DEL: removed old iso14443.c since @pwpiwi renamed it..

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index eb5a4d9586253b7b43b9785aeed2ee506bfaee99..7d40d22e5aa44551835ae4ada1f69947f132e488 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -1,606 +1,536 @@
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------

-// Copyright (C) 2014 
+// Copyright (C) 2014

 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------
 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------

-// Low frequency commands
+// Low frequency demod/decode commands

 //-----------------------------------------------------------------------------
 
 //-----------------------------------------------------------------------------
 

-#include <stdio.h>

 #include <stdlib.h>
 #include <string.h>
 #include "lfdemod.h"
 #include <stdlib.h>
 #include <string.h>
 #include "lfdemod.h"

+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
+//get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
+int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
+{
+       *high=0;
+       *low=255;
+       // get high and low thresholds 
+       for (size_t i=0; i < size; i++){
+               if (BitStream[i] > *high) *high = BitStream[i];
+               if (BitStream[i] < *low) *low = BitStream[i];
+       }
+       if (*high < 123) return -1; // just noise
+       *high = ((*high-128)*fuzzHi + 12800)/100;
+       *low = ((*low-128)*fuzzLo + 12800)/100;
+       return 1;
+}
+
+// by marshmellow
+// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
+// returns 1 if passed
+uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
+{
+       uint8_t ans = 0;
+       for (uint8_t i = 0; i < bitLen; i++){
+               ans ^= ((bits >> i) & 1);
+       }
+       //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+       return (ans == pType);
+}
+
+//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)
+{
+       uint8_t foundCnt=0;
+       for (int idx=0; idx < *size - pLen; idx++){
+               if (memcmp(BitStream+idx, preamble, pLen) == 0){
+                       //first index found
+                       foundCnt++;
+                       if (foundCnt == 1){
+                               *startIdx = idx;
+                       }
+                       if (foundCnt == 2){
+                               *size = idx - *startIdx;
+                               return 1;
+                       }
+               }
+       }
+       return 0;
+}

 
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID
 
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID

-uint64_t Em410xDecode(uint8_t *BitStream, uint32_t BitLen)
+uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)

 {
        //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
        //  otherwise could be a void with no arguments
        //set defaults
 {
        //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
        //  otherwise could be a void with no arguments
        //set defaults

-       int high = 0, low = 128;
-       uint64_t lo = 0; 

        uint32_t i = 0;
        uint32_t i = 0;

-       uint32_t initLoopMax = 65;
-
-       if (initLoopMax > BitLen) 
-               initLoopMax = BitLen;
-
-       for (; i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
-       {
-               if (BitStream[i] > high)
-                       high = BitStream[i];
-               else if (BitStream[i] < low)
-                       low = BitStream[i];
-       }
+       if (BitStream[1]>1) return 0;  //allow only 1s and 0s

 
 

-       if (((high !=1)||(low !=0))){  //allow only 1s and 0s 
-               return 0;
-       }
-
-       uint8_t parityTest = 0;

        // 111111111 bit pattern represent start of frame
        // 111111111 bit pattern represent start of frame

-       uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
+       //  include 0 in front to help get start pos
+       uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};

        uint32_t idx = 0;
        uint32_t idx = 0;

-       uint32_t j = 0;
-       uint8_t resetCnt = 0;
-       while( (idx + 64) < BitLen) {
-
-       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;//sizeof(frame_marker_mask);
-               for ( i = 0; i < 10; ++i){
-                       for( j = 0; j < 5; ++j){
-                               parityTest += BitStream[(i*5) + j + idx];        
-                       }
-                       if (parityTest == ( (parityTest >> 1) << 1)){
-                               parityTest = 0;
-                               for (j = 0; j < 4; ++j){
-                                       lo = ( lo << 1LL)|( BitStream[( i * 5 ) + j + idx]);
+       uint32_t parityBits = 0;
+       uint8_t errChk = 0;
+       uint8_t FmtLen = 10;
+       *startIdx = 0;
+       errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
+       if (errChk == 0 || *size < 64) return 0;
+       if (*size > 64) FmtLen = 22;
+       *startIdx += 1; //get rid of 0 from preamble
+       idx = *startIdx + 9;
+       for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
+               parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
+               //check even parity - quit if failed
+               if (parityTest(parityBits, 5, 0) == 0) return 0;
+               //set uint64 with ID from BitStream
+               for (uint8_t ii=0; ii<4; ii++){
+                       *hi = (*hi << 1) | (*lo >> 63);
+                       *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
+               }
+       }
+       if (errChk != 0) return 1;
+       //skip last 5 bit parity test for simplicity.
+       // *size = 64 | 128;
+       return 0;
+}
+
+//by marshmellow
+//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++;
+                                               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

