X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/db8296025f78251ffa2c28d6fe995bbb0a386c77..refs/pull/166/head:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 063c8a74..7398f1b2 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -9,8 +9,22 @@
 //-----------------------------------------------------------------------------
 
 #include <stdlib.h>
-#include <string.h>
 #include "lfdemod.h"
+#include <string.h>
+
+//to allow debug print calls when used not on device
+void dummy(char *fmt, ...){}
+
+#ifndef ON_DEVICE
+#include "ui.h"
+#include "cmdparser.h"
+#include "cmddata.h"
+#define prnt PrintAndLog
+#else 
+	uint8_t g_debugMode=0;
+#define prnt dummy
+#endif
+
 uint8_t justNoise(uint8_t *BitStream, size_t size)
 {
 	static const uint8_t THRESHOLD = 123;
@@ -52,6 +66,81 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
 	return (ans == pType);
 }
 
+// by marshmellow
+// takes a array of binary values, start position, length of bits per parity (includes parity bit),
+//   Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) 
+size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
+{
+	uint32_t parityWd = 0;
+	size_t j = 0, bitCnt = 0;
+	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]);
+		}
+		j--; // overwrite parity with next data
+		// if parity fails then return 0
+		if (pType == 2) { // then marker bit which should be a 1
+			if (!BitStream[j]) return 0;
+		} else {
+			if (parityTest(parityWd, pLen, pType) == 0) return 0;			
+		}
+		bitCnt+=(pLen-1);
+		parityWd = 0;
+	}
+	// if we got here then all the parities passed
+	//return ID start index and size
+	return bitCnt;
+}
+
+// by marshmellow
+// takes a array of binary values, length of bits per parity (includes parity bit),
+//   Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run)
+size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
+{
+	uint32_t parityWd = 0;
+	size_t j = 0, bitCnt = 0;
+	for (int word = 0; word < sourceLen; word+=pLen-1) {
+		for (int bit=0; bit < pLen-1; bit++){
+			parityWd = (parityWd << 1) | BitSource[word+bit];
+			dest[j++] = (BitSource[word+bit]);
+		}
+		// if parity fails then return 0
+		if (pType == 2) { // then marker bit which should be a 1
+			dest[j++]=1;
+		} else {
+			dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
+		}
+		bitCnt += pLen;
+		parityWd = 0;
+	}
+	// if we got here then all the parities passed
+	//return ID start index and size
+	return bitCnt;
+}
+
+uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
+{
+	uint32_t num = 0;
+	for(int i = 0 ; i < numbits ; i++)
+	{
+		num = (num << 1) | (*src);
+		src++;
+	}
+	return num;
+}
+
+//least significant bit first
+uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
+{
+	uint32_t num = 0;
+	for(int i = 0 ; i < numbits ; i++)
+	{
+		num = (num << 1) | *(src + (numbits-(i+1)));
+	}
+	return num;
+}
+
 //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)
@@ -128,6 +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;
@@ -184,6 +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 ASK: clk %d, beststart %d", *clk, start);
 
 	uint8_t initLoopMax = 255;
 	if (initLoopMax > *size) initLoopMax = *size;
@@ -196,19 +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 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 = 1024;
+	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) {
@@ -219,6 +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++;						
 				} 
@@ -385,15 +479,15 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 	// sync to first lo-hi transition, and threshold
 
 	// Need to threshold first sample
-
-	if(dest[0] < threshold_value) dest[0] = 0;
+	// skip 160 samples to allow antenna/samples to settle
+	if(dest[160] < threshold_value) dest[0] = 0;
 	else dest[0] = 1;
 
 	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 with anywhere
+	// 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
-	for(idx = 1; idx < size; idx++) {
+	for(idx = 161; idx < size-20; idx++) {
 		// threshold current value
 
 		if (dest[idx] < threshold_value) dest[idx] = 0;
@@ -404,11 +498,11 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 			preLastSample = LastSample;
 			LastSample = currSample;
 			currSample = idx-last_transition;
-			if (currSample < (fclow-2)){            //0-5 = garbage noise
+			if (currSample < (fclow-2)){            //0-5 = garbage noise (or 0-3)
 				//do nothing with extra garbage
-			} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves
+			} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves  or 3-6 = 5
 				if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample	== 0 )){
-					dest[numBits-1]=1;  //correct last 9 wave surrounded by 8 waves
+					dest[numBits-1]=1;  //correct previous 9 wave surrounded by 8 waves
 				}
 				dest[numBits++]=1;
 
