X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/f44a01235cab467edd375bec109e57e4076157cd..0f7279b22d72bed2bc2533d9aa3b9c1bc1ccf9ae:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 25e52552..49c5877e 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -5,588 +5,651 @@
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------
-// Low frequency commands
+// Low frequency demod/decode commands
 //-----------------------------------------------------------------------------
 
 #include <stdlib.h>
-#include <string.h>
 #include "lfdemod.h"
+#include <string.h>
+
+//un_comment 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
+
+//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++)
+		val = bits[idx] < THRESHOLD;
+	return val;
+}
+
+//by marshmellow
+//get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
+int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
+{
+	*high=0;
+	*low=255;
+	// get high and low thresholds 
+	for (size_t i=0; i < size; i++){
+		if (BitStream[i] > *high) *high = BitStream[i];
+		if (BitStream[i] < *low) *low = BitStream[i];
+	}
+	if (*high < 123) return -1; // just noise
+	*high = ((*high-128)*fuzzHi + 12800)/100;
+	*low = ((*low-128)*fuzzLo + 12800)/100;
+	return 1;
+}
+
+// by marshmellow
+// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
+// returns 1 if passed
+uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
+{
+	uint8_t ans = 0;
+	for (uint8_t i = 0; i < bitLen; i++){
+		ans ^= ((bits >> i) & 1);
+	}
+	//prnt("DEBUG: ans: %d, ptype: %d",ans,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 for Always 1's; 3 for Always 0'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
+		switch (pType) {
+			case 3:  if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
+			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);
+		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; 3 Always 0's), and binary Length (length to run)
+//   Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
+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
+		switch (pType) {
+			case 3: dest[j++]=0; break; // marker bit which should be a 0
+			case 2: dest[j++]=1; break; // marker bit which should be a 1
+			default: 
+				dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
+				break;
+		}
+		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)
+{
+	// Sanity check.  If preamble length is bigger than bitstream length.
+	if ( *size <= pLen ) return 0;
+	
+	uint8_t foundCnt = 0;
+	for (int idx = 0; idx < *size - pLen; idx++){
+		if (memcmp(BitStream+idx, preamble, pLen) == 0){
+			//first index found
+			foundCnt++;
+			if (foundCnt == 1){
+				*startIdx = idx;
+			}
+			if (foundCnt == 2){
+				*size = idx - *startIdx;
+				return 1;
+			}
+		}
+	}
+	return 0;
+}
 
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID
-uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
+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
-	int high=0, low=128;
-	uint64_t lo=0;
-
 	uint32_t i = 0;
-	uint32_t initLoopMax = 65;
-	if (initLoopMax>size) initLoopMax=size;
+	if (BitStream[1]>1) return -1;  //allow only 1s and 0s
 
-	for (;i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
-	{
-		if (BitStream[i] > high)
-			high = BitStream[i];
-		else if (BitStream[i] < low)
-			low = BitStream[i];
-	}
-	if (((high !=1)||(low !=0))){  //allow only 1s and 0s
-		// PrintAndLog("no data found");
-		return 0;
-	}
-	uint8_t parityTest=0;
 	// 111111111 bit pattern represent start of frame
-	uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
+	//  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 ii=0;
-	uint8_t resetCnt = 0;
-	while( (idx + 64) < size) {
- restart:
-		// search for a start of frame marker
-		if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
-		{ // frame marker found
-			idx+=9;
-			for (i=0; i<10;i++){
-				for(ii=0; ii<5; ++ii){
-					parityTest += BitStream[(i*5)+ii+idx];
-				}
-				if (parityTest== ((parityTest>>1)<<1)){
-					parityTest=0;
-					for (ii=0; ii<4;++ii){
-						lo=(lo<<1LL)|(BitStream[(i*5)+ii+idx]);
-					}
-					//PrintAndLog("DEBUG: EM parity passed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d,lo: %d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1],lo);
-				}else {//parity failed
-					//PrintAndLog("DEBUG: EM parity failed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1]);
-					parityTest=0;
-					idx-=8;
-					if (resetCnt>5)return 0;
-					resetCnt++;
-					goto restart;//continue;
-				}
-			}
-			//skip last 5 bit parity test for simplicity.
-			return lo;
-		}else{
-			idx++;
+	uint32_t parityBits = 0;
+	uint8_t errChk = 0;
+	uint8_t FmtLen = 10;
+	*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]);
 		}
 	}
+	if (errChk != 0) return 1;
+	//skip last 5 bit parity test for simplicity.
+	// *size = 64 | 128;
 	return 0;
 }
 
 //by marshmellow
-//takes 2 arguments - clock and invert both as integers
-//attempts to demodulate ask while decoding manchester
-//prints binary found and saves in graphbuffer for further commands
-int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
-{
-	int i;
-	int high = 0, low = 128;
-	*clk=DetectASKClock(BinStream, *size, *clk); //clock default
-
-	if (*clk<8) *clk =64;
-	if (*clk<32) *clk=32;
-	if (*invert != 0 && *invert != 1) *invert=0;
-	uint32_t initLoopMax = 200;
-	if (initLoopMax > *size) initLoopMax=*size;
-	// Detect high and lows
-	for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values
-	{
-		if (BinStream[i] > high)
-			high = BinStream[i];
-		else if (BinStream[i] < low)
-			low = BinStream[i];
-	}
-	if ((high < 158) ){  //throw away static
-		//PrintAndLog("no data found");
-		return -2;
-	}
-	//25% fuzz in case highs and lows aren't clipped [marshmellow]
-	high=(int)(((high-128)*.75)+128);
-	low= (int)(((low-128)*.75)+128);
-
-	//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-	int lastBit = 0;  //set first clock check
-	uint32_t bitnum = 0;     //output counter
-	int 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
-	int iii = 0;
-	uint32_t gLen = *size;
-	if (gLen > 3000) gLen=3000;
-	uint8_t errCnt =0;
-	uint32_t bestStart = *size;
-	uint32_t bestErrCnt = (*size/1000);
-	uint32_t maxErr = (*size/1000);
-	//PrintAndLog("DEBUG - lastbit - %d",lastBit);
-	//loop to find first wave that works
-	for (iii=0; iii < gLen; ++iii){
-		if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){
-			lastBit=iii-*clk;
-			errCnt=0;
-			//loop through to see if this start location works
-			for (i = iii; i < *size; ++i) {
-				if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
-					lastBit+=*clk;
-				} else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
-					//low found and we are expecting a bar
-					lastBit+=*clk;
-				} else {
-					//mid value found or no bar supposed to be here
-					if ((i-lastBit)>(*clk+tol)){
-						//should have hit a high or low based on clock!!
-
-						//debug
-						//PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
+//demodulates strong heavily clipped samples
+int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
+{
+	size_t bitCnt=0, smplCnt=0, errCnt=0;
+	uint8_t waveHigh = 0;
+	for (size_t i=0; i < *size; i++){
+		if (BinStream[i] >= high && waveHigh){
+			smplCnt++;
+		} else if (BinStream[i] <= low && !waveHigh){
+			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++;
-						lastBit+=*clk;//skip over until hit too many errors
-						if (errCnt>(maxErr)) break;  //allow 1 error for every 1000 samples else start over
+						if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
+						BinStream[bitCnt++] = 7;
+					} else if (waveHigh) {
+						BinStream[bitCnt++] = invert;
+						BinStream[bitCnt++] = invert;
+					} else if (!waveHigh) {
+						BinStream[bitCnt++] = invert ^ 1;
+						BinStream[bitCnt++] = invert ^ 1;
 					}
+					waveHigh ^= 1;  
+					smplCnt = 0;
+				} else if (smplCnt > (clk/2) - (clk/4)-1) {
+					if (waveHigh) {
+						BinStream[bitCnt++] = invert;
+					} else if (!waveHigh) {
+						BinStream[bitCnt++] = invert ^ 1;
+					}
+					waveHigh ^= 1;  
+					smplCnt = 0;
+				} else if (!bitCnt) {
+					//first bit
+					waveHigh = (BinStream[i] >= high);
+					smplCnt = 1;
+				} else {
+					smplCnt++;
+					//transition bit oops
 				}
-				if ((i-iii) >(400 * *clk)) break; //got plenty of bits
-			}
-			//we got more than 64 good bits and not all errors
-			if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<maxErr)) {
-				//possible good read
-				if (errCnt==0){
-					bestStart=iii;
-					bestErrCnt=errCnt;
-					break;  //great read - finish
-				}
-				if (errCnt<bestErrCnt){  //set this as new best run
-					bestErrCnt=errCnt;
-					bestStart = iii;
-				}
+			} else { //haven't hit new high or new low yet
+				smplCnt++;
 			}
 		}
 	}
-	if (bestErrCnt<maxErr){
-		//best run is good enough set to best run and set overwrite BinStream
-		iii=bestStart;
-		lastBit = bestStart - *clk;
-		bitnum=0;
-		for (i = iii; i < *size; ++i) {
-			if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
-				lastBit += *clk;
-				BinStream[bitnum] = *invert;
-				bitnum++;
-			} else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
-				//low found and we are expecting a bar
-				lastBit+=*clk;
-				BinStream[bitnum] = 1-*invert;
-				bitnum++;
-			} else {
-				//mid value found or no bar supposed to be here
-				if ((i-lastBit)>(*clk+tol)){
-					//should have hit a high or low based on clock!!
-
-					//debug
-					//PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
-					if (bitnum > 0){
-						BinStream[bitnum]=77;
-						bitnum++;
-					}
+	*size = bitCnt;
+	return errCnt;
+}
 
