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fix: crapto3.3 sometimes crashing with hf mf mifare on Fudan clones (no par, all...
[proxmark3-svn] / common / lfdemod.c
diff --git a/common/lfdemod.c b/common/lfdemod.c
index 4a80a10c7b715341648d4014e746d11ca8fa6fbf..1b53c44560fac2c7722903cd5d8f89fd90be1191 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -9,609 +9,682 @@
 //-----------------------------------------------------------------------------
 
 #include <stdlib.h>
 //-----------------------------------------------------------------------------
 
 #include <stdlib.h>
-#include <string.h>
 #include "lfdemod.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;
+       //test samples are not just noise
+       uint8_t justNoise1 = 1;
+       for(size_t idx=0; idx < size && justNoise1 ;idx++){
+               justNoise1 = BitStream[idx] < THRESHOLD;
+       }
+       return justNoise1;
+}
 
 //by marshmellow
 
 //by marshmellow
-//get high and low with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
+//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 
 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 (int i=0; i < size; i++){
+       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
                if (BitStream[i] > *high) *high = BitStream[i];
                if (BitStream[i] < *low) *low = BitStream[i];
        }
        if (*high < 123) return -1; // just noise
-       *high = (int)(((*high-128)*(((float)fuzzHi)/100))+128);
-       *low = (int)(((*low-128)*(((float)fuzzLo)/100))+128);
+       *high = ((*high-128)*fuzzHi + 12800)/100;
+       *low = ((*low-128)*fuzzLo + 12800)/100;
        return 1;
 }
 
        return 1;
 }
 
-//by marshmellow
-//takes 1s and 0s and searches for EM410x format - output EM ID
-uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
+// 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)
 {
 {
-       //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
-       uint64_t lo=0;
-       uint32_t i = 0;
-       if (BitStream[10]>1){  //allow only 1s and 0s
-               // PrintAndLog("no data found");
-               return 0;
+       uint8_t ans = 0;
+       for (uint8_t i = 0; i < bitLen; i++){
+               ans ^= ((bits >> i) & 1);
        }
        }
-       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};
-       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=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; //try 5 times
-                                       resetCnt++;
-                                       goto restart;//continue;
-                               }
+       if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
+       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]);
+               }
+               if (word+pLen > bLen) break;
+
+               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)
+{
+       return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
+}
+
+// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone 
+// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
+bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
+       // Sanity check.  If preamble length is bigger than bitstream length.
+       if ( *size <= pLen ) return false;
+
+       uint8_t foundCnt = 0;
+       for (size_t idx = 0; idx < *size - pLen; idx++) {
+               if (memcmp(BitStream+idx, preamble, pLen) == 0) {
+                       //first index found
+                       foundCnt++;
+                       if (foundCnt == 1) {
+                               if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
+                               *startIdx = idx;
+                               if (findone) return true;
+                       } else if (foundCnt == 2) {
+                               *size = idx - *startIdx;
+                               return true;
                        }
                        }
-                       //skip last 5 bit parity test for simplicity.
-                       return lo;
-               }else{
-                       idx++;
                }
        }
                }
        }
-       return 0;
+       return false;
+}
+
+// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
+size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
+       size_t i = 0;
+       size_t waveSizeCnt = 0;
+       uint8_t thresholdCnt = 0;
+       bool isAboveThreshold = dest[i++] >= threshold_value;
+       for (; i < size-20; i++ ) {
+               if(dest[i] < threshold_value && isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;                     
+                       isAboveThreshold = false;
+                       waveSizeCnt = 0;
+               } else if (dest[i] >= threshold_value && !isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;                     
+                       isAboveThreshold = true;
+                       waveSizeCnt = 0;
+               } else {
+                       waveSizeCnt++;
+               }
+               if (thresholdCnt > 10) break;
+       }
+       if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
+       return i;
 }
 
 //by marshmellow
 }
 
 //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)
+//takes 1s and 0s and searches for EM410x format - output EM ID
+uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
 {
 {
-       int i;
-       *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
-       // 25% fuzz in case highs and lows aren't clipped [marshmellow]
-       int high, low, ans;
-       ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
-       if (ans<1) return -2; //just noise
-
-       // 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!!
+       //sanity checks
+       if (*size < 64) return 0;
+       if (BitStream[1]>1) return 0;  //allow only 1s and 0s
 