@@ -439,23 +533,8 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
 		
 		//if lastval was 1, we have a 1->0 crossing
 		if (dest[idx-1]==1) {
-			if (!numBits) {
-				if (n < rfLen/fclow) {
-					n=0;
-					lastval = dest[idx];
-					continue;
-				}
-				n = (n * fclow + rfLen/4) / rfLen;
-			} else {
-				n = (n * fclow + rfLen/2) / rfLen;
-			}
+			n = (n * fclow + rfLen/2) / rfLen;
 		} else {// 0->1 crossing 
-			//test first bitsample too small
-			if (!numBits && n < rfLen/fchigh) {
-				n=0;
-				lastval = dest[idx];
-				continue;
-			}
 			n = (n * fchigh + rfLen/2) / rfLen; 
 		}
 		if (n == 0) n = 1;
@@ -477,6 +556,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
 	}
 	return numBits;
 }
+
 //by marshmellow  (from holiman's base)
 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
@@ -551,28 +631,6 @@ int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, ui
 	return (int)startIdx;
 }
 
-uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
-{
-	uint32_t num = 0;
-	for(int i = 0 ; i < numbits ; i++)
-	{
-		num = (num << 1) | (*src);
-		src++;
-	}
-	return num;
-}
-
-//least significant bit first
-uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
-{
-	uint32_t num = 0;
-	for(int i = 0 ; i < numbits ; i++)
-	{
-		num = (num << 1) | *(src + (numbits-(i+1)));
-	}
-	return num;
-}
-
 int IOdemodFSK(uint8_t *dest, size_t size)
 {
 	if (justNoise(dest, size)) return -1;
@@ -622,33 +680,6 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
 	return (int) startIdx;
 }
 
-// by marshmellow
-// takes a array of binary values, start position, length of bits per parity (includes parity bit),
-//   Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) 
-size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
-{
-	uint32_t parityWd = 0;
-	size_t j = 0, bitCnt = 0;
-	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]);
-		}
-		j--; // overwrite parity with next data
-		// if parity fails then return 0
-		if (pType == 2) { // then marker bit which should be a 1
-			if (!BitStream[j]) return 0;
-		} else {
-			if (parityTest(parityWd, pLen, pType) == 0) return 0;			
-		}
-		bitCnt+=(pLen-1);
-		parityWd = 0;
-	}
-	// if we got here then all the parities passed
-	//return ID start index and size
-	return bitCnt;
-}
-
 // 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)
@@ -686,7 +717,7 @@ int AWIDdemodFSK(uint8_t *dest, size_t *size)
 }
 
 // by marshmellow
-// FSK Demod then try to locate an Farpointe Data (pyramid) ID
+// FSK Demod then try to locate a Farpointe Data (pyramid) ID
 int PyramiddemodFSK(uint8_t *dest, size_t *size)
 {
 	//make sure buffer has data
@@ -707,35 +738,24 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
 	return (int)startIdx;
 }
 