                                }
                                }

-                       } else {
-                               //parity failed
-                               parityTest = 0;
-                               idx -= 8;
-                               if (resetCnt > 5) return 0;
-                               resetCnt++;
-                               goto restart;//continue;
+                       } else { //haven't hit new high or new low yet
+                               smplCnt++;

                        }
                }
                        }
                }

-               //skip last 5 bit parity test for simplicity.
-               return lo;
-               } else {
-                       idx++;
-               }
-       }       
-       return 0;
+       }
+       *size = bitCnt;
+       return errCnt;

 }
 
 //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, uint32_t *BitLen, int *clk, int *invert)
+void askAmp(uint8_t *BitStream, size_t size)

 {
 {

-       int i;
-       int high = 0, low = 128;
-       *clk = DetectASKClock(BinStream, (size_t)*BitLen, *clk); //clock default
-       
-       if (*clk < 8 )    *clk = 64;
-       if (*clk < 32 )   *clk = 32;
+       for(size_t i = 1; i<size; i++){
+               if (BitStream[i]-BitStream[i-1]>=30) //large jump up
+                       BitStream[i]=127;
+               else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
+                       BitStream[i]=-127;
+       }
+       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 (*invert != 1) *invert = 0;

-       
-       uint32_t initLoopMax = 200;
-       if (initLoopMax > *BitLen) 
-               initLoopMax = *BitLen;
-  
-       // Detect high and lows 
-       // 200 samples should be enough to find high and low values
-       for (i = 0; i < initLoopMax; ++i) {
-               if (BinStream[i] > high)
-                       high = BinStream[i];
-               else if (BinStream[i] < low)
-                       low = BinStream[i];
-       }
-  
-       //throw away static 
-       if ((high < 158) )
-               return -2;
+       if (amp==1) askAmp(BinStream, *size);

 
 

-       //25% fuzz in case highs and lows aren't clipped [marshmellow]
-       high = (int)(high * .75);
-       low  = (int)(low+128 * .25);
- 
-       int lastBit = 0;      // set first clock check
-       uint32_t bitnum = 0;  // output counter
-
-       // clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
-       //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely 
-       int tol = ( *clk == 32 ) ? 1 : 0;  
-
-       int j = 0;
-       uint32_t gLen = *BitLen;
-
-       if (gLen > 3000) gLen = 3000;
-
-       uint8_t errCnt = 0;
-       uint32_t bestStart = *BitLen;
-       uint32_t bestErrCnt = (*BitLen/1000);
-       uint32_t maxErr = bestErrCnt;
-
-  //loop to find first wave that works
-       for (j=0; j < gLen; ++j){
-  
-               if ((BinStream[j] >= high)||(BinStream[j] <= low)){
-                 lastBit = j - *clk;    
-                 errCnt = 0;
-         
-      //loop through to see if this start location works
-      for (i = j; i < *BitLen; ++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!!
-           
-            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 ((i-j) >(400 * *clk)) break; //got plenty of bits
-      }
-      //we got more than 64 good bits and not all errors
-      if ((((i-j)/ *clk) > (64 + errCnt)) && (errCnt < maxErr)) {
-        //possible good read
-        if (errCnt == 0){
-                       bestStart = j;
-                       bestErrCnt = errCnt;
-                       break;  //great read - finish
-        } 
-        if (errCnt < bestErrCnt){  //set this as new best run
-          bestErrCnt = errCnt;
-          bestStart = j;
-        }
-      }
-    }
-  }
-  if (bestErrCnt < maxErr){
-       //best run is good enough set to best run and set overwrite BinStream
-       j = bestStart;
-       lastBit = bestStart - *clk;
-       bitnum = 0;
-    for (i = j; i < *BitLen; ++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
+       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)) {
+               errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
+               if (askType) //askman
+                       return manrawdecode(BinStream, size, 0);        
+               else //askraw
+                       return errCnt;
+       }
+
+       int lastBit;  //set first clock check - can go negative
+       size_t i, bitnum = 0;     //output counter
+       uint8_t midBit = 0;
+       uint8_t tol = 0;  //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+       if (*clk <= 32) tol = 1;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
+       size_t MaxBits = 1024;
+       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) {
+                                       BinStream[bitnum++]=7;
+                                       errCnt++;                                               
+                               } 
+                       } else { //in tolerance - looking for peak
+                               continue;
+                       }
+                       midBit = 0;

                        lastBit += *clk;
                        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!!
-                               if (bitnum > 0){
-                                       BinStream[bitnum] = 77;
-                                       bitnum++;
-                               }
-                               lastBit += *clk;//skip over error
+               } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
+                       if (BinStream[i] >= high) {
+                               BinStream[bitnum++] = *invert;
+                       } else if (BinStream[i] <= low) {
+                               BinStream[bitnum++] = *invert ^ 1;
+                       } else if (i-lastBit >= *clk/2+tol) {
+                               BinStream[bitnum] = BinStream[bitnum-1];
+                               bitnum++;
+                       } else { //in tolerance - looking for peak
+                               continue;

