X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/5c72368e2da3724c74a093104ffc7553d16338c8..68541dddc2734755f4fd306e327dffa89640ecdd:/common/lfdemod.c?ds=inline diff --git a/common/lfdemod.c b/common/lfdemod.c index 062818ef..f81ac236 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -5,993 +5,1904 @@ // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- -// Low frequency commands +// Low frequency demod/decode commands - by marshmellow, holiman, iceman and +// many others who came before +// +// NOTES: +// LF Demod functions are placed here to allow the flexability to use client or +// device side. Most BUT NOT ALL of these functions are currenlty safe for +// device side use currently. (DetectST for example...) +// +// There are likely many improvements to the code that could be made, please +// make suggestions... +// +// we tried to include author comments so any questions could be directed to +// the source. +// +// There are 4 main sections of code below: +// Utilities Section: +// for general utilities used by multiple other functions +// 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 +#include // for memset, memcmp and size_t #include "lfdemod.h" +#include // for uint_32+ +#include // for bool +#include "parity.h" // for parity test -//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 - uint64_t lo=0; - uint32_t i = 0; - if (BitStream[10]>1){ //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=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; //try 5 times - resetCnt++; - goto restart;//continue; - } - } - //skip last 5 bit parity test for simplicity. - return lo; - }else{ - idx++; - } +//********************************************************************************************** +//---------------------------------Utilities Section-------------------------------------------- +//********************************************************************************************** +#define LOWEST_DEFAULT_CLOCK 32 +#define FSK_PSK_THRESHOLD 123 + +//to allow debug print calls when used not on device +void dummy(char *fmt, ...){} +#ifndef ON_DEVICE +#include "ui.h" +#include "cmdparser.h" +#include "cmddata.h" +#define prnt PrintAndLog +#else + uint8_t g_debugMode=0; +#define prnt dummy +#endif + +uint8_t justNoise(uint8_t *BitStream, size_t size) { + //test samples are not just noise + uint8_t justNoise1 = 1; + for(size_t idx=0; idx < size && justNoise1 ;idx++){ + justNoise1 = BitStream[idx] < FSK_PSK_THRESHOLD; } - return 0; + return justNoise1; } //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!! +//get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise +int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) { + *high=0; + *low=255; + // get high and low thresholds + for (size_t i=0; i < size; i++){ + if (BitStream[i] > *high) *high = BitStream[i]; + if (BitStream[i] < *low) *low = BitStream[i]; + } + if (*high < FSK_PSK_THRESHOLD) return -1; // just noise + *high = ((*high-128)*fuzzHi + 12800)/100; + *low = ((*low-128)*fuzzLo + 12800)/100; + return 1; +} - //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); +// by marshmellow +// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType +// returns 1 if passed +bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) { + return oddparity32(bits) ^ pType; +} - 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= bLen) break; + parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; + BitStream[bitCnt++] = (BitStream[startIdx+word+bit]); } - } - if (bestErrCnt= 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++; - } + if (word+pLen > bLen) break; - lastBit+=*clk;//skip over error - } - } - if (bitnum >=400) break; + bitCnt--; // overwrite parity with next data + // if parity fails then return 0 + switch (pType) { + case 3: if (BitStream[bitCnt]==1) {return 0;} break; //should be 0 spacer bit + case 2: if (BitStream[bitCnt]==0) {return 0;} break; //should be 1 spacer bit + default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity } - *size=bitnum; - } else{ - *invert=bestStart; - *clk=iii; - return -1; + parityWd = 0; } - return bestErrCnt; + // if we got here then all the parities passed + //return size + return bitCnt; } -//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; +// by marshmellow +// takes a array of binary values, length of bits per parity (includes parity bit), +// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run) +// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added +size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) { + uint32_t parityWd = 0; + size_t j = 0, bitCnt = 0; + for (int word = 0; word < sourceLen; word+=pLen-1) { + for (int bit=0; bit < pLen-1; bit++){ + parityWd = (parityWd << 1) | BitSource[word+bit]; + dest[j++] = (BitSource[word+bit]); } - if (bestErr>errCnt){ - bestErr=errCnt; - bestRun=ii; + // if parity fails then return 0 + switch (pType) { + case 3: dest[j++]=0; break; // marker bit which should be a 0 + case 2: dest[j++]=1; break; // marker bit which should be a 1 + default: + dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1; + break; } - errCnt=0; + bitCnt += pLen; + parityWd = 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; + // if we got here then all the parities passed + //return ID start index and size + return bitCnt; +} + +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 errCnt; + return num; } +//least significant bit first +uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) { + uint32_t num = 0; + for(int i = 0 ; i < numbits ; i++) + { + num = (num << 1) | *(src + (numbits-(i+1))); + } + return num; +} -//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++; +// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone +// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits +bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) { + // Sanity check. If preamble length is bigger than bitstream length. + if ( *size <= pLen ) return false; + + uint8_t foundCnt = 0; + for (size_t idx = 0; idx < *size - pLen; idx++) { + if (memcmp(BitStream+idx, preamble, pLen) == 0) { + //first index found + foundCnt++; + if (foundCnt == 1) { + if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); + *startIdx = idx; + if (findone) return true; + } else if (foundCnt == 2) { + *size = idx - *startIdx; + return true; + } } - if(bitnum>250) break; } - *size=bitnum; - return errCnt; + return false; } //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++; - } +//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length +uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) { + return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0; +} - 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; +// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup. +size_t findModStart(uint8_t dest[], size_t size, uint8_t expWaveSize) { + size_t i = 0; + size_t waveSizeCnt = 0; + uint8_t thresholdCnt = 0; + bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD; + for (; i < size-20; i++ ) { + if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = false; + waveSizeCnt = 0; + } else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = true; + waveSizeCnt = 0; + } else { + waveSizeCnt++; } + if (thresholdCnt > 10) break; } - if (bitnum>16){ - for (i=0; i < bitnum; ++i){ - BinStream[i]=BitStream[i]; - } - *size=bitnum; - } else return -1; - return errCnt; + if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt); + return i; } -//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 +int getClosestClock(int testclk) { + uint8_t fndClk[] = {8,16,32,40,50,64,128}; - // Need to threshold first sample + for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) + if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1) + return fndClk[clkCnt]; - if(dest[0] < threshold_value) dest[0] = 0; - else dest[0] = 1; + return 0; +} - 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 +void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) { + while ((samples[*i] > low) && (*i < size)) + *i+=1; +} - if (dest[idx] < threshold_value) dest[idx] = 0; - else dest[idx] = 1; +void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) { + while ((samples[*i] < high) && (*i < size)) + *i+=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++; - } +// load wave counters +bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) { + size_t i=0, firstLow, firstHigh; + size_t testsize = (size < 512) ? size : 512; + + if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) { + if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); + return false; //just noise } - 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); -} + // get to first full low to prime loop and skip incomplete first pulse + getNextHigh(samples, size, *high, &i); + getNextLow(samples, size, *low, &i); + *skip = i; -//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; + // populate tmpbuff buffer with pulse lengths + while (i < size) { + // measure from low to low + firstLow = i; + //find first high point for this wave + getNextHigh(samples, size, *high, &i); + firstHigh = i; - for( idx=1; idx < size; idx++) { + getNextLow(samples, size, *low, &i); - 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 (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK)) + break; + + highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low + lowToLowWaveLen[*waveCnt] = i - firstLow; + *waveCnt += 1; + if (i-firstLow < *minClk && i < size) { + *minClk = i - firstLow; } - if (n == 0) n = 1; + } + return true; +} + +size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) { + uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array... - 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); + uint16_t avgWaveVal=0, lastAvgWaveVal=0; + size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave; + for (; i= samples[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+8)){ //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 > FSK_PSK_THRESHOLD) *curPhase ^= 1; + return firstFullWave; } - numBits += n; + waveStart = i+1; + avgWaveVal = 0; } - n=0; - lastval=dest[idx]; - }//end for - return numBits; + avgWaveVal += samples[i+2]; + } + return 0; } -//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; + +//by marshmellow +//amplify based on ask edge