X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/cf194819cc71d7e0121e896e71989efc6dbfc280..7666f4608e8ade0ada08777d1cc33469c5d9471d:/common/lfdemod.c?ds=sidebyside diff --git a/common/lfdemod.c b/common/lfdemod.c index cf11b25b..8324c440 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -81,10 +81,9 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p j--; // 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 - default: //test parity - if (parityTest(parityWd, pLen, pType) == 0) return 0; break; + 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 + default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity } bitCnt+=(pLen-1); parityWd = 0; @@ -260,15 +259,18 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int //by marshmellow void askAmp(uint8_t *BitStream, size_t size) { + uint8_t Last = 128; for(size_t i = 1; i=30) //large jump up - BitStream[i]=255; - else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down - BitStream[i]=0; + Last = 255; + else if(BitStream[i-1]-BitStream[i]>=20) //large jump down + Last = 0; + + BitStream[i-1] = Last; } 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) @@ -278,7 +280,7 @@ 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 ASK: clk %d, beststart %d", *clk, start); + 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; @@ -1553,8 +1555,8 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { int tol = 0; int i, j, skip, start, end, low, high, minClk, waveStart; bool complete = false; - int tmpbuff[bufsize / 64]; - int waveLen[bufsize / 64]; + 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; @@ -1586,7 +1588,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { waveStart = i; while ((buffer[i] > low) && (i < bufsize)) ++i; - if (j >= (bufsize/64)) { + if (j >= (bufsize/32)) { break; } waveLen[j] = i - waveStart; //first high to first low @@ -1632,6 +1634,8 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { 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 (waveLen[i+2] > clk*1+tol) phaseoff = 0; @@ -1645,7 +1649,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { 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] >= 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 @@ -1667,12 +1671,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { 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 ( 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; - } 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) { @@ -1680,8 +1687,20 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { return false; } 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; + } + } + } + size_t newloc = 0; i=0; + if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen); + // 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) @@ -1695,11 +1714,12 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { if (i+newloc < dataloc) buffer[i+newloc] = buffer[dataloc]; - dataloc++; + dataloc++; } } 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;