X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/1888664863b3f2d3b185fd1c724a6dcf4f4cb15a..refs/pull/471/head:/common/lfdemod.c?ds=sidebyside diff --git a/common/lfdemod.c b/common/lfdemod.c index 8324c440..f470371a 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -5,16 +5,47 @@ // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- -// Low frequency demod/decode 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 // for memset, memcmp and size_t #include "lfdemod.h" -#include +#include // for uint_32+ +#include // for bool +#include "parity.h" // for parity test + +//********************************************************************************************** +//---------------------------------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" @@ -25,21 +56,18 @@ void dummy(char *fmt, ...){} #define prnt dummy #endif -uint8_t justNoise(uint8_t *BitStream, size_t size) -{ - static const uint8_t THRESHOLD = 123; +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] < THRESHOLD; + justNoise1 = BitStream[idx] < FSK_PSK_THRESHOLD; } return justNoise1; } //by marshmellow //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) -{ +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 @@ -47,7 +75,7 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi if (BitStream[i] > *high) *high = BitStream[i]; if (BitStream[i] < *low) *low = BitStream[i]; } - if (*high < 123) return -1; // just noise + if (*high < FSK_PSK_THRESHOLD) return -1; // just noise *high = ((*high-128)*fuzzHi + 12800)/100; *low = ((*low-128)*fuzzLo + 12800)/100; return 1; @@ -56,40 +84,35 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi // 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 -uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) -{ - uint8_t ans = 0; - for (uint8_t i = 0; i < bitLen; i++){ - ans ^= ((bits >> i) & 1); - } - //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType); - return (ans == pType); +bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) { + return oddparity32(bits) ^ pType; } // by marshmellow -// takes a array of binary values, start position, length of bits per parity (includes parity bit), -// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run) -size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) -{ +// takes a array of binary values, start position, length of bits per parity (includes parity bit - MAX 32), +// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run) +size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) { uint32_t parityWd = 0; - size_t j = 0, bitCnt = 0; - for (int word = 0; word < (bLen); word+=pLen){ - for (int bit=0; bit < pLen; bit++){ + size_t bitCnt = 0; + for (int word = 0; word < (bLen); word+=pLen) { + for (int bit=0; bit < pLen; bit++) { + if (word+bit >= bLen) break; parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; - BitStream[j++] = (BitStream[startIdx+word+bit]); + BitStream[bitCnt++] = (BitStream[startIdx+word+bit]); } - j--; // overwrite parity with next data + if (word+pLen > bLen) break; + + bitCnt--; // overwrite parity with next data // if parity fails then return 0 switch (pType) { - case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit - case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit + 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 } - bitCnt+=(pLen-1); parityWd = 0; } // if we got here then all the parities passed - //return ID start index and size + //return size return bitCnt; } @@ -97,8 +120,7 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p // 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) -{ +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) { @@ -122,8 +144,7 @@ size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t p return bitCnt; } -uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) -{ +uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) { uint32_t num = 0; for(int i = 0 ; i < numbits ; i++) { @@ -134,8 +155,7 @@ uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) } //least significant bit first -uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) -{ +uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) { uint32_t num = 0; for(int i = 0 ; i < numbits ; i++) { @@ -144,242 +164,160 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) return num; } -//by marshmellow -//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) -{ - uint8_t foundCnt=0; - for (int idx=0; idx < *size - pLen; idx++){ - if (memcmp(BitStream+idx, preamble, pLen) == 0){ +// 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 (foundCnt == 1) { + if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); *startIdx = idx; - } - if (foundCnt == 2){ + if (findone) return true; + } else if (foundCnt == 2) { *size = idx - *startIdx; - return 1; + return true; } } } - return 0; + return false; } //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) -{ - //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 - uint32_t i = 0; - if (BitStream[1]>1) return 0; //allow only 1s and 0s +//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; +} - // 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}; - uint32_t idx = 0; - uint32_t parityBits = 0; - uint8_t errChk = 0; - uint8_t FmtLen = 10; - *startIdx = 0; - errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); - if (errChk == 0 || *size < 64) return 0; - if (*size > 64) FmtLen = 22; - *startIdx += 1; //get rid of 0 from preamble - idx = *startIdx + 9; - for (i=0; i> 63); - *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]); +// 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 (errChk != 0) return 1; - //skip last 5 bit parity test for simplicity. - // *size = 64 | 128; + if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt); + return i; +} + +int