                        }
                        }

+                       midBit = 1;

                }
                }

-               if (bitnum >= 400) break;
-               }
-               *BitLen = bitnum;
-       } else {
-               *invert = bestStart;
-               *clk = j;
-               return -1; 
-       }       
-  return bestErrCnt;
+               if (bitnum >= MaxBits) break;
+       }
+       *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 * bits, int *bitlen)
-{
-  int bitnum = 0;
-  int errCnt = 0;
-  int bestErr = 1000;
-  int bestRun = 0;
-  int i = 1;
-  int j = 1;
-
-       for (; j < 3; ++j){
-               i = 1;
-               for ( i = i + j; i < *bitlen-2; i += 2){
-                       if ( bits[i]==1 && (bits[i+1]==0)){
-                       } else if ((bits[i]==0)&& bits[i+1]==1){
-                       } else {
+int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
+{
+       uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
+       size_t i, 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 = j;
-               }       
-               errCnt = 0;
-       }
-       errCnt = bestErr;
-       if (errCnt < 20){
-               j = bestRun;
-               i = 1;
-               for ( i = i+j; i < *bitlen-2; i += 2){
-                       if ( bits[i] == 1 && bits[i + 1] == 0 ){
-                                       bits[bitnum++] = 0;
-                       } else if ( bits[i] == 0 && bits[i + 1] == 1 ){
-                                       bits[bitnum++] = 1;
-                       } else {
-                               bits[bitnum++] = 77;
-                       }
-                       if ( bitnum > 300 ) break;
+
+               if (bestErr>errCnt){
+                       bestErr=errCnt;
+                       bestRun=ii;

                }
                }

-               *bitlen = bitnum;
-       }   
-       return errCnt;
+               errCnt=0;
+       }
+       //decode
+       for (i=bestRun; i < *size-3; i+=2){
+               if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
+                       BitStream[bitnum++]=invert;
+               } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
+                       BitStream[bitnum++]=invert^1;
+               } else {
+                       BitStream[bitnum++]=7;
+               }
+               if(bitnum>MaxBits) break;
+       }
+       *size=bitnum;
+       return bestErr;

 }
 
 }
 

+//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
-int BiphaseRawDecode(uint8_t * bits, int *bitlen, int offset)
+//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)

 {
 {

-       uint8_t bitnum = 0;
-       uint32_t errCnt = 0;
-       uint32_t i = offset;
-       
-       for (; i < *bitlen-2; i += 2 ){
-               if ( (bits[i]==1 && bits[i+1]==0)||
-                        (bits[i]==0 && bits[i+1]==1)){
-                       bits[bitnum++] = 1;
-               } else if ( (bits[i]==0 && bits[i+1]==0)||
-                                       (bits[i]==1 && bits[i+1]==1)){
-                       bits[bitnum++] = 0;
+       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 {
                } else {

-                       bits[bitnum++] = 77;
+                       BitStream[bitnum++]=7;

                        errCnt++;
                }
                        errCnt++;
                }

-               if ( bitnum > 250) break;
-       }  
-       *bitlen = bitnum;
+               if(bitnum>MaxBits) break;
+       }
+       *size=bitnum;