-/*
-void dummy(char *fmt, ...){}
-
-#ifndef ON_DEVICE
-#include "ui.h"
-#define prnt PrintAndLog
-#else 
-
-#define prnt dummy
-#endif
-*/
 // by marshmellow
 // to detect a wave that has heavily clipped (clean) samples
 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
 {
-	uint16_t allPeaks=1;
+	bool allArePeaks = true;
 	uint16_t cntPeaks=0;
 	size_t loopEnd = 512+160;
 	if (loopEnd > size) loopEnd = size;
 	for (size_t i=160; i<loopEnd; i++){
 		if (dest[i]>low && dest[i]<high) 
-			allPeaks=0;
+			allArePeaks = false;
 		else
 			cntPeaks++;
 	}
-	if (allPeaks == 0){
-		if (cntPeaks > 300) return 1;
+	if (!allArePeaks){
+		if (cntPeaks > 300) return true;
 	}
-	return allPeaks;
+	return allArePeaks;
 }
 // by marshmellow
 // to help detect clocks on heavily clipped samples
@@ -767,7 +787,7 @@ int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
 			minClk = i - startwave;
 	}
 	// set clock
-	//prnt("minClk: %d",minClk);
+	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];
@@ -801,6 +821,7 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 	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;
@@ -852,7 +873,7 @@ 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
-					//prnt("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i);
+			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;
@@ -874,8 +895,8 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 				best = iii;
 			}
 		}
+		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 (bestErr[best] > maxErr) return -1;
 	if (!clockFnd) *clock = clk[best];
 	return bestStart[best];
 }
@@ -902,7 +923,7 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 	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;
-	//prnt("DEBUG: FC: %d",fc);
+	if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
 
 	//find first full wave
 	for (i=160; i<loopCnt; i++){
@@ -923,7 +944,7 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 			}
 		}
 	}
-	//prnt("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
+	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--){
@@ -931,7 +952,7 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 		waveStart = 0;
 		errCnt=0;
 		peakcnt=0;
-		//prnt("DEBUG: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
+		if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
 
 		for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
 			//top edge of wave = start of new wave 
@@ -944,7 +965,7 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 					waveLenCnt = waveEnd-waveStart;
 					if (waveLenCnt > fc){ 
 						//if this wave is a phase shift
-						//prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+1,fc);
+						if (g_debugMode == 2) prnt("DEBUG PSK: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,i+1,fc);
 						if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
 							peakcnt++;
 							lastClkBit+=clk[clkCnt];
@@ -973,7 +994,7 @@ int DetectPSKClock(uint8_t dest[], size_t size, int clock)
 		if (peaksdet[i] > peaksdet[best]) {
 			best = i;
 		}
-		//prnt("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
+		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];
 }
@@ -983,26 +1004,15 @@ int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
 	size_t i = 0;
 	size_t transition1 = 0;
 	int lowestTransition = 255;
-	uint8_t lastWasHigh=0;
-	//find first valid beginning of a high/low wave
-	if (dest[i] >= peak) {
-		for (; i < size; i++) {
-			if (dest[i] <= low) break;
-		}
-		lastWasHigh=0;
-	} else if (dest[i] <= low) {
-		for (; i < size; i++) {
-			if (dest[i] >= peak) break;
-		}
-		lastWasHigh=1;	
-	} else {
-		for (; i < size; i++) {
-			if (dest[i] >= peak || dest[i] <= low) {
-				lastWasHigh = (dest[i] >= peak);
-				break;
-			}
-		}
-	}
+	bool lastWasHigh = false;
+
+	//find first valid beginning of a high or low wave
+	while ((dest[i] >= peak || dest[i] <= low) && (i < size))
+		++i;
+	while ((dest[i] < peak && dest[i] > low) && (i < size))
+		++i;
+	lastWasHigh = (dest[i] >= peak);
+
 	if (i==size) return 0;
 	transition1 = i;
 
@@ -1014,6 +1024,7 @@ int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
 		}
 	}
 	if (lowestTransition == 255) lowestTransition = 0;
+	if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
 	return lowestTransition;
 }
 
@@ -1035,7 +1046,6 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 	if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
 