 
-                                               //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);
+       // 111111111 bit pattern represent start of frame
+       //  include 0 in front to help get start pos
+       uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
+       uint8_t errChk = 0;
+       uint8_t FmtLen = 10; // sets of 4 bits = end data 
+       *startIdx = 0;
+       errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
+       if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
+       if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
+
+       //skip last 4bit parity row for simplicity
+       *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
+       if (*size == 40) { // std em410x format
+               *hi = 0;
+               *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
+       } else if (*size == 88) { // long em format
+               *hi = (bytebits_to_byte(BitStream, 24)); 
+               *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
+       } else {
+               return 0;
+       }
+       return 1;
+}
 
 
+//by marshmellow
+//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++;
                                                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
+//amplify based on ask edge detection
+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-1] = Last;
+       }
+       return;
+}
+ 
+//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);        
+               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
+       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;
+                       }
+                       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;
                        }
                        }
-                       if (bitnum >=400) break;
+                       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
 }
 
 //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 manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
 {
 {
-       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 {
+       uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
+       size_t i, ii;
+       uint16_t bestErr = 1000, bestRun = 0;
+       if (*size < 16) return -1;
+       //find correct start position [alignment]
+       for (ii=0;ii<2;++ii){
+               for (i=ii; i<*size-3; i+=2)
+                       if (BitStream[i]==BitStream[i+1])
                                errCnt++;
                                errCnt++;
-                       }
-                       if(bitnum>300) break;
-               }
+
                if (bestErr>errCnt){
                        bestErr=errCnt;
                        bestRun=ii;
                }
                errCnt=0;
        }
                if (bestErr>errCnt){
                        bestErr=errCnt;
                        bestRun=ii;
                }
                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
 
 //by marshmellow
-//take 01 or 10 = 0 and 11 or 00 = 1
+//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)
 {
 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
 {
-       uint8_t bitnum=0;
-       uint32_t errCnt =0;
-       uint32_t i;
-       i=offset;
-       for (;i<*size-2; i+=2){
+       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^invert;
                } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
                        BitStream[bitnum++]=invert;
                } else {
                if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
                        BitStream[bitnum++]=1^invert;
                } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
                        BitStream[bitnum++]=invert;
                } else {
-                       BitStream[bitnum++]=77;
+                       BitStream[bitnum++]=7;
                        errCnt++;
                }
                        errCnt++;
                }
-               if(bitnum>250) break;
+               if(bitnum>MaxBits) break;
        }
        *size=bitnum;
        return errCnt;
 }
 
        }
        *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)
+// 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)
 {
 {
-       uint32_t i;
-       // int invert=0;  //invert default
-       int clk2 = *clk;
-       *clk=DetectASKClock(BinStream, *size, *clk); //clock default
-       //uint8_t BitStream[502] = {0};
-
-       //HACK: if clock not detected correctly - default
-       if (*clk<8) *clk =64;
-       if (*clk<32 && clk2==0) *clk=32;
-       if (*invert != 0 && *invert != 1) *invert =0;
-       uint32_t initLoopMax = 200;
-       if (initLoopMax > *size) initLoopMax=*size;
-       // Detect high and lows
-       //25% fuzz in case highs and lows aren't clipped [marshmellow]
-       int high, low, ans;
-       ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
-       if (ans<1) return -2; //just noise
-
-       //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);
-       uint32_t maxErr = bestErrCnt;
-       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++;
-                                               //}
-
-                                               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 ((i-iii)>(500 * *clk)) break; //got enough bits
-                       }
-                       //we got more than 64 good bits and not all errors
-                       if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<(*size/1000))) {
-                               //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;
-                               }
-                       }
-               }
+       size_t startIdx=0;
+       uint8_t preamble[] = {1,1,1,1,1,0};
+
+       uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -3; //preamble not found
+       if (*size != 96) return -2; //should have found 96 bits
+       //check first 6 spacer bits to verify format
+       if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
+               //confirmed proper separator bits found
+               //return start position
+               return (int) startIdx;
        }
        }
-       if (bestErrCnt<maxErr){
-               //best run is good enough - set to best run and 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++;
-                               midBit=0;
-                       } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
-                               //low found and we are expecting a bar
-                               lastBit+=*clk;
-                               BinStream[bitnum] = 1-*invert;
-                               bitnum++;
-                               midBit=0;
-                       } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-                               //mid bar?
-                               midBit=1;
-                               BinStream[bitnum] = 1 - *invert;
-                               bitnum++;
-                       } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-                               //mid bar?
-                               midBit=1;
-                               BinStream[bitnum] = *invert;
-                               bitnum++;
-                       } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
-                               //no mid bar found
-                               midBit=1;
-                               if (bitnum!=0) BinStream[bitnum] = BinStream[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){
-                                               BinStream[bitnum]=77;
-                                               bitnum++;
-                                       }
-
-                                       lastBit+=*clk;//skip over error
-                               }
-                       }
-                       if (bitnum >=400) break;
-               }
-               *size=bitnum;
-       } else{
-               *invert=bestStart;
-               *clk=iii;
-               return -1;
-       }
-       return bestErrCnt;
+       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)
 {
 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;
        if (fchigh==0) fchigh=10;
        if (fclow==0) fclow=8;
        //set the threshold close to 0 (graph) or 128 std to avoid static
        uint8_t threshold_value = 123; 
        if (fchigh==0) fchigh=10;
        if (fclow==0) fclow=8;
        //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;
+       if ( size < 1024 ) return 0; // not enough samples
 
