X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/5daad8266013a5600e958d256dfd58f451bc758b..00baf27097ca945936d52afde1f8da831decbe59:/common/lfdemod.c?ds=inline

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 11340ef0..797bce40 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -7,29 +7,33 @@
 //-----------------------------------------------------------------------------
 // Low frequency demod/decode commands
 //-----------------------------------------------------------------------------
-
-#include <stdlib.h>
 #include "lfdemod.h"
-#include <string.h>
 
 //un_comment to allow debug print calls when used not on device
 void dummy(char *fmt, ...){}
+void dummy_sgc (int clock, int startidx) {}
 
 #ifndef ON_DEVICE
-#include "ui.h"
-#include "cmdparser.h"
-#include "cmddata.h"
-#define prnt PrintAndLog
+# include "ui.h"		 // plotclock, plotclockstartindex
+# include "cmdparser.h"
+# include "cmddata.h"
+# define prnt PrintAndLog
+# define sgc SetGraphClock
+void SetGraphClock(int clock, int startidx){
+	PlotClock = clock;
+	PlockClockStartIndex = startidx;	
+}
 #else 
-	uint8_t g_debugMode=0;
-#define prnt dummy
+  uint8_t g_debugMode = 0;
+# define prnt dummy
+# define sgc dummy_sgc
 #endif
 
 //test samples are not just noise
 uint8_t justNoise(uint8_t *bits, size_t size) {
 	#define THRESHOLD 123
 	uint8_t val = 1;
-	for(size_t idx=0; idx < size && val ;idx++)
+	for(size_t idx = 0; idx < size && val; idx++)
 		val = bits[idx] < THRESHOLD;
 	return val;
 }
@@ -60,7 +64,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
 	for (uint8_t i = 0; i < bitLen; i++){
 		ans ^= ((bits >> i) & 1);
 	}
-	//PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+	if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
 	return (ans == pType);
 }
 
@@ -71,11 +75,13 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
 {
 	uint32_t parityWd = 0;
 	size_t j = 0, bitCnt = 0;
-	for (int word = 0; word < (bLen); word+=pLen){
+	for (int word = 0; word < (bLen); word += pLen){
 		for (int bit=0; bit < pLen; bit++){
 			parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
 			BitStream[j++] = (BitStream[startIdx+word+bit]);
 		}
+		if (word+pLen > bLen) break;
+
 		j--; // overwrite parity with next data
 		// if parity fails then return 0
 		switch (pType) {
@@ -83,7 +89,7 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
 			case 2:  if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
 			default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
 		}
-		bitCnt+=(pLen-1);
+		bitCnt += (pLen-1);
 		parityWd = 0;
 	}
 	// if we got here then all the parities passed
@@ -141,72 +147,112 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
 	return num;
 }
 
+//by marshmellow
+// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
+bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
+	return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
+}
 //by marshmellow
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
-uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
+// param @findone:  look for a repeating preamble or only the first.
+// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
+bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)
 {
 	// Sanity check.  If preamble length is bigger than bitstream length.
-	if ( *size <= pLen ) return 0;
+	if ( *size <= pLen ) return false;
 	
 	uint8_t foundCnt = 0;
 	for (int idx = 0; idx < *size - pLen; idx++){
 		if (memcmp(BitStream+idx, preamble, pLen) == 0){
+			if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
 			//first index found
 			foundCnt++;
 			if (foundCnt == 1){
 				*startIdx = idx;
+				if (findone) return true;
 			}
 			if (foundCnt == 2){
 				*size = idx - *startIdx;
-				return 1;
+				return true;
 			}
 		}
 	}
-	return 0;
+	return false;
+}
+
+// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
+size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
+	size_t i = 0;
+	size_t waveSizeCnt = 0;
+	uint8_t thresholdCnt = 0;
+	bool isAboveThreshold = dest[i++] >= threshold_value;
+	for (; i < size-20; i++ ) {
+		if(dest[i] < threshold_value && isAboveThreshold) {
+			thresholdCnt++;
+			if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;			
+			isAboveThreshold = false;
+			waveSizeCnt = 0;
+		} else if (dest[i] >= threshold_value && !isAboveThreshold) {
+			thresholdCnt++;
+			if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;			
+			isAboveThreshold = true;
+			waveSizeCnt = 0;
+		} else {
+			waveSizeCnt++;
+		}
+		if (thresholdCnt > 10) break;
+	}
+	if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
+	return i;
 }
 
