X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/38b3509542c4a5451a5701be0b073acbd7f79465..d1869c3336e82b7f2eb68b7fa9a5bdb865ff6b23:/common/lfdemod.c diff --git a/common/lfdemod.c b/common/lfdemod.c index 982a724a..5ed2d16c 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -9,11 +9,10 @@ //----------------------------------------------------------------------------- #include -#include #include "lfdemod.h" -#include "common.h" +#include -//un_comment to allow debug print calls when used not on device +//to allow debug print calls when used not on device void dummy(char *fmt, ...){} #ifndef ON_DEVICE @@ -218,6 +217,7 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int 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; @@ -274,7 +274,7 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr if (*clk==0 || start < 0) return -3; if (*invert != 1) *invert = 0; if (amp==1) askAmp(BinStream, *size); - if (g_debugMode==2) prnt("DEBUG: clk %d, beststart %d", *clk, start); + if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d", *clk, start); uint8_t initLoopMax = 255; if (initLoopMax > *size) initLoopMax = *size; @@ -287,20 +287,21 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr size_t errCnt = 0; // if clean clipped waves detected run alternate demod if (DetectCleanAskWave(BinStream, *size, high, low)) { - if (g_debugMode==2) prnt("DEBUG: Clean Wave Detected"); + 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; } + if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); - int lastBit; //set first clock check - can go negative + 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; + 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) { @@ -311,6 +312,7 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr 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++; } @@ -1199,7 +1201,7 @@ int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) return (int) startidx; } -// by marshmellow - demodulate NRZ wave +// 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){ if (justNoise(dest, *size)) return -1; @@ -1518,3 +1520,158 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) *size = numBits; 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; + bool complete = false; + int tmpbuff[bufsize / 64]; + size_t testsize = (bufsize < 512) ? bufsize : 512; + //int phaseoff = 0; + high = low = 128; + memset(tmpbuff, 0, sizeof(tmpbuff)); + + if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) { + if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); + return false; //just noise + } + + i = 0; + j = 0; + minClk = 255; + // get to first full low to prime loop and skip incomplete first pulse + while ((buffer[i] < high) && (i < bufsize)) + ++i; + while ((buffer[i] > low) && (i < bufsize)) + ++i; + skip = i; + + // populate tmpbuff buffer with pulse lengths + while (i < bufsize) { + // measure from low to low + while ((buffer[i] > low) && (i < bufsize)) + ++i; + start= i; + while ((buffer[i] < high) && (i < bufsize)) + ++i; + while ((buffer[i] > low) && (i < bufsize)) + ++i; + if (j >= (bufsize/64)) { + break; + } + tmpbuff[j++] = i - start; + if (i-start < minClk && i < bufsize) { + minClk = i - start; + } + } + // set clock - might be able to get this externally and remove this work... + if (!clk) { + for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { + tol = fndClk[clkCnt]/8; + if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) { + clk=fndClk[clkCnt]; + break; + } + } + // clock not found - ERROR + if (!clk) { + if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); + return false; + } + } else tol = clk/8; + + *foundclock = clk; + + // 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) { //1 to 2 clocks depending on 2 bits prior + if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol) { //2 clocks + if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol) { //1 1/2 to 2 clocks + if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= (clk*3)/2+tol) { //1 to 1 1/2 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; + } + + // 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 + end = skip; + for (i += 3; i < j - 4; ++i) { + end += tmpbuff[i]; + if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior + if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol) { //2 clocks + if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol) { //1 1/2 to 2 clocks + if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= (clk*3)/2+tol) { //1 to 1 1/2 clocks for end of ST + first bit + complete = true; + break; + } + } + } + } + } + //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", skip, end, end-skip, clk, (end-skip)/clk); + //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 (datalen % clk > clk/8) { + if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk); + return false; + } else { + // padd the amount off - could be problematic... but shouldn't happen often + datalen += datalen % clk; + } + // 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; + size_t newloc = 0; + i=0; + // 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... (we cut out the 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