode(BinStream, size, 0, &alignPos); + *startIdx += *clk/2 * alignPos; + if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos); + return errCnt; + } else { //askraw + return errCnt; + } + } + if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx); + if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); + + 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 + 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; + + for (i = start; i < *size; ++i) { + if (i-lastBit >= *clk-tol){ + if (BinStream[i] >= high) { + BinStream[bitnum++] = *invert; + } else if (BinStream[i] <= low) { + BinStream[bitnum++] = *invert ^ 1; + } else if (i-lastBit >= *clk+tol) { + if (bitnum > 0) { + if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); + BinStream[bitnum++]=7; + errCnt++; + } + } else { //in tolerance - looking for peak + continue; + } + midBit = 0; + lastBit += *clk; + } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ + if (BinStream[i] >= high) { + BinStream[bitnum++] = *invert; + } else if (BinStream[i] <= low) { + BinStream[bitnum++] = *invert ^ 1; + } else if (i-lastBit >= *clk/2+tol) { + BinStream[bitnum] = BinStream[bitnum-1]; + bitnum++; + } else { //in tolerance - looking for peak + continue; + } + midBit = 1; + } + if (bitnum >= MaxBits) break; + } + *size = bitnum; + return errCnt; +} + +int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) { + int start = 0; + return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start); +} + +// 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_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) { + 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; + if (lastBit == 0) { + *startIdx = i - (numBits * *clk); + if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx); + } + lastBit = i-1; + } + } + *size = numBits; + return 0; +} +int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) { + int startIdx = 0; + return nrzRawDemod_ext(dest, size, clk, invert, &startIdx); +} + +//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq]) +size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) { + size_t last_transition = 0; + size_t idx = 1; + if (fchigh==0) fchigh=10; + if (fclow==0) fclow=8; + //set the threshold close to 0 (graph) or 128 std to avoid static + uint8_t threshold_value = 123; + size_t preLastSample = 0; + size_t LastSample = 0; + size_t currSample = 0; + 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 + if(dest[idx] < threshold_value) dest[0] = 0; + else dest[0] = 1; + + last_transition = idx; + 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 < size; idx++) { + // threshold current value + if (dest[idx] < threshold_value) dest[idx] = 0; + else dest[idx] = 1; + + // Check for 0->1 transition + if (dest[idx-1] < dest[idx]) { + preLastSample = LastSample; + LastSample = currSample; + currSample = idx-last_transition; + if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3) + //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 (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){ + dest[numBits-1]=1; + } + dest[numBits++]=1; + if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; + } 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; + if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; + } else { //9+ = 10 sample waves (or 6+ = 7) + dest[numBits++]=0; + if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh; + } + last_transition = idx; + } + } + return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 +} + +//translate 11111100000 to 10 +//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock +size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) { + uint8_t lastval=dest[0]; + size_t idx=0; + size_t numBits=0; + uint32_t n=1; + for( idx=1; idx < size; idx++) { + n++; + if (dest[idx]==lastval) continue; //skip until we hit a transition + + //find out how many bits (n) we collected (use 1/2 clk tolerance) + //if lastval was 1, we have a 1->0 crossing + if (dest[idx-1]==1) { + n = (n * fclow + rfLen/2) / rfLen; + } else {// 0->1 crossing + n = (n * fchigh + rfLen/2) / rfLen; + } + if (n == 0) n = 1; + + //first transition - save startidx + if (numBits == 0) { + if (lastval == 1) { //high to low + *startIdx += (fclow * idx) - (n*rfLen); + if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen); + } else { + *startIdx += (fchigh * idx) - (n*rfLen); + if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen); + } + } + + //add to our destination the bits we collected + memset(dest+numBits, dest[idx-1]^invert , n); + numBits += n; + n=0; + lastval=dest[idx]; + }//end for + // if valid extra bits at the end were all the same frequency - add them in + if (n > rfLen/fchigh) { + if (dest[idx-2]==1) { + n = (n * fclow + rfLen/2) / rfLen; + } else { + n = (n * fchigh + rfLen/2) / rfLen; + } + memset(dest+numBits, dest[idx-1]^invert , n); + numBits += n; + } + return numBits; +} + +//by marshmellow (from holiman's base) +// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) +int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) { + // FSK demodulator + size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx); + size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx); + return size; +} + +int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) { + int startIdx=0; + return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx); +} + +// by marshmellow +// convert psk1 demod to psk2 demod +// only transition waves are 1s +void psk1TOpsk2(uint8_t *BitStream, size_t size) { + size_t i=1; + uint8_t lastBit=BitStream[0]; + for (; i> 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; + + //find start of modulating data in trace + uint8_t threshold_value = 123; //-5 + i = findModStart(dest, *size, threshold_value, fc); + + //find first phase shift + int avgWaveVal=0, lastAvgWaveVal=0; + waveStart = i; + for (; i= dest[i+2]){ + waveEnd = i+1; + if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart); + waveLenCnt = waveEnd-waveStart; + 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 (could cause inverting) + if (lastAvgWaveVal > threshold_value) curPhase ^= 1; + break; + } + + waveStart = i+1; + avgWaveVal = 0; + } + avgWaveVal += dest[i+2]; + } + if (firstFullWave == 0) { + // no phase shift detected - could be all 1's or 0's - doesn't matter where we start + // so skip a little to ensure we are past any Start Signal + firstFullWave = 160; + memset(dest, curPhase, firstFullWave / *clock); + } else { + memset(dest, curPhase^1, firstFullWave / *clock); + } + //advance bits + numBits += (firstFullWave / *clock); + *startIdx = firstFullWave - (*clock * numBits)+2; + //set start of wave as clock align + lastClkBit = firstFullWave; + if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx); + 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++){ + //top edge of wave = start of new wave + if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ + if (waveStart == 0) { + waveStart = i+1; + waveLenCnt = 0; + avgWaveVal = dest[i+1]; + } else { //waveEnd + waveEnd = i+1; + waveLenCnt = waveEnd-waveStart; + lastAvgWaveVal = avgWaveVal/waveLenCnt; + if (waveLenCnt > fc){ + //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); + //this wave is a phase shift + //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc); + if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit + curPhase ^= 1; + dest[numBits++] = curPhase; + lastClkBit += *clock; + } else if (i < lastClkBit+10+fc){ + //noise after a phase shift - ignore + } else { //phase shift before supposed to based on clock + errCnt++; + dest[numBits++] = 7; + } + } 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; + } + } + avgWaveVal += dest[i+1]; + } + *size = numBits; + return errCnt; +} + +int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) { + int startIdx = 0; + return pskRawDemod_ext(dest, size, clock, invert, &startIdx); +} + +//********************************************************************************************** +//-----------------Tag format detection section------------------------------------------------- +//********************************************************************************************** // by marshmellow // FSK Demod then try to locate an AWID ID