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID
+// actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
 int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
 {
-	//no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
-	//  otherwise could be a void with no arguments
-	//set defaults
-	uint32_t i = 0;
-	if (BitStream[1]>1) return -1;  //allow only 1s and 0s
-
-	// 111111111 bit pattern represent start of frame
-	//  include 0 in front to help get start pos
-	uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
-	uint32_t idx = 0;
-	uint32_t parityBits = 0;
-	uint8_t errChk = 0;
-	uint8_t FmtLen = 10;
+	// sanity check
+	if (*size < 64) return -3;	
+	if (BitStream[1] > 1) return -1; 
+	
+	uint8_t fmtlen;
 	*startIdx = 0;
-	errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
-	if (errChk == 0 ) return -4;
-	if (*size < 64) return -3;
-	if (*size > 64) FmtLen = 22;
-	*startIdx += 1; //get rid of 0 from preamble
-	idx = *startIdx + 9;
-	for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
-		parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
-		//check even parity - quit if failed
-		if (parityTest(parityBits, 5, 0) == 0) return -5;
-		//set uint64 with ID from BitStream
-		for (uint8_t ii=0; ii<4; ii++){
-			*hi = (*hi << 1) | (*lo >> 63);
-			*lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
-		}
+	
+	// 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))
+		return -2;
+
+	//XL and normal size.
+	if (*size != 64 && *size != 128) return -3;
+	
+	fmtlen = (*size == 128) ? 22 : 10;
+
+	//skip last 4bit parity row for simplicity
+	*size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);  
+	
+	switch (*size) {
+	   case 40: { 
+	    // std em410x format
+		*hi = 0;
+		*lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
+		break;
+	    } 
+	    case 88:  { 
+	    // long em format
+		*hi = (bytebits_to_byte(BitStream, 24)); 
+		*lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
+		break;
+	    } 
+	    default: return -4;	
 	}
-	if (errChk != 0) return 1;
-	//skip last 5 bit parity test for simplicity.
-	// *size = 64 | 128;
-	return 0;
+	return 1;
 }
 
 //by marshmellow
 //demodulates strong heavily clipped samples
+//RETURN: num of errors.  if 0, is ok.
 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
 {
 	size_t bitCnt=0, smplCnt=0, errCnt=0;
@@ -218,11 +264,12 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
 			smplCnt++;
 		} else { //transition
 			if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
+
 				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;
+						BinStream[bitCnt++] = 7;
 					} else if (waveHigh) {
 						BinStream[bitCnt++] = invert;
 						BinStream[bitCnt++] = invert;
@@ -280,8 +327,10 @@ 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);
 
+	sgc(*clk, start);
+		
 	uint8_t initLoopMax = 255;
 	if (initLoopMax > *size) initLoopMax = *size;
 	// Detect high and lows
@@ -297,8 +346,8 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
 		errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
 		if (askType) //askman
 			return manrawdecode(BinStream, size, 0);	
-		else //askraw
-			return errCnt;
+		//askraw
+		return errCnt;
 	}
 	if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
 
@@ -345,40 +394,43 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
 	*size = bitnum;
 	return errCnt;
 }
-
 //by marshmellow
 //take 10 and 01 and manchester decode
 //run through 2 times and take least errCnt
-int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
-{
-	uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
-	size_t i, ii;
-	uint16_t bestErr = 1000, bestRun = 0;
+int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
+
+	// sanity check
 	if (*size < 16) return -1;
+	
+	int errCnt = 0, bestErr = 1000;
+	uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
+	size_t i, k;
+
 	//find correct start position [alignment]
-	for (ii=0;ii<2;++ii){
-		for (i=ii; i<*size-3; i+=2)
-			if (BitStream[i]==BitStream[i+1])
+	for (k = 0; k < 2; ++k){
+		for (i = k; i < *size-3; i += 2) {
+			if (BitStream[i] == BitStream[i+1])
 				errCnt++;
-
-		if (bestErr>errCnt){
-			bestErr=errCnt;
-			bestRun=ii;
 		}
-		errCnt=0;
+		if (bestErr > errCnt){
+			bestErr = errCnt;
+			bestRun = k;
+		}
+		errCnt = 0;
 	}
+	
 	//decode
-	for (i=bestRun; i < *size-3; i+=2){
-		if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
-			BitStream[bitnum++]=invert;
-		} else if((BitStream[i] == 0) && BitStream[i+1] == 1){
-			BitStream[bitnum++]=invert^1;
+	for (i = bestRun; i < *size-3; i += 2){
+		if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
+			BitStream[bitnum++] = invert;
+		} else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
+			BitStream[bitnum++] = invert^1;
 		} else {
-			BitStream[bitnum++]=7;
+			BitStream[bitnum++] = 7;
 		}
-		if(bitnum>MaxBits) break;
+		if (bitnum > MaxBits) break;
 	}
-	*size=bitnum;
+	*size = bitnum;
 	return bestErr;
 }
 