 
-       // sync to first lo-hi transition, and threshold
+       //find start of modulating data in trace 
+       idx = findModStart(dest, size, threshold_value, fchigh);
 
        // Need to threshold first sample
 
        // Need to threshold first sample
-
-       if(dest[0] < threshold_value) dest[0] = 0;
+       if(dest[idx] < threshold_value) dest[0] = 0;
        else dest[0] = 1;
        else dest[0] = 1;
-
+       idx++;
+       
        size_t numBits = 0;
        // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
        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
        // 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 < size-20; idx++) {
                // threshold current value
 
                if (dest[idx] < threshold_value) dest[idx] = 0;
                else dest[idx] = 1;
 
                // Check for 0->1 transition
                // 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
                                //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))){
+                                       dest[numBits-1]=1;
+                               }
+                               dest[numBits++]=1;
+
+                       } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
+                               //do nothing with beginning garbage and reset..  should be rare..
+                               numBits = 0; 
+                       } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
+                               dest[numBits++]=1;
+                       } else {                                        //9+ = 10 sample waves (or 6+ = 7)
+                               dest[numBits++]=0;
                        }
                        last_transition = idx;
                        }
                        last_transition = idx;
-                       numBits++;
                }
        }
        return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
 }
 
                }
        }
        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
 //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];
 {
        uint8_t lastval=dest[0];
-       uint32_t idx=0;
+       size_t idx=0;
        size_t numBits=0;
        uint32_t n=1;
        size_t numBits=0;
        uint32_t n=1;
-
        for( idx=1; idx < size; idx++) {
        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 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-1)/(float)fchigh));  //-1 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 == 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
                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;
 }
        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);
 //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;
 }
        return size;
 }
+
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
 // 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
        // 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
+               if (dest[idx] && !dest[idx+1])  // 1 0
+                       *lo=(*lo<<1)|1;
+               else // 0 1
+                       *lo=(*lo<<1)|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)
 {
 }
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {
-       static const uint8_t THRESHOLD = 129;
-       uint32_t idx=0;
+       if (justNoise(dest, size)) return -1;
        //make sure buffer has data
        //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
        // 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
        //|           |           |           |           |           |           |
        //Index map
        //0           10          20          30          40          50          60
        //|           |           |           |           |           |           |
@@ -621,659 +694,1128 @@ int IOdemodFSK(uint8_t *dest, size_t size)
        //
        //XSF(version)facility:codeone+codetwo
        //Handle the data
        //
        //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 0;
-}
+       return -5;
+} 
 
 // by marshmellow
 
 // 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
-int parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
+// 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;
+}
+
+// find presco preamble 0x10D in already demoded data
+int PrescoDemod(uint8_t *dest, size_t *size) {
+       //make sure buffer has data
+       if (*size < 64*2) return -2;
+
+       size_t startIdx = 0;
+       uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       //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)
 {
 {
-       uint8_t ans = 0;
-       for (int i = 0; i < bitLen; i++){
-               ans ^= ((bits >> i) & 1);
-       }
-  //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
-       return (ans == pType);
+       //make sure buffer has enough data
+       if (*size < 128) return -1;
+
+       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
+       return (int)startIdx;
 }
 
