X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/63744b568145c239b7f9dfe2ed43f0ed40c20bcd..refs/pull/166/head:/common/lfdemod.c
diff --git a/common/lfdemod.c b/common/lfdemod.c
index 8eb1c19b..7398f1b2 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -9,11 +9,10 @@
//-----------------------------------------------------------------------------
#include <stdlib.h>
-#include <string.h>
#include "lfdemod.h"
-#include "common.h"
+#include <string.h>
-//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 +1520,166 @@ 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, waveStart;
+ bool complete = false;
+ int tmpbuff[bufsize / 64];
+ int waveLen[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;
+ //first high point for this wave
+ waveStart = i;
+ while ((buffer[i] > low) && (i < bufsize))
+ ++i;
+ if (j >= (bufsize/64)) {
+ break;
+ }
+ waveLen[j] = i - waveStart; //first high to first low
+ 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 && 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
+ 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;
+ }
+ if (waveLen[i+2] > clk*1+tol)
+ phaseoff = 0;
+ else
+ phaseoff = clk/2;
+
+ // 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 && 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
+ complete = true;
+ break;
+ }
+ }
+ }
+ }
+ }
+ end -= phaseoff;
+ //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, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff);
+ //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]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
+ for(i=0; i < clk/2-tol; ++i) {
+ buffer[dataloc+i] = high+5;
+ }
+ }
+ for (i=0; i<datalen; ++i) {
+ if (i+newloc < bufsize) {
+ if (i+newloc < dataloc)
+ buffer[i+newloc] = buffer[dataloc];
+
+ dataloc++;
+ }
+ }
+ newloc += i;
+ //skip next ST
+ dataloc += clk*4;
+ }
+ *size = newloc;
+ return true;
+}