-					lastBit+=*clk;//skip over error
-				}
+//by marshmellow
+void askAmp(uint8_t *BitStream, size_t size)
+{
+	uint8_t last = 128;
+	for(size_t i = 1; i < size; ++i){
+		if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
+			last = 255;
+		else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
+			last = 0;
+		
+		BitStream[i] = last;
+	}
+}
+
+//by marshmellow
+//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
+int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
+{
+	if (*size==0) return -1;
+	int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
+	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, amp %d", *clk, start, amp);
+
+	uint8_t initLoopMax = 255;
+	if (initLoopMax > *size) initLoopMax = *size;
+	// Detect high and lows
+	//25% clip in case highs and lows aren't clipped [marshmellow]
+	int high, low;
+	if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) 
+		return -2; //just noise
+
+	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);	
+		//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
+	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 = 3072;    //max bits to collect
+	lastBit = start - *clk;
+
+	for (i = start; i < *size; ++i) {
+		if (i-lastBit >= *clk-tol){
+			if (BinStream[i] >= high) {
+				BinStream[bitnum++] = *invert;
+			} else if (BinStream[i] <= low) {
+				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++;						
+				} 
+			} else { //in tolerance - looking for peak
+				continue;
 			}
-			if (bitnum >=400) break;
+			midBit = 0;
+			lastBit += *clk;
+		} else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
+			if (BinStream[i] >= high) {
+				BinStream[bitnum++] = *invert;
+			} else if (BinStream[i] <= low) {
+				BinStream[bitnum++] = *invert ^ 1;
+			} else if (i-lastBit >= *clk/2+tol) {
+				BinStream[bitnum] = BinStream[bitnum-1];
+				bitnum++;
+			} else { //in tolerance - looking for peak
+				continue;
+			}
+			midBit = 1;
 		}
-		*size=bitnum;
-	} else{
-		*invert=bestStart;
-		*clk=iii;
-		return -1;
+		if (bitnum >= MaxBits) break;
 	}
-	return bestErrCnt;
+	*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)
-{
-	int bitnum=0;
-	int errCnt =0;
-	int i=1;
-	int bestErr = 1000;
-	int bestRun = 0;
-	int ii=1;
-	for (ii=1;ii<3;++ii){
-		i=1;
-		for (i=i+ii;i<*size-2;i+=2){
-			if(BitStream[i]==1 && (BitStream[i+1]==0)){
-			} else if((BitStream[i]==0)&& BitStream[i+1]==1){
-			} else {
+int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){
+	uint16_t bitnum = 0, MaxBits = 512, errCnt = 0;
+	size_t i, k;
+	uint16_t bestErr = 1000, bestRun = 0;
+	if (*size < 16) return -1;
+	//find correct start position [alignment]
+	for (k=0; k < 2; ++k){
+		for (i=k; i<*size-3; i += 2)
+			if (BitStream[i] == BitStream[i+1])
 				errCnt++;
-			}
-			if(bitnum>300) break;
-		}
-		if (bestErr>errCnt){
-			bestErr=errCnt;
-			bestRun=ii;
+
+		if (bestErr > errCnt){
+			bestErr = errCnt;
+			bestRun = k;
 		}
 		errCnt=0;
 	}
-	errCnt=bestErr;
-	if (errCnt<20){
-		ii=bestRun;
-		i=1;
-		for (i=i+ii;i < *size-2;i+=2){
-			if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
-				BitStream[bitnum++]=0;
-			} else if((BitStream[i] == 0) && BitStream[i+1] == 1){
-				BitStream[bitnum++]=1;
-			} else {
-				BitStream[bitnum++]=77;
-				//errCnt++;
-			}
-			if(bitnum>300) break;
+	//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;
+		} else {
+			BitStream[bitnum++] = 7;
 		}
-		*size=bitnum;
+		if (bitnum>MaxBits) break;
 	}
-	return errCnt;
+	*size=bitnum;
+	return bestErr;
 }
 
+uint32_t manchesterEncode2Bytes(uint16_t datain) {
+	uint32_t output = 0;
+	uint8_t curBit = 0;
+	for (uint8_t i=0; i<16; i++) {
+		curBit = (datain >> (15-i) & 1);
+		output |= (1<<(((15-i)*2)+curBit));
+	}
+	return output;
+}
+
+//by marshmellow
+//encode binary data into binary manchester 
+int ManchesterEncode(uint8_t *BitStream, size_t size)
+{
+	size_t modIdx=20000, i=0;
+	if (size>modIdx) return -1;
+	for (size_t idx=0; idx < size; idx++){
+		BitStream[idx+modIdx++] = BitStream[idx];
+		BitStream[idx+modIdx++] = BitStream[idx]^1;
+	}
+	for (; i<(size*2); i++){
+		BitStream[i] = BitStream[i+20000];
+	}
+	return i;
+}
 
