ADD: `data detectclock` - added clock blocks in plot window. Its a draft. Not working...

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 7f8333ac1185420dc039ebfb334e6b404ac5e36d..58b843e23e474786bab5a4a79ebd969c07c4d213 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -206,6 +206,7 @@ size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_
 int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
 {
        // sanity check
+       if (*size < 64) return -3;      
        if (BitStream[1] > 1) return -1; 
        
        uint8_t fmtlen;
@@ -214,11 +215,13 @@ int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *h
        // preamble 0111111111
        // include 0 in front to help get start pos
        uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
-       if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx)) 
+       if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
                return -2;
-       if (*size < 64) return -3;
+
+       //XL and normal size.
+       if (*size != 64 && *size != 128) return -3;
        
-       fmtlen = (*size == 110) ? 22 : 10;
+       fmtlen = (*size == 128) ? 22 : 10;
 
        //skip last 4bit parity row for simplicity
        *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);  
@@ -1680,9 +1683,14 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
        return errCnt;
 }
 
+bool DetectST(uint8_t  buffer[], size_t *size, int *foundclock) {
+       size_t ststart = 0, stend = 0;
+       return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
+}
+
 //by marshmellow
 //attempt to identify a Sequence Terminator in ASK modulated raw wave
-bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
+bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
        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};
@@ -1837,7 +1845,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        size_t newloc = 0;
        i=0;
        if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);            
-
+       bool firstrun = true;
        // 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)
@@ -1845,6 +1853,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
                        for(i=0; i < clk/2-tol; ++i) {
                                buffer[dataloc+i] = high+5;
                        }
+               } //test for single sample outlier (high between two lows) in the case of very strong waves
+               if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
+                       buffer[dataloc] = buffer[dataloc+2];
+                       buffer[dataloc+1] = buffer[dataloc+2];
+               }
+               if (firstrun) {
+                       *stend = dataloc;
+                       *ststart = dataloc-(clk*4);
+                       firstrun=false;
                }
                for (i=0; i<datalen; ++i) {
                        if (i+newloc < bufsize) {