        return errCnt;
 }
 
        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, int *bitLen, int *clk, int *invert)
-{
-  uint32_t i;
-  uint32_t initLoopMax = 200;
-  int high = 0, low = 128;
-  uint8_t BitStream[502] = {0x00};
-  
-  *clk = DetectASKClock(BinStream, *bitLen, *clk); //clock default
-  
-  if (*clk < 8)                *clk = 64;      
-  if (*clk < 32)       *clk = 32;      
-  if (*invert != 1) *invert = 0;
-
-  if (initLoopMax > *bitLen) 
-       initLoopMax = *bitLen;
-  
-  // Detect high and lows 
-  for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
-  {
-    if (BinStream[i] > high)
-               high = BinStream[i];
-    else if (BinStream[i] < low)
-               low = BinStream[i];
-  }
-  
-  //throw away static
-       if ((high < 158)){  
-               return -2;
-       }
-  
-       //25% fuzz in case highs and lows aren't clipped [marshmellow]
-       high = (int)(high * .75);
-       low  = (int)(low+128 * .25);
-
-  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 gLen = *bitLen;
-  if (gLen > 500) gLen = 500;
-
-  uint32_t j = 0;
-  uint8_t errCnt = 0;
-  uint32_t bestStart = *bitLen;
-  uint32_t bestErrCnt = (*bitLen / 1000);
-  uint32_t errCntLimit = bestErrCnt;
-  uint8_t midBit = 0;
-  
-  //loop to find first wave that works
-  for (j = 0; j < gLen; ++j){
-  
-    if ((BinStream[j] >= high)||(BinStream[j] <= low)){
-      lastBit = j - *clk;    
-      //loop through to see if this start location works
-      for (i = j; i < *bitLen; ++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!!
-
-            if (bitnum > 0){
-              BitStream[bitnum] = 77;
-              bitnum++;
-            }
-
-            errCnt++;
-            lastBit += *clk;//skip over until hit too many errors
-            if (errCnt > errCntLimit){  //allow 1 error for every 1000 samples else start over
-              errCnt = 0;
-              bitnum = 0;//start over
-              break;
-            }
-          }          
-        }
-        if (bitnum > 500) break;
-      }
-      //we got more than 64 good bits and not all errors
-         //possible good read
-      if ((bitnum > (64 + errCnt)) && (errCnt < errCntLimit)) {
-
-               //great read - finish
-        if (errCnt == 0) break;  
-               
-               //if current run == bestErrCnt run (after exhausted testing) then finish 
-        if (bestStart == j) break;  
-        
-               //set this as new best run
-               if (errCnt < bestErrCnt){
-          bestErrCnt = errCnt;
-          bestStart = j;
-        }
-      }
-    }
-    if (j >= gLen){ //exhausted test
-      //if there was a ok test go back to that one and re-run the best run (then dump after that run)
-      if (bestErrCnt < errCntLimit) 
-               j = bestStart;
-    }
-  }
-       if (bitnum > 16){
-
-               for (i = 0; i < bitnum; ++i){
-                       BinStream[i] = BitStream[i];
-               }
-               *bitLen = bitnum;
-       } else {
-               return -1;
+// by marshmellow
+// demod gProxIIDemod 
+// error returns as -x 
+// success returns start position in BitStream
+// BitStream must contain previously askrawdemod and biphasedemoded data
+int gProxII_Demod(uint8_t BitStream[], size_t *size)
+{
+       size_t startIdx=0;
+       uint8_t preamble[] = {1,1,1,1,1,0};
+
+       uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -3; //preamble not found
+       if (*size != 96) return -2; //should have found 96 bits
+       //check first 6 spacer bits to verify format
+       if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
+               //confirmed proper separator bits found
+               //return start position
+               return (int) startIdx;

        }
        }

-  return errCnt;
+       return -5;

 }
 }

-//translate wave to 11111100000 (1 for each short wave 0 for each long wave) 
+
+//translate wave to 11111100000 (1 for each short wave 0 for each long wave)

 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
 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;
-       
-       if (fchigh == 0) fchigh = 10;
-       if (fclow == 0) fclow = 8;
-       
-       // we do care about the actual theshold value as sometimes near the center of the
-       // wave we may get static that changes direction of wave for one value
-       // if our value is too low it might affect the read.  and if our tag or
-       // antenna is weak a setting too high might not see anything. [marshmellow]
-       if ( size < 100)
-               return 0;
-       
-       // Find high from first 100 samples
-       for ( idx = 1; idx < 100; idx++ ){
-               if ( maxVal < dest[idx]) 
-                       maxVal = dest[idx];
-       }
-       
-    // set close to the top of the wave threshold with 25% margin for error
-    // less likely to get a false transition up there. 
-    // (but have to be careful not to go too high and miss some short waves)
-       uint8_t threshold_value = (uint8_t)(maxVal * .75);
-       
+       size_t last_transition = 0;
+       size_t idx = 1;
+       //uint32_t maxVal=0;
+       if (fchigh==0) fchigh=10;
+       if (fclow==0) fclow=8;
+       //set the threshold close to 0 (graph) or 128 std to avoid static
+       uint8_t threshold_value = 123; 
+

        // sync to first lo-hi transition, and threshold
        // sync to first lo-hi transition, and threshold

+

        // Need to threshold first sample
        // Need to threshold first sample

-       
-       dest[0] = (dest[0] < threshold_value) ? 0 : 1;
+
+       if(dest[0] < threshold_value) dest[0] = 0;
+       else dest[0] = 1;

 
        size_t numBits = 0;
 
        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
        // 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++) {
        // 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
        // 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++) {

-

                // threshold current value
                // threshold current value

-               dest[idx] = (dest[idx] < threshold_value) ? 0 : 1;
+
+               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
 
                // 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 ((idx-last_transition)<(fclow-2)){            //0-5 = garbage noise

                                //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 ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
+                               dest[numBits++]=1;
+                       } else if ((idx-last_transition) > (fchigh+1) && !numBits) { //12 + and first bit = garbage 
+                               //do nothing with beginning garbage
+                       } else {                                         //9+ = 10 waves
+                               dest[numBits++]=0;