 // by marshmellow
 }
 
 // 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), and binary Length (length to run) 
-size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
+// FSK Demod then try to locate an AWID ID
+int AWIDdemodFSK(uint8_t *dest, size_t *size)
 {
 {
-       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--;
-               // if parity fails then return 0
-               if (parityTest(parityWd, pLen, pType) == 0) return -1;
-               bitCnt+=(pLen-1);
-               parityWd = 0;
-       }
-       // if we got here then all the parities passed
-       //return ID start index and size
-       return bitCnt;
+       //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
 }
 
 // by marshmellow
-// FSK Demod then try to locate an AWID ID
-int AWIDdemodFSK(uint8_t *dest, size_t size)
+// FSK Demod then try to locate a Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t *size)
 {
 {
-       static const uint8_t THRESHOLD = 123;
-       uint32_t idx=0;
        //make sure buffer has data
        //make sure buffer has data
-       if (size < 96*50) return -1;
+       if (*size < 128*50) return -5;
+
        //test samples are not just noise
        //test samples are not just noise
-       uint8_t justNoise = 1;
-       for(idx=0; idx < size && justNoise ;idx++){
-               justNoise = dest[idx] < THRESHOLD;
-       }
-       if(justNoise) return -2;
+       if (justNoise(dest, *size)) return -1;
 
        // FSK demodulator
 
        // FSK demodulator
-       size = fskdemod(dest, size, 50, 1, 10, 8);  //  RF/64 and invert
-       if (size < 96) return -3;  //did we get a good demod?
-
-       uint8_t mask[] = {0,0,0,0,0,0,0,1};
-       for( idx=0; idx < (size - 96); idx++) {
-               if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
-                       // frame marker found
-                       //return ID start index and size
-                       return idx;  
-                       //size should always be 96
-               }
-       }
-       //never found mask
-       return -4;
+       *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+       if (*size < 128) return -2;  //did we get a good demod?
+
+       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+       size_t startIdx = 0;
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       if (*size != 128) return -3;
+       return (int)startIdx;
 }
 
 // by marshmellow
 }
 
 // by marshmellow
-// FSK Demod then try to locate an Farpointe Data (pyramid) ID
-int PyramiddemodFSK(uint8_t *dest, size_t size)
+// 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)
 {
 {
-  static const uint8_t THRESHOLD = 123;
-  uint32_t idx=0;
- // size_t size2 = size;
-  //make sure buffer has data
-  if (size < 128*50) return -5;
-  //test samples are not just noise
-  uint8_t justNoise = 1;
-  for(idx=0; idx < size && justNoise ;idx++){
-    justNoise = dest[idx] < THRESHOLD;
-  }
-  if(justNoise) return -1;
-
-  // FSK demodulator
-  size = fskdemod(dest, size, 50, 1, 10, 8);  //  RF/64 and invert
-  if (size < 128) return -2;  //did we get a good demod?
-
-  uint8_t mask[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
-  for( idx=0; idx < (size - 128); idx++) {
-    if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
-      // frame marker found
-      return idx;
-    }
-  }
-  //never found mask
-  return -4;
+       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, int *clock) {
+       uint8_t fndClk[] = {8,16,32,40,50,64,128};
+       size_t startwave;
+       size_t i = 100;
+       size_t minClk = 255;
+       int shortestWaveIdx = 0;
+               // get to first full low to prime loop and skip incomplete first pulse
+       while ((dest[i] < high) && (i < size))
+               ++i;
+       while ((dest[i] > low) && (i < size))
+               ++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;
+                       shortestWaveIdx = startwave;
+               }
+       }
+       // set clock
+       if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
+       for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
+               if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) {
+                       *clock = fndClk[clkCnt];
+                       return shortestWaveIdx;
+               }
+       }
+       return 0;
 }
 
 // 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?
 }
 
 // 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 clk[]={8,16,32,40,50,64,100,128,256};
-       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
        int peak, low;
 
        //get high and low peak
        int peak, low;
-       getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+       if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
        