@@ -457,9 +509,11 @@ 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 (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx)) 
+		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
@@ -474,7 +528,6 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 {
 	size_t last_transition = 0;
 	size_t idx = 1;
-	//uint32_t maxVal=0;
 	if (fchigh==0) fchigh=10;
 	if (fclow==0) fclow=8;
 	//set the threshold close to 0 (graph) or 128 std to avoid static
@@ -482,19 +535,22 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 	size_t preLastSample = 0;
 	size_t LastSample = 0;
 	size_t currSample = 0;
-	// sync to first lo-hi transition, and threshold
+	if ( size < 1024 ) return 0; // not enough samples
+
+	//find start of modulating data in trace 
+	idx = findModStart(dest, size, threshold_value, fchigh);
 
 	// Need to threshold first sample
-	// skip 160 samples to allow antenna/samples to settle
-	if(dest[160] < threshold_value) dest[0] = 0;
+	if(dest[idx] < threshold_value) dest[0] = 0;
 	else dest[0] = 1;
+	idx++;
 
 	size_t numBits = 0;
 	// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
 	// or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
 	// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
 	//  (could also be fc/5 && fc/7 for fsk1 = 4-9)
-	for(idx = 161; idx < size-20; idx++) {
+	for(; idx < size-20; idx++) {
 		// threshold current value
 
 		if (dest[idx] < threshold_value) dest[idx] = 0;
@@ -509,13 +565,14 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 				//do nothing with extra garbage
 			} else if (currSample < (fchigh-1)) {           //6-8 = 8 sample waves  (or 3-6 = 5)
 				//correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
-				if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample	== 0 )){
+				if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
 					dest[numBits-1]=1;
 				}
 				dest[numBits++]=1;
 
-			} else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage 
-				//do nothing with beginning garbage
+			} else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
+				//do nothing with beginning garbage and reset..  should be rare..
+				numBits = 0; 
 			} else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
 				dest[numBits++]=1;
 			} else {                                        //9+ = 10 sample waves (or 6+ = 7)
@@ -538,7 +595,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
 	uint32_t n=1;
 	for( idx=1; idx < size; idx++) {
 		n++;
-		if (dest[idx]==lastval) continue; 
+		if (dest[idx]==lastval) continue; //skip until we hit a transition
 		
 		//find out how many bits (n) we collected
 		//if lastval was 1, we have a 1->0 crossing
@@ -589,9 +646,8 @@ int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32
 	if (*size < 96*2) return -2;
 	// 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
 	uint8_t preamble[] = {0,0,0,1,1,1,0,1};
-	// find bitstring in array  
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -3; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+		return -3; //preamble not found
 
 	numStart = startIdx + sizeof(preamble);
 	// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
@@ -602,10 +658,11 @@ int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32
 		*hi2 = (*hi2<<1)|(*hi>>31);
 		*hi = (*hi<<1)|(*lo>>31);
 		//Then, shift in a 0 or one into low
+		*lo <<= 1;
 		if (dest[idx] && !dest[idx+1])  // 1 0
-			*lo=(*lo<<1)|1;
+			*lo |= 1;
 		else // 0 1
-			*lo=(*lo<<1)|0;
+			*lo |= 0;
 	}
 	return (int)startIdx;
 }
@@ -622,9 +679,8 @@ int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, ui
 
 	// 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
 	uint8_t preamble[] = {0,0,0,0,1,1,1,1};
-
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -3; //preamble not found
+	if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+		return -3; //preamble not found
 
 	numStart = startIdx + sizeof(preamble);
 	// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
@@ -661,8 +717,8 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 	//Handle the data
 	size_t startIdx = 0;
 	uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
+		return -4; //preamble not found
 
 	if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
 		//confirmed proper separator bits found
@@ -677,11 +733,11 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 int VikingDemod_AM(uint8_t *dest, size_t *size) {
 	//make sure buffer has data
 	if (*size < 64*2) return -2;
-
 	size_t startIdx = 0;
 	uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+		return -4; //preamble not found
+	
 	uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ 
 						 bytebits_to_byte(dest+startIdx+8,8) ^ 
 						 bytebits_to_byte(dest+startIdx+16,8) ^ 
@@ -693,80 +749,77 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
 	if ( checkCalc != 0xA8 ) return -5;	
 	if (*size != 64) return -6;
 	//return start position
-	return (int) startIdx;
+	return (int)startIdx;
 }
 