                        }
                        last_transition = idx;
                        }
                        last_transition = idx;

-                       numBits++;

                }
        }
                }
        }

-       //it returns the number of bytes, but each byte represents a bit: 1 or 0
-       return numBits; 
-}
-
-uint32_t myround2(float f)
-{
-  if (f >= 2000) return 2000;//something bad happened
-  return (uint32_t) (f + (float)0.5);
+       return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0

 }
 
 }
 

-//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 )
+//translate 11111100000 to 10
+size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
+               uint8_t invert, uint8_t fchigh, uint8_t fclow)

 {
 {

-       uint8_t lastval = dest[0];
-       uint32_t idx = 0;
-       uint32_t n = 1;
-       size_t numBits = 0;
-
-       for( idx = 1; idx < size; idx++) {
-
-               if (dest[idx] == lastval) {
-                       n++;
-                       continue;
-               }
+       uint8_t lastval=dest[0];
+       size_t idx=0;
+       size_t numBits=0;
+       uint32_t n=1;
+       for( idx=1; idx < size; idx++) {
+               n++;
+               if (dest[idx]==lastval) continue; 
+               

                //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-2)/(float)fchigh));  //-2 for fudge factor
+               if (dest[idx-1]==1) {
+                       if (!numBits && n < rfLen/fclow) {
+                               n=0;
+                               lastval = dest[idx];
+                               continue;
+                       }
+                       n = (n * fclow + rfLen/2) / rfLen;
+               } else {// 0->1 crossing 
+                       //test first bitsample too small
+                       if (!numBits && n < rfLen/fchigh) {
+                               n=0;
+                               lastval = dest[idx];
+                               continue;
+                       }
+                       n = (n * fchigh + rfLen/2) / rfLen; 

                }
                if (n == 0) n = 1;
 
                }
                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;
-               }
-               n = 0;
-               lastval = dest[idx];
+               memset(dest+numBits, dest[idx-1]^invert , n);
+               numBits += n;
+               n=0;
+               lastval=dest[idx];

        }//end for
        }//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);

-       if ( size > 0 )
-               size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
+       size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);

        return size;
 }
 
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
        return size;
 }
 
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it

-int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
+int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)

 {
 {

-       size_t idx = 0;
-       int numshifts = 0;
+       if (justNoise(dest, *size)) return -1;

 
 

+       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};
+       *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

 
 

-       uint8_t mask_len =  sizeof frame_marker_mask /  sizeof frame_marker_mask[0];
-       
-       //one scan
-       while( idx + mask_len < size) {
-       // search for a start of frame marker
-               if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
-               { // frame marker found
-                       idx += mask_len;
-                       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 + mask_len < 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++;
+       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, int 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)

 {
 {

-       //HACK:  potential overflow in numbits is larger then uint32 bits.
+       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 (int)startIdx;
+}
+
+uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
+{

        uint32_t num = 0;
        uint32_t num = 0;

-       for(int i = 0 ; i < numbits ; ++i)      {
+       for(int i = 0 ; i < numbits ; i++)
+       {

                num = (num << 1) | (*src);
                src++;
        }
                num = (num << 1) | (*src);
                src++;
        }


@@ -609,27 +539,12 @@ uint32_t bytebits_to_byte(uint8_t *src, int numbits)
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {

+       if (justNoise(dest, size)) return -1;

        //make sure buffer has data
        //make sure buffer has data

-       if (size < 100) return -1;
-       
-       uint32_t idx = 0;
-       uint8_t testMax = 0;
-       
-       //test samples are not just noise
-       for (; idx < 65; ++idx ){
-               if (testMax < dest[idx])
-                       testMax = dest[idx];
-       }
-
-       //if not, just noise
-       if (testMax < 20) return -2;
-               
+       if (size < 66*64) return -2;

        // FSK demodulator
        // FSK demodulator

-       size = fskdemod(dest, size, 64, 1, 10, 8);  //  RF/64 and invert
-       
-       //did we get a good demod?
-       if (size < 65) return -3;
-       
+       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
        //|           |           |           |           |           |           |