 //by marshmellow
-//take 01 or 10 = 0 and 11 or 00 = 1
-int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset)
-{
-	uint8_t bitnum=0;
-	uint32_t errCnt =0;
-	uint32_t i=1;
-	i=offset;
-	for (;i<*size-2;i+=2){
+//take 01 or 10 = 1 and 11 or 00 = 0
+//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
+//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
+int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
+{
+	uint16_t bitnum = 0;
+	uint16_t errCnt = 0;
+	size_t i = offset;
+	uint16_t MaxBits=512;
+	//if not enough samples - error
+	if (*size < 51) return -1;
+	//check for phase change faults - skip one sample if faulty
+	uint8_t offsetA = 1, offsetB = 1;
+	for (; i<48; i+=2){
+		if (BitStream[i+1]==BitStream[i+2]) offsetA=0; 
+		if (BitStream[i+2]==BitStream[i+3]) offsetB=0;					
+	}
+	if (!offsetA && offsetB) offset++;
+	for (i=offset; i<*size-3; i+=2){
+		//check for phase error
+		if (BitStream[i+1]==BitStream[i+2]) {
+			BitStream[bitnum++]=7;
+			errCnt++;
+		}
 		if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
-			BitStream[bitnum++]=1;
+			BitStream[bitnum++]=1^invert;
 		} else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
-			BitStream[bitnum++]=0;
+			BitStream[bitnum++]=invert;
 		} else {
-			BitStream[bitnum++]=77;
+			BitStream[bitnum++]=7;
 			errCnt++;
 		}
-		if(bitnum>250) break;
+		if(bitnum>MaxBits) break;
 	}
 	*size=bitnum;
 	return errCnt;
 }
 
-//by marshmellow
-//takes 2 arguments - clock and invert both 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)
-{
-	uint32_t i;
-	// int invert=0;  //invert default
-	int high = 0, low = 128;
-	*clk=DetectASKClock(BinStream, *size, *clk); //clock default
-	uint8_t BitStream[502] = {0};
-
-	if (*clk<8) *clk =64;
-	if (*clk<32) *clk=32;
-	if (*invert != 0 && *invert != 1) *invert =0;
-	uint32_t initLoopMax = 200;
-	if (initLoopMax > *size) initLoopMax=*size;
-	// Detect high and lows
-	for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
-	{
-		if (BinStream[i] > high)
-			high = BinStream[i];
-		else if (BinStream[i] < low)
-			low = BinStream[i];
-	}
-	if ((high < 158)){  //throw away static
-		//   PrintAndLog("no data found");
-		return -2;
-	}
-	//25% fuzz in case highs and lows aren't clipped [marshmellow]
-	high=(int)(((high-128)*.75)+128);
-	low= (int)(((low-128)*.75)+128);
-
-	//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-	int lastBit = 0;  //set first clock check
-	uint32_t bitnum = 0;     //output counter
-	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
-	uint32_t iii = 0;
-	uint32_t gLen = *size;
-	if (gLen > 500) gLen=500;
-	uint8_t errCnt =0;
-	uint32_t bestStart = *size;
-	uint32_t bestErrCnt = (*size/1000);
-	uint8_t midBit=0;
-	//PrintAndLog("DEBUG - lastbit - %d",lastBit);
-	//loop to find first wave that works
-	for (iii=0; iii < gLen; ++iii){
-		if ((BinStream[iii]>=high) || (BinStream[iii]<=low)){
-			lastBit=iii-*clk;
-			//loop through to see if this start location works
-			for (i = iii; i < *size; ++i) {
-				if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
-					lastBit+=*clk;
-					BitStream[bitnum] = *invert;
-					bitnum++;
-					midBit=0;
-				} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
-					//low found and we are expecting a bar
-					lastBit+=*clk;
-					BitStream[bitnum] = 1- *invert;
-					bitnum++;
-					midBit=0;
-				} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-					//mid bar?
-					midBit=1;
-					BitStream[bitnum]= 1- *invert;
-					bitnum++;
-				} else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-					//mid bar?
-					midBit=1;
-					BitStream[bitnum]= *invert;
-					bitnum++;
-				} else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
-					//no mid bar found
-					midBit=1;
-					BitStream[bitnum]= BitStream[bitnum-1];
-					bitnum++;
-				} else {
-					//mid value found or no bar supposed to be here
-
-					if ((i-lastBit)>(*clk+tol)){
-						//should have hit a high or low based on clock!!
-						//debug
-						//PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
-						if (bitnum > 0){
-							BitStream[bitnum]=77;
-							bitnum++;
-						}
+// by marshmellow
+// 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};
 
-						errCnt++;
-						lastBit+=*clk;//skip over until hit too many errors
-						if (errCnt > ((*size/1000))){  //allow 1 error for every 1000 samples else start over
-							errCnt=0;
-							bitnum=0;//start over
-							break;
-						}
-					}
-				}
-				if (bitnum>500) break;
-			}
-			//we got more than 64 good bits and not all errors
-			if ((bitnum > (64+errCnt)) && (errCnt<(*size/1000))) {
-				//possible good read
-				if (errCnt==0) break;  //great read - finish
-				if (bestStart == iii) break;  //if current run == bestErrCnt run (after exhausted testing) then finish
-				if (errCnt<bestErrCnt){  //set this as new best run
-					bestErrCnt=errCnt;
-					bestStart = iii;
-				}
-			}
-		}
-		if (iii>=gLen){ //exhausted test
-			//if there was a ok test go back to that one and re-run the best run (then dump after that run)
-			if (bestErrCnt < (*size/1000)) iii=bestStart;
-		}
+	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;
 	}
-	if (bitnum>16){
-		for (i=0; i < bitnum; ++i){
-			BinStream[i]=BitStream[i];
-		}
-		*size=bitnum;
-	} else return -1;
-	return errCnt;
+	return -5; //spacer bits not found - not a valid gproxII
 }
-//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
+
+//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
-	uint32_t last_transition = 0;
-	uint32_t idx = 1;
-	uint32_t maxVal=0;
+	size_t last_transition = 0;
+	size_t idx = 1;
+	//uint32_t maxVal=0;
 	if (fchigh==0) fchigh=10;
 	if (fclow==0) fclow=8;
-	// we do care about the actual theshold value as sometimes near the center of the
-	// wave we may get static that changes direction of wave for one value
-	// if our value is too low it might affect the read.  and if our tag or
-	// antenna is weak a setting too high might not see anything. [marshmellow]
-	if (size<100) return 0;
-	for(idx=1; idx<100; idx++){
-		if(maxVal<dest[idx]) maxVal = dest[idx];
-	}
-	// set close to the top of the wave threshold with 25% margin for error
-	// less likely to get a false transition up there.
-	// (but have to be careful not to go too high and miss some short waves)
-	uint8_t threshold_value = (uint8_t)(((maxVal-128)*.75)+128);
-
+	//set the threshold close to 0 (graph) or 128 std to avoid static
+	uint8_t threshold_value = 123; 
+	size_t preLastSample = 0;
+	size_t LastSample = 0;
+	size_t currSample = 0;
 	// 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++) {
+	//  (could also be fc/5 && fc/7 for fsk1 = 4-9)
+	for(idx = 161; idx < size-20; idx++) {
 		// threshold current value
 
 		if (dest[idx] < threshold_value) dest[idx] = 0;
 		else dest[idx] = 1;
 