 // by iceman
 // find Visa2000 preamble in already demoded data
 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
-	if (*size < 96*2) return -1; //make sure buffer has data
+	if (*size < 96) return -1; //make sure buffer has data
 	size_t startIdx = 0;
 	uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -2; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -2; //preamble not found
 	if (*size != 96) return -3; //wrong demoded size
 	//return start position
-	return (int) startIdx;
+	return (int)startIdx;
+}
+// by iceman
+// find Noralsy preamble in already demoded data
+int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
+	if (*size < 96) return -1; //make sure buffer has data
+	size_t startIdx = 0;
+	uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -2; //preamble not found
+	if (*size != 96) return -3; //wrong demoded size
+	//return start position
+	return (int)startIdx;
 }
-
 // find presco preamble 0x10D in already demoded data
 int PrescoDemod(uint8_t *dest, size_t *size) {
-	//make sure buffer has data
-	if (*size < 64*2) return -2;
-
+	if (*size < 128*2) return -1; //make sure buffer has data
 	size_t startIdx = 0;
-	uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -2; //preamble not found
+	if (*size != 128) return -3; //wrong demoded size
 	//return start position
-	return (int) startIdx;
+	return (int)startIdx;
 }
 
 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
 // BitStream must contain previously askrawdemod and biphasedemoded data
-int FDXBdemodBI(uint8_t *dest, size_t *size)
-{
-	//make sure buffer has enough data
-	if (*size < 128) return -1;
-
+int FDXBdemodBI(uint8_t *dest, size_t *size) {
+	if (*size < 128*2) return -1; 	//make sure buffer has enough data
 	size_t startIdx = 0;
 	uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
-
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -2; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -2; //preamble not found
+	if (*size != 128) return -3; //wrong demoded size
+	//return start position
 	return (int)startIdx;
 }
 
 // ASK/Diphase fc/64 (inverted Biphase)
 // Note: this i s not a demod, this is only a detection
 // the parameter *dest needs to be demoded before call
+// 0xFFFF preamble, 64bits
 int JablotronDemod(uint8_t *dest, size_t *size){
-	//make sure buffer has enough data
-	if (*size < 64) return -1;
-
+	if (*size < 64*2) return -1;	//make sure buffer has enough data
 	size_t startIdx = 0;
-	// 0xFFFF preamble, 64bits
-	uint8_t preamble[] = {
-		        1,1,1,1,
-	            1,1,1,1,
-				1,1,1,1,
-				1,1,1,1,
-				0
-		};
-
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
-	if (*size != 64) return -3;
+	uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+		return -2; //preamble not found
+	if (*size != 64) return -3; // wrong demoded size
 	
 	uint8_t checkchksum = 0;
 	for (int i=16; i < 56; i += 8) {
 		checkchksum += bytebits_to_byte(dest+startIdx+i,8);
 	}
 	checkchksum ^= 0x3A;
-
 	uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
-	
-	if ( checkchksum != crc ) return -5;	
+	if ( checkchksum != crc ) return -5;
 	return (int)startIdx;
 }
 
@@ -785,8 +838,8 @@ int AWIDdemodFSK(uint8_t *dest, size_t *size)
 
 	uint8_t preamble[] = {0,0,0,0,0,0,0,1};
 	size_t startIdx = 0;
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -4; //preamble not found
 	if (*size != 96) return -5;
 	return (int)startIdx;
 }
@@ -804,11 +857,10 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
 	// FSK demodulator
 	*size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
 	if (*size < 128) return -2;  //did we get a good demod?
-
-	uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
 	size_t startIdx = 0;
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -4; //preamble not found
 	if (*size != 128) return -3;
 	return (int)startIdx;
 }
@@ -821,8 +873,21 @@ int NedapDemod(uint8_t *dest, size_t *size) {
 	size_t startIdx = 0;
 	//uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
 	uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
-	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-	if (errChk == 0) return -4; //preamble not found
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -4; //preamble not found
+	return (int) startIdx;
+}
+
+// Find IDTEC PSK1, RF  Preamble == 0x4944544B, Demodsize 64bits
+// by iceman
+int IdteckDemodPSK(uint8_t *dest, size_t *size) {
+	//make sure buffer has data
+	if (*size < 64*2) return -1;	
+	size_t startIdx = 0;
+	uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};
+	if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+		return -2; //preamble not found
+	if (*size != 64) return -3; // wrong demoded size
 	return (int) startIdx;
 }
 