@@ -639,23 +554,138 @@ 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 -5;
+}
+
+// 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)
+{
+       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;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an AWID ID
+int AWIDdemodFSK(uint8_t *dest, size_t *size)
+{
+       //make sure buffer has enough data
+       if (*size < 96*50) return -1;
+
+       if (justNoise(dest, *size)) return -2;
+
+       // FSK demodulator
+       *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+       if (*size < 96) return -3;  //did we get a good demod?
+
+       uint8_t preamble[] = {0,0,0,0,0,0,0,1};
+       size_t startIdx = 0;
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       if (*size != 96) return -5;
+       return (int)startIdx;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t *size)
+{
+       //make sure buffer has data
+       if (*size < 128*50) return -5;
+
+       //test samples are not just noise
+       if (justNoise(dest, *size)) return -1;
+
+       // FSK demodulator
+       *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+       if (*size < 128) return -2;  //did we get a good demod?
+
+       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+       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
+// to detect a wave that has heavily clipped (clean) samples
+uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
+{
+       uint16_t allPeaks=1;
+       uint16_t cntPeaks=0;
+       size_t loopEnd = 512+60;
+       if (loopEnd > size) loopEnd = size;
+       for (size_t i=60; i<loopEnd; i++){
+               if (dest[i]>low && dest[i]<high) 
+                       allPeaks=0;
+               else
+                       cntPeaks++;
+       }
+       if (allPeaks == 0){
+               if (cntPeaks > 300) return 1;
+       }
+       return allPeaks;
+}
+
+// by marshmellow
+// to help detect clocks on heavily clipped samples
+// based on count of low to low
+int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
+{
+       uint8_t fndClk[] = {8,16,32,40,50,64,128};
+       size_t startwave;
+       size_t i = 0;
+       size_t minClk = 255;
+               // get to first full low to prime loop and skip incomplete first pulse
+       while ((dest[i] < high) && (i < size))
+               ++i;
+       while ((dest[i] > low) && (i < size))
+               ++i;
+
+       // loop through all samples
+       while (i < size) {
+               // measure from low to low
+               while ((dest[i] > low) && (i < size))
+                       ++i;
+               startwave= i;
+               while ((dest[i] < high) && (i < size))
+                       ++i;
+               while ((dest[i] > low) && (i < size))
+                       ++i;
+               //get minimum measured distance
+               if (i-startwave < minClk && i < size)
+                       minClk = i - startwave;
+       }
+       // set clock
+       for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
+               if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
+                       return fndClk[clkCnt];

        }
        return 0;
 }
        }
        return 0;
 }


@@ -663,88 +693,764 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 // by marshmellow
 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
 // maybe somehow adjust peak trimming value based on samples to fix?
 // 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[] = {16,32,40,50,64,100,128,256};
-       uint8_t clkLen = sizeof clk / sizeof clk[0];
+       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) return -1; //not enough samples
+
+       //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;
+       if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
+       
+       //test for large clean peaks
+       if (!clockFnd){
+               if (DetectCleanAskWave(dest, size, peak, low)==1){
+                       int ans = DetectStrongAskClock(dest, size, peak, low);
+                       for (i=clkEnd-1; i>0; i--){
+                               if (clk[i] == ans) {
+                                       *clock = ans;
+                                       //clockFnd = i;
+                                       return 0;  // for strong waves i don't use the 'best start position' yet...
+                                       //break; //clock found but continue to find best startpos [not yet]
+                               }
+                       }
+               }
+       }

        
        

+       uint8_t ii;
+       uint8_t clkCnt, tol = 0;
+       uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
+       uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
+       size_t errCnt = 0;
+       size_t arrLoc, loopEnd;
+
+       if (clockFnd>0) {
+               clkCnt = clockFnd;
+               clkEnd = clockFnd+1;
+       }
+       else clkCnt=1;
+
+       //test each valid clock from smallest to greatest to see which lines up
+       for(; clkCnt < clkEnd; clkCnt++){
+               if (clk[clkCnt] <= 32){
+                       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;
+               //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 then we can stop here and a low clock (common clocks)
+                       //  this is correct one - return this clock
+                                       //PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %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;
+                       }
+               }
+       }
+       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;
+                       }
+               }
+       }
+       //if (bestErr[best] > maxErr) return -1;
+       if (!clockFnd) *clock = clk[best];
+       return bestStart[best];
+}
+
+//by marshmellow
+//detect psk clock by reading each phase shift
+// a phase shift is determined by measuring the sample length of each wave
+int DetectPSKClock(uint8_t dest[], size_t size, int clock)
+{
+       uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
+       uint16_t loopCnt = 4096;  //don't need to loop through entire array...
+       if (size == 0) return 0;
+       if (size<loopCnt) loopCnt = size;
+

        //if we already have a valid clock quit
        //if we already have a valid clock quit