 	int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
-	//prnt("DEBUG: peak: %d, low: %d",peak,low);
 	size_t ii;
 	uint8_t clkCnt;
 	uint8_t tol = 0;
@@ -1043,14 +1053,14 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 	int16_t peakcnt = 0;
 	int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
 	uint16_t maxPeak = 255;
-	uint8_t firstpeak = 0;
+	bool firstpeak = false;
 	//test for large clipped waves
 	for (i=0; i<loopCnt; i++){
 		if (dest[i] >= peak || dest[i] <= low){
 			if (!firstpeak) continue;
 			smplCnt++;
 		} else {
-			firstpeak=1;
+			firstpeak=true;
 			if (smplCnt > 6 ){
 				if (maxPeak > smplCnt){
 					maxPeak = smplCnt;
@@ -1062,8 +1072,12 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 			}
 		}
 	}
-	uint8_t samePeak=0;
-	uint8_t	errBitHigh=0;
+	bool errBitHigh = 0;
+	bool bitHigh = 0;
+	uint8_t ignoreCnt = 0;
+	uint8_t ignoreWindow = 4;
+	bool lastPeakHigh = 0;
+	int lastBit = 0; 
 	peakcnt=0;
 	//test each valid clock from smallest to greatest to see which lines up
 	for(clkCnt=0; clkCnt < 8; ++clkCnt){
@@ -1072,42 +1086,41 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 		//try lining up the peaks by moving starting point (try first 256)
 		for (ii=20; ii < loopCnt; ++ii){
 			if ((dest[ii] >= peak) || (dest[ii] <= low)){
-				peakcnt=0;
-				uint8_t bitHigh =0;
-				uint8_t ignoreCnt = 0;
-				uint8_t ignoreWindow = 4;
-				int lastBit = ii-clk[clkCnt]; 
+				peakcnt = 0;
+				bitHigh = false;
+				ignoreCnt = 0;
+				lastBit = ii-clk[clkCnt]; 
 				//loop through to see if this start location works
 				for (i = ii; i < size-20; ++i) {
-					// if we are at a clock bit
+					//if we are at a clock bit
 					if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
 						//test high/low
 						if (dest[i] >= peak || dest[i] <= low) {
-							if (samePeak) peakcnt--;
-							bitHigh=1;
-							peakcnt++;
-							errBitHigh = 0;
+							//if same peak don't count it
+							if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
+								peakcnt++;
+							}
+							lastPeakHigh = (dest[i] >= peak);
+							bitHigh = true;
+							errBitHigh = false;
 							ignoreCnt = ignoreWindow;
 							lastBit += clk[clkCnt];
-							samePeak = 1;
 						} else if (i == lastBit + clk[clkCnt] + tol) {
 							lastBit += clk[clkCnt];
-							samePeak = 0;
 						}
 					//else if not a clock bit and no peaks
 					} else if (dest[i] < peak && dest[i] > low){
-						samePeak = 0;
 						if (ignoreCnt==0){
-							bitHigh=0;
-							if (errBitHigh==1) peakcnt--;
-							errBitHigh=0;
+							bitHigh=false;
+							if (errBitHigh==true) peakcnt--;
+							errBitHigh=false;
 						} else {
 							ignoreCnt--;
 						}
 						// else if not a clock bit but we have a peak
-					} else if ((dest[i]>=peak || dest[i]<=low) && (bitHigh==0)) {
+					} else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
 						//error bar found no clock...
-						errBitHigh=1;
+						errBitHigh=true;
 					}
 				}
 				if(peakcnt>peaksdet[clkCnt]) {
@@ -1119,14 +1132,14 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 	int iii=7;
 	uint8_t best=0;
 	for (iii=7; iii > 0; iii--){
-		if (peaksdet[iii] > peaksdet[best]){
-			best = iii;
-		} else if (peaksdet[iii] == peaksdet[best] && lowestTransition){
-			if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))){
+		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;
 		}
-		//prnt("DEBUG: 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[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
 	}
 
 	return clk[best];
@@ -1188,7 +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;
@@ -1236,18 +1249,18 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 	size_t i;
 	if (size == 0) return 0;
 
-	uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+	uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
 	rfLensFnd=0;
 	fcCounter=0;
 	rfCounter=0;
 	firstBitFnd=0;
 	//PrintAndLog("DEBUG: fcTol: %d",fcTol);
-	// prime i to first up transition
-	for (i = 1; i < size-1; i++)
+	// 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])
 			break;
 
-	for (; i < size-1; i++){
+	for (; i < size-20; i++){
 		fcCounter++;
 		rfCounter++;
 