@@ -848,13 +913,14 @@ uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t lo
 // by marshmellow
 // to help detect clocks on heavily clipped samples
 // based on count of low to low
-int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
+int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock)
 {
-	uint8_t fndClk[] = {8,16,32,40,50,64,128};
+	uint8_t clocks[] = {8,16,32,40,50,64,128};
 	size_t startwave;
 	size_t i = 100;
 	size_t minClk = 255;
-		// get to first full low to prime loop and skip incomplete first pulse
+	int shortestWaveIdx = 0;
+	// get to first full low to prime loop and skip incomplete first pulse
 	while ((dest[i] < high) && (i < size))
 		++i;
 	while ((dest[i] > low) && (i < size))
@@ -871,14 +937,18 @@ int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
 		while ((dest[i] > low) && (i < size))
 			++i;
 		//get minimum measured distance
-		if (i-startwave < minClk && i < size)
+		if (i-startwave < minClk && i < size) {
 			minClk = i - startwave;
+			shortestWaveIdx = startwave;
+		}
 	}
 	// set clock
 	if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
 	for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
-		if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
-			return fndClk[clkCnt];
+		if (minClk >= clocks[clkCnt]-(clocks[clkCnt]/8) && minClk <= clocks[clkCnt]+1) {
+			*clock = clocks[clkCnt];
+			return shortestWaveIdx;
+		}
 	}
 	return 0;
 }
@@ -889,15 +959,15 @@ int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
 // return start index of best starting position for that clock and return clock (by reference)
 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 {
-	size_t i=1;
+	size_t i = 1;
 	uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
 	uint8_t clkEnd = 9;
 	uint8_t loopCnt = 255;  //don't need to loop through entire array...
-	if (size <= loopCnt+60) return -1; //not enough samples
+	if (size <= loopCnt + 60) return -1; //not enough samples
 	size -= 60; //sometimes there is a strange end wave - filter out this....
 	//if we already have a valid clock
-	uint8_t clockFnd=0;
-	for (;i<clkEnd;++i)
+	uint8_t clockFnd = 0;
+	for (; i < clkEnd; ++i)
 		if (clk[i] == *clock) clockFnd = i;
 		//clock found but continue to find best startpos
 
@@ -908,15 +978,10 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 	//test for large clean peaks
 	if (!clockFnd){
 		if (DetectCleanAskWave(dest, size, peak, low)==1){
-			int ans = DetectStrongAskClock(dest, size, peak, low);
-			if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
-			for (i=clkEnd-1; i>0; i--){
-				if (clk[i] == ans) {
-					*clock = ans;
-					//clockFnd = i;
-					return 0;  // for strong waves i don't use the 'best start position' yet...
-					//break; //clock found but continue to find best startpos [not yet]
-				}
+			int ans = DetectStrongAskClock(dest, size, peak, low, clock);
+			if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i", clock ,ans);
+			if (ans > 0){
+					return ans;  // return shortest wave start pos
 			}
 		}
 	}
@@ -927,27 +992,31 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 	size_t errCnt = 0;
 	size_t arrLoc, loopEnd;
 
-	if (clockFnd>0) {
+	if (clockFnd > 0) {
 		clkCnt = clockFnd;
 		clkEnd = clockFnd+1;
+	} else {
+		clkCnt = 1;
 	}
-	else clkCnt=1;
 
 	//test each valid clock from smallest to greatest to see which lines up
-	for(; clkCnt < clkEnd; clkCnt++){
-		if (clk[clkCnt] <= 32){
+	for (; clkCnt < clkEnd; clkCnt++) {
+		if (clk[clkCnt] <= 32) {
 			tol=1;
-		}else{
+		} else {
 			tol=0;
 		}
 		//if no errors allowed - keep start within the first clock
-		if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
-		bestErr[clkCnt]=1000;
+		if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) 
+			loopCnt = clk[clkCnt] * 2;
+
+		bestErr[clkCnt] = 1000;
+
 		//try lining up the peaks by moving starting point (try first few clocks)
 		for (ii=0; ii < loopCnt; ii++){
 			if (dest[ii] < peak && dest[ii] > low) continue;
 
-			errCnt=0;
+			errCnt = 0;
 			// now that we have the first one lined up test rest of wave array
 			loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
 			for (i=0; i < loopEnd; ++i){
@@ -961,60 +1030,67 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 			}
 			//if we found no errors then we can stop here and a low clock (common clocks)
 			//  this is correct one - return this clock
-			if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
-			if(errCnt==0 && clkCnt<7) { 
+			if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
+			if (errCnt==0 && clkCnt<7) { 
 				if (!clockFnd) *clock = clk[clkCnt];
 				return ii;
 			}
 			//if we found errors see if it is lowest so far and save it as best run
-			if(errCnt<bestErr[clkCnt]){
-				bestErr[clkCnt]=errCnt;
-				bestStart[clkCnt]=ii;
+			if (errCnt < bestErr[clkCnt]) {
+				bestErr[clkCnt] = errCnt;
+				bestStart[clkCnt] = ii;
 			}
 		}
 	}
-	uint8_t iii;
-	uint8_t best=0;
-	for (iii=1; iii<clkEnd; ++iii){
-		if (bestErr[iii] < bestErr[best]){
-			if (bestErr[iii] == 0) bestErr[iii]=1;
+	uint8_t k;
+	uint8_t best = 0;
+	for (k=1; k < clkEnd; ++k){
+		if (bestErr[k] < bestErr[best]){
+			if (bestErr[k] == 0) bestErr[k]=1;
 			// current best bit to error ratio     vs  new bit to error ratio
-			if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
-				best = iii;
+			if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
+				best = k;
 			}
 		}
-		if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]);
+		if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d", clk[k], bestErr[k], clk[best], bestStart[best]);
 	}
 	if (!clockFnd) *clock = clk[best];
+	
 	return bestStart[best];
 }
 