-       for (; i < clkLen; ++i)
-               if (clk[i] == clock) 
-                       return clock;
-                       
-       int peak = 0;
-       int low = 128;  
-       int loopCnt = 256;
-       if (size < loopCnt) 
-               loopCnt = size;
+       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;
+       //PrintAndLog("DEBUG: FC: %d",fc);
+
+       //find first full wave
+       for (i=0; i<loopCnt; i++){
+               if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
+                       if (waveStart == 0) {
+                               waveStart = i+1;
+                               //PrintAndLog("DEBUG: waveStart: %d",waveStart);
+                       } else {
+                               waveEnd = i+1;
+                               //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
+                               waveLenCnt = waveEnd-waveStart;
+                               if (waveLenCnt > fc){
+                                       firstFullWave = waveStart;
+                                       fullWaveLen=waveLenCnt;
+                                       break;
+                               } 
+                               waveStart=0;
+                       }
+               }
+       }
+       //PrintAndLog("DEBUG: 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;
+               //PrintAndLog("DEBUG: 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
+                                               //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+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;
+               }
+               //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
+       }
+       return clk[best];
+}
+
+//by marshmellow
+//detect nrz clock by reading #peaks vs no peaks(or errors)
+int DetectNRZClock(uint8_t dest[], size_t size, int clock)
+{
+       size_t i=0;
+       uint8_t clk[]={8,16,32,40,50,64,100,128,255};
+       size_t loopCnt = 4096;  //don't need to loop through entire array...
+       if (size == 0) return 0;
+       if (size<loopCnt) loopCnt = size;
+
+       //if we already have a valid clock quit
+       for (; i < 8; ++i)
+               if (clk[i] == clock) return clock;
+

        //get high and low peak
        //get high and low peak

-       for ( i = 0; i < loopCnt; ++i ){
-               if(dest[i] > peak) 
-                       peak = dest[i]; 
-               if(dest[i] < low) 
-                       low = dest[i];
-       }
-
-       peak = (int)(peak * .75);
-       low  = (int)(low+128 * .25);
- 
-       int ii, cnt, bestErr, tol = 0;
-       int errCnt[clkLen];
-       memset(errCnt, 0x00, clkLen);
-       
-       int tmpIndex, tmphigh, tmplow;
-       
+       int peak, low;
+       if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
+
+       //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
+       size_t ii;
+       uint8_t clkCnt;
+       uint8_t tol = 0;
+       uint16_t peakcnt=0;
+       uint16_t peaksdet[]={0,0,0,0,0,0,0,0};
+       uint16_t maxPeak=0;
+       //test for large clipped waves
+       for (i=0; i<loopCnt; i++){
+               if (dest[i] >= peak || dest[i] <= low){
+                       peakcnt++;
+               } else {
+                       if (peakcnt>0 && maxPeak < peakcnt){
+                               maxPeak = peakcnt;
+                       }
+                       peakcnt=0;
+               }
+       }
+       peakcnt=0;

        //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( cnt = 0; cnt < clkLen; ++cnt ){
+       for(clkCnt=0; clkCnt < 8; ++clkCnt){
+               //ignore clocks smaller than largest peak
+               if (clk[clkCnt]<maxPeak) continue;

 
 

-               tol = (clk[cnt] == 32) ? 1 : 0;
-               bestErr = 1000;
-               tmpIndex = tmphigh = tmplow = 0;
+               //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)){
+                               peakcnt=0;
+                               // now that we have the first one lined up test rest of wave array
+                               for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
+                                       if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
+                                               peakcnt++;
+                                       }
+                               }
+                               if(peakcnt>peaksdet[clkCnt]) {
+                                       peaksdet[clkCnt]=peakcnt;
+                               }
+                       }
+               }
+       }
+       int iii=7;
+       uint8_t best=0;
+       for (iii=7; iii > 0; iii--){
+               if (peaksdet[iii] > peaksdet[best]){
+                       best = iii;
+               }
+               //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
+       }
+       return clk[best];
+}

 
 

-               //try lining up the peaks by moving starting point (try first 256) 
-               for (ii=0; ii < loopCnt; ++ii){
-               
-                       // not a peak? continue
-                       if ( (dest[ii] < peak) && (dest[ii] > low)) 
-                               continue;
+// by marshmellow
+// convert psk1 demod to psk2 demod
+// only transition waves are 1s
+void psk1TOpsk2(uint8_t *BitStream, size_t size)
+{
+       size_t i=1;
+       uint8_t lastBit=BitStream[0];
+       for (; i<size; i++){
+               if (BitStream[i]==7){
+                       //ignore errors
+               } else if (lastBit!=BitStream[i]){
+                       lastBit=BitStream[i];
+                       BitStream[i]=1;
+               } else {
+                       BitStream[i]=0;
+               }
+       }
+       return;
+}

 
 