 		// Check for 0->1 transition
-		if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
-			if ((idx-last_transition)<(fclow-2)){            //0-5 = garbage noise
+		if (dest[idx-1] < dest[idx]) {
+			preLastSample = LastSample;
+			LastSample = currSample;
+			currSample = idx-last_transition;
+			if (currSample < (fclow-2)){            //0-5 = garbage noise (or 0-3)
 				//do nothing with extra garbage
-			} else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
-				dest[numBits]=1;
-			} else {							//9+ = 10 waves
-				dest[numBits]=0;
+			} 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 )){
+					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 == (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)
+				dest[numBits++]=0;
 			}
 			last_transition = idx;
-			numBits++;
 		}
 	}
 	return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
 }
 
-uint32_t myround2(float f)
-{
-	if (f >= 2000) return 2000;//something bad happened
-	return (uint32_t) (f + (float)0.5);
-}
-
 //translate 11111100000 to 10
-size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits,
-    uint8_t invert, uint8_t fchigh, uint8_t fclow)
+//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
+size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
+		uint8_t invert, uint8_t fchigh, uint8_t fclow)
 {
 	uint8_t lastval=dest[0];
-	uint32_t idx=0;
+	size_t idx=0;
 	size_t numBits=0;
 	uint32_t n=1;
-
 	for( idx=1; idx < size; idx++) {
-
-		if (dest[idx]==lastval) {
-			n++;
-			continue;
-		}
+		n++;
+		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
-		if ( dest[idx-1]==1 ) {
-			n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
-		} else {// 0->1 crossing
-			n=myround2((float)(n+1)/((float)(rfLen-2)/(float)fchigh));  //-2 for fudge factor
+		if (dest[idx-1]==1) {
+			n = (n * fclow + rfLen/2) / rfLen;
+		} else {// 0->1 crossing 
+			n = (n * fchigh + rfLen/2) / rfLen; 
 		}
 		if (n == 0) n = 1;
 
-		if(n < maxConsequtiveBits) //Consecutive
-		{
-			if(invert==0){ //invert bits
-				memset(dest+numBits, dest[idx-1] , n);
-			}else{
-				memset(dest+numBits, dest[idx-1]^1 , n);
-			}
-			numBits += n;
-		}
+		//add to our destination the bits we collected		
+		memset(dest+numBits, dest[idx-1]^invert , n);
+		numBits += n;
 		n=0;
 		lastval=dest[idx];
 	}//end for
+	// if valid extra bits at the end were all the same frequency - add them in
+	if (n > rfLen/fchigh) {
+		if (dest[idx-2]==1) {
+			n = (n * fclow + rfLen/2) / rfLen;
+		} else {
+			n = (n * fchigh + rfLen/2) / rfLen;
+		}
+		memset(dest+numBits, dest[idx-1]^invert , n);
+		numBits += n;
+	}
 	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)
 {
 	// FSK demodulator
 	size = fsk_wave_demod(dest, size, fchigh, fclow);
-	size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
+	size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
 	return size;
 }
+
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
-int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
+int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
 {
+	if (justNoise(dest, *size)) return -1;
 
-	size_t idx=0; //, found=0; //size=0,
+	size_t numStart=0, size2 = *size, startIdx=0; 
 	// FSK demodulator
-	size = fskdemod(dest, size,50,0,10,8);
-
-	// final loop, go over previously decoded manchester data and decode into usable tag ID
-	// 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
-	uint8_t frame_marker_mask[] = {1,1,1,0,0,0};
-	int numshifts = 0;
-	idx = 0;
-	//one scan
-	while( idx + sizeof(frame_marker_mask) < size) {
-		// search for a start of frame marker
-		if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
-		{ // frame marker found
-			idx+=sizeof(frame_marker_mask);
-			while(dest[idx] != dest[idx+1] && idx < size-2)
-			{
-				// Keep going until next frame marker (or error)
-				// Shift in a bit. Start by shifting high registers
-				*hi2 = (*hi2<<1)|(*hi>>31);
-				*hi = (*hi<<1)|(*lo>>31);
-				//Then, shift in a 0 or one into low
-				if (dest[idx] && !dest[idx+1])	// 1 0
-					*lo=(*lo<<1)|0;
-				else // 0 1
-					*lo=(*lo<<1)|1;
-				numshifts++;
-				idx += 2;
-			}
-			// Hopefully, we read a tag and	 hit upon the next frame marker
-			if(idx + sizeof(frame_marker_mask) < size)
-			{
-				if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
-				{
-					//good return
-					return idx;
-				}
-			}
-			// reset
-			*hi2 = *hi = *lo = 0;
-			numshifts = 0;
-		}else	{
-			idx++;
+	*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
+	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
+
+	numStart = startIdx + sizeof(preamble);
+	// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
+	for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
+		if (dest[idx] == dest[idx+1]){
+			return -4; //not manchester data
 		}
+		*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 |= 1;
+		else // 0 1
+			*lo |= 0;
 	}
-	return -1;
+	return (int)startIdx;
 }
 
-uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
+// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
+int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
 {
-	uint32_t num = 0;
-	for(int i = 0 ; i < numbits ; i++)
-	{
-		num = (num << 1) | (*src);
-		src++;
+	if (justNoise(dest, *size)) return -1;
+	
+	size_t numStart=0, size2 = *size, startIdx=0;
+	// FSK demodulator
+	*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
+	if (*size < 96) return -2;
+
+	// 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
+
+	numStart = startIdx + sizeof(preamble);
+	// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
+	for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
+		if (dest[idx] == dest[idx+1]) 
+			return -4; //not manchester data
+		*hi2 = (*hi2<<1)|(*hi>>31);
+		*hi = (*hi<<1)|(*lo>>31);
+		//Then, shift in a 0 or one into low
+		if (dest[idx] && !dest[idx+1])	// 1 0
+			*lo=(*lo<<1)|1;
+		else // 0 1
+			*lo=(*lo<<1)|0;
 	}
-	return num;
+	return (int)startIdx;
 }
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {
-	static const uint8_t THRESHOLD = 140;
-	uint32_t idx=0;
+	if (justNoise(dest, size)) return -1;
 	//make sure buffer has data
-	if (size < 66) return -1;
-	//test samples are not just noise
-	uint8_t justNoise = 1;
-	for(idx=0;idx< size && justNoise ;idx++){
-		justNoise = dest[idx] < THRESHOLD;
-	}
-	if(justNoise) return 0;
-
+	if (size < 66*64) return -2;
 	// FSK demodulator
-	size = fskdemod(dest, size, 64, 1, 10, 8);  //  RF/64 and invert
-	if (size < 65) return -1;  //did we get a good demod?
+	size = fskdemod(dest, size, 64, 1, 10, 8);  // FSK2a RF/64 
+	if (size < 65) return -3;  //did we get a good demod?
 	//Index map
 	//0           10          20          30          40          50          60
 	//|           |           |           |           |           |           |
@@ -596,16 +659,235 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 	//
 	//XSF(version)facility:codeone+codetwo
 	//Handle the data
-	uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
-	for( idx=0; idx < (size - 65); idx++) {
-		if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
-			//frame marker found
-			if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){
-				//confirmed proper separator bits found
-				//return start position
-				return (int) idx;
-			}
-		}
+	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 (!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
+		//return start position
+		return (int) startIdx;
+	}
+	return -5;
+}
+
+// by marshmellow
+// find viking preamble 0xF200 in already demoded data
+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
+	uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ 
+						 bytebits_to_byte(dest+startIdx+8,8) ^ 
+						 bytebits_to_byte(dest+startIdx+16,8) ^ 
+						 bytebits_to_byte(dest+startIdx+24,8) ^ 
+						 bytebits_to_byte(dest+startIdx+32,8) ^ 
+						 bytebits_to_byte(dest+startIdx+40,8) ^ 
+						 bytebits_to_byte(dest+startIdx+48,8) ^ 
+						 bytebits_to_byte(dest+startIdx+56,8);
+	if ( checkCalc != 0xA8 ) return -5;	
+	if (*size != 64) return -6;
+	//return start position
+	return (int)startIdx;
+}
+
+// by iceman
+// find Visa2000 preamble in already demoded data
+int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
+	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 (*size != 96) return -3; //wrong demoded size
+	//return start position
+	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};
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) 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) {
+	if (*size < 128*2) return -1; //make sure buffer has data
+	size_t startIdx = 0;
+	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};
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -2; //preamble not found
+	if (*size != 128) return -3; //wrong demoded size
+	//return start position
+	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) {
+	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 (*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){
+	if (*size < 64*2) return -1;	//make sure buffer has enough data
+	size_t startIdx = 0;
+	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 -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;
+	return (int)startIdx;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an AWID ID
+int AWIDdemodFSK(uint8_t *dest, size_t *size)
+{
+	//make sure buffer has enough data
+	if (*size < 96*50) return -1;
+
+	if (justNoise(dest, *size)) return -2;
+
+	// FSK demodulator
+	*size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+	if (*size < 96) return -3;  //did we get a good demod?
+
+	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 (*size != 96) return -5;
+	return (int)startIdx;
+}
+
+// by marshmellow
+// FSK Demod then try to locate a Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t *size)
+{
+	//make sure buffer has data
+	if (*size < 128*50) return -5;
+
+	//test samples are not just noise
+	if (justNoise(dest, *size)) return -1;
+
+	// 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[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
+	size_t startIdx = 0;
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -4; //preamble not found
+	if (*size != 128) return -3;
+	return (int)startIdx;
+}
+
+// find nedap preamble in already demoded data
+int NedapDemod(uint8_t *dest, size_t *size) {
+	//make sure buffer has data
+	if (*size < 128) return -3;
+
+	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
+	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};
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -2; //preamble not found
+	if (*size != 64) return -3; // wrong demoded size
+	return (int) startIdx;
+}
+
+// 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)
+{
+	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) 
+			allArePeaks = false;
+		else
+			cntPeaks++;
+	}
+	if (!allArePeaks){
+		if (cntPeaks > 300) return true;
+	}
+	return allArePeaks;
+}
+// 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)
+{
+	uint8_t fndClk[] = {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
+	while ((dest[i] < high) && (i < size))
+		++i;
+	while ((dest[i] > low) && (i < size))
+		++i;
+
+	// loop through all samples
+	while (i < size) {
+		// measure from low to low
+		while ((dest[i] > low) && (i < size))
+			++i;
+		startwave= i;
+		while ((dest[i] < high) && (i < size))
+			++i;
+		while ((dest[i] > low) && (i < size))
+			++i;
+		//get minimum measured distance
+		if (i-startwave < minClk && i < size)
+			minClk = i - 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];
 	}
 	return 0;
 }
@@ -613,407 +895,912 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 // by marshmellow
 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
 // maybe somehow adjust peak trimming value based on samples to fix?
-int DetectASKClock(uint8_t dest[], size_t size, int clock)
+// 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)
 {
-	int i=0;
-	int peak=0;
-	int low=128;
-	int clk[]={16,32,40,50,64,100,128,256};
-	int loopCnt = 256;  //don't need to loop through entire array...
-	if (size<loopCnt) loopCnt = size;
-
-	//if we already have a valid clock quit
-	for (;i<8;++i)
-		if (clk[i] == clock) return clock;
+	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
+	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)
+		if (clk[i] == *clock) clockFnd = i;
+		//clock found but continue to find best startpos
 
 	//get high and low peak
-	for (i=0; i < loopCnt; ++i){
-		if(dest[i] > peak){
-			peak = dest[i];
-		}
-		if(dest[i] < low){
-			low = dest[i];
+	int peak, low;
+	if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
+	
+	//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]
+				}
+			}
 		}
 	}
-	peak=(int)(((peak-128)*.75)+128);
-	low= (int)(((low-128)*.75)+128);
-	int ii;
-	int clkCnt;
-	int tol = 0;
-	int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000};
-	int errCnt=0;
+	uint8_t ii;
+	uint8_t clkCnt, tol = 0;
+	uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
+	uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
+	size_t errCnt = 0;
+	size_t arrLoc, loopEnd;
+
+	if (clockFnd>0) {
+		clkCnt = clockFnd;
+		clkEnd = clockFnd+1;
+	} else {
+		clkCnt=1;
+	}
+
 	//test each valid clock from smallest to greatest to see which lines up
-	for(clkCnt=0; clkCnt < 6; ++clkCnt){
-		if (clk[clkCnt] == 32){
+	for(; clkCnt < clkEnd; clkCnt++) {
+		if (clk[clkCnt] <= 32) {
 			tol=1;
-		}else{
+		} else {
 			tol=0;
 		}
-		bestErr[clkCnt]=1000;
-		//try lining up the peaks by moving starting point (try first 256)
-		for (ii=0; ii< loopCnt; ++ii){
-			if ((dest[ii] >= peak) || (dest[ii] <= low)){
-				errCnt=0;
-				// now that we have the first one lined up test rest of wave array
-				for (i=0; i<((int)(size/clk[clkCnt])-1); ++i){
-					if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
-					}else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
-					}else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
-					}else{  //error no peak detected
-						errCnt++;
-					}
+		//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;
+
+		//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;
+			// 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){
+				arrLoc = ii + (i * clk[clkCnt]);
+				if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
+				}else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
+				}else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
+				}else{  //error no peak detected
+					errCnt++;
 				}
-				//if we found no errors this is correct one - return this clock
-				if(errCnt==0) return clk[clkCnt];
-				//if we found errors see if it is lowest so far and save it as best run
-				if(errCnt<bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
+			}
+			//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 (!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;
 			}
 		}
 	}
-	int iii=0;
-	int best=0;
-	for (iii=0; iii<7;++iii){
-		if (bestErr[iii]<bestErr[best]){
-			//                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;
+	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[k])/bestErr[k] ){
+				best = k;
 			}
 		}
+		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]);
 	}
-	return clk[best];
+	if (!clockFnd) *clock = clk[best];
+	return bestStart[best];
 }
 
 //by marshmellow
-//detect psk clock by reading #peaks vs no peaks(or errors)
-int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
+//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)
 {
-	int i=0;
-	int peak=0;
-	int low=128;
-	int clk[]={16,32,40,50,64,100,128,256};
-	int loopCnt = 2048;  //don't need to loop through entire array...
-	if (size<loopCnt) loopCnt = size;
+	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;
 