        
-       int ii;
-       int clkCnt;
-       int tol = 0;
-       int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
-       int errCnt=0;
+       //test for large clean peaks
+       if (!clockFnd){
+               if (DetectCleanAskWave(dest, size, peak, low)==1){
+                       int ans = DetectStrongAskClock(dest, size, peak, low, clock);
+                       if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
+                       if (ans > 0) {
+                               return ans; //return shortest wave start position
+                       }
+               }
+       }
+       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
        //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{
                        tol=0;
                }
                        tol=1;
                }else{
                        tol=0;
                }
+               //if no errors allowed - keep start within the first clock
+               if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
                bestErr[clkCnt]=1000;
                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++;
-                                       }
+               //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<8;++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]) ){
+       uint8_t iii;
+       uint8_t best=0;
+       for (iii=1; iii<clkEnd; ++iii){
+               if (bestErr[iii] < bestErr[best]){
+                       if (bestErr[iii] == 0) bestErr[iii]=1;
+                       // 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;
                        }
                }
                                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]);
        }
        }
-       return clk[best];
+       if (!clockFnd) *clock = clk[best];
+       return bestStart[best];
+}
+
+
+int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
+       int firstPhaseShift = 0;
+       return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
 }
 
 //by marshmellow
 }
 
 //by marshmellow
-//detect psk clock by reading #peaks vs no peaks(or errors)
-int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
-{
-       int i=0;
-       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;
+//detect psk clock by reading each phase shift
+// a phase shift is determined by measuring the sample length of each wave
+int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
+       uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
+       uint16_t loopCnt = 4096;  //don't need to loop through entire array...
+       if (size == 0) return 0;
+       if (size<loopCnt) loopCnt = size-20;
+
+       //if we already have a valid clock quit
+       size_t i=1;
+       for (; i < 8; ++i)
+               if (clk[i] == clock) return clock;
+
+       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;
+                       }
+               }
+       }
+       *firstPhaseShift = firstFullWave;
+       if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
+       //test each valid clock from greatest to smallest to see which lines up
+       for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
+               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 (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;
+               }
+       }
+       if (lowestTransition == 255) lowestTransition = 0;
+       if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
+       return lowestTransition;
+}
+
+int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
+       size_t bestStart=0;
+       return DetectNRZClock_ext(dest, size, clock, &bestStart);
+}
+
 
 
+//by marshmellow
+//detect nrz clock by reading #peaks vs no peaks(or errors)
+int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
+       size_t i=0;
+       uint8_t clk[]={8,16,32,40,50,64,100,128,255};
+       size_t loopCnt = 4096;  //don't need to loop through entire array...
+       if (size == 0) return 0;
+       if (size<loopCnt) loopCnt = size-20;
        //if we already have a valid clock quit
        for (; i < 8; ++i)
                if (clk[i] == clock) return clock;
 
        //get high and low peak
        int peak, low;
        //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;
-       getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+       if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
 
 
-       //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
-       int ii;
+       int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
+       size_t ii;
        uint8_t clkCnt;
        uint8_t tol = 0;
        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=1;
-               }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; 
+       size_t bestStart[]={0,0,0,0,0,0,0,0,0};
+       peakcnt=0;
+       //test each valid clock from smallest to greatest to see which lines up
+       for(clkCnt=0; clkCnt < 8; ++clkCnt){
+               //ignore clocks smaller than smallest peak
+               if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
                //try lining up the peaks by moving starting point (try first 256)
                //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)){
                        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){
-                                               peakcnt++;
-                                       }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
-                                               peakcnt++;
-                                       }else{  //error no peak detected
-                                               errCnt++;
+                               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 ((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++;
+                                                       }
+                                                       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]) {
                                        }
                                }
                                if(peakcnt>peaksdet[clkCnt]) {
+                                       bestStart[clkCnt]=ii;
                                        peaksdet[clkCnt]=peakcnt;
                                        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)){
+       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;
                        }
                                best = iii;
                        }
-                       //ratio2=bits/peaksdet[iii]; //debug
+               } 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);
        }
        }
+       *clockStartIdx  = bestStart[best];
        return clk[best];
 }
 