detection - not accurate enough to use all the time +void askAmp(uint8_t *BitStream, size_t size) { + uint8_t Last = 128; + for(size_t i = 1; i=30) //large jump up + Last = 255; + else if(BitStream[i-1]-BitStream[i]>=20) //large jump down + Last = 0; + + BitStream[i-1] = Last; + } + return; } -// 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++; - } +uint32_t manchesterEncode2Bytes(uint16_t datain) { + uint32_t output = 0; + uint8_t curBit = 0; + for (uint8_t i=0; i<16; i++) { + curBit = (datain >> (15-i) & 1); + output |= (1<<(((15-i)*2)+curBit)); } - return -1; + return output; } -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++; +//by marshmellow +//encode binary data into binary manchester +//NOTE: BitStream must have triple the size of "size" available in memory to do the swap +int ManchesterEncode(uint8_t *BitStream, size_t size) { + //allow up to 4K out (means BitStream must be at least 2048+4096 to handle the swap) + size = (size>2048) ? 2048 : size; + size_t modIdx = size; + size_t i; + for (size_t idx=0; idx < size; idx++){ + BitStream[idx+modIdx++] = BitStream[idx]; + BitStream[idx+modIdx++] = BitStream[idx]^1; } - return num; + for (i=0; i<(size*2); i++){ + BitStream[i] = BitStream[i+size]; + } + return i; } -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; +// 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) { + bool allArePeaks = true; + uint16_t cntPeaks=0; + size_t loopEnd = 512+160; + if (loopEnd > size) loopEnd = size; + for (size_t i=160; ilow && dest[i] 300) return true; + } + return allArePeaks; +} - // 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; - } +//********************************************************************************************** +//-------------------Clock / Bitrate Detection Section------------------------------------------ +//********************************************************************************************** + +// by marshmellow +// to help detect clocks on heavily clipped samples +// based on count of low to low +int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) { + size_t startwave; + size_t i = 100; + size_t minClk = 255; + int shortestWaveIdx = 0; + // get to first full low to prime loop and skip incomplete first pulse + getNextHigh(dest, size, high, &i); + getNextLow(dest, size, low, &i); + + // loop through all samples + while (i < size) { + // measure from low to low + startwave = i; + + getNextHigh(dest, size, high, &i); + getNextLow(dest, size, low, &i); + //get minimum measured distance + if (i-startwave < minClk && i < size) { + minClk = i - startwave; + shortestWaveIdx = startwave; } } - return 0; + // set clock + if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk); + *clock = getClosestClock(minClk); + if (*clock == 0) + return 0; + + return shortestWaveIdx; } // 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]; + 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, clock); + if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans); + if (ans > 0) { + return ans; //return shortest wave start position + } } } - 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; + 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=0; clkCnt < 6; ++clkCnt){ - if (clk[clkCnt] == 32){ + 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 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++; - } + //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 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 || 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 *clockStartIdx) { + size_t i=0; + uint8_t clk[]={8,16,32,40,50,64,100,128,255}; + size_t loopCnt = 4096; //don't need to loop through entire array... + if (size == 0) return 0; + 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); - //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low); - int ii; + int peak, low; + if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0; + + int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low); + size_t 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; + uint16_t smplCnt = 0; + int16_t peakcnt = 0; + int16_t peaksdet[] = {0,0,0,0,0,0,0,0}; + uint16_t minPeak = 255; + bool firstpeak = true; + //test for large clipped waves - ignore first peak + for (i=0; i= peak || dest[i] <= low) { + if (firstpeak) continue; + smplCnt++; + } else { + firstpeak = false; + if (smplCnt > 0) { + if (minPeak > smplCnt && smplCnt > 7) minPeak = smplCnt; + peakcnt++; + if (g_debugMode == 2) prnt("DEBUG NRZ: minPeak: %d, smplCnt: %d, peakcnt: %d",minPeak,smplCnt,peakcnt); + smplCnt = 0; + } } + } + if (minPeak < 8) return 0; + bool errBitHigh = 0; + bool bitHigh = 0; + uint8_t ignoreCnt = 0; + uint8_t ignoreWindow = 4; + bool lastPeakHigh = 0; + int lastBit = 0; + size_t bestStart[]={0,0,0,0,0,0,0,0,0}; + peakcnt=0; + //test each valid clock from smallest to greatest to see which lines up + for(clkCnt=0; clkCnt < 8; ++clkCnt) { + //ignore clocks smaller than smallest peak + if (clk[clkCnt] < minPeak - (clk[clkCnt]/4)) continue; //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++; + 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]) { + bestStart[clkCnt]=ii; 