-	//get high and low peak
-	for (i=0; i < loopCnt; ++i){
-		if(dest[i] > peak){
-			peak = dest[i];
+	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};
+	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++){
+		if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
+			if (waveStart == 0) {
+				waveStart = i+1;
+				//prnt("DEBUG: waveStart: %d",waveStart);
+			} else {
+				waveEnd = i+1;
+				//prnt("DEBUG: waveEnd: %d",waveEnd);
+				waveLenCnt = waveEnd-waveStart;
+				if (waveLenCnt > fc){
+					firstFullWave = waveStart;
+					fullWaveLen=waveLenCnt;
+					break;
+				} 
+				waveStart=0;
+			}
+		}
+	}
+	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--){
+		lastClkBit = firstFullWave; //set end of wave as clock align
+		waveStart = 0;
+		errCnt=0;
+		peakcnt=0;
+		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 
+			if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
+				if (waveStart == 0) {
+					waveStart = i+1;
+					waveLenCnt=0;
+				} else { //waveEnd
+					waveEnd = i+1;
+					waveLenCnt = waveEnd-waveStart;
+					if (waveLenCnt > fc){ 
+						//if this wave is a phase shift
+						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];
+						} else if (i<lastClkBit+8){
+							//noise after a phase shift - ignore
+						} else { //phase shift before supposed to based on clock
+							errCnt++;
+						}
+					} else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
+						lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
+					}
+					waveStart=i+1;
+				}
+			}
 		}
-		if(dest[i] < low){
-			low = dest[i];
+		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]) {
+			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];
+}
+
+int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
+	//find shortest transition from high to low
+	size_t i = 0;
+	size_t transition1 = 0;
+	int lowestTransition = 255;
+	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;
+
+	for (;i < size; i++) {
+		if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
+			lastWasHigh = (dest[i] >= peak);
+			if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
+			transition1 = i;
 		}
 	}
-	peak=(int)(((peak-128)*.90)+128);
-	low= (int)(((low-128)*.90)+128);
-	//PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
-	int ii;
+	if (lowestTransition == 255) lowestTransition = 0;
+	if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
+	return lowestTransition;
+}
+
+//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};
+	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;
+
+	//get high and low peak
+	int peak, low;
+	if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
+
+	int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
+	size_t ii;
 	uint8_t clkCnt;
 	uint8_t tol = 0;
-	int peakcnt=0;
-	int errCnt=0;
-	int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
-	int peaksdet[]={0,0,0,0,0,0,0,0,0};
-	//test each valid clock from smallest to greatest to see which lines up
-	for(clkCnt=0; clkCnt < 6; ++clkCnt){
-		if (clk[clkCnt] == 32){
-			tol=0;
-		}else{
-			tol=0;
+	uint16_t smplCnt = 0;
+	int16_t peakcnt = 0;
+	int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
+	uint16_t maxPeak = 255;
+	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=true;
+			if (smplCnt > 6 ){
+				if (maxPeak > smplCnt){
+					maxPeak = smplCnt;
+					//prnt("maxPk: %d",maxPeak);
+				}
+				peakcnt++;
+				//prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
+				smplCnt=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){
+		//ignore clocks smaller than smallest peak
+		if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
 		//try lining up the peaks by moving starting point (try first 256)
-		for (ii=0; ii< loopCnt; ++ii){
+		for (ii=20; ii < loopCnt; ++ii){
 			if ((dest[ii] >= peak) || (dest[ii] <= low)){
-				errCnt=0;
 				peakcnt=0;
-				// now that we have the first one lined up test rest of wave array
-				for (i=0; i < ((int)(size/clk[clkCnt])-1); ++i){
-					if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
-						peakcnt++;
-					}else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
+				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 ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
+						//test high/low
+						if (dest[i] >= peak || dest[i] <= low) {
+							//if same peak don't count it
+							if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
 						peakcnt++;
-					}else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
-						peakcnt++;
-					}else{  //error no peak detected
-						errCnt++;
+							}
+							lastPeakHigh = (dest[i] >= peak);
+							bitHigh = true;
+							errBitHigh = false;
+							ignoreCnt = ignoreWindow;
+							lastBit += clk[clkCnt];
+						} else if (i == lastBit + clk[clkCnt] + tol) {
+							lastBit += clk[clkCnt];
+						}
+					//else if not a clock bit and no peaks
+					} else if (dest[i] < peak && dest[i] > low){
+						if (ignoreCnt==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)) {
+						//error bar found no clock...
+						errBitHigh=true;
 					}
 				}
 				if(peakcnt>peaksdet[clkCnt]) {
 					peaksdet[clkCnt]=peakcnt;
-					bestErr[clkCnt]=errCnt;
 				}
 			}
 		}
 	}
-	int iii=0;
-	int best=0;
-	//int ratio2;  //debug
-	int ratio;
-	//int bits;
-	for (iii=0; iii < 7; ++iii){
-		ratio=1000;
-		//ratio2=1000;  //debug
-		//bits=size/clk[iii];  //debug
-		if (peaksdet[iii] > 0){
-			ratio=bestErr[iii]/peaksdet[iii];
-			if (((bestErr[best]/peaksdet[best]) > (ratio)+1)){
-				best = iii;
-			}
-			//ratio2=bits/peaksdet[iii]; //debug
+	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;
 		}
-		//PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d, ratio: %d, bits: %d, peakbitr: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best],ratio, bits,ratio2);
+		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];
 }
 
-//by marshmellow (attempt to get rid of high immediately after a low)
-void pskCleanWave(uint8_t *bitStream, size_t size)
-{
-	int i;
-	int low=128;
-	int high=0;
-	int gap = 4;
- // int loopMax = 2048;
-	int newLow=0;
-	int newHigh=0;
-	for (i=0; i < size; ++i){
-		if (bitStream[i] < low) low=bitStream[i];
-		if (bitStream[i] > high) high=bitStream[i];
-	}
-	high = (int)(((high-128)*.80)+128);
-	low = (int)(((low-128)*.90)+128);
-	//low = (uint8_t)(((int)(low)-128)*.80)+128;
-	for (i=0; i < size; ++i){
-		if (newLow == 1){
-			bitStream[i]=low+8;
-			gap--;
-			if (gap == 0){
-				newLow=0;
-				gap=4;
-			}
-		}else if (newHigh == 1){
-			bitStream[i]=high-8;
-			gap--;
-			if (gap == 0){
-				newHigh=0;
-				gap=4;
-			}
+// 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;
+		} else {
+			BitStream[i]=0;
 		}
-		if (bitStream[i] <= low) newLow=1;
-		if (bitStream[i] >= high) newHigh=1;
 	}
 	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;
+		}
+		BitStream[i]=phase;
+	}
+	return;
+}
 
