X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/b62b5e2527e36cdbfda2e3d2a7ce8a46e45969e1..refs/pull/471/head:/common/lfdemod.c?ds=sidebyside diff --git a/common/lfdemod.c b/common/lfdemod.c index d2e0fca4..f470371a 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -505,13 +505,14 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) { return bestStart[best]; } -int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){ +int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low, bool *strong) { //find shortest transition from high to low + *strong = false; size_t i = 0; size_t transition1 = 0; int lowestTransition = 255; bool lastWasHigh = false; - + size_t transitionSampleCount = 0; //find first valid beginning of a high or low wave while ((dest[i] >= peak || dest[i] <= low) && (i < size)) ++i; @@ -527,10 +528,17 @@ int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){ lastWasHigh = (dest[i] >= peak); if (i-transition1 < lowestTransition) lowestTransition = i-transition1; transition1 = i; + } else if (dest[i] < peak && dest[i] > low) { + transitionSampleCount++; } } 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; } @@ -550,7 +558,9 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx int peak, low; if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0; - int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low); + 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; @@ -1767,22 +1777,53 @@ int IOdemodFSK(uint8_t *dest, size_t size, int *waveStartIdx) { } // 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; +// 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; - } - if (*size != 64 && *size != 224) return -2; + } + if (found_size != 64) return -2; if (*invert==1) - for (size_t i = startidx; i < *size + startidx; i++) + 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; + } + 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; + // 224 formats are typically PSK2 (afaik 2017 Marshmellow) + // note loses 1 bit at beginning of transformation... + // don't need to verify array is big enough as to get here there has to be a full preamble after all of our data + psk1TOpsk2(bitStream + (startidx-1), found_size+2); + startidx++; + + *size = found_size; return (int) startidx; }