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)){ + 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; } - //ratio2=bits/peaksdet[iii]; //debug + } else if (peaksdet[iii] > peaksdet[best]) { + best = iii; } - //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); + if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, minPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],minPeak, clk[best], lowestTransition); } + *clockStartIdx = bestStart[best]; 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; +//by marshmellow +//countFC is to detect the field clock lengths. +//counts and returns the 2 most common wave lengths +//mainly used for FSK field clock detection +uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) { + uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + uint8_t fcLensFnd = 0; + uint8_t lastFCcnt = 0; + uint8_t fcCounter = 0; + size_t i; + if (size < 180) return 0; + + // prime i to first up transition + for (i = 160; i < size-20; i++) + if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]) + break; + + for (; i < size-20; i++){ + if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){ + // new up transition + fcCounter++; + if (fskAdj){ + //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8) + if (lastFCcnt==5 && fcCounter==9) fcCounter--; + //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5) + if ((fcCounter==9) || fcCounter==4) fcCounter++; + // save last field clock count (fc/xx) + lastFCcnt = fcCounter; + } + // find which fcLens to save it to: + for (int ii=0; ii<15; ii++){ + if (fcLens[ii]==fcCounter){ + fcCnts[ii]++; + fcCounter=0; + break; + } } - }else if (newHigh == 1){ - bitStream[i]=high-8; - gap--; - if (gap == 0){ - newHigh=0; - gap=4; + if (fcCounter>0 && fcLensFnd<15){ + //add new fc length + fcCnts[fcLensFnd]++; + fcLens[fcLensFnd++]=fcCounter; } + fcCounter=0; + } else { + // count sample + fcCounter++; } - 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; + + uint8_t best1=14, best2=14, best3=14; + uint16_t maxCnt1=0; + // go through fclens and find which ones are bigest 2 + for (i=0; i<15; i++){ + // get the 3 best FC values + if (fcCnts[i]>maxCnt1) { + best3=best2; + best2=best1; + maxCnt1=fcCnts[i]; + best1=i; + } else if(fcCnts[i]>fcCnts[best2]){ + best3=best2; + best2=i; + } else if(fcCnts[i]>fcCnts[best3]){ + best3=i; + } + if (g_debugMode==2) prnt("DEBUG countfc: FC %u, Cnt %u, best fc: %u, best2 fc: %u",fcLens[i],fcCnts[i],fcLens[best1],fcLens[best2]); + if (fcLens[i]==0) break; + } + if (fcLens[best1]==0) return 0; + uint8_t fcH=0, fcL=0; + if (fcLens[best1]>fcLens[best2]){ + fcH=fcLens[best1]; + fcL=fcLens[best2]; + } else{ + fcH=fcLens[best2]; + fcL=fcLens[best1]; + } + if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) { + if (g_debugMode==2) prnt("DEBUG countfc: fc is too large: %u > %u. Not psk or fsk",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]); + return 0; //lots of waves not psk or fsk + } + // TODO: take top 3 answers and compare to known Field clocks to get top 2 + + uint16_t fcs = (((uint16_t)fcH)<<8) | fcL; + if (fskAdj) return fcs; + return (uint16_t)fcLens[best2] << 8 | fcLens[best1]; +} + +//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, size_t *firstPhaseShift, uint8_t *curPhase, uint8_t *fc) { + 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+3>8); + if ((fcs>>8) == 10 && *fc == 8) return 0; + if (*fc!=2 && *fc!=4 && *fc!=8) return 0; + + //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, tol=1; + uint16_t peakcnt=0, errCnt=0, waveLenCnt=0, fullWaveLen=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}; + + //find start of modulating data in trace + i = findModStart(dest, size, *fc); + + firstFullWave = pskFindFirstPhaseShift(dest, size, curPhase, i, *fc, &fullWaveLen); + 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; + fullWaveLen = 0; + } + + *firstPhaseShift = firstFullWave; + if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); + //test each valid clock from greatest to smallest to see which lines up + for(clkCnt=7; clkCnt >= 1 ; clkCnt--) { + tol = *fc/2; + 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 + clk[clkCnt] + tol + *fc){ + lastClkBit+=clk[clkCnt]; //no phase shift but clock bit + } + waveStart=i+1; + } } } - if (i == (start + long_wait)) { + 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 DetectPSKClock(uint8_t dest[], size_t size, int clock) { +// size_t firstPhaseShift = 0; +// uint8_t curPhase = 0; +// return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift, &curPhase); +//} + +//by marshmellow +//detects the bit clock for FSK given the high and low Field Clocks +uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) { + uint8_t clk[] = {8,16,32,40,50,64,100,128,0}; + uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + 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 = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(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 peak / up transition + for (i = 160; i < size-20; i++) + if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]) break; + + for (; i < size-20; 