-//redesigned by marshmellow adjusted from existing decode functions
-//indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
+// redesigned by marshmellow adjusted from existing decode functions
+// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
 {
 	//26 bit 40134 format  (don't know other formats)
-	int i;
-	int long_wait;
-	long_wait = 29;//29 leading zeros in format
-	int start;
-	int first = 0;
-	int first2 = 0;
-	int bitCnt = 0;
-	int ii;
-	// Finding the start of a UID
-	for (start = 0; start <= *size - 250; start++) {
-		first = bitStream[start];
-		for (i = start; i < start + long_wait; i++) {
-			if (bitStream[i] != first) {
-				break;
-			}
+	uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+	uint8_t preamble_i[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
+	size_t startidx = 0; 
+	if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
+		// if didn't find preamble try again inverting
+		if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
+		*invert ^= 1;
+	} 
+	if (*size != 64 && *size != 224) return -2;
+	if (*invert==1)
+		for (size_t i = startidx; i < *size; i++)
+			bitStream[i] ^= 1;
+
+	return (int) startidx;
+}
+
+// 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;
+	*clk = DetectNRZClock(dest, *size, *clk);
+	if (*clk==0) return -2;
+	size_t i, gLen = 4096;
+	if (gLen>*size) gLen = *size-20;
+	int high, low;
+	if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
+
+	uint8_t bit=0;
+	//convert wave samples to 1's and 0's
+	for(i=20; i < *size-20; i++){
+		if (dest[i] >= high) bit = 1;
+		if (dest[i] <= low)  bit = 0;
+		dest[i] = bit;
+	}
+	//now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit) 
+	size_t lastBit = 0;
+	size_t numBits = 0;
+	for(i=21; i < *size-20; i++) {
+		//if transition detected or large number of same bits - store the passed bits
+		if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
+			memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
+			numBits += (i - lastBit + (*clk/4)) / *clk;
+			lastBit = i-1;
 		}
-		if (i == (start + long_wait)) {
+	}
+	*size = numBits;
+	return 0;
+}
+
+//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 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};
+	uint8_t rfLensFnd = 0;
+	uint8_t lastFCcnt = 0;
+	uint16_t fcCounter = 0;
+	uint16_t rfCounter = 0;
+	uint8_t firstBitFnd = 0;
+	size_t i;
+	if (size == 0) return 0;
+
+	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;
+	//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])
 			break;
+
+	for (; i < size-20; i++){
+		fcCounter++;
+		rfCounter++;
+
+		if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) 
+			continue;		
+		// else new peak 
+		// if we got less than the small fc + tolerance then set it to the small fc
+		if (fcCounter < fcLow+fcTol) 
+			fcCounter = fcLow;
+		else //set it to the large fc
+			fcCounter = fcHigh;
+
+		//look for bit clock  (rf/xx)
+		if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
+			//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-4) && rfLens[ii] <= (rfCounter+4)){
+						rfCnts[ii]++;
+						rfCounter = 0;
+						break;
+					}
+				}
+				if (rfCounter > 0 && rfLensFnd < 15){
+					//prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+					rfCnts[rfLensFnd]++;
+					rfLens[rfLensFnd++] = rfCounter;
+				}
+			} else {
+				firstBitFnd++;
+			}
+			rfCounter=0;
+			lastFCcnt=fcCounter;
 		}
+		fcCounter=0;
 	}
-	if (start == *size - 250 + 1) {
-		// did not find start sequence
-		return -1;
-	}
-	//found start once now test length by finding next one
-	// Inverting signal if needed
-	if (first == 1) {
-		for (i = start; i < *size; i++) {
-			bitStream[i] = !bitStream[i];
+	uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
+
+	for (i=0; i<15; i++){
+		//get highest 2 RF values  (might need to get more values to compare or compare all?)
+		if (rfCnts[i]>rfCnts[rfHighest]){
+			rfHighest3=rfHighest2;
+			rfHighest2=rfHighest;
+			rfHighest=i;
+		} else if(rfCnts[i]>rfCnts[rfHighest2]){
+			rfHighest3=rfHighest2;
+			rfHighest2=i;
+		} else if(rfCnts[i]>rfCnts[rfHighest3]){
+			rfHighest3=i;
 		}
-		*invert = 1;
-	}else *invert=0;
+		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; 
+	
+	if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
 
-	int iii;
-	for (ii=start+29; ii <= *size - 250; ii++) {
-		first2 = bitStream[ii];
-		for (iii = ii; iii < ii + long_wait; iii++) {
-			if (bitStream[iii] != first2) {
-				break;
+	// 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>=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;
+				}
 			}
 		}
-		if (iii == (ii + long_wait)) {
+	}
+
+	if (ii<0) return 0; // oops we went too far
+
+	return clk[ii];
+}
+
+//by marshmellow
+//countFC is to detect the field clock lengths.
+//counts and returns the 2 most common wave lengths
+//mainly used for FSK field clock detection
+uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
+{
+	uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+	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;
+	size_t i;
+	if (size == 0) return 0;
+
+	// prime i to first up transition
+	for (i = 160; i < size-20; i++)
+		if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
 			break;
+
+	for (; i < size-20; i++){
+		if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
+			// new up transition
+			fcCounter++;
+			if (fskAdj){
+				//if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
+				if (lastFCcnt==5 && fcCounter==9) fcCounter--;
+				//if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
+				if ((fcCounter==9) || fcCounter==4) fcCounter++;
+			// save last field clock count  (fc/xx)
+			lastFCcnt = fcCounter;
+			}
+			// find which fcLens to save it to:
+			for (int ii=0; ii<15; ii++){
+				if (fcLens[ii]==fcCounter){
+					fcCnts[ii]++;
+					fcCounter=0;
+					break;
+				}
+			}
+			if (fcCounter>0 && fcLensFnd<15){
+				//add new fc length 
+				fcCnts[fcLensFnd]++;
+				fcLens[fcLensFnd++]=fcCounter;
+			}
+			fcCounter=0;
+		} else {
+			// count sample
+			fcCounter++;
 		}
 	}
-	if (ii== *size - 250 + 1){
-		// did not find second start sequence
-		return -2;
+	
+	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<15; i++){
+		// get the 3 best FC values
+		if (fcCnts[i]>maxCnt1) {
+			best3=best2;
+			best2=best1;
+			maxCnt1=fcCnts[i];
+			best1=i;
+		} else if(fcCnts[i]>fcCnts[best2]){
+			best3=best2;
+			best2=i;
+		} 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];
+		fcL=fcLens[best2];
+	} else{
+		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
 	}
-	bitCnt=ii-start;
+	// TODO: take top 3 answers and compare to known Field clocks to get top 2
+
+	uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+	if (fskAdj) return fcs;	
+	return fcLens[best1];
+}
 