getClosestClock(int testclk) { + uint8_t fndClk[] = {8,16,32,40,50,64,128}; + + for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) + if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1) + return fndClk[clkCnt]; + return 0; } -//by marshmellow -//demodulates strong heavily clipped samples -int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low) -{ - size_t bitCnt=0, smplCnt=0, errCnt=0; - uint8_t waveHigh = 0; - for (size_t i=0; 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; - } - waveHigh ^= 1; - smplCnt = 0; - } else if (smplCnt > (clk/2) - (clk/4)-1) { - if (waveHigh) { - BinStream[bitCnt++] = invert; - } else if (!waveHigh) { - BinStream[bitCnt++] = invert ^ 1; - } - waveHigh ^= 1; - smplCnt = 0; - } else if (!bitCnt) { - //first bit - waveHigh = (BinStream[i] >= high); - smplCnt = 1; - } else { - smplCnt++; - //transition bit oops - } - } else { //haven't hit new high or new low yet - smplCnt++; - } - } - } - *size = bitCnt; - return errCnt; +void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) { + while ((samples[*i] > low) && (*i < size)) + *i+=1; } -//by marshmellow -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; +void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) { + while ((samples[*i] < high) && (*i < size)) + *i+=1; +} - BitStream[i-1] = Last; +// 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; -} - -//by marshmellow -//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester -int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) -{ - 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); - 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 + // 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; - 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); - if (askType) //askman - return manrawdecode(BinStream, size, 0); - else //askraw - return errCnt; + // 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; + + getNextLow(samples, size, *low, &i); + + 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 (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); + return true; +} - 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; +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... - for (i = start; i < *size; ++i) { - if (i-lastBit >= *clk-tol){ - if (BinStream[i] >= high) { - BinStream[bitnum++] = *invert; - } else if (BinStream[i] <= low) { - BinStream[bitnum++] = *invert ^ 1; - } else if (i-lastBit >= *clk+tol) { - if (bitnum > 0) { - if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); - BinStream[bitnum++]=7; - errCnt++; - } - } else { //in tolerance - looking for peak - continue; - } - midBit = 0; - lastBit += *clk; - } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ - if (BinStream[i] >= high) { - BinStream[bitnum++] = *invert; - } else if (BinStream[i] <= low) { - BinStream[bitnum++] = *invert ^ 1; - } else if (i-lastBit >= *clk/2+tol) { - BinStream[bitnum] = BinStream[bitnum-1]; - bitnum++; - } else { //in tolerance - looking for peak - continue; + 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; } - midBit = 1; + waveStart = i+1; + avgWaveVal = 0; } - if (bitnum >= MaxBits) break; + avgWaveVal += samples[i+2]; } - *size = bitnum; - return errCnt; + return 0; } //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) -{ - 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++; +//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; - if (bestErr>errCnt){ - bestErr=errCnt; - bestRun=ii; - } - errCnt=0; - } - //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; + BitStream[i-1] = Last; } - *size=bitnum; - return bestErr; + return; } uint32_t manchesterEncode2Bytes(uint16_t datain) { @@ -394,546 +332,437 @@ uint32_t manchesterEncode2Bytes(uint16_t datain) { //by marshmellow //encode binary data into binary manchester -int ManchesterEncode(uint8_t *BitStream, size_t size) -{ - size_t modIdx=20000, i=0; - if (size>modIdx) return -1; +//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; } - for (; i<(size*2); i++){ - BitStream[i] = BitStream[i+20000]; + for (i=0; i<(size*2); i++){ + BitStream[i] = BitStream[i+size]; } return 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; - } - 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 -// 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; +// 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; } -//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) -{ - size_t last_transition = 0; - size_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; - size_t preLastSample = 0; - size_t LastSample = 0; - size_t currSample = 0; - // sync to first lo-hi transition, and threshold +//********************************************************************************************** +//-------------------Clock / Bitrate Detection Section------------------------------------------ +//********************************************************************************************** - // Need to threshold first sample - // skip 160 samples to allow antenna/samples to settle - if(dest[160] < threshold_value) dest[0] = 0; - else dest[0] = 1; +// 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); - 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 = 161; idx < size-20; idx++) { - // threshold current value + // loop through all samples + while (i < size) { + // measure from low to low + startwave = i; - if (dest[idx] < threshold_value) dest[idx] = 0; - else dest[idx] = 1; + 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; + } + } + // set clock + if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk); + *clock = getClosestClock(minClk); + if (*clock == 0) + return 0; + + return shortestWaveIdx; +} - // 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 (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){ - dest[numBits-1]=1; - } - dest[numBits++]=1; +// 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? +// return start index of best starting position for that clock and return clock (by reference) +int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) { + size_t i=1; + uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255}; + uint8_t clkEnd = 9; + uint8_t loopCnt = 255; //don't need to loop through entire array... + if (size <= loopCnt+60) return -1; //not enough samples + size -= 60; //sometimes there is a strange end wave - filter out this.... + //if we already have a valid clock + uint8_t clockFnd=0; + for (;i (fchigh) && !numBits) { //12 + and first bit = unusable garbage - //do nothing with beginning garbage - } 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; - } else { //9+ = 10 sample waves (or 6+ = 7) - dest[numBits++]=0; + //get high and low peak + int peak, low; + if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1; + + //test for large clean peaks + if (!clockFnd){ + if (DetectCleanAskWave(dest, size, peak, low)==1){ + int ans = DetectStrongAskClock(dest, size, peak, low, 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 } - last_transition = idx; } } - return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 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; -//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) -{ - 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 - //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 (clockFnd>0) { + clkCnt = clockFnd; + clkEnd = clockFnd+1; + } + else clkCnt=1; + + //test each valid clock from smallest to greatest to see which lines up + for(; clkCnt < clkEnd; clkCnt++){ + if (clk[clkCnt] <= 32){ + tol=1; + }else{ + tol=0; } - if (n == 0) n = 1; + //if no errors allowed - keep start within the first clock + if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2; + bestErr[clkCnt]=1000; + //try lining up the peaks by moving starting point (try first few clocks) + for (ii=0; ii < loopCnt; ii++){ + if (dest[ii] < peak && dest[ii] > low) continue; - //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; + errCnt=0; + // now that we have the first one lined up test rest of wave array + loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1; + for (i=0; i < loopEnd; ++i){ + arrLoc = ii + (i * clk[clkCnt]); + if (dest[arrLoc] >= peak || dest[arrLoc] <= low){ + }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){ + }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){ + }else{ //error no peak detected + errCnt++; + } + } + //if we found no errors then we can stop here and a low clock (common clocks) + // this is correct one - return this clock + if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i); + if(errCnt==0 && clkCnt<7) { + if (!clockFnd) *clock = clk[clkCnt]; + return ii; + } + //if we found errors see if it is lowest so far and save it as best run + if(errCnt= peak || dest[i] <= low) && (i < size)) + ++i; + while ((dest[i] < peak && dest[i] > low) && (i < size)) + ++i; + lastWasHigh = (dest[i] >= peak); - 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 + if (i==size) return 0; + transition1 = i; - 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 + 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; + } else if (dest[i] < peak && dest[i] > low) { + transitionSampleCount++; } - *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; + if (lowestTransition == 255) lowestTransition = 0; + if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition); + // if less than 10% of the samples were not peaks (or 90% were peaks) then we have a strong wave + if (transitionSampleCount / size < 10) { + *strong = true; + lowestTransition = getClosestClock(lowestTransition); + } + return lowestTransition; } -// 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; -} - -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; -} - -// 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; -} - -// 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; -} - -// 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 - return (int)startIdx; -} - -// 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 -// 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 -// 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; -} -// 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, uint8_t high, uint8_t low) -{ - uint8_t fndClk[] = {8,16,32,40,50,64,128}; - size_t startwave; - size_t i = 100; - size_t minClk = 255; - // get to first full low to prime loop and skip incomplete first pulse - while ((dest[i] < high) && (i < size)) - ++i; - while ((dest[i] > low) && (i < size)) - ++i; - - // loop through all samples - while (i < size) { - // measure from low to low - while ((dest[i] > low) && (i < size)) - ++i; - startwave= i; - while ((dest[i] < high) && (i < size)) - ++i; - while ((dest[i] > low) && (i < size)) - ++i; - //get minimum measured distance - if (i-startwave < minClk && i < size) - minClk = i - startwave; - } - // set clock - if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk); - for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { - if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) - return fndClk[clkCnt]; - } - 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? -// return start index of best starting position for that clock and return clock (by reference) -int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) -{ - size_t i=1; - uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255}; - uint8_t clkEnd = 9; - uint8_t loopCnt = 255; //don't need to loop through entire array... - if (size <= loopCnt+60) return -1; //not enough samples - size -= 60; //sometimes there is a strange end wave - filter out