//----------------------------------------------------------------------------- // Copyright (C) 2014 // // This code is licensed to you under the terms of the GNU GPL, version 2 or, // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- // Low frequency commands //----------------------------------------------------------------------------- #include #include #include "lfdemod.h" //by marshmellow //takes 1s and 0s and searches for EM410x format - output EM ID uint64_t Em410xDecode(uint8_t *BitStream, size_t size) { //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 int high=0, low=255; uint64_t lo=0; uint32_t i = 0; uint32_t initLoopMax = 65; if (initLoopMax>size) initLoopMax=size; for (;i < initLoopMax; ++i) //65 samples should be plenty to find high and low values { if (BitStream[i] > high) high = BitStream[i]; else if (BitStream[i] < low) low = BitStream[i]; } if (((high !=1)||(low !=0))){ //allow only 1s and 0s // PrintAndLog("no data found"); return 0; } uint8_t parityTest=0; // 111111111 bit pattern represent start of frame uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1}; uint32_t idx = 0; uint32_t ii=0; uint8_t resetCnt = 0; while( (idx + 64) < size) { restart: // search for a start of frame marker if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0) { // frame marker found idx+=9; for (i=0; i<10;i++){ for(ii=0; ii<5; ++ii){ parityTest += BitStream[(i*5)+ii+idx]; } if (parityTest== ((parityTest>>1)<<1)){ parityTest=0; for (ii=0; ii<4;++ii){ lo=(lo<<1LL)|(BitStream[(i*5)+ii+idx]); } //PrintAndLog("DEBUG: EM parity passed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d,lo: %d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1],lo); }else {//parity failed //PrintAndLog("DEBUG: EM parity failed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1]); parityTest=0; idx-=8; if (resetCnt>5)return 0; resetCnt++; goto restart;//continue; } } //skip last 5 bit parity test for simplicity. return lo; }else{ idx++; } } return 0; } //by marshmellow //takes 2 arguments - clock and invert both as integers //attempts to demodulate ask while decoding manchester //prints binary found and saves in graphbuffer for further commands int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) { int i; int high = 0, low = 255; *clk=DetectASKClock(BinStream, *size, *clk); //clock default if (*clk<8) *clk =64; if (*clk<32) *clk=32; if (*invert != 0 && *invert != 1) *invert=0; uint32_t initLoopMax = 200; if (initLoopMax > *size) initLoopMax=*size; // Detect high and lows for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values { if (BinStream[i] > high) high = BinStream[i]; else if (BinStream[i] < low) low = BinStream[i]; } if ((high < 129) ){ //throw away static (anything < 1 graph) //PrintAndLog("no data found"); return -2; } //25% fuzz in case highs and lows aren't clipped [marshmellow] high=(int)(((high-128)*.75)+128); low= (int)(((low-128)*.75)+128); //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check uint32_t bitnum = 0; //output counter int 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 int iii = 0; uint32_t gLen = *size; if (gLen > 3000) gLen=3000; uint8_t errCnt =0; uint32_t bestStart = *size; uint32_t bestErrCnt = (*size/1000); uint32_t maxErr = (*size/1000); //PrintAndLog("DEBUG - lastbit - %d",lastBit); //loop to find first wave that works for (iii=0; iii < gLen; ++iii){ if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){ lastBit=iii-*clk; errCnt=0; //loop through to see if this start location works for (i = iii; i < *size; ++i) { if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){ lastBit+=*clk; } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){ //low found and we are expecting a bar lastBit+=*clk; } else { //mid value found or no bar supposed to be here if ((i-lastBit)>(*clk+tol)){ //should have hit a high or low based on clock!! //debug //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit); errCnt++; lastBit+=*clk;//skip over until hit too many errors if (errCnt>(maxErr)) break; //allow 1 error for every 1000 samples else start over } } if ((i-iii) >(400 * *clk)) break; //got plenty of bits } //we got more than 64 good bits and not all errors if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt= high) && ((i-lastBit) > (*clk-tol))){ lastBit += *clk; BinStream[bitnum] = *invert; bitnum++; } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){ //low found and we are expecting a bar lastBit+=*clk; BinStream[bitnum] = 1-*invert; bitnum++; } else { //mid value found or no bar supposed to be here if ((i-lastBit)>(*clk+tol)){ //should have hit a high or low based on clock!! //debug //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit); if (bitnum > 0){ BinStream[bitnum]=77; bitnum++; } lastBit+=*clk;//skip over error } } if (bitnum >=400) break; } *size=bitnum; } else{ *invert=bestStart; *clk=iii; return -1; } return bestErrCnt; } //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) { int bitnum=0; int errCnt =0; int i=1; int bestErr = 1000; int bestRun = 0; int ii=1; for (ii=1;ii<3;++ii){ i=1; for (i=i+ii;i<*size-2;i+=2){ if(BitStream[i]==1 && (BitStream[i+1]==0)){ } else if((BitStream[i]==0)&& BitStream[i+1]==1){ } else { errCnt++; } if(bitnum>300) break; } if (bestErr>errCnt){ bestErr=errCnt; bestRun=ii; } errCnt=0; } errCnt=bestErr; if (errCnt<20){ ii=bestRun; i=1; for (i=i+ii;i < *size-2;i+=2){ if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ BitStream[bitnum++]=0; } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ BitStream[bitnum++]=1; } else { BitStream[bitnum++]=77; //errCnt++; } if(bitnum>300) break; } *size=bitnum; } return errCnt; } //by marshmellow //take 01 or 10 = 0 and 11 or 00 = 1 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset) { uint8_t bitnum=0; uint32_t errCnt =0; uint32_t i=1; i=offset; for (;i<*size-2;i+=2){ if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ BitStream[bitnum++]=1; } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ BitStream[bitnum++]=0; } else { BitStream[bitnum++]=77; errCnt++; } if(bitnum>250) break; } *size=bitnum; return errCnt; } //by marshmellow //takes 2 arguments - clock and invert both as integers //attempts to demodulate ask only //prints binary found and saves in graphbuffer for further commands int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) { uint32_t i; // int invert=0; //invert default int high = 0, low = 255; *clk=DetectASKClock(BinStream, *size, *clk); //clock default uint8_t BitStream[502] = {0}; if (*clk<8) *clk =64; if (*clk<32) *clk=32; if (*invert != 0 && *invert != 1) *invert =0; uint32_t initLoopMax = 200; if (initLoopMax > *size) initLoopMax=*size; // Detect high and lows for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values { if (BinStream[i] > high) high = BinStream[i]; else if (BinStream[i] < low) low = BinStream[i]; } if ((high < 129)){ //throw away static high has to be more than 0 on graph. //noise <= -10 here // PrintAndLog("no data found"); return -2; } //25% fuzz in case highs and lows aren't clipped [marshmellow] high=(int)(((high-128)*.75)+128); low= (int)(((low-128)*.75)+128); //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check uint32_t bitnum = 0; //output counter 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 uint32_t iii = 0; uint32_t gLen = *size; if (gLen > 500) gLen=500; uint8_t errCnt =0; uint32_t bestStart = *size; uint32_t bestErrCnt = (*size/1000); uint8_t midBit=0; //PrintAndLog("DEBUG - lastbit - %d",lastBit); //loop to find first wave that works for (iii=0; iii < gLen; ++iii){ if ((BinStream[iii]>=high) || (BinStream[iii]<=low)){ lastBit=iii-*clk; //loop through to see if this start location works for (i = iii; i < *size; ++i) { if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){ lastBit+=*clk; BitStream[bitnum] = *invert; bitnum++; midBit=0; } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){ //low found and we are expecting a bar lastBit+=*clk; BitStream[bitnum] = 1- *invert; bitnum++; midBit=0; } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ //mid bar? midBit=1; BitStream[bitnum]= 1- *invert; bitnum++; } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ //mid bar? midBit=1; BitStream[bitnum]= *invert; bitnum++; } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){ //no mid bar found midBit=1; BitStream[bitnum]= BitStream[bitnum-1]; bitnum++; } else { //mid value found or no bar supposed to be here if ((i-lastBit)>(*clk+tol)){ //should have hit a high or low based on clock!! //debug //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit); if (bitnum > 0){ BitStream[bitnum]=77; bitnum++; } errCnt++; lastBit+=*clk;//skip over until hit too many errors if (errCnt > ((*size/1000))){ //allow 1 error for every 1000 samples else start over errCnt=0; bitnum=0;//start over break; } } } if (bitnum>500) break; } //we got more than 64 good bits and not all errors if ((bitnum > (64+errCnt)) && (errCnt<(*size/1000))) { //possible good read if (errCnt==0) break; //great read - finish if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish if (errCnt=gLen){ //exhausted test //if there was a ok test go back to that one and re-run the best run (then dump after that run) if (bestErrCnt < (*size/1000)) iii=bestStart; } } if (bitnum>16){ for (i=0; i < bitnum; ++i){ BinStream[i]=BitStream[i]; } *size=bitnum; } else return -1; return errCnt; } //translate wave to 11111100000 (1 for each short wave 0 for each long wave) size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow) { uint32_t last_transition = 0; uint32_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 uint8_t threshold_value = 123; // sync to first lo-hi transition, and threshold // Need to threshold first sample if(dest[0] < threshold_value) dest[0] = 0; else dest[0] = 1; 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 with anywhere // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10 for(idx = 1; 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]) { // 0 -> 1 transition if ((idx-last_transition)<(fclow-2)){ //0-5 = garbage noise //do nothing with extra garbage } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves dest[numBits]=1; } else { //9+ = 10 waves dest[numBits]=0; } last_transition = idx; numBits++; } } return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 } uint32_t myround2(float f) { if (f >= 2000) return 2000;//something bad happened return (uint32_t) (f + (float)0.5); } //translate 11111100000 to 10 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits, uint8_t invert, uint8_t fchigh, uint8_t fclow) { uint8_t lastval=dest[0]; uint32_t idx=0; size_t numBits=0; uint32_t n=1; for( idx=1; idx < size; idx++) { if (dest[idx]==lastval) { n++; continue; } //if lastval was 1, we have a 1->0 crossing if ( dest[idx-1]==1 ) { n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow)); } else {// 0->1 crossing n=myround2((float)(n+1)/((float)(rfLen-1)/(float)fchigh)); //-1 for fudge factor } if (n == 0) n = 1; if(n < maxConsequtiveBits) //Consecutive { if(invert==0){ //invert bits memset(dest+numBits, dest[idx-1] , n); }else{ memset(dest+numBits, dest[idx-1]^1 , n); } numBits += n; } n=0; lastval=dest[idx]; }//end for return numBits; } //by marshmellow (from holiman's base) // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) { // FSK demodulator size = fsk_wave_demod(dest, size, fchigh, fclow); size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow); return size; } // loop to get raw HID waveform then FSK demodulate the TAG ID from it int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) { size_t idx=0; //, found=0; //size=0, // FSK demodulator size = fskdemod(dest, size,50,0,10,8); // final loop, go over previously decoded manchester data and decode into usable tag ID // 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0 uint8_t frame_marker_mask[] = {1,1,1,0,0,0}; int numshifts = 0; idx = 0; //one scan while( idx + sizeof(frame_marker_mask) < size) { // search for a start of frame marker if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0) { // frame marker found idx+=sizeof(frame_marker_mask); while(dest[idx] != dest[idx+1] && idx < size-2) { // Keep going until next frame marker (or error) // Shift in a bit. Start by shifting high registers *hi2 = (*hi2<<1)|(*hi>>31); *hi = (*hi<<1)|(*lo>>31); //Then, shift in a 0 or one into low if (dest[idx] && !dest[idx+1]) // 1 0 *lo=(*lo<<1)|0; else // 0 1 *lo=(*lo<<1)|1; numshifts++; idx += 2; } // Hopefully, we read a tag and hit upon the next frame marker if(idx + sizeof(frame_marker_mask) < size) { if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0) { //good return return idx; } } // reset *hi2 = *hi = *lo = 0; numshifts = 0; }else { idx++; } } return -1; } uint32_t bytebits_to_byte(uint8_t* src, size_t numbits) { uint32_t num = 0; for(int i = 0 ; i < numbits ; i++) { num = (num << 1) | (*src); src++; } return num; } int IOdemodFSK(uint8_t *dest, size_t size) { static const uint8_t THRESHOLD = 129; uint32_t idx=0; //make sure buffer has data if (size < 66) return -1; //test samples are not just noise uint8_t justNoise = 1; for(idx=0;idx< size && justNoise ;idx++){ justNoise = dest[idx] < THRESHOLD; } if(justNoise) return 0; // FSK demodulator size = fskdemod(dest, size, 64, 1, 10, 8); // RF/64 and invert if (size < 65) return -1; //did we get a good demod? //Index map //0 10 20 30 40 50 60 //| | | | | | | //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23 //----------------------------------------------------------------------------- //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11 // //XSF(version)facility:codeone+codetwo //Handle the data uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1}; for( idx=0; idx < (size - 65); idx++) { if ( memcmp(dest + idx, mask, sizeof(mask))==0) { //frame marker found if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){ //confirmed proper separator bits found //return start position return (int) idx; } } } return 0; } // by marshmellow // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping) // maybe somehow adjust peak trimming value based on samples to fix? int DetectASKClock(uint8_t dest[], size_t size, int clock) { int i=0; int peak=0; int low=255; int clk[]={16,32,40,50,64,100,128,256}; int loopCnt = 256; //don't need to loop through entire array... if (size peak){ peak = dest[i]; } if(dest[i] < low){ low = dest[i]; } } peak=(int)(((peak-128)*.75)+128); low= (int)(((low-128)*.75)+128); int ii; int clkCnt; int tol = 0; int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000}; int errCnt=0; //test each valid clock from smallest to greatest to see which lines up for(clkCnt=0; clkCnt < 6; ++clkCnt){ if (clk[clkCnt] == 32){ tol=1; }else{ tol=0; } bestErr[clkCnt]=1000; //try lining up the peaks by moving starting point (try first 256) for (ii=0; ii< loopCnt; ++ii){ if ((dest[ii] >= peak) || (dest[ii] <= low)){ errCnt=0; // now that we have the first one lined up test rest of wave array for (i=0; i<((int)(size/clk[clkCnt])-1); ++i){ if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){ }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){ }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){ }else{ //error no peak detected errCnt++; } } //if we found no errors this is correct one - return this clock if(errCnt==0) return clk[clkCnt]; //if we found errors see if it is lowest so far and save it as best run if(errCnt peak){ peak = dest[i]; } if(dest[i] < low){ low = dest[i]; } } peak=(int)(((peak-128)*.75)+128); low= (int)(((low-128)*.75)+128); //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low); int ii; uint8_t clkCnt; uint8_t tol = 0; int peakcnt=0; int errCnt=0; int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; int peaksdet[]={0,0,0,0,0,0,0,0,0}; //test each valid clock from smallest to greatest to see which lines up for(clkCnt=0; clkCnt < 6; ++clkCnt){ if (clk[clkCnt] == 32){ tol=1; }else{ tol=0; } //try lining up the peaks by moving starting point (try first 256) for (ii=0; ii< loopCnt; ++ii){ if ((dest[ii] >= peak) || (dest[ii] <= low)){ errCnt=0; peakcnt=0; // now that we have the first one lined up test rest of wave array for (i=0; i < ((int)(size/clk[clkCnt])-1); ++i){ if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){ peakcnt++; }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){ peakcnt++; }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){ peakcnt++; }else{ //error no peak detected errCnt++; } } if(peakcnt>peaksdet[clkCnt]) { peaksdet[clkCnt]=peakcnt; bestErr[clkCnt]=errCnt; } } } } int iii=0; int best=0; //int ratio2; //debug int ratio; //int bits; for (iii=0; iii < 7; ++iii){ ratio=1000; //ratio2=1000; //debug //bits=size/clk[iii]; //debug if (peaksdet[iii] > 0){ ratio=bestErr[iii]/peaksdet[iii]; if (((bestErr[best]/peaksdet[best]) > (ratio)+1)){ best = iii; } //ratio2=bits/peaksdet[iii]; //debug } //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d, ratio: %d, bits: %d, peakbitr: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best],ratio, bits,ratio2); } return clk[best]; } //by marshmellow (attempt to get rid of high immediately after a low) void pskCleanWave(uint8_t *bitStream, size_t size) { int i; int low=255; int