-	// Dumping UID
-	i = start;
-	for (ii = 0; ii < bitCnt; ii++) {
-		bitStream[ii] = bitStream[i++];
+//by marshmellow - demodulate PSK1 wave 
+//uses wave lengths (# Samples) 
+int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
+{
+	if (size == 0) return -1;
+	uint16_t loopCnt = 4096;  //don't need to loop through entire array...
+	if (*size<loopCnt) loopCnt = *size;
+
+	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);
+	if (fc!=2 && fc!=4 && fc!=8) return -1;
+	//prnt("DEBUG: FC: %d",fc);
+	*clock = DetectPSKClock(dest, *size, *clock);
+	if (*clock == 0) return -1;
+	int avgWaveVal=0, lastAvgWaveVal=0;
+	//find first phase shift
+	for (i=0; i<loopCnt; i++){
+		if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
+			waveEnd = i+1;
+			//prnt("DEBUG: waveEnd: %d",waveEnd);
+			waveLenCnt = waveEnd-waveStart;
+			if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //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
+				break;
+			} 
+			waveStart = i+1;
+			avgWaveVal = 0;
+		}
+		avgWaveVal += dest[i+2];
 	}
-	*size=bitCnt;
-	return 1;
+	if (firstFullWave == 0) {
+		// no phase shift detected - could be all 1's or 0's - doesn't matter where we start
+		// so skip a little to ensure we are past any Start Signal
+		firstFullWave = 160;
+		memset(dest, curPhase, firstFullWave / *clock);
+	} else {
+		memset(dest, curPhase^1, firstFullWave / *clock);
+	}
+	//advance bits
+	numBits += (firstFullWave / *clock);
+	//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);
+	waveStart = 0;
+	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]){
+			if (waveStart == 0) {
+				waveStart = i+1;
+				waveLenCnt = 0;
+				avgWaveVal = dest[i+1];
+			} else { //waveEnd
+				waveEnd = i+1;
+				waveLenCnt = waveEnd-waveStart;
+				lastAvgWaveVal = avgWaveVal/waveLenCnt;
+				if (waveLenCnt > fc){  
+					//prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
+					//this wave is a phase shift
+					//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;
+						lastClkBit += *clock;
+					} else if (i < lastClkBit+10+fc){
+						//noise after a phase shift - ignore
+					} else { //phase shift before supposed to based on clock
+						errCnt++;
+						dest[numBits++] = 7;
+					}
+				} else if (i+1 > lastClkBit + *clock + tol + fc){
+					lastClkBit += *clock; //no phase shift but clock bit
+					dest[numBits++] = curPhase;
+				}
+				avgWaveVal = 0;
+				waveStart = i+1;
+			}
+		}
+		avgWaveVal += dest[i+1];
+	}
+	*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 / 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));
 
-//by marshmellow - demodulate PSK wave or NRZ wave (both similar enough)
-//peaks switch bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
-int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
-{
-	pskCleanWave(dest,*size);
-	int clk2 = DetectpskNRZClock(dest, *size, *clk);
-	*clk=clk2;
-	uint32_t i;
-	uint8_t high=0, low=128;
-	uint32_t gLen = *size;
-	if (gLen > 1280) gLen=1280;
-	// get high
-	for (i=0; i < gLen; ++i){
-		if (dest[i] > high) high = dest[i];
-		if (dest[i] < low) low = dest[i];
+	
+	if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
+		if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
+		return false; //just noise
 	}
-	//fudge high/low bars by 25%
-	high = (uint8_t)((((int)(high)-128)*.75)+128);
-	low = (uint8_t)((((int)(low)-128)*.80)+128);
+	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;
 
-	//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-	int lastBit = 0;  //set first clock check
-	uint32_t bitnum = 0;     //output counter
-	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=2;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
-	uint32_t iii = 0;
-	uint8_t errCnt =0;
-	uint32_t bestStart = *size;
-	uint32_t maxErr = (*size/1000);
-	uint32_t bestErrCnt = maxErr;
-	//uint8_t midBit=0;
-	uint8_t curBit=0;
-	uint8_t bitHigh=0;
-	uint8_t ignorewin=*clk/8;
-	//PrintAndLog("DEBUG - lastbit - %d",lastBit);
-	//loop to find first wave that works - align to clock
-	for (iii=0; iii < gLen; ++iii){
-		if ((dest[iii]>=high) || (dest[iii]<=low)){
-			lastBit=iii-*clk;
-			//loop through to see if this start location works
-			for (i = iii; i < *size; ++i) {
-				//if we found a high bar and we are at a clock bit
-				if ((dest[i]>=high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
-					bitHigh=1;
-					lastBit+=*clk;
-					ignorewin=*clk/8;
-					bitnum++;
-				//else if low bar found and we are at a clock point
-				}else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
-					bitHigh=1;
-					lastBit+=*clk;
-					ignorewin=*clk/8;
-					bitnum++;
-				//else if no bars found
-				}else if(dest[i] < high && dest[i] > low) {
-					if (ignorewin==0){
-						bitHigh=0;
-					}else ignorewin--;
-										//if we are past a clock point
-					if (i >= lastBit+*clk+tol){ //clock val
-						lastBit+=*clk;
-						bitnum++;
+	// 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/32)) {
+			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;
 					}
-				//else if bar found but we are not at a clock bit and we did not just have a clock bit
-				}else if ((dest[i]>=high || dest[i]<=low) && (i<lastBit+*clk-tol || i>lastBit+*clk+tol) && (bitHigh==0)){
-					//error bar found no clock...
-					errCnt++;
 				}
-				if (bitnum>=1000) break;
 			}
-			//we got more than 64 good bits and not all errors
-			if ((bitnum > (64+errCnt)) && (errCnt < (maxErr))) {
-				//possible good read
-				if (errCnt == 0){
-					bestStart = iii;
-					bestErrCnt = errCnt;
-					break;  //great read - finish
-				}
-				if (bestStart == iii) break;  //if current run == bestErrCnt run (after exhausted testing) then finish
-				if (errCnt < bestErrCnt){  //set this as new best run
-					bestErrCnt = errCnt;
-					bestStart = iii;
+		}
+	}
+	// first ST not found - ERROR
+	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;
+	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 && 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
+						complete = true;
+						break;
+					}
 				}
 			}
 		}
 	}
-	if (bestErrCnt < maxErr){
-		//best run is good enough set to best run and set overwrite BinStream
-		iii=bestStart;
-		lastBit=bestStart-*clk;
-		bitnum=0;
-		for (i = iii; i < *size; ++i) {
-			//if we found a high bar and we are at a clock bit
-			if ((dest[i] >= high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
-				bitHigh=1;
-				lastBit+=*clk;
-				curBit=1-*invert;
-				dest[bitnum]=curBit;
-				ignorewin=*clk/8;
-				bitnum++;
-			//else if low bar found and we are at a clock point
-			}else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
-				bitHigh=1;
-				lastBit+=*clk;
-				curBit=*invert;
-				dest[bitnum]=curBit;
-				ignorewin=*clk/8;
-				bitnum++;
-			//else if no bars found
-			}else if(dest[i]<high && dest[i]>low) {
-				if (ignorewin==0){
-					bitHigh=0;
-				}else ignorewin--;
-				//if we are past a clock point
-				if (i>=lastBit+*clk+tol){ //clock val
-					lastBit+=*clk;
-					dest[bitnum]=curBit;
-					bitnum++;
-				}
-			//else if bar found but we are not at a clock bit and we did not just have a clock bit
-			}else if ((dest[i]>=high || dest[i]<=low) && ((i<lastBit+*clk-tol) || (i>lastBit+*clk+tol)) && (bitHigh==0)){
-				//error bar found no clock...
-				bitHigh=1;
-				dest[bitnum]=77;
-				bitnum++;
-				errCnt++;
+	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 ( 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;
+	}
+	// 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;
+	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;
 			}
-			if (bitnum >=1000) break;
 		}
-		*size=bitnum;
-	} else{
-		*size=bitnum;
-		*clk=bestStart;
-		return -1;
 	}
+	
+	size_t newloc = 0;
+	i=0;
+	if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);		
 
-	if (bitnum>16){
-		*size=bitnum;
-	} else return -1;
-	return errCnt;
-}
+	// 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)
+		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  -  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;
+	return true;
+}