+int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
+	int firstPhaseShift = 0;
+	return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
+}
+
 //by marshmellow
 //detect psk clock by reading each phase shift
 // a phase shift is determined by measuring the sample length of each wave
-int DetectPSKClock(uint8_t dest[], size_t size, int clock)
-{
-	uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
+int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
+	uint8_t clk[] = {255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
 	uint16_t loopCnt = 4096;  //don't need to loop through entire array...
-	if (size == 0) return 0;
-	if (size<loopCnt) loopCnt = size-20;
 
 	//if we already have a valid clock quit
 	size_t i=1;
 	for (; i < 8; ++i)
 		if (clk[i] == clock) return clock;
 
+	if (size < 160+20) return 0;
+	// size must be larger than 20 here, and 160 later on.
+	if (size < loopCnt) loopCnt = size-20;	
+
 	size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
 	uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
 	uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
-	uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
-	uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
+	uint16_t bestErr[] = {1000,1000,1000,1000,1000,1000,1000,1000,1000};
+	uint16_t peaksdet[] = {0,0,0,0,0,0,0,0,0};
 	fc = countFC(dest, size, 0);
 	if (fc!=2 && fc!=4 && fc!=8) return -1;
 	if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
 
 	//find first full wave
-	for (i=160; i<loopCnt; i++){
+	for (i=160; i < loopCnt; i++){
 		if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
 			if (waveStart == 0) {
 				waveStart = i+1;
@@ -1032,10 +1108,11 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 			}
 		}
 	}
-	if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
+	*firstPhaseShift = firstFullWave;
+	if (g_debugMode == 2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
 	
 	//test each valid clock from greatest to smallest to see which lines up
-	for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
+	for (clkCnt=7; clkCnt >= 1 ; clkCnt--){
 		lastClkBit = firstFullWave; //set end of wave as clock align
 		waveStart = 0;
 		errCnt=0;
@@ -1069,19 +1146,17 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 				}
 			}
 		}
-		if (errCnt == 0){
-			return clk[clkCnt];
-		}
-		if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
-		if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
+		if (errCnt == 0) return clk[clkCnt];
+		if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt] = errCnt;
+		if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt] = peakcnt;
 	} 
 	//all tested with errors 
 	//return the highest clk with the most peaks found
-	uint8_t best=7;
-	for (i=7; i>=1; i--){
-		if (peaksdet[i] > peaksdet[best]) {
+	uint8_t best = 7;
+	for (i=7; i >= 1; i--){
+		if (peaksdet[i] > peaksdet[best])
 			best = i;
-		}
+
 		if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
 	}
 	return clk[best];
@@ -1116,18 +1191,25 @@ int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
 	return lowestTransition;
 }
 
+int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
+	int bestStart = 0;
+	return DetectNRZClock_ext(dest, size, clock, &bestStart);
+}
+
 //by marshmellow
 //detect nrz clock by reading #peaks vs no peaks(or errors)
-int DetectNRZClock(uint8_t dest[], size_t size, int clock)
-{
-	size_t i=0;
-	uint8_t clk[]={8,16,32,40,50,64,100,128,255};
+int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, int *clockStartIdx) {
+	size_t i = 0;
+	uint8_t clk[] = {8,16,32,40,50,64,100,128,255};
 	size_t loopCnt = 4096;  //don't need to loop through entire array...
-	if (size == 0) return 0;
-	if (size<loopCnt) loopCnt = size-20;
+
 	//if we already have a valid clock quit
 	for (; i < 8; ++i)
 		if (clk[i] == clock) return clock;
+	
+	if (size < 20) return 0;
+	// size must be larger than 20 here
+	if (size < loopCnt) loopCnt = size-20;
 