        return clk[best];
 }
 
-//by marshmellow (attempt to get rid of high immediately after a low)
-void pskCleanWave(uint8_t *BitStream, size_t size)
+// by marshmellow
+// convert psk1 demod to psk2 demod
+// only transition waves are 1s
+void psk1TOpsk2(uint8_t *BitStream, size_t size)
 {
 {
-       int i;
-       int gap = 4;
-       int newLow=0;
-       int newHigh=0;
-       int high, low;
-       getHiLo(BitStream, size, &high, &low, 80, 90);
- 
-       for (i=0; i < size; ++i){
-               if (newLow == 1){
-                       if (BitStream[i]>low){
-                               BitStream[i]=low+8;
-                               gap--;
-                       }
-                       if (gap == 0){
-                               newLow=0;
-                               gap=4;
-                       }
-               }else if (newHigh == 1){
-                       if (BitStream[i]<high){
-                               BitStream[i]=high-8;
-                               gap--;
-                       }
-                       if (gap == 0){
-                               newHigh=0;
-                               gap=4;
-                       }
+       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;
 }
 
        }
        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 indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
 {
        //26 bit 40134 format  (don't know other formats)
-       int i;
-       int 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;
+}
+
+uint8_t        detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
+       int firstClockEdge = 0;
+       return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
+}
+
+//by marshmellow
+//detects the bit clock for FSK given the high and low Field Clocks
+uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
+       uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
+       uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+       uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+       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;
+       //PrintAndLog("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;
                        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 it is inbetween set it to the last counter
+               if (fcCounter < fcHigh && fcCounter > fcLow)
+                       fcCounter = lastFCcnt;
+               else if (fcCounter < fcLow+fcTol) 
+                       fcCounter = fcLow;
+               else //set it to the large fc
+                       fcCounter = fcHigh;
+
+               //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){
+                                       //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+                                       rfCnts[rfLensFnd]++;
+                                       rfLens[rfLensFnd++] = rfCounter;
+                               }
+                       } else {
+                               *firstClockEdge = i;
+                               firstBitFnd++;
+                       }
+                       rfCounter=0;
+                       lastFCcnt=fcCounter;
                }
                }
+               fcCounter=0;
        }
        }
-       if (start == *size - 250 + 1) {
-               // did not find start sequence
-               return -1;
-       }
-       // 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;
-
-       int iii;
-       //found start once now test length by finding next one
-       for (ii=start+29; ii <= *size - 250; ii++) {
-               first2 = bitStream[ii];
-               for (iii = ii; iii < ii + long_wait; iii++) {
-                       if (bitStream[iii] != first2) {
-                               break;
+               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]);
+
+       // 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<2) 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 < 180) 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;
                        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]);
        }
        }
-       bitCnt=ii-start;
-
-       // Dumping UID
-       i = start;
-       for (ii = 0; ii < bitCnt; ii++) {
-               bitStream[ii] = bitStream[i++];
+       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];
        }
        }
-       *size=bitCnt;
-       return 1;
-}
+       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;
+       if (fskAdj) return fcs; 
+       return fcLens[best1];
+}
 
