X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/3bc66a96fe60139015ddaa0b8fb12259675ff897..e74fc2ecbab43a083766502610efb7b36dfac5c4:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index bee87ece..db945d0a 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -354,7 +354,6 @@ void askAmp(uint8_t *BitStream, size_t size)
 //by marshmellow
 //takes 3 arguments - clock, invert and maxErr as integers
 //attempts to demodulate ask only
-//prints binary found and saves in graphbuffer for further commands
 int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
 {
 	uint32_t i;
@@ -501,6 +500,28 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
 	}
 	return bestErrCnt;
 }
+
+// demod gProxIIDemod 
+// error returns as -x 
+// success returns start position in BitStream
+// BitStream must contain previously askrawdemod and biphasedemoded data
+int gProxII_Demod(uint8_t BitStream[], size_t *size)
+{
+	size_t startIdx=0;
+	uint8_t preamble[] = {1,1,1,1,1,0};
+
+	uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -3; //preamble not found
+	if (*size != 96) return -2; //should have found 96 bits
+	//check first 6 spacer bits to verify format
+	if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
+		//confirmed proper separator bits found
+		//return start position
+		return (int) startIdx;
+	}
+	return -5;
+}
+
 //translate wave to 11111100000 (1 for each short wave 0 for each long wave)
 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
@@ -1073,11 +1094,9 @@ void psk1TOpsk2(uint8_t *BitStream, size_t size)
 // from only transition waves are 1s to phase shifts change bit
 void psk2TOpsk1(uint8_t *BitStream, size_t size)
 {
-	size_t i;
-	uint8_t phase=BitStream[0];
-	//uint8_t lastBit=BitStream[0];
-	for (i=1; i<size; i++){
-		if (phase!=BitStream[i]){
+	uint8_t phase=0;
+	for (size_t i=0; i<size; i++){
+		if (BitStream[i]==1){
 			phase ^=1;
 		}
 		BitStream[i]=phase;
@@ -1570,7 +1589,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
   if (*size<loopCnt) loopCnt = *size;
 
   uint8_t curPhase = *invert;
-  size_t i, waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
+  size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
   uint8_t fc=0, fullWaveLen=0, tol=1;
   uint16_t errCnt=0, waveLenCnt=0;
   fc = countPSK_FC(dest, *size);
@@ -1579,30 +1598,24 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
   *clock = DetectPSKClock(dest, *size, *clock);
   if (*clock==0) return -1;
   int avgWaveVal=0, lastAvgWaveVal=0;
-  //find first full wave
+  //find first phase shift
   for (i=0; i<loopCnt; i++){
     if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
-      if (waveStart == 0) {
-        waveStart = i+1;
-        avgWaveVal=dest[i+1];
-        //PrintAndLog("DEBUG: waveStart: %d",waveStart);
-      } else {
-        waveEnd = i+1;
-        //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
-        waveLenCnt = waveEnd-waveStart;
-        lastAvgWaveVal = avgWaveVal/waveLenCnt;
-        if (waveLenCnt > fc){
-          firstFullWave = waveStart;
-          fullWaveLen=waveLenCnt;
-          //if average wave value is > graph 0 then it is an up wave or a 1
-          if (lastAvgWaveVal > 128) curPhase^=1;
-          break;
-        } 
-        waveStart=0;
-        avgWaveVal=0;
-      }
+      waveEnd = i+1;
+      //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
+      waveLenCnt = waveEnd-waveStart;
+      if (waveLenCnt > fc && waveStart > fc){ //not first peak and is a large wave 
+        lastAvgWaveVal = avgWaveVal/(waveLenCnt);
+        firstFullWave = waveStart;
+        fullWaveLen=waveLenCnt;
+        //if average wave value is > graph 0 then it is an up wave or a 1
+        if (lastAvgWaveVal > 123) curPhase^=1;  //fudge graph 0 a little 123 vs 128
+        break;
+      } 
+      waveStart = i+1;
+      avgWaveVal = 0;
     }
-    avgWaveVal+=dest[i+1];
+    avgWaveVal+=dest[i+2];
   }
   //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);  
   lastClkBit = firstFullWave; //set start of wave as clock align
@@ -1610,7 +1623,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
   errCnt=0;
   size_t numBits=0;
   //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
-
+  dest[numBits++] = curPhase; //set first read bit
   for (i = firstFullWave+fullWaveLen-1; i < *size-3; i++){
     //top edge of wave = start of new wave 
     if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
@@ -1622,26 +1635,23 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
         waveEnd = i+1;
         waveLenCnt = waveEnd-waveStart;
         lastAvgWaveVal = avgWaveVal/waveLenCnt;
-        if (waveLenCnt > fc){ 
+        if (waveLenCnt > fc){  
           //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
           //if this wave is a phase shift
           //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
           if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
             curPhase^=1;
-            dest[numBits] = curPhase;
-            numBits++;
+            dest[numBits++] = curPhase;
             lastClkBit += *clock;
-          } else if (i<lastClkBit+10){
+          } else if (i<lastClkBit+10+fc){
             //noise after a phase shift - ignore
           } else { //phase shift before supposed to based on clock
             errCnt++;
-            dest[numBits] = 77;
-            numBits++;
+            dest[numBits++] = 77;
           }
         } else if (i+1 > lastClkBit + *clock + tol + fc){
           lastClkBit += *clock; //no phase shift but clock bit
-          dest[numBits] = curPhase;
-          numBits++;
+          dest[numBits++] = curPhase;
         }
         avgWaveVal=0;
         waveStart=i+1;