X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/dc065b4e3467effd6b4f695dd3bc781da872d394..1e090a61a149a58a57e9d9acbf5e5532387867a4:/common/lfdemod.c diff --git a/common/lfdemod.c b/common/lfdemod.c index 062818ef..4a80a10c 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -5,13 +5,30 @@ // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- -// Low frequency commands +// Low frequency demod/decode commands //----------------------------------------------------------------------------- #include #include #include "lfdemod.h" +//by marshmellow +//get high and low with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise +int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) +{ + *high=0; + *low=255; + // get high and low thresholds + for (int i=0; i < size; i++){ + if (BitStream[i] > *high) *high = BitStream[i]; + if (BitStream[i] < *low) *low = BitStream[i]; + } + if (*high < 123) return -1; // just noise + *high = (int)(((*high-128)*(((float)fuzzHi)/100))+128); + *low = (int)(((*low-128)*(((float)fuzzLo)/100))+128); + return 1; +} + //by marshmellow //takes 1s and 0s and searches for EM410x format - output EM ID uint64_t Em410xDecode(uint8_t *BitStream, size_t size) @@ -72,7 +89,6 @@ uint64_t Em410xDecode(uint8_t *BitStream, size_t size) int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) { int i; - int high = 0, low = 255; *clk=DetectASKClock(BinStream, *size, *clk); //clock default if (*clk<8) *clk =64; @@ -81,22 +97,12 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) uint32_t initLoopMax = 200; if (initLoopMax > *size) initLoopMax=*size; // Detect high and lows - for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values - { - if (BinStream[i] > high) - high = BinStream[i]; - else if (BinStream[i] < low) - low = BinStream[i]; - } - if ((high < 129) ){ //throw away static (anything < 1 graph) - //PrintAndLog("no data found"); - return -2; - } - //25% fuzz in case highs and lows aren't clipped [marshmellow] - high=(int)(((high-128)*.75)+128); - low= (int)(((low-128)*.75)+128); + // 25% fuzz in case highs and lows aren't clipped [marshmellow] + int high, low, ans; + ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75); + if (ans<1) return -2; //just noise - //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); + // PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check uint32_t bitnum = 0; //output counter int tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave @@ -108,13 +114,13 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) uint32_t bestStart = *size; uint32_t bestErrCnt = (*size/1000); uint32_t maxErr = (*size/1000); - //PrintAndLog("DEBUG - lastbit - %d",lastBit); - //loop to find first wave that works + // PrintAndLog("DEBUG - lastbit - %d",lastBit); + // loop to find first wave that works for (iii=0; iii < gLen; ++iii){ if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){ lastBit=iii-*clk; errCnt=0; - //loop through to see if this start location works + // loop through to see if this start location works for (i = iii; i < *size; ++i) { if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){ lastBit+=*clk; @@ -242,17 +248,17 @@ int manrawdecode(uint8_t * BitStream, size_t *size) //by marshmellow //take 01 or 10 = 0 and 11 or 00 = 1 -int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset) +int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) { uint8_t bitnum=0; uint32_t errCnt =0; - uint32_t i=1; + uint32_t i; i=offset; - for (;i<*size-2;i+=2){ + for (;i<*size-2; i+=2){ if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ - BitStream[bitnum++]=1; + BitStream[bitnum++]=1^invert; } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ - BitStream[bitnum++]=0; + BitStream[bitnum++]=invert; } else { BitStream[bitnum++]=77; errCnt++; @@ -271,31 +277,21 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) { uint32_t i; // int invert=0; //invert default - int high = 0, low = 255; + int clk2 = *clk; *clk=DetectASKClock(BinStream, *size, *clk); //clock default - uint8_t BitStream[502] = {0}; + //uint8_t