 	//get high and low peak
 	int peak, low;
@@ -1148,7 +1230,7 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 			if (!firstpeak) continue;
 			smplCnt++;
 		} else {
-			firstpeak=true;
+			firstpeak = true;
 			if (smplCnt > 6 ){
 				if (maxPeak > smplCnt){
 					maxPeak = smplCnt;
@@ -1156,7 +1238,7 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 				}
 				peakcnt++;
 				//prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
-				smplCnt=0;
+				smplCnt = 0;
 			}
 		}
 	}
@@ -1166,7 +1248,8 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 	uint8_t ignoreWindow = 4;
 	bool lastPeakHigh = 0;
 	int lastBit = 0; 
-	peakcnt=0;
+	int bestStart[] = {0,0,0,0,0,0,0,0,0};
+	peakcnt = 0;
 	//test each valid clock from smallest to greatest to see which lines up
 	for(clkCnt=0; clkCnt < 8; ++clkCnt){
 		//ignore clocks smaller than smallest peak
@@ -1186,7 +1269,7 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 						if (dest[i] >= peak || dest[i] <= low) {
 							//if same peak don't count it
 							if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
-						peakcnt++;
+								peakcnt++;
 							}
 							lastPeakHigh = (dest[i] >= peak);
 							bitHigh = true;
@@ -1198,9 +1281,10 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 						}
 					//else if not a clock bit and no peaks
 					} else if (dest[i] < peak && dest[i] > low){
-						if (ignoreCnt==0){
+						if (ignoreCnt == 0){
 							bitHigh=false;
-							if (errBitHigh==true) peakcnt--;
+							if (errBitHigh==true) 
+								peakcnt--;
 							errBitHigh=false;
 						} else {
 							ignoreCnt--;
@@ -1211,61 +1295,58 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 						errBitHigh=true;
 					}
 				}
-				if(peakcnt>peaksdet[clkCnt]) {
-					peaksdet[clkCnt]=peakcnt;
+				if (peakcnt > peaksdet[clkCnt]) {
+					bestStart[clkCnt]=ii;
+					peaksdet[clkCnt] = peakcnt;
 				}
 			}
 		}
 	}
-	int iii=7;
-	uint8_t best=0;
-	for (iii=7; iii > 0; iii--){
-		if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
-			if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
-			best = iii;
-		}
-		} else if (peaksdet[iii] > peaksdet[best]){
-			best = iii;
+
+	uint8_t best = 0;
+	for (int m = 7; m > 0; m--){
+		if ((peaksdet[m] >= (peaksdet[best]-1)) && (peaksdet[m] <= peaksdet[best]+1) && lowestTransition) {
+			if (clk[m] > (lowestTransition - (clk[m]/8)) && clk[m] < (lowestTransition + (clk[m]/8))) {
+				best = m;
+			}
+		} else if (peaksdet[m] > peaksdet[best]){
+			best = m;
 		}
-		if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
+		if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d", clk[m], peaksdet[m], maxPeak, clk[best], lowestTransition);
 	}
-
+	*clockStartIdx	= bestStart[best];
 	return clk[best];
 }
 
 // by marshmellow
 // convert psk1 demod to psk2 demod
 // only transition waves are 1s
-void psk1TOpsk2(uint8_t *BitStream, size_t size)
-{
-	size_t i=1;
-	uint8_t lastBit=BitStream[0];
-	for (; i<size; i++){
-		if (BitStream[i]==7){
-			//ignore errors
-		} else if (lastBit!=BitStream[i]){
-			lastBit=BitStream[i];
-			BitStream[i]=1;
+void psk1TOpsk2(uint8_t *bits, size_t size) {
+	uint8_t lastBit = bits[0];
+	for (size_t i = 1; i < size; i++){
+		//ignore errors		
+		if (bits[i] == 7) continue;
+			
+		if (lastBit != bits[i]){
+			lastBit = bits[i];
+			bits[i] = 1;
 		} else {
-			BitStream[i]=0;
+			bits[i] = 0;
 		}
 	}
-	return;
 }
 
 // by marshmellow
 // convert psk2 demod to psk1 demod
 // from only transition waves are 1s to phase shifts change bit
-void psk2TOpsk1(uint8_t *BitStream, size_t size)
-{
-	uint8_t phase=0;
-	for (size_t i=0; i<size; i++){
-		if (BitStream[i]==1){
-			phase ^=1;
+void psk2TOpsk1(uint8_t *bits, size_t size) {
+	uint8_t phase = 0;
+	for (size_t i = 0; i < size; i++){
+		if (bits[i] == 1){
+			phase ^= 1;
 		}
-		BitStream[i]=phase;
+		bits[i] = phase;
 	}
-	return;
 }
 
 // redesigned by marshmellow adjusted from existing decode functions
@@ -1322,10 +1403,14 @@ int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
 	return 0;
 }
 