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 it is inbetween set it to the last counter + if (fcCounter < fcHigh && fcCounter > fcLow) + fcCounter = lastFCcnt; + else if (fcCounter < fcLow+fcTol) + fcCounter = fcLow; + else //set it to the large fc + fcCounter = fcHigh; + + //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-4) && rfLens[ii] <= (rfCounter+4)){ + rfCnts[ii]++; + rfCounter = 0; + break; + } + } + if (rfCounter > 0 && rfLensFnd < 15){ + //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter); + rfCnts[rfLensFnd]++; + rfLens[rfLensFnd++] = rfCounter; + } + } else { + *firstClockEdge = i; + firstBitFnd++; + } + rfCounter=0; + lastFCcnt=fcCounter; } + fcCounter=0; } - if (start == *size - 250 + 1) { - // did not find start sequence - return -1; + uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15; + + for (i=0; i<15; i++){ + //get highest 2 RF values (might need to get more values to compare or compare all?) + if (rfCnts[i]>rfCnts[rfHighest]){ + rfHighest3=rfHighest2; + rfHighest2=rfHighest; + rfHighest=i; + } else if(rfCnts[i]>rfCnts[rfHighest2]){ + rfHighest3=rfHighest2; + rfHighest2=i; + } else if(rfCnts[i]>rfCnts[rfHighest3]){ + rfHighest3=i; + } + if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]); + } + // set allowed clock remainder tolerance to be 1 large field clock length+1 + // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off + uint8_t tol1 = fcHigh+1; + + if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]); + + // loop to find the highest clock that has a remainder less than the tolerance + // compare samples counted divided by + // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less) + int ii=7; + for (; ii>=2; ii--){ + if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){ + if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){ + if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){ + if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]); + break; + } + } + } } - // Inverting signal if needed - if (first == 1) { - for (i = start; i < *size; i++) { - bitStream[i] = !bitStream[i]; + + if (ii<2) return 0; // oops we went too far + + return clk[ii]; +} + +uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) { + int firstClockEdge = 0; + return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge); +} + +//********************************************************************************************** +//--------------------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, size_t *i) { + if (buffSize < *i+4) return false; + + for (; *i < buffSize - 4; *i+=1) { + *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; + } + } + } } - *invert = 1; - }else *invert=0; + } + 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 + int clk = 0; + int tol = 0; + int j=0, high, low, skip=0, start=0, end=0, minClk=255; + size_t i = 0; + //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow] + int tmpbuff[bufsize / LOWEST_DEFAULT_CLOCK]; // 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 / LOWEST_DEFAULT_CLOCK]; // 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)); + memset(waveLen, 0, sizeof(waveLen)); - 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) { + if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false; + // set clock - might be able to get this externally and remove this work... + clk = getClosestClock(minClk); + // clock not found - ERROR + if (clk == 0) { + if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); + return false; + } + *foundclock = clk; + + tol = clk/8; + 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 wave: %i, skip: %i, j=%i", start, skip, 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; + i+=3; + if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) { + //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/4)] <= 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/4); ++i ) { + if ( buffer[dataloc - (clk*4) - i] <= low ) { + dataloc -= i; break; } } - if (iii == (ii + long_wait)) { - 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+clk/4]low) { + for(i=0; i < clk/2-tol; ++i) { + buffer[dataloc+i] = high+5; + } + } //test for small spike outlier (high between two lows) in the case of very strong waves + if (buffer[dataloc] > low && buffer[dataloc+clk/4] <= low) { + for(i=0; i < clk/4; ++i) { + buffer[dataloc+i] = buffer[dataloc+clk/4]; + } + } + if (firstrun) { + *stend = dataloc; + *ststart = dataloc-(clk*4); + firstrun=false; } + for (i=0; i 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) { + errCnt++; + BitStream[bitCnt++] = 7; + continue; + } + BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert; + + if (bitCnt > MaxBits) break; } - bitCnt=ii-start; + *size = bitCnt; + return errCnt; +} - // Dumping UID - i = start; - for (ii = 0; ii < bitCnt; ii++) { - bitStream[ii] = bitStream[i++]; +//by marshmellow +//take 01 or 10 = 1 and 11 or 00 = 0 +//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010 +//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding +int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) { + uint16_t bitnum = 0; + uint16_t errCnt = 0; + size_t i = offset; + uint16_t MaxBits=512; + //if not enough samples - error + if (*size < 51) return -1; + //check for phase change faults - skip one sample if faulty + uint8_t offsetA = 1, offsetB = 1; + for (; i<48; i+=2){ + if (BitStream[i+1]==BitStream[i+2]) offsetA=0; + if (BitStream[i+2]==BitStream[i+3]) offsetB=0; } - *size=bitCnt; - return 1; + if (!offsetA && offsetB) offset++; + for (i=offset; i<*size-3; i+=2){ + //check for phase error + if (BitStream[i+1]==BitStream[i+2]) { + BitStream[bitnum++]=7; + errCnt++; + } + if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ + BitStream[bitnum++]=1^invert; + } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ + BitStream[bitnum++]=invert; + } else { + BitStream[bitnum++]=7; + errCnt++; + } + if(bitnum>MaxBits) 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++; -//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) + 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) { - 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++; + *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; } - //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 (*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++; } } } - 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; + *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 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 { //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(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) { + if (justNoise(dest, *size)) return -1; + size_t clkStartIdx = 0; + *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx); + 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; +} + +//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 + 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, fchigh); + // Need to threshold first sample + if(dest[idx] < FSK_PSK_THRESHOLD) 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] < FSK_PSK_THRESHOLD) 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; } - //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++; + 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; } - if (bitnum >=1000) break; + last_transition = idx; } - *size=bitnum; - } else{ - *size=bitnum; - *clk=bestStart; - return -1; } + 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); + } + } - if (bitnum>16){ - *size=bitnum; - } else return -1; + //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= dest[i+2]) { + if (waveStart == 0) { + waveStart = i+1; + waveLenCnt = 0; + avgWaveVal = dest[i+1]; + } else { //waveEnd + waveEnd = i+1; + waveLenCnt = waveEnd-waveStart; + if (waveLenCnt > fc) { + //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 += dest[i+1]; + continue; + } + 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 +int AWIDdemodFSK(uint8_t *dest, size_t *size) { + //make sure buffer has enough data + if (*size < 96*50) return -1; + + if (justNoise(dest, *size)) return -2; + + // FSK demodulator + *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 + if (*size < 96) return -3; //did we get a good demod? + + uint8_t preamble[] = {0,0,0,0,0,0,0,1}; + size_t startIdx = 0; + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -4; //preamble not found + if (*size != 96) return -5; + return (int)startIdx; +} + +//by marshmellow +//takes 1s and 0s and searches for EM410x format - output EM ID +uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) +{ + //sanity checks + if (*size < 64) return 0; + if (BitStream[1]>1) return 0; //allow only 1s and 0s + + // 111111111 bit pattern represent start of frame + // include 0 in front to help get start pos + uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; + uint8_t errChk = 0; + uint8_t FmtLen = 10; // sets of 4 bits = end data + *startIdx = 0; + errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); + if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0; + if (*size == 128) FmtLen = 22; // 22 sets of 4 bits + + //skip last 4bit parity row for simplicity + *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5); + if (*size == 40) { // std em410x format + *hi = 0; + *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32)); + } else if (*size == 88) { // long em format + *hi = (bytebits_to_byte(BitStream, 24)); + *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32)); + } else { + if (g_debugMode) prnt("Error removing parity: %u", *size); + return 0; + } + return 1; +} + +// Ask/Biphase Demod then try to locate an ISO 11784/85 ID +// BitStream must contain previously askrawdemod and biphasedemoded data +int FDXBdemodBI(uint8_t *dest, size_t *size) { + //make sure buffer has enough data + if (*size < 128) return -1; + + size_t startIdx = 0; + uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1}; + + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -2; //preamble not found + if (*size != 128) return -3; //wrong size for fdxb + //return start position + return (int)startIdx; +} + +// by marshmellow +// demod gProxIIDemod +// error returns as -x +// success returns start position in BitStream +// BitStream must contain previously askrawdemod and biphasedemoded data +int gProxII_Demod(uint8_t