X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/294352747265506ba4ea3dc214c5b755203a783a..refs/pull/208/head:/common/lfdemod.c
diff --git a/common/lfdemod.c b/common/lfdemod.c
index 7d40df3a..8324c440 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -270,7 +270,7 @@ void askAmp(uint8_t *BitStream, size_t size)
}
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)
@@ -280,7 +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;
@@ -1555,8 +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;
@@ -1588,7 +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
@@ -1634,6 +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;
@@ -1647,7 +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
@@ -1669,12 +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) {
@@ -1682,8 +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)
@@ -1697,11 +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;