this.... - //if we already have a valid clock - uint8_t clockFnd=0; - for (;i0; i--){ - if (clk[i] == ans) { - *clock = ans; - //clockFnd = i; - return 0; // for strong waves i don't use the 'best start position' yet... - //break; //clock found but continue to find best startpos [not yet] + if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0; + + bool strong = false; + int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low, &strong); + if (strong) return lowestTransition; + size_t ii; + uint8_t clkCnt; + uint8_t tol = 0; + uint16_t smplCnt = 0; + int16_t peakcnt = 0; + int16_t peaksdet[] = {0,0,0,0,0,0,0,0}; + uint16_t 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=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; } } } } - 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; + int iii=7; + uint8_t best=0; + for (iii=7; iii > 0; iii--) { + if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) { + if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) { + best = iii; + } + } else if (peaksdet[iii] > peaksdet[best]) { + best = iii; + } + if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, minPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],minPeak, clk[best], lowestTransition); } - else clkCnt=1; + *clockStartIdx = bestStart[best]; + return clk[best]; +} - //test each valid clock from smallest to greatest to see which lines up - for(; clkCnt < clkEnd; clkCnt++){ - if (clk[clkCnt] <= 32){ - tol=1; - }else{ - tol=0; - } - //if no errors allowed - keep start within the first clock - if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2; - bestErr[clkCnt]=1000; - //try lining up the peaks by moving starting point (try first few clocks) - for (ii=0; ii < loopCnt; ii++){ - if (dest[ii] < peak && dest[ii] > low) continue; +//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; - 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++; - } + // 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; } - //if we found no errors then we can stop here and a low clock (common clocks) - // this is correct one - return this clock - if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i); - if(errCnt==0 && clkCnt<7) { - if (!clockFnd) *clock = clk[clkCnt]; - return ii; + // find which fcLens to save it to: + for (int ii=0; ii<15; ii++){ + if (fcLens[ii]==fcCounter){ + fcCnts[ii]++; + fcCounter=0; + break; + } } - //if we found errors see if it is lowest so far and save it as best run - if(errCnt0 && fcLensFnd<15){ + //add new fc length + fcCnts[fcLensFnd]++; + fcLens[fcLensFnd++]=fcCounter; } + fcCounter=0; + } else { + // count sample + fcCounter++; } } - uint8_t iii; - uint8_t best=0; - for (iii=1; iiimaxCnt1) { + 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 ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]); + 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 (!clockFnd) *clock = clk[best]; - return bestStart[best]; + 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) -{ +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>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; @@ -941,37 +770,28 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock) if (clk[i] == clock) return clock; size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0; - uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1; - uint16_t peakcnt=0, errCnt=0, waveLenCnt=0; + + 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}; - fc = countFC(dest, size, 0); - if (fc!=2 && fc!=4 && fc!=8) return -1; - if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc); - //find first full wave - for (i=160; i= dest[i+2]){ - if (waveStart == 0) { - waveStart = i+1; - //prnt("DEBUG: waveStart: %d",waveStart); - } else { - waveEnd = i+1; - //prnt("DEBUG: waveEnd: %d",waveEnd); - waveLenCnt = waveEnd-waveStart; - if (waveLenCnt > fc){ - firstFullWave = waveStart; - fullWaveLen=waveLenCnt; - break; - } - waveStart=0; - } - } + //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--){ + for(clkCnt=7; clkCnt >= 1 ; clkCnt--) { + tol = *fc/2; lastClkBit = firstFullWave; //set end of wave as clock align waveStart = 0; errCnt=0; @@ -987,9 +807,9 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock) } else { //waveEnd waveEnd = i+1; waveLenCnt = waveEnd-waveStart; - if (waveLenCnt > fc){ + 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 (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]; @@ -998,238 +818,543 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock) } else { //phase shift before supposed to based on clock errCnt++; } - } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){ + } else if (i+1 > lastClkBit + clk[clkCnt] + tol + *fc){ lastClkBit+=clk[clkCnt]; //no phase shift but clock bit } waveStart=i+1; } } } - if (errCnt == 0){ - return clk[clkCnt]; - } - if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt; - if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt; - } - //all tested with errors - //return the highest clk with the most peaks found - uint8_t best=7; - for (i=7; i>=1; i--){ - if (peaksdet[i] > peaksdet[best]) { - best = i; - } - if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]); + 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]; +} + +//by marshmellow +//detects the bit clock for FSK given the high and low Field Clocks +uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, 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; + } + 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; + } + } + } } - return clk[best]; -} - -int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){ - //find shortest transition from high to low - size_t i = 0; - size_t transition1 = 0; - int lowestTransition = 255; - bool lastWasHigh = false; - //find first valid beginning of a high or low wave - while ((dest[i] >= peak || dest[i] <= low) && (i < size)) - ++i; - while ((dest[i] < peak && dest[i] > low) && (i < size)) - ++i; - lastWasHigh = (dest[i] >= peak); + if (ii<2) return 0; // oops we went too far - if (i==size) return 0; - transition1 = i; + return clk[ii]; +} - 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; +//********************************************************************************************** +//--------------------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; + } + } + } } } - if (lowestTransition == 255) lowestTransition = 0; - if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition); - return lowestTransition; + return false; } - //by marshmellow -//detect nrz clock by reading #peaks vs no peaks(or errors) -int DetectNRZClock(uint8_t dest[], size_t size, int clock) -{ - size_t i=0; - uint8_t clk[]={8,16,32,40,50,64,100,128,255}; - size_t loopCnt = 4096; //don't need to loop through entire array... - if (size == 0) return 0; - if (size= peak || dest[i] <= low){ - if (!firstpeak) continue; - smplCnt++; - } else { - firstpeak=true; - if (smplCnt > 6 ){ - if (maxPeak > smplCnt){ - maxPeak = smplCnt; - //prnt("maxPk: %d",maxPeak); - } - peakcnt++; - //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt); - smplCnt=0; + 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; } } } - bool errBitHigh = 0; - bool bitHigh = 0; - uint8_t ignoreCnt = 0; - uint8_t ignoreWindow = 4; - bool lastPeakHigh = 0; - int lastBit = 0; - peakcnt=0; - //test each valid clock from smallest to greatest to see which lines up - for(clkCnt=0; clkCnt < 8; ++clkCnt){ - //ignore clocks smaller than smallest peak - if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue; - //try lining up the peaks by moving starting point (try first 256) - for (ii=20; ii < loopCnt; ++ii){ - if ((dest[ii] >= peak) || (dest[ii] <= low)){ - peakcnt = 0; - bitHigh = false; - ignoreCnt = 0; - lastBit = ii-clk[clkCnt]; - //loop through to see if this start location works - for (i = ii; i < size-20; ++i) { - //if we are at a clock bit - if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) { - //test high/low - if (dest[i] >= peak || dest[i] <= low) { - //if same peak don't count it - if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) { - peakcnt++; - } - lastPeakHigh = (dest[i] >= peak); - bitHigh = true; - errBitHigh = false; - ignoreCnt = ignoreWindow; - lastBit += clk[clkCnt]; - } else if (i == lastBit + clk[clkCnt] + tol) { - lastBit += clk[clkCnt]; - } - //else if not a clock bit and no peaks - } else if (dest[i] < peak && dest[i] > low){ - if (ignoreCnt==0){ - bitHigh=false; - if (errBitHigh==true) peakcnt--; - errBitHigh=false; - } else { - ignoreCnt--; - } - // else if not a clock bit but we have a peak - } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) { - //error bar found no clock... - errBitHigh=true; - } - } - if(peakcnt>peaksdet[clkCnt]) { - peaksdet[clkCnt]=peakcnt; - } + + 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]; } } - } - 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; + if (firstrun) { + *stend = dataloc; + *ststart = dataloc-(clk*4); + firstrun=false; + } + for (i=0; i peaksdet[best]){ - best = iii; } - if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition); + newloc += i; + //skip next ST - we just assume it will be there from now on... + if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4)); + dataloc += clk*4; + } + *size = newloc; + return true; +} + +//by marshmellow +//take 11 10 01 11 00 and make 01100 ... miller decoding +//check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row +//decodes miller encoded binary +//NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as! +int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) { + if (*size < 16) return -1; + uint16_t MaxBits = 512, errCnt = 0; + size_t i, bitCnt=0; + uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0; + uint8_t halfClkErr = 0; + //find alignment, needs 4 1s or 0s to properly align + for (i=1; i < *size-1; i++) { + alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0; + curBit = BitStream[i]; + if (alignCnt == 4) break; + } + // for now error if alignment not found. later add option to run it with multiple offsets... + if (alignCnt != 4) { + if (g_debugMode) prnt("ERROR MillerDecode: alignment not found so either your bitstream is not miller or your data does not have a 101 in it"); + return -1; + } + alignedIdx = (i-1) % 2; + for (i=alignedIdx; i < *size-3; i+=2) { + halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF); + if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (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; + } + *size = bitCnt; + return errCnt; +} + +//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; + } + if (!offsetA && offsetB) *offset+=1; + 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; } - - return clk[best]; + *size=bitnum; + return errCnt; } -// 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 (; ierrCnt){ + 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[i]=0; + BitStream[bitnum++]=7; } + if(bitnum>MaxBits) break; } - return; + *size=bitnum; + return bestErr; } -// by marshmellow -// convert psk2 demod to psk1 demod -// from only transition waves are 1s to phase shifts change bit -void psk2TOpsk1(uint8_t *BitStream, size_t size) +//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) { - uint8_t phase=0; - for (size_t i=0; i= high); + for (size_t i=1; i < *size; i++){ + if (BinStream[i] >= high && waveHigh){ + smplCnt++; + } else if (BinStream[i] <= low && !waveHigh){ + smplCnt++; + } else { //transition + if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ + if (smplCnt > clk-(clk/4)-1) { //full clock + if (smplCnt > clk + (clk/4)+1) { //too many samples + errCnt++; + if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); + BinStream[bitCnt++] = 7; + } else if (waveHigh) { + BinStream[bitCnt++] = invert; + BinStream[bitCnt++] = invert; + } else if (!waveHigh) { + BinStream[bitCnt++] = invert ^ 1; + BinStream[bitCnt++] = invert ^ 1; + } + if (*startIdx==0) *startIdx = i-clk; + waveHigh = !waveHigh; + smplCnt = 0; + } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock + if (waveHigh) { + BinStream[bitCnt++] = invert; + } else if (!waveHigh) { + BinStream[bitCnt++] = invert ^ 1; + } + if (*startIdx==0) *startIdx = i-(clk/2); + waveHigh = !waveHigh; + smplCnt = 0; + } else { + smplCnt++; + //transition bit oops + } + } else { //haven't hit new high or new low yet + smplCnt++; + } } - BitStream[i]=phase; } - return; + *size = bitCnt; + return errCnt; } -// redesigned by marshmellow adjusted from existing decode functions -// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more -int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) -{ - //26 bit 40134 format (don't know other formats) - uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; - uint8_t preamble_i[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0}; - size_t startidx = 0; - if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){ - // if didn't find preamble try again inverting - if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1; - *invert ^= 1; - } - if (*size != 64 && *size != 224) return -2; - if (*invert==1) - for (size_t i = startidx; i < *size; i++) - bitStream[i] ^= 1; +//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); - return (int) startidx; + //start pos from detect ask clock is 1/2 clock offset + // NOTE: can be negative (demod assumes rest of wave was there) + *startIdx = start - (*clk/2); + uint8_t initLoopMax = 255; + if (initLoopMax > *size) initLoopMax = *size; + // Detect high and lows + //25% clip in case highs and lows aren't clipped [marshmellow] + int high, low; + if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) + return -2; //just noise + + size_t errCnt = 0; + // if clean clipped waves detected run alternate demod + if (DetectCleanAskWave(BinStream, *size, high, low)) { + if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod"); + errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx); + if (askType) { //askman + uint8_t alignPos = 0; + errCnt = manrawdecode(BinStream, size, 0, &alignPos); + *startIdx += *clk/2 * alignPos; + if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos); + return errCnt; + } else { //askraw + return errCnt; + } + } + if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx); + if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); + + int lastBit; //set first clock check - can go negative + size_t i, bitnum = 0; //output counter + uint8_t midBit = 0; + uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave + if (*clk <= 32) tol = 1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely + size_t MaxBits = 3072; //max bits to collect + lastBit = start - *clk; + + for (i = start; i < *size; ++i) { + if (i-lastBit >= *clk-tol){ + if (BinStream[i] >= high) { + BinStream[bitnum++] = *invert; + } else if (BinStream[i] <= low) { + BinStream[bitnum++] = *invert ^ 1; + } else if (i-lastBit >= *clk+tol) { + if (bitnum > 0) { + if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); + BinStream[bitnum++]=7; + errCnt++; + } + } else { //in tolerance - looking for peak + continue; + } + midBit = 0; + lastBit += *clk; + } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ + if (BinStream[i] >= high) { + BinStream[bitnum++] = *invert; + } else if (BinStream[i] <= low) { + BinStream[bitnum++] = *invert ^ 1; + } else if (i-lastBit >= *clk/2+tol) { + BinStream[bitnum] = BinStream[bitnum-1]; + bitnum++; + } else { //in tolerance - looking for peak + continue; + } + midBit = 1; + } + if (bitnum >= MaxBits) break; + } + *size = bitnum; + return errCnt; +} + +int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) { + int start = 0; + return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start); } // by marshmellow - demodulate NRZ wave - requires a read with strong signal // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak -int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){ +int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) { if (justNoise(dest, *size)) return -1; - *clk = DetectNRZClock(dest, *size, *clk); + 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; @@ -1251,6 +1376,10 @@ int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){ 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; } } @@ -1258,257 +1387,202 @@ int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){ return 0; } -//by marshmellow -//detects the bit clock for FSK given the high and low Field Clocks -uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) -{ - 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++; +//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 - if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) - continue; - // else new peak - // if we got less than the small fc + tolerance then set it to the small fc - if (fcCounter < fcLow+fcTol) - fcCounter = fcLow; - else //set it to the large fc - fcCounter = fcHigh; + //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; - //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; + // 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 { - firstBitFnd++; + 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; } - rfCounter=0; - lastFCcnt=fcCounter; + last_transition = idx; } - fcCounter=0; } - uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15; + return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 +} - 