BitStream[], size_t *size) { + size_t startIdx=0; + uint8_t preamble[] = {1,1,1,1,1,0}; + + uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -3; //preamble not found + if (*size != 96) return -2; //should have found 96 bits + //check first 6 spacer bits to verify format + if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){ + //confirmed proper separator bits found + //return start position + return (int) startIdx; + } + return -5; //spacer bits not found - not a valid gproxII +} + +// 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) { + if (justNoise(dest, *size)) return -1; + + size_t numStart=0, size2=*size, startIdx=0; + // FSK demodulator + *size = fskdemod(dest, size2,50,1,10,8); //fsk2a + if (*size < 96*2) return -2; + // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 + uint8_t preamble[] = {0,0,0,1,1,1,0,1}; + // find bitstring in array + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -3; //preamble not found + + numStart = startIdx + sizeof(preamble); + // final loop, go over previously decoded FSK data and manchester decode into usable tag ID + for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ + if (dest[idx] == dest[idx+1]){ + return -4; //not manchester data + } + *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)|1; + else // 0 1 + *lo=(*lo<<1)|0; + } + return (int)startIdx; +} + +int IOdemodFSK(uint8_t *dest, size_t size) { + if (justNoise(dest, size)) return -1; + //make sure buffer has data + if (size < 66*64) return -2; + // FSK demodulator + size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64 + if (size < 65) return -3; //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 + size_t startIdx = 0; + uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1}; + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx); + if (errChk == 0) return -4; //preamble not found + + if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){ + //confirmed proper separator bits found + //return start position + return (int) startIdx; + } + return -5; +} + +// 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 + startidx; i++) + bitStream[i] ^= 1; + + return (int) startidx; +} + +// loop to get raw paradox waveform then FSK demodulate the TAG ID from it +int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) { + if (justNoise(dest, *size)) return -1; + + size_t numStart=0, size2=*size, startIdx=0; + // FSK demodulator + *size = fskdemod(dest, size2,50,1,10,8); //fsk2a + if (*size < 96) return -2; + + // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 + uint8_t preamble[] = {0,0,0,0,1,1,1,1}; + + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -3; //preamble not found + + numStart = startIdx + sizeof(preamble); + // final loop, go over previously decoded FSK data and manchester decode into usable tag ID + for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ + if (dest[idx] == dest[idx+1]) + return -4; //not manchester data + *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)|1; + else // 0 1 + *lo=(*lo<<1)|0; + } + return (int)startIdx; +} + +// find presco preamble 0x10D in already demoded data +int PrescoDemod(uint8_t *dest, size_t *size) { + //make sure buffer has data + if (*size < 64*2) return -2; + + size_t startIdx = 0; + uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0}; + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -4; //preamble not found + //return start position + return (int) startIdx; +} + +// by marshmellow +// FSK Demod then try to locate a Farpointe Data (pyramid) ID +int PyramiddemodFSK(uint8_t *dest, size_t *size) { + //make sure buffer has data + if (*size < 128*50) return -5; + + //test samples are not just noise + if (justNoise(dest, *size)) return -1; + + // FSK demodulator + *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 + if (*size < 128) return -2; //did we get a good demod? + + uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; + size_t startIdx = 0; + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -4; //preamble not found + if (*size != 128) return -3; + return (int)startIdx; +} + +// by marshmellow +// find viking preamble 0xF200 in already demoded data +int VikingDemod_AM(uint8_t *dest, size_t *size) { + //make sure buffer has data + if (*size < 64*2) return -2; + + size_t startIdx = 0; + uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); + if (errChk == 0) return -4; //preamble not found + uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8) + ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) + ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8); + if ( checkCalc != 0xA8 ) return -5; + if (*size != 64) return -6; + //return start position + return (int) startIdx; +} + +// by iceman +// find Visa2000 preamble in already demoded data +int Visa2kDemod_AM(uint8_t *dest, size_t *size) { + if (*size < 96) return -1; //make sure buffer has data + size_t startIdx = 0; + uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0}; + if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0) + return -2; //preamble not found + if (*size != 96) return -3; //wrong demoded size + //return start position + return (int)startIdx; +}