BitStream[502] = {0}; + //HACK: if clock not detected correctly - default if (*clk<8) *clk =64; - if (*clk<32) *clk=32; + if (*clk<32 && clk2==0) *clk=32; if (*invert != 0 && *invert != 1) *invert =0; uint32_t initLoopMax = 200; if (initLoopMax > *size) initLoopMax=*size; // Detect high and lows - for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values - { - if (BinStream[i] > high) - high = BinStream[i]; - else if (BinStream[i] < low) - low = BinStream[i]; - } - if ((high < 129)){ //throw away static high has to be more than 0 on graph. - //noise <= -10 here - // PrintAndLog("no data found"); - return -2; - } //25% fuzz in case highs and lows aren't clipped [marshmellow] - high=(int)(((high-128)*.75)+128); - low= (int)(((low-128)*.75)+128); + int high, low, ans; + ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75); + if (ans<1) return -2; //just noise //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check @@ -310,6 +306,7 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) uint8_t errCnt =0; uint32_t bestStart = *size; uint32_t bestErrCnt = (*size/1000); + uint32_t maxErr = bestErrCnt; uint8_t midBit=0; //PrintAndLog("DEBUG - lastbit - %d",lastBit); //loop to find first wave that works @@ -320,30 +317,30 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) for (i = iii; i < *size; ++i) { if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){ lastBit+=*clk; - BitStream[bitnum] = *invert; - bitnum++; + //BitStream[bitnum] = *invert; + //bitnum++; midBit=0; } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){ //low found and we are expecting a bar lastBit+=*clk; - BitStream[bitnum] = 1- *invert; - bitnum++; + //BitStream[bitnum] = 1- *invert; + //bitnum++; midBit=0; } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ //mid bar? midBit=1; - BitStream[bitnum]= 1- *invert; - bitnum++; + //BitStream[bitnum]= 1- *invert; + //bitnum++; } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ //mid bar? midBit=1; - BitStream[bitnum]= *invert; - bitnum++; + //BitStream[bitnum]= *invert; + //bitnum++; } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){ //no mid bar found midBit=1; - BitStream[bitnum]= BitStream[bitnum-1]; - bitnum++; + //BitStream[bitnum]= BitStream[bitnum-1]; + //bitnum++; } else { //mid value found or no bar supposed to be here @@ -351,45 +348,94 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert) //should have hit a high or low based on clock!! //debug //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit); - if (bitnum > 0){ - BitStream[bitnum]=77; - bitnum++; - } + //if (bitnum > 0){ + // BitStream[bitnum]=77; + // bitnum++; + //} errCnt++; lastBit+=*clk;//skip over until hit too many errors if (errCnt > ((*size/1000))){ //allow 1 error for every 1000 samples else start over errCnt=0; - bitnum=0;//start over + // bitnum=0;//start over break; } } } - if (bitnum>500) break; + if ((i-iii)>(500 * *clk)) break; //got enough bits } //we got more than 64 good bits and not all errors - if ((bitnum > (64+errCnt)) && (errCnt<(*size/1000))) { + if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<(*size/1000))) { //possible good read - if (errCnt==0) break; //great read - finish - if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish + if (errCnt==0){ + bestStart=iii; + bestErrCnt=errCnt; + break; //great read - finish + } if (errCnt=gLen){ //exhausted test - //if there was a ok test go back to that one and re-run the best run (then dump after that run) - if (bestErrCnt < (*size/1000)) iii=bestStart; - } } - if (bitnum>16){ - for (i=0; i < bitnum; ++i){ - BinStream[i]=BitStream[i]; + if (bestErrCnt= high) && ((i-lastBit) > (*clk-tol))){ + lastBit += *clk; + BinStream[bitnum] = *invert; + bitnum++; + midBit=0; + } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){ + //low found and we are expecting a bar + lastBit+=*clk; + BinStream[bitnum] = 1-*invert; + bitnum++; + midBit=0; + } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ + //mid bar? + midBit=1; + BinStream[bitnum] = 1 - *invert; + bitnum++; + } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){ + //mid bar? + midBit=1; + BinStream[bitnum] = *invert; + bitnum++; + } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){ + //no mid bar found + midBit=1; + if (bitnum!