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https://github.com/Proxmark/proxmark3.git
synced 2025-08-14 02:26:59 -07:00
Add LF ASK Sequence Terminator detection...
...and demodulate data beginning after the first ST also add some type casts in print calls.
This commit is contained in:
marshmellow42
parent
38b3509542
commit
d1869c3336
8 changed files with 238 additions and 37 deletions
175
common/lfdemod.c
175
common/lfdemod.c
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@ -9,11 +9,10 @@
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//-----------------------------------------------------------------------------
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#include <stdlib.h>
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#include <string.h>
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#include "lfdemod.h"
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#include "common.h"
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#include <string.h>
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//un_comment to allow debug print calls when used not on device
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//to allow debug print calls when used not on device
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void dummy(char *fmt, ...){}
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#ifndef ON_DEVICE
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@ -218,6 +217,7 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
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if (smplCnt > clk-(clk/4)-1) { //full clock
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if (smplCnt > clk + (clk/4)+1) { //too many samples
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errCnt++;
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if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
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BinStream[bitCnt++]=7;
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} else if (waveHigh) {
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BinStream[bitCnt++] = invert;
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@ -274,7 +274,7 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
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if (*clk==0 || start < 0) return -3;
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if (*invert != 1) *invert = 0;
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if (amp==1) askAmp(BinStream, *size);
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if (g_debugMode==2) prnt("DEBUG: clk %d, beststart %d", *clk, start);
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if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d", *clk, start);
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uint8_t initLoopMax = 255;
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if (initLoopMax > *size) initLoopMax = *size;
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@ -287,20 +287,21 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
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size_t errCnt = 0;
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// if clean clipped waves detected run alternate demod
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if (DetectCleanAskWave(BinStream, *size, high, low)) {
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if (g_debugMode==2) prnt("DEBUG: Clean Wave Detected");
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if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
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errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
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if (askType) //askman
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return manrawdecode(BinStream, size, 0);
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else //askraw
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return errCnt;
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}
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if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
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int lastBit; //set first clock check - can go negative
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int lastBit; //set first clock check - can go negative
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size_t i, bitnum = 0; //output counter
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uint8_t midBit = 0;
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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
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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
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size_t MaxBits = 3072;
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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
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size_t MaxBits = 3072; //max bits to collect
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lastBit = start - *clk;
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for (i = start; i < *size; ++i) {
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@ -311,6 +312,7 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
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BinStream[bitnum++] = *invert ^ 1;
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} else if (i-lastBit >= *clk+tol) {
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if (bitnum > 0) {
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if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
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BinStream[bitnum++]=7;
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errCnt++;
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}
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@ -1199,7 +1201,7 @@ int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
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return (int) startidx;
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}
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// by marshmellow - demodulate NRZ wave
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// by marshmellow - demodulate NRZ wave - requires a read with strong signal
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// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
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int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
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if (justNoise(dest, *size)) return -1;
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@ -1518,3 +1520,158 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
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*size = numBits;
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return errCnt;
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}
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//by marshmellow
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//attempt to identify a Sequence Terminator in ASK modulated raw wave
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bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
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size_t bufsize = *size;
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//need to loop through all samples and identify our clock, look for the ST pattern
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uint8_t fndClk[] = {8,16,32,40,50,64,128};
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int clk = 0;
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int tol = 0;
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int i, j, skip, start, end, low, high, minClk;
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bool complete = false;
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int tmpbuff[bufsize / 64];
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size_t testsize = (bufsize < 512) ? bufsize : 512;
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//int phaseoff = 0;
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high = low = 128;
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memset(tmpbuff, 0, sizeof(tmpbuff));
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if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
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if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
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return false; //just noise
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}
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i = 0;
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j = 0;
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minClk = 255;
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// get to first full low to prime loop and skip incomplete first pulse
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while ((buffer[i] < high) && (i < bufsize))
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++i;
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while ((buffer[i] > low) && (i < bufsize))
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++i;
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skip = i;
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// populate tmpbuff buffer with pulse lengths
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while (i < bufsize) {
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// measure from low to low
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while ((buffer[i] > low) && (i < bufsize))
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++i;
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start= i;
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while ((buffer[i] < high) && (i < bufsize))
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++i;
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while ((buffer[i] > low) && (i < bufsize))
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++i;
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if (j >= (bufsize/64)) {
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break;
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}
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tmpbuff[j++] = i - start;
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if (i-start < minClk && i < bufsize) {
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minClk = i - start;
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}
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}
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// set clock - might be able to get this externally and remove this work...
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if (!clk) {
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for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
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tol = fndClk[clkCnt]/8;
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if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
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clk=fndClk[clkCnt];
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break;
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}
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}
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// clock not found - ERROR
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if (!clk) {
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if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
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return false;
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}
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} else tol = clk/8;
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*foundclock = clk;
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// look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
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start = -1;
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for (i = 0; i < j - 4; ++i) {
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skip += tmpbuff[i];
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if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior
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if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol) { //2 clocks
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if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol) { //1 1/2 to 2 clocks
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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
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start = i + 3;
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break;
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}
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}
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}
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}
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}
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// first ST not found - ERROR
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if (start < 0) {
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if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
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return false;
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}
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// skip over the remainder of ST
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skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
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// now do it again to find the end
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end = skip;
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for (i += 3; i < j - 4; ++i) {
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end += tmpbuff[i];
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if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior
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if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol) { //2 clocks
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if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol) { //1 1/2 to 2 clocks
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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
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complete = true;
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break;
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}
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}
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}
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}
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}
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//didn't find second ST - ERROR
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if (!complete) {
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if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
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return false;
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}
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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);
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//now begin to trim out ST so we can use normal demod cmds
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start = skip;
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size_t datalen = end - start;
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// check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
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if (datalen % clk > clk/8) {
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if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
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return false;
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} else {
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// padd the amount off - could be problematic... but shouldn't happen often
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datalen += datalen % clk;
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}
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// if datalen is less than one t55xx block - ERROR
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if (datalen/clk < 8*4) {
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if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
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return false;
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}
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size_t dataloc = start;
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size_t newloc = 0;
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i=0;
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// warning - overwriting buffer given with raw wave data with ST removed...
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while ( dataloc < bufsize-(clk/2) ) {
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//compensate for long high at end of ST not being high... (we cut out the high part)
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if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
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for(i=0; i < clk/2-tol; ++i) {
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buffer[dataloc+i] = high+5;
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}
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}
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for (i=0; i<datalen; ++i) {
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if (i+newloc < bufsize) {
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if (i+newloc < dataloc)
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buffer[i+newloc] = buffer[dataloc];
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dataloc++;
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}
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}
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newloc += i;
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//skip next ST
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dataloc += clk*4;
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}
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*size = newloc;
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return true;
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}
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