 
-//by marshmellow - demodulate PSK1 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)
+//by marshmellow - demodulate PSK1 wave 
+//uses wave lengths (# Samples) 
+int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 {
 {
-       pskCleanWave(dest,*size);
-       int clk2 = DetectpskNRZClock(dest, *size, *clk);
-       *clk=clk2;
-       uint32_t i;
-       int high, low, ans;
-       ans = getHiLo(dest, 1260, &high, &low, 75, 80); //25% fuzz on high 20% fuzz on low
-       if (ans<1) return -2; //just noise
-       uint32_t gLen = *size;
-       //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 = 1;  //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++;
+       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=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
+       uint16_t fc=0, fullWaveLen=0, tol=1;
+       uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
+       fc = countFC(dest, *size, 1);
+       uint8_t fc2 = fc >> 8;
+       if (fc2 == 10) return -1; //fsk found - quit
+       fc = fc & 0xFF;
+       if (fc!=2 && fc!=4 && fc!=8) return -1;
+       //PrintAndLog("DEBUG: FC: %d",fc);
+       *clock = DetectPSKClock(dest, *size, *clock);
+       if (*clock == 0) return -1;
+
+       //find start of modulating data in trace 
+       uint8_t threshold_value = 123; //-5
+       i = findModStart(dest, *size, threshold_value, fc);
+
+       //find first phase shift
+       int avgWaveVal=0, lastAvgWaveVal=0;
+       waveStart = i;
+       for (; i<loopCnt; i++) {
+               // find peak 
+               if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
+                       waveEnd = i+1;
+                       if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
+                       waveLenCnt = waveEnd-waveStart;
+                       if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
+                               lastAvgWaveVal = avgWaveVal/(waveLenCnt);
+                               firstFullWave = waveStart;
+                               fullWaveLen=waveLenCnt;
+                               //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
+                               if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
+                               break;
+                       } 
+                       waveStart = i+1;
+                       avgWaveVal = 0;
+               }
+               avgWaveVal += dest[i+2];
+       }
+       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 PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
+       waveStart = 0;
+       dest[numBits++] = curPhase; //set first read bit
+       for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
+               //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){  
+                                       //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
+                                       //this wave is a phase shift
+                                       //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
+                                       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 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++;
+                               } else if (i+1 > lastClkBit + *clock + tol + fc){
+                                       lastClkBit += *clock; //no phase shift but clock bit
+                                       dest[numBits++] = curPhase;
+                               } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
+                                       errCnt2++;
+                                       if(errCnt2 > 101) return errCnt2;
                                }
                                }
-                               if (bitnum>=1000) break;
+                               avgWaveVal = 0;
+                               waveStart = i+1;
                        }
                        }
-                       //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 (errCnt < bestErrCnt){  //set this as new best run
-                                       bestErrCnt = errCnt;
-                                       bestStart = iii;
+               }
+               avgWaveVal += dest[i+1];
+       }
+       *size = numBits;
+       return errCnt;
+}
+
+bool DetectST(uint8_t  buffer[], size_t *size, int *foundclock) {
+       size_t ststart = 0, stend = 0;
+       return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
+}
+
+//by marshmellow
+//attempt to identify a Sequence Terminator in ASK modulated raw wave
+bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
+       size_t bufsize = *size;
+       //need to loop through all samples and identify our clock, look for the ST pattern
+       uint8_t fndClk[] = {8,16,32,40,50,64,128};
+       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));
+
+       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/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;
+                                       }
                                }
                        }
                }
        }
                                }
                        }
                }
        }
-       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++;
+       // 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;
+                                       }
                                }
                                }
-                       //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++;
                        }
                        }
-                       if (bitnum >=1000) break;
                }
                }
-               *size=bitnum;
-       } else{
-               *size=bitnum;
-               *clk=bestStart;
-               return -1;
        }
        }
+       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;
+                       }
+               }
+       }
+       
+       size_t newloc = 0;
+       i=0;
+       if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);            
+       bool firstrun = true;
+       // warning - overwriting buffer given with raw wave data with ST removed...
+       while ( dataloc < bufsize-(clk/2) ) {
+               //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
+               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;
+                       }
+               } //test for single sample outlier (high between two lows) in the case of very strong waves
+               if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
+                       buffer[dataloc] = buffer[dataloc+2];
+                       buffer[dataloc+1] = buffer[dataloc+2];
+               }
+               if (firstrun) {
+                       *stend = dataloc;
+                       *ststart = dataloc-(clk*4);
+                       firstrun=false;
+               }
+               for (i=0; i<datalen; ++i) {
+                       if (i+newloc < bufsize) {
+                               if (i+newloc < dataloc)
+                                       buffer[i+newloc] = buffer[dataloc];
 
 
-       if (bitnum>16){
-               *size=bitnum;
-       } else return -1;
-       return errCnt;
+                               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;
 }
 