+uint8_t	detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
+	int firstClockEdge = 0;
+	return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
+}
+
 //by marshmellow
 //detects the bit clock for FSK given the high and low Field Clocks
-uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
-{
+uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
 	uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
 	uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
 	uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
@@ -1342,7 +1427,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 	fcCounter=0;
 	rfCounter=0;
 	firstBitFnd=0;
-	//PrintAndLog("DEBUG: fcTol: %d",fcTol);
+	//prnt("DEBUG: fcTol: %d",fcTol);
 	// prime i to first peak / up transition
 	for (i = 160; i < size-20; i++)
 		if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
@@ -1356,7 +1441,10 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 			continue;		
 		// else new peak 
 		// if we got less than the small fc + tolerance then set it to the small fc
-		if (fcCounter < fcLow+fcTol) 
+		// if it is inbetween set it to the last counter
+		if (fcCounter < fcHigh && fcCounter > fcLow)
+			fcCounter = lastFCcnt;
+		else if (fcCounter < fcLow+fcTol) 
 			fcCounter = fcLow;
 		else //set it to the large fc
 			fcCounter = fcHigh;
@@ -1373,11 +1461,12 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 					}
 				}
 				if (rfCounter > 0 && rfLensFnd < 15){
-					//PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+					//prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
 					rfCnts[rfLensFnd]++;
 					rfLens[rfLensFnd++] = rfCounter;
 				}
 			} else {
+				*firstClockEdge = i;
 				firstBitFnd++;
 			}
 			rfCounter=0;
@@ -1422,7 +1511,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 		}
 	}
 
-	if (ii<0) return 0; // oops we went too far
+	if (ii<2) return 0; // oops we went too far
 
 	return clk[ii];
 }
@@ -1436,10 +1525,10 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 	uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
 	uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
 	uint8_t fcLensFnd = 0;
-	uint8_t lastFCcnt=0;
+	uint8_t lastFCcnt = 0;
 	uint8_t fcCounter = 0;
 	size_t i;
-	if (size == 0) return 0;
+	if (size < 180) return 0;
 
 	// prime i to first up transition
 	for (i = 160; i < size-20; i++)
@@ -1526,27 +1615,37 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 
 	size_t numBits=0;
 	uint8_t curPhase = *invert;
-	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 = countFC(dest, *size, 0);
+	size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
+	uint16_t fc=0, fullWaveLen=0, tol=1;
+	uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
+	fc = countFC(dest, *size, 1);
+	uint8_t fc2 = fc >> 8;
+	if (fc2 == 10) return -1; //fsk found - quit
+	fc = fc & 0xFF;
 	if (fc!=2 && fc!=4 && fc!=8) return -1;
-	//PrintAndLog("DEBUG: FC: %d",fc);
+	//prnt("DEBUG: FC: %d",fc);
 	*clock = DetectPSKClock(dest, *size, *clock);
 	if (*clock == 0) return -1;
-	int avgWaveVal=0, lastAvgWaveVal=0;
+
+	//find start of modulating data in trace 
+	uint8_t threshold_value = 123; //-5
+	i = findModStart(dest, *size, threshold_value, fc);
+
 	//find first phase shift
-	for (i=0; i<loopCnt; i++){
+	int avgWaveVal=0, lastAvgWaveVal=0;
+	waveStart = i;
+	for (; i<loopCnt; i++){
+		// find peak 
 		if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
 			waveEnd = i+1;
-			//PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
+			if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
 			waveLenCnt = waveEnd-waveStart;
-			if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
+			if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
 				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
+				//if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
+				if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
 				break;
 			} 
 			waveStart = i+1;
@@ -1567,7 +1666,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 	//set start of wave as clock align
 	lastClkBit = firstFullWave;
 	if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);  
-	if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
+	if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
 	waveStart = 0;
 	dest[numBits++] = curPhase; //set first read bit
 	for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
@@ -1582,9 +1681,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 				waveLenCnt = waveEnd-waveStart;
 				lastAvgWaveVal = avgWaveVal/waveLenCnt;
 				if (waveLenCnt > fc){  
-					//PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
+					//prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
 					//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);
+					//prnt("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;
@@ -1598,6 +1697,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 				} else if (i+1 > lastClkBit + *clock + tol + fc){
 					lastClkBit += *clock; //no phase shift but clock bit
 					dest[numBits++] = curPhase;
+				} else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
+					errCnt2++;
+					if(errCnt2 > 101) return errCnt2;
 				}
 				avgWaveVal = 0;
 				waveStart = i+1;
@@ -1609,9 +1711,14 @@ 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};
@@ -1619,13 +1726,15 @@ 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;
 	memset(tmpbuff, 0, sizeof(tmpbuff));
+	memset(waveLen, 0, sizeof(waveLen));
 
+	
 	if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
 		if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
 		return false; //just noise
@@ -1652,7 +1761,7 @@ 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
@@ -1698,6 +1807,8 @@ 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;
@@ -1711,7 +1822,7 @@ 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
@@ -1733,12 +1844,15 @@ 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) {
@@ -1746,8 +1860,20 @@ 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);		
+	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)
@@ -1755,6 +1881,15 @@ 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) {
@@ -1766,6 +1901,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
 		}
 		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;