=0) BinStream[bitnum] = BinStream[bitnum-1]; + bitnum++; + + } else { + //mid value found or no bar supposed to be here + if ((i-lastBit)>(*clk+tol)){ + //should have hit a high or low based on clock!! + + //debug + //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit); + if (bitnum > 0){ + BinStream[bitnum]=77; + bitnum++; + } + + lastBit+=*clk;//skip over error + } + } + if (bitnum >=400) break; } *size=bitnum; - } else return -1; - return errCnt; + } else{ + *invert=bestStart; + *clk=iii; + return -1; + } + return bestErrCnt; } //translate wave to 11111100000 (1 for each short wave 0 for each long wave) size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow) @@ -589,37 +635,128 @@ int IOdemodFSK(uint8_t *dest, size_t size) return 0; } +// 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 +int parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) +{ + uint8_t ans = 0; + for (int i = 0; i < bitLen; i++){ + ans ^= ((bits >> i) & 1); + } + //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType); + return (ans == 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), 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++){ + parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; + BitStream[j++] = (BitStream[startIdx+word+bit]); + } + j--; + // if parity fails then return 0 + if (parityTest(parityWd, pLen, pType) == 0) return -1; + bitCnt+=(pLen-1); + parityWd = 0; + } + // if we got here then all the parities passed + //return ID start index and size + return bitCnt; +} + +// by marshmellow +// FSK Demod then try to locate an AWID ID +int AWIDdemodFSK(uint8_t *dest, size_t size) +{ + static const uint8_t THRESHOLD = 123; + uint32_t idx=0; + //make sure buffer has data + if (size < 96*50) return -1; + //test samples are not just noise + uint8_t justNoise = 1; + for(idx=0; idx < size && justNoise ;idx++){ + justNoise = dest[idx] < THRESHOLD; + } + if(justNoise) return -2; + + // FSK demodulator + size = fskdemod(dest, size, 50, 1, 10, 8); // RF/64 and invert + if (size < 96) return -3; //did we get a good demod? + + uint8_t mask[] = {0,0,0,0,0,0,0,1}; + for( idx=0; idx < (size - 96); idx++) { + if ( memcmp(dest + idx, mask, sizeof(mask))==0) { + // frame marker found + //return ID start index and size + return idx; + //size should always be 96 + } + } + //never found mask + return -4; +} + +// by marshmellow +// FSK Demod then try to locate an Farpointe Data (pyramid) ID +int PyramiddemodFSK(uint8_t *dest, size_t size) +{ + static const uint8_t THRESHOLD = 123; + uint32_t idx=0; + // size_t size2 = size; + //make sure buffer has data + if (size < 128*50) return -5; + //test samples are not just noise + uint8_t justNoise = 1; + for(idx=0; idx < size && justNoise ;idx++){ + justNoise = dest[idx] < THRESHOLD; + } + if(justNoise) return -1; + + // FSK demodulator + size = fskdemod(dest, size, 50, 1, 10, 8); // RF/64 and invert + if (size < 128) return -2; //did we get a good demod? + + uint8_t mask[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; + for( idx=0; idx < (size - 128); idx++) { + if ( memcmp(dest + idx, mask, sizeof(mask))==0) { + // frame marker found + return idx; + } + } + //never found mask + return -4; +} + // by marshmellow // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping) // maybe somehow adjust peak trimming value based on samples to fix? int DetectASKClock(uint8_t dest[], size_t size, int clock) { int i=0; - int peak=0; - int low=255; - int clk[]={16,32,40,50,64,100,128,256}; + int clk[]={8,16,32,40,50,64,100,128,256}; int loopCnt = 256; //don't need to loop through entire array... if (size peak){ - peak = dest[i]; - } - if(dest[i] < low){ - low = dest[i]; - } - } - peak=(int)(((peak-128)*.75)+128); - low= (int)(((low-128)*.75)+128); + int peak, low; + getHiLo(dest, loopCnt, &peak, &low, 75, 