 }
 
-
-//by marshmellow
-//countFC is to detect the field clock and bit clock rates.
-//for fsk or ask not psk or nrz
-uint32_t countFC(uint8_t *BitStream, size_t size)
-{
-  // get high/low thresholds
-  int high, low;
-  getHiLo(BitStream,10, &high, &low, 100, 100);
-  // get zero crossing
-  uint8_t zeroC = (high-low)/2+low;
-  uint8_t clk[]={8,16,32,40,50,64,100,128};
-  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 rfLens[] = {0,0,0,0,0,0,0,0,0,0,0};
-  // uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0};
-  uint8_t fcLensFnd = 0;
-  uint8_t rfLensFnd = 0;
-  uint8_t lastBit=0;
-  uint8_t curBit=0;
-  uint8_t lastFCcnt=0;
-  uint32_t errCnt=0;
-  uint32_t fcCounter = 0;
-  uint32_t rfCounter = 0;
-  uint8_t firstBitFnd = 0;
-  int i;
-  
-  // prime i to first up transition
-  for (i = 1; i < size; i++)
-    if (BitStream[i]>=zeroC && BitStream[i-1]<zeroC)
-      break;
-
-  for (; i < size; i++){
-    curBit = BitStream[i];
-    lastBit = BitStream[i-1];
-    if (lastBit<zeroC && curBit >= zeroC){
-      // new up transition
-      fcCounter++;
-      rfCounter++;
-      if (fcCounter > 3 && fcCounter < 256){ 
-        //we've counted enough that it could be a valid field clock
-  
-        //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 odd and not rc/5 add one (for when we get a fc 9 instead of 10)
-        if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
-     
-        //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<10; ii++){
-              if (rfLens[ii]==rfCounter){
-                //rfCnts[ii]++;
-                rfCounter=0;
-                break;
-              }
-            }
-            if (rfCounter>0 && rfLensFnd<10){
-              //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
-              //rfCnts[rfLensFnd]++;
-              rfLens[rfLensFnd++]=rfCounter;
-            }
-          } else {
-            //PrintAndLog("DEBUG i: %d",i);
-            firstBitFnd++;
-          }
-          rfCounter=0;
-          lastFCcnt=fcCounter;
-        }
-
-        // save last field clock count  (fc/xx)
-        // find which fcLens to save it to:
-        for (int ii=0; ii<10; ii++){
-          if (fcLens[ii]==fcCounter){
-            fcCnts[ii]++;
-            fcCounter=0;
-            break;
-          }
-        }
-        if (fcCounter>0 && fcLensFnd<10){
-          //add new fc length 
-          //PrintAndLog("FCCntr %d",fcCounter);
-          fcCnts[fcLensFnd]++;
-          fcLens[fcLensFnd++]=fcCounter;
-        }
-      } else{
-        // hmmm this should not happen often - count them
-        errCnt++;
-      }
-      // reset counter
-      fcCounter=0;
-    } else {
-      // count sample
-      fcCounter++;
-      rfCounter++;
-    }
-  }
-  // if too many errors return errors as negative number (IS THIS NEEDED?)
-  if (errCnt>100) return -1*errCnt;
-  
-  uint8_t maxCnt1=0, best1=9, best2=9, best3=9, rfHighest=10, rfHighest2=10, rfHighest3=10;
-
-  // go through fclens and find which ones are bigest 2  
-  for (i=0; i<10; i++){
-    // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d, RF %d",fcLens[i],fcCnts[i],errCnt,rfLens[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;
-    }
-    //get highest 2 RF values  (might need to get more values to compare or compare all?)
-    if (rfLens[i]>rfLens[rfHighest]){
-      rfHighest3=rfHighest2;
-      rfHighest2=rfHighest;
-      rfHighest=i;
-    } else if(rfLens[i]>rfLens[rfHighest2]){
-      rfHighest3=rfHighest2;
-      rfHighest2=i;
-    } else if(rfLens[i]>rfLens[rfHighest3]){
-      rfHighest3=i;
-    }
-  }
-
-  // set allowed clock remainder tolerance to be 1 large field clock length 
-  //   we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
-  int tol1 = (fcLens[best1]>fcLens[best2]) ? fcLens[best1] : fcLens[best2]; 
-  
-  // loop to find the highest clock that has a remainder less than the tolerance
-  //   compare samples counted divided by 
-  int ii=7;
-  for (; ii>=0; 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){
-          break;
-        }
-      }
-    }
-  }
-
-  if (ii<0) ii=7; // oops we went too far
-
-  // TODO: take top 3 answers and compare to known Field clocks to get top 2
-
-  uint32_t fcs=0;
-  // PrintAndLog("DEBUG: Best %d  best2 %d best3 %d, clk %d, clk2 %d",fcLens[best1],fcLens[best2],fcLens[best3],clk[i],clk[ii]);
-  //
-
-  if (fcLens[best1]>fcLens[best2]){
-    fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best1])<<8) | ((fcLens[best2]));
-  } else {
-    fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best2])<<8) | ((fcLens[best1]));    
-  }
-
-  return fcs;
+// 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};
+       if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
+               return -2; //preamble not found
+       if (*size != 96) return -3; //wrong demoded size
+       //return start position
+       return (int)startIdx;
 }
 }
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