@@ -1265,7 +1278,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 			//not the same size as the last wave - start of new bit sequence
 			if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
 				for (int ii=0; ii<15; ii++){
-					if (rfLens[ii] == rfCounter){
+					if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
 						rfCnts[ii]++;
 						rfCounter = 0;
 						break;
@@ -1287,7 +1300,6 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 	uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
 
 	for (i=0; i<15; i++){
-		//PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
 		//get highest 2 RF values  (might need to get more values to compare or compare all?)
 		if (rfCnts[i]>rfCnts[rfHighest]){
 			rfHighest3=rfHighest2;
@@ -1299,20 +1311,23 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 		} else if(rfCnts[i]>rfCnts[rfHighest3]){
 			rfHighest3=i;
 		}
+		if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
 	}  
 	// set allowed clock remainder tolerance to be 1 large field clock length+1 
 	//   we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off  
 	uint8_t tol1 = fcHigh+1; 
 	
-	//PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
+	if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
 
 	// loop to find the highest clock that has a remainder less than the tolerance
 	//   compare samples counted divided by
+	// test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
 	int ii=7;
-	for (; ii>=0; ii--){
+	for (; ii>=2; ii--){
 		if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
 			if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
 				if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
+					if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
 					break;
 				}
 			}
@@ -1330,8 +1345,8 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
 //mainly used for FSK field clock detection
 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};
-	uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
+	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 fcCounter = 0;
@@ -1339,11 +1354,11 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 	if (size == 0) return 0;
 
 	// prime i to first up transition
-	for (i = 1; i < size-1; i++)
+	for (i = 160; i < size-20; i++)
 		if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
 			break;
 
-	for (; i < size-1; i++){
+	for (; i < size-20; i++){
 		if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
 			// new up transition
 			fcCounter++;
@@ -1356,14 +1371,14 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 			lastFCcnt = fcCounter;
 			}
 			// find which fcLens to save it to:
-			for (int ii=0; ii<10; ii++){
+			for (int ii=0; ii<15; ii++){
 				if (fcLens[ii]==fcCounter){
 					fcCnts[ii]++;
 					fcCounter=0;
 					break;
 				}
 			}
-			if (fcCounter>0 && fcLensFnd<10){
+			if (fcCounter>0 && fcLensFnd<15){
 				//add new fc length 
 				fcCnts[fcLensFnd]++;
 				fcLens[fcLensFnd++]=fcCounter;
@@ -1375,11 +1390,10 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 		}
 	}
 	
-	uint8_t best1=9, best2=9, best3=9;
+	uint8_t best1=14, best2=14, best3=14;
 	uint16_t maxCnt1=0;
 	// go through fclens and find which ones are bigest 2  
-	for (i=0; i<10; i++){
-		// PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);    
+	for (i=0; i<15; i++){
 		// get the 3 best FC values
 		if (fcCnts[i]>maxCnt1) {
 			best3=best2;
@@ -1392,7 +1406,9 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 		} else if(fcCnts[i]>fcCnts[best3]){
 			best3=i;
 		}
+		if (g_debugMode==2) prnt("DEBUG countfc: FC %u, Cnt %u, best fc: %u, best2 fc: %u",fcLens[i],fcCnts[i],fcLens[best1],fcLens[best2]);
 	}
+	if (fcLens[best1]==0) return 0;
 	uint8_t fcH=0, fcL=0;
 	if (fcLens[best1]>fcLens[best2]){
 		fcH=fcLens[best1];
@@ -1401,11 +1417,13 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
 		fcH=fcLens[best2];
 		fcL=fcLens[best1];
 	}
-
+	if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
+		if (g_debugMode==2) prnt("DEBUG countfc: fc is too large: %u > %u. Not psk or fsk",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]);
+		return 0; //lots of waves not psk or fsk
+	}
 	// TODO: take top 3 answers and compare to known Field clocks to get top 2
 
 	uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
-	// PrintAndLog("DEBUG: Best %d  best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
 	if (fskAdj) return fcs;	
 	return fcLens[best1];
 }
@@ -1502,3 +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;
+}