75); + int ii; int clkCnt; int tol = 0; - int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000}; + int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; int errCnt=0; //test each valid clock from smallest to greatest to see which lines up for(clkCnt=0; clkCnt < 6; ++clkCnt){ @@ -651,7 +788,7 @@ int DetectASKClock(uint8_t dest[], size_t size, int clock) } int iii=0; int best=0; - for (iii=0; iii<7;++iii){ + for (iii=0; iii<8;++iii){ if (bestErr[iii] peak){ - peak = dest[i]; - } - if(dest[i] < low){ - low = dest[i]; - } - } - peak=(int)(((peak-128)*.75)+128); - low= (int)(((low-128)*.75)+128); + int peak, low; + getHiLo(dest, loopCnt, &peak, &low, 75, 75); + //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low); int ii; uint8_t clkCnt; @@ -698,7 +826,7 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock) int peaksdet[]={0,0,0,0,0,0,0,0,0}; //test each valid clock from smallest to greatest to see which lines up for(clkCnt=0; clkCnt < 6; ++clkCnt){ - if (clk[clkCnt] == 32){ + if (clk[clkCnt] >= 32){ tol=1; }else{ tol=0; @@ -749,40 +877,37 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock) } //by marshmellow (attempt to get rid of high immediately after a low) -void pskCleanWave(uint8_t *bitStream, size_t size) +void pskCleanWave(uint8_t *BitStream, size_t size) { int i; - int low=255; - int high=0; int gap = 4; - // int loopMax = 2048; - int newLow=0; + int newLow=0; int newHigh=0; - for (i=0; i < size; ++i){ - if (bitStream[i] < low) low=bitStream[i]; - if (bitStream[i] > high) high=bitStream[i]; - } - high = (int)(((high-128)*.80)+128); - low = (int)(((low-128)*.90)+128); - //low = (uint8_t)(((int)(low)-128)*.80)+128; - for (i=0; i < size; ++i){ + int high, low; + getHiLo(BitStream, size, &high, &low, 80, 90); + + for (i=0; i < size; ++i){ if (newLow == 1){ - bitStream[i]=low+8; - gap--; + if (BitStream[i]>low){ + BitStream[i]=low+8; + gap--; + } if (gap == 0){ newLow=0; gap=4; } }else if (newHigh == 1){ - bitStream[i]=high-8; - gap--; + if (BitStream[i]= high) newHigh=1; + if (BitStream[i] <= low) newLow=1; + if (BitStream[i] >= high) newHigh=1; } return; } @@ -853,7 +978,7 @@ int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) } -//by marshmellow - demodulate PSK wave or NRZ wave (both similar enough) +//by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough) //peaks switch bit (high=1 low=0) each clock cycle = 1 bit determined by last peak int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) { @@ -861,22 +986,14 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) int clk2 = DetectpskNRZClock(dest, *size, *clk); *clk=clk2; uint32_t i; - uint8_t high=0, low=255; + int high, low, ans; + ans = getHiLo(dest, 1260, &high, &low, 75, 80); //25% fuzz on high 20% fuzz on low + if (ans<1) return -2; //just noise uint32_t gLen = *size; - if (gLen > 1280) gLen=1280; - // get high - for (i=0; i < gLen; ++i){ - if (dest[i] > high) high = dest[i]; - if (dest[i] < low) low = dest[i]; - } - //fudge high/low bars by 25% - high = (uint8_t)((((int)(high)-128)*.75)+128); - low = (uint8_t)((((int)(low)-128)*.80)+128); - //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low); int lastBit = 0; //set first clock check uint32_t bitnum = 0; //output counter - uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave + uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave if (*clk==32) tol = 2; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely uint32_t iii = 0; uint8_t errCnt =0; @@ -931,7 +1048,6 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) bestErrCnt = errCnt; break; //great read - finish } - if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish if (errCnt < bestErrCnt){ //set this as new best run bestErrCnt = errCnt; bestStart = iii; @@ -995,3 +1111,169 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) return errCnt; } + +//by marshmellow +//countFC is to detect the field clock and bit clock rates. +//for fsk or ask not psk or nrz +uint32_t countFC(uint8_t *BitStream, size_t size) +{ + // get high/low thresholds + int high, low; + getHiLo(BitStream,10, &high, &low, 100, 100); + // get zero crossing + uint8_t zeroC = (high-low)/2+low; + uint8_t clk[]={8,16,32,40,50,64,100,128}; + uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0}; + uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0}; + uint8_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0}; + // uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0}; + uint8_t fcLensFnd = 0; + uint8_t rfLensFnd = 0; + uint8_t lastBit=0; + uint8_t curBit=0; + uint8_t lastFCcnt=0; + uint32_t errCnt=0; + uint32_t fcCounter = 0; + uint32_t rfCounter = 0; + uint8_t firstBitFnd = 0; + int i; + + // prime i to first up transition + for (i = 1; i < size; i++) + if (BitStream[i]>=zeroC && BitStream[i-1]= zeroC){ + // new up transition + fcCounter++; + rfCounter++; + if (fcCounter > 3 && fcCounter < 256){ + //we've counted enough that it could be a valid field clock + + //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 odd and not rc/5 add one (for when we get a fc 9 instead of 10) + if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++; + + //look for bit clock (rf/xx) + if ((fcCounterlastFCcnt)){ + //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<10; ii++){ + if (rfLens[ii]==rfCounter){ + //rfCnts[ii]++; + rfCounter=0; + break; + } + } + if (rfCounter>0 && rfLensFnd<10){ + //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter); + //rfCnts[rfLensFnd]++; + rfLens[rfLensFnd++]=rfCounter; + } + } else { + //PrintAndLog("DEBUG i: %d",i); + firstBitFnd++; + } + rfCounter=0; + lastFCcnt=fcCounter; + } + + // save last field clock count (fc/xx) + // find which fcLens to save it to: + for (int ii=0; ii<10; ii++){ + if (fcLens[ii]==fcCounter){ + fcCnts[ii]++; + fcCounter=0; + break; + } + } + if (fcCounter>0 && fcLensFnd<10){ + //add new fc length + //PrintAndLog("FCCntr %d",fcCounter); + fcCnts[fcLensFnd]++; + fcLens[fcLensFnd++]=fcCounter; + } + } else{ + // hmmm this should not happen often - count them + errCnt++; + } + // reset counter + fcCounter=0; + } else { + // count sample + fcCounter++; + rfCounter++; + } + } + // if too many errors return errors as negative number (IS THIS NEEDED?) + if (errCnt>100) return -1*errCnt; + + uint8_t maxCnt1=0, best1=9, best2=9, best3=9, rfHighest=10, rfHighest2=10, rfHighest3=10; + + // go through fclens and find which ones are bigest 2 + for (i=0; i<10; i++){ + // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d, RF %d",fcLens[i],fcCnts[i],errCnt,rfLens[i]); + + // get the 3 best FC values + if (fcCnts[i]>maxCnt1) { + best3=best2; + best2=best1; + maxCnt1=fcCnts[i]; + best1=i; + } else if(fcCnts[i]>fcCnts[best2]){ + best3=best2; + best2=i; + } else if(fcCnts[i]>fcCnts[best3]){ + best3=i; + } + //get highest 2 RF values (might need to get more values to compare or compare all?) + if (rfLens[i]>rfLens[rfHighest]){ + rfHighest3=rfHighest2; + rfHighest2=rfHighest; + rfHighest=i; + } else if(rfLens[i]>rfLens[rfHighest2]){ + rfHighest3=rfHighest2; + rfHighest2=i; + } else if(rfLens[i]>rfLens[rfHighest3]){ + rfHighest3=i; + } + } + + // set allowed clock remainder tolerance to be 1 large field clock length + // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off + int tol1 = (fcLens[best1]>fcLens[best2]) ? fcLens[best1] : fcLens[best2]; + + // loop to find the highest clock that has a remainder less than the tolerance + // compare samples counted divided by + int ii=7; + for (; ii>=0; 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){ + break; + } + } + } + } + + if (ii<0) ii=7; // oops we went too far + + // TODO: take top 3 answers and compare to known Field clocks to get top 2 + + uint32_t fcs=0; + // PrintAndLog("DEBUG: Best %d best2 %d best3 %d, clk %d, clk2 %d",fcLens[best1],fcLens[best2],fcLens[best3],clk[i],clk[ii]); + // + + if (fcLens[best1]>fcLens[best2]){ + fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best1])<<8) | ((fcLens[best2])); + } else { + fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best2])<<8) | ((fcLens[best1])); + } + + return fcs; +}