high=0; int gap = 4; // int loopMax = 2048; int newLow=0; int newHigh=0; for (i=0; i < size; ++i){ if (bitStream[i] < low) low=bitStream[i]; if (bitStream[i] > high) high=bitStream[i]; } high = (int)(((high-128)*.80)+128); low = (int)(((low-128)*.90)+128); //low = (uint8_t)(((int)(low)-128)*.80)+128; for (i=0; i < size; ++i){ if (newLow == 1){ bitStream[i]=low+8; gap--; if (gap == 0){ newLow=0; gap=4; } }else if (newHigh == 1){ bitStream[i]=high-8; gap--; if (gap == 0){ newHigh=0; gap=4; } } if (bitStream[i] <= low) newLow=1; if (bitStream[i] >= high) newHigh=1; } 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 PSK wave or NRZ wave (both similar enough) //peaks switch bit (high=1 low=0) each clock cycle = 1 bit determined by last peak int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) { pskCleanWave(dest,*size); int clk2 = DetectpskNRZClock(dest, *size, *clk); *clk=clk2; uint32_t i; uint8_t high=0, low=255; uint32_t gLen = *size; if (gLen > 1280) gLen=1280; // get high for (i=0; i < gLen; ++i){ if (dest[i] > high) high = dest[i]; if (dest[i] < low) low = dest[i]; } //fudge high/low bars by 25% high = (uint8_t)((((int)(high)-128)*.75)+128); low = (uint8_t)((((int)(low)-128)*.80)+128); //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check uint32_t bitnum = 0; //output counter 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 = 2; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely uint32_t iii = 0; uint8_t errCnt =0; uint32_t bestStart = *size; uint32_t maxErr = (*size/1000); uint32_t bestErrCnt = maxErr; //uint8_t midBit=0; uint8_t curBit=0; uint8_t bitHigh=0; uint8_t ignorewin=*clk/8; //PrintAndLog("DEBUG - lastbit - %d",lastBit); //loop to find first wave that works - align to clock for (iii=0; iii < gLen; ++iii){ if ((dest[iii]>=high) || (dest[iii]<=low)){ lastBit=iii-*clk; //loop through to see if this start location works for (i = iii; i < *size; ++i) { //if we found a high bar and we are at a clock bit if ((dest[i]>=high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){ bitHigh=1; lastBit+=*clk; ignorewin=*clk/8; bitnum++; //else if low bar found and we are at a clock point }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){ bitHigh=1; lastBit+=*clk; ignorewin=*clk/8; bitnum++; //else if no bars found }else if(dest[i] < high && dest[i] > low) { if (ignorewin==0){ bitHigh=0; }else ignorewin--; //if we are past a clock point if (i >= lastBit+*clk+tol){ //clock val lastBit+=*clk; bitnum++; } //else if bar found but we are not at a clock bit and we did not just have a clock bit }else if ((dest[i]>=high || dest[i]<=low) && (ilastBit+*clk+tol) && (bitHigh==0)){ //error bar found no clock... errCnt++; } if (bitnum>=1000) break; } //we got more than 64 good bits and not all errors if ((bitnum > (64+errCnt)) && (errCnt < (maxErr))) { //possible good read if (errCnt == 0){ bestStart = iii; bestErrCnt = errCnt; break; //great read - finish } if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish if (errCnt < bestErrCnt){ //set this as new best run bestErrCnt = errCnt; bestStart = iii; } } } } if (bestErrCnt < maxErr){ //best run is good enough set to best run and set overwrite BinStream iii=bestStart; lastBit=bestStart-*clk; bitnum=0; for (i = iii; i < *size; ++i) { //if we found a high bar and we are at a clock bit if ((dest[i] >= high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){ bitHigh=1; lastBit+=*clk; curBit=1-*invert; dest[bitnum]=curBit; ignorewin=*clk/8; bitnum++; //else if low bar found and we are at a clock point }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){ bitHigh=1; lastBit+=*clk; curBit=*invert; dest[bitnum]=curBit; ignorewin=*clk/8; bitnum++; //else if no bars found }else if(dest[i]low) { if (ignorewin==0){ bitHigh=0; }else ignorewin--; //if we are past a clock point if (i>=lastBit+*clk+tol){ //clock val lastBit+=*clk; dest[bitnum]=curBit; bitnum++; } //else if bar found but we are not at a clock bit and we did not just have a clock bit }else if ((dest[i]>=high || dest[i]<=low) && ((ilastBit+*clk+tol)) && (bitHigh==0)){ //error bar found no clock... bitHigh=1; dest[bitnum]=77; bitnum++; errCnt++; } if (bitnum >=1000) break; } *size=bitnum; } else{ *size=bitnum; *clk=bestStart; return -1; } if (bitnum>16){ *size=bitnum; } else return -1; return errCnt; }