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; +//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 (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; - } + 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 (ii<0) return 0; // oops we went too far - - return clk[ii]; + //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 -//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 == 0) 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; +//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, int *startIdx) { + if (justNoise(dest, size)) return 0; + // FSK demodulator + size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx); + size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx); + return size; +} - 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; - } - } - if (fcCounter>0 && fcLensFnd<15){ - //add new fc length - fcCnts[fcLensFnd]++; - fcLens[fcLensFnd++]=fcCounter; - } - fcCounter=0; +// 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 (; imaxCnt1) { - 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; + return; +} + +// by marshmellow +// convert psk2 demod to psk1 demod +// from only transition waves are 1s to phase shifts change bit +void psk2TOpsk1(uint8_t *BitStream, size_t size) { + uint8_t phase=0; + for (size_t i=0; ifcLens[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 + BitStream[i]=phase; } - // 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 fcLens[best1]; + return; } //by marshmellow - demodulate PSK1 wave //uses wave lengths (# Samples) -int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) -{ - if (size == 0) return -1; - uint16_t loopCnt = 4096; //don't need to loop through entire array... - if (*size= dest[i+2]){ - waveEnd = i+1; - //PrintAndLog("DEBUG: waveEnd: %d",waveEnd); - waveLenCnt = waveEnd-waveStart; - if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //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 - if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128 - break; - } - waveStart = i+1; - avgWaveVal = 0; - } - avgWaveVal += dest[i+2]; - } + uint8_t fc=0; + size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; + uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal; + uint16_t errCnt=0, errCnt2=0; + + *clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc); + if (*clock <= 0) return -1; + //if clock detect found firstfullwave... + uint16_t tol = fc/2; if (firstFullWave == 0) { - // no phase shift detected - could be all 1's or 0's - doesn't matter where we start - // so skip a little to ensure we are past any Start Signal - firstFullWave = 160; - memset(dest, curPhase, firstFullWave / *clock); + //find start of modulating data in trace + i = findModStart(dest, *size, fc); + //find first phase shift + 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; + memset(dest, curPhase, firstFullWave / *clock); + } else { + memset(dest, curPhase^1, firstFullWave / *clock); + } } else { memset(dest, curPhase^1, firstFullWave / *clock); } //advance bits numBits += (firstFullWave / *clock); + *startIdx = firstFullWave - (*clock * numBits)+2; //set start of wave as clock align lastClkBit = firstFullWave; - if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen); - if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); + if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx); + if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); waveStart = 0; dest[numBits++] = curPhase; //set first read bit - for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ + for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++) { //top edge of wave = start of new wave - if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ + if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]) { if (waveStart == 0) { waveStart = i+1; waveLenCnt = 0; @@ -1516,24 +1590,27 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) } else { //waveEnd waveEnd = i+1; waveLenCnt = waveEnd-waveStart; - lastAvgWaveVal = avgWaveVal/waveLenCnt; - if (waveLenCnt > fc){ - //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); + 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 + if (i+1 >= lastClkBit + *clock - tol) { //should be a clock bit curPhase ^= 1; dest[numBits++] = curPhase; lastClkBit += *clock; - } else if (i < lastClkBit+10+fc){ + } 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){ + } 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; @@ -1545,183 +1622,299 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) return errCnt; } -//by marshmellow -//attempt to identify a Sequence Terminator in ASK modulated raw wave -bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { - size_t bufsize = *size; - //need to loop through all samples and identify our clock, look for the ST pattern - uint8_t fndClk[] = {8,16,32,40,50,64,128}; - int clk = 0; - int tol = 0; - int i, j, skip, start, end, low, high, minClk, waveStart; - bool complete = false; - int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured - int waveLen[bufsize / 32]; // 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)); +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, int *waveStartIdx) { + //make sure buffer has enough data + if (*size < 96*50) return -1; + + // FSK demodulator + *size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // 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}; - if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) { - if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); - return false; //just noise + 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; } - i = 0; - j = 0; - minClk = 255; - // get to first full low to prime loop and skip incomplete first pulse - while ((buffer[i] < high) && (i < bufsize)) - ++i; - while ((buffer[i] > low) && (i < bufsize)) - ++i; - skip = i; + return -5; //spacer bits not found - not a valid gproxII +} - // populate tmpbuff buffer with pulse lengths - while (i < bufsize) { - // measure from low to low - while ((buffer[i] > low) && (i < bufsize)) - ++i; - start= i; - while ((buffer[i] < high) && (i < bufsize)) - ++i; - //first high point for this wave - waveStart = i; - while ((buffer[i] > low) && (i < bufsize)) - ++i; - if (j >= (bufsize/32)) { - break; - } - waveLen[j] = i - waveStart; //first high to first low - tmpbuff[j++] = i - start; - if (i-start < minClk && i < bufsize) { - minClk = i - start; +// 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, int *waveStartIdx) { + size_t numStart=0, size2=*size, startIdx=0; + // FSK demodulator fsk2a so invert and fc/10/8 + *size = fskdemod(dest, size2, 50, 1, 10, 8, waveStartIdx); + 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; } - // set clock - might be able to get this externally and remove this work... - if (!clk) { - for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { - tol = fndClk[clkCnt]/8; - if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) { - clk=fndClk[clkCnt]; - break; - } - } - // clock not found - ERROR - if (!clk) { - if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); - return false; - } - } else tol = clk/8; + return (int)startIdx; +} - *foundclock = clk; +int IOdemodFSK(uint8_t *dest, size_t size, int *waveStartIdx) { + //make sure buffer has data + if (size < 66*64) return -2; + // FSK demodulator RF/64, fsk2a so invert, and fc/10/8 + size = fskdemod(dest, size, 64, 1, 10, 8, waveStartIdx); + 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 - // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2) - start = -1; - for (i = 0; i < j - 4; ++i) { - skip += tmpbuff[i]; - if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior - if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 - if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave - if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit - start = i + 3; - break; - } - } - } - } - } - // first ST not found - ERROR - if (start < 0) { - if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting"); - return false; - } else { - if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j); + if (!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; } - 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 + return -5; +} - // now do it again to find the end - end = skip; - for (i += 3; i < j - 4; ++i) { - end += tmpbuff[i]; - if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior - if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 - if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave - if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit - complete = true; - break; - } - } - } - } - } - end -= phaseoff; - //didn't find second ST - ERROR - if (!complete) { - if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting"); - return false; - } - 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; +// redesigned by marshmellow adjusted from existing decode functions +// indala id decoding +int indala64decode(uint8_t *bitStream, size_t *size, uint8_t *invert) { + //standard 64 bit indala formats including 26 bit 40134 format + uint8_t preamble64[] = {1,0,1,0, 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 preamble64_i[] = {0,1,0,1, 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; + size_t found_size = *size; + bool found = preambleSearch(bitStream, preamble64, sizeof(preamble64), &found_size, &startidx); + if (!found) { + found = preambleSearch(bitStream, preamble64_i, sizeof(preamble64_i), &found_size, &startidx); + if (!found) return -1; + *invert ^= 1; } - size_t dataloc = start; - if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) { - //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start - for ( i=0; i <= (clk/8); ++i ) { - if ( buffer[dataloc - (clk*4) - i] <= low ) { - dataloc -= i; - break; - } - } + if (found_size != 64) return -2; + if (*invert==1) + for (size_t i = startidx; i < found_size + startidx; i++) + bitStream[i] ^= 1; + + // note: don't change *size until we are sure we got it... + *size = found_size; + return (int) startidx; +} + +int indala224decode(uint8_t *bitStream, size_t *size, uint8_t *invert) { + //large 224 bit indala formats (different preamble too...) + uint8_t preamble224[] = {1,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,1}; + uint8_t preamble224_i[] = {0,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,0}; + size_t startidx = 0; + size_t found_size = *size; + bool found = preambleSearch(bitStream, preamble224, sizeof(preamble224), &found_size, &startidx); + if (!found) { + found = preambleSearch(bitStream, preamble224_i, sizeof(preamble224_i), &found_size, &startidx); + if (!found) return -1; + *invert ^= 1; } - - size_t newloc = 0; - i=0; - if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen); + if (found_size != 224) return -2; + if (*invert==1 && startidx > 0) + for (size_t i = startidx-1; i < found_size + startidx + 2; i++) + bitStream[i] ^= 1; - // warning - overwriting buffer given with raw wave data with ST removed... - while ( dataloc < bufsize-(clk/2) ) { - //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part) - if (buffer[dataloc]low && buffer[dataloc+3]low) { - for(i=0; i < clk/2-tol; ++i) { - buffer[dataloc+i] = high+5; - } - } - for (i=0; i>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; } - *size = newloc; - return true; + 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, int *waveStartIdx) { + //make sure buffer has data + if (*size < 128*50) return -5; + + // FSK demodulator + *size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // 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; }