-                       errCnt[cnt] = 0;
-                       
-                       // now that we have the first one lined up test rest of wave array
-                       for ( i = 0; i < ((int)(size / clk[cnt]) - 1); ++i){
-                         
-                               tmpIndex = ii + (i * clk[cnt] );
-                               tmplow  = dest[ tmpIndex - tol];
-                               tmphigh = dest[ tmpIndex + tol];
-                               
-                               if ( dest[tmpIndex] >= peak || dest[tmpIndex] <= low ) {
+// 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
+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;
+                       }
+               }
+               if (i == (start + long_wait)) {
+                       break;
+               }
+       }
+       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];
+               }
+               *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 (iii == (ii + long_wait)) {
+                       break;
+               }
+       }
+       if (ii== *size - 250 + 1){
+               // did not find second start sequence
+               return -2;
+       }
+       bitCnt=ii-start;
+
+       // Dumping UID
+       i = start;
+       for (ii = 0; ii < bitCnt; ii++) {
+               bitStream[ii] = bitStream[i++];
+       }
+       *size=bitCnt;
+       return 1;
+}
+
+// by marshmellow - demodulate NRZ wave (both similar enough)
+// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
+// there probably is a much simpler way to do this.... 
+int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
+{
+       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;
+       int high, low;
+       if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
+       int lastBit = 0;  //set first clock check
+       size_t iii = 0, bitnum = 0; //bitnum counter
+       uint16_t errCnt = 0, MaxBits = 1000;
+       size_t bestErrCnt = maxErr+1;
+       size_t bestPeakCnt = 0, bestPeakStart = 0;
+       uint8_t bestFirstPeakHigh=0, firstPeakHigh=0, curBit=0, bitHigh=0, errBitHigh=0;
+       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
+       uint16_t peakCnt=0;
+       uint8_t ignoreWindow=4;
+       uint8_t ignoreCnt=ignoreWindow; //in case of noise near peak
+       //loop to find first wave that works - align to clock
+       for (iii=0; iii < gLen; ++iii){
+               if ((dest[iii]>=high) || (dest[iii]<=low)){
+                       if (dest[iii]>=high) firstPeakHigh=1;
+                       else firstPeakHigh=0;
+                       lastBit=iii-*clk;
+                       peakCnt=0;
+                       errCnt=0;
+                       //loop through to see if this start location works
+                       for (i = iii; i < *size; ++i) {
+                               // if we are at a clock bit
+                               if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
+                                       //test high/low
+                                       if (dest[i] >= high || dest[i] <= low) {
+                                               bitHigh = 1;
+                                               peakCnt++;
+                                               errBitHigh = 0;
+                                               ignoreCnt = ignoreWindow;
+                                               lastBit += *clk;
+                                       } else if (i == lastBit + *clk + tol) {
+                                               lastBit += *clk;
+                                       }
+                               //else if no bars found
+                               } else if (dest[i] < high && dest[i] > low){
+                                       if (ignoreCnt==0){
+                                               bitHigh=0;
+                                               if (errBitHigh==1) errCnt++;
+                                               errBitHigh=0;
+                                       } else {
+                                               ignoreCnt--;
+                                       }
+                               } else if ((dest[i]>=high || dest[i]<=low) && (bitHigh==0)) {
+                                       //error bar found no clock...
+                                       errBitHigh=1;

                                }
                                }

-                               else if ( tmplow >= peak || tmplow <= low){
-                               }                                       
-                               else if ( tmphigh >= peak || tmphigh <= low){
+                               if (((i-iii) / *clk)>=MaxBits) break;
+                       }
+                       //we got more than 64 good bits and not all errors
+                       if (((i-iii) / *clk) > 64 && (errCnt <= (maxErr))) {
+                               //possible good read
+                               if (!errCnt || peakCnt > bestPeakCnt){
+                                       bestFirstPeakHigh=firstPeakHigh;
+                                       bestErrCnt = errCnt;
+                                       bestPeakCnt = peakCnt;
+                                       bestPeakStart = iii;
+                                       if (!errCnt) break;  //great read - finish
+                               }
+                       }
+               }
+       }
+       //PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart);
+       if (bestErrCnt > maxErr) return bestErrCnt;             
+
+       //best run is good enough set to best run and set overwrite BinStream
+       lastBit = bestPeakStart - *clk;
+       memset(dest, bestFirstPeakHigh^1, bestPeakStart / *clk);
+       bitnum += (bestPeakStart / *clk);
+       for (i = bestPeakStart; i < *size; ++i) {
+               // if expecting a clock bit
+               if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
+                       // test high/low
+                       if (dest[i] >= high || dest[i] <= low) {
+                               peakCnt++;
+                               bitHigh = 1;
+                               errBitHigh = 0;
+                               ignoreCnt = ignoreWindow;
+                               curBit = *invert;
+                               if (dest[i] >= high) curBit ^= 1;
+                               dest[bitnum++] = curBit;
+                               lastBit += *clk;
+                       //else no bars found in clock area
+                       } else if (i == lastBit + *clk + tol) {
+                               dest[bitnum++] = curBit;
+                               lastBit += *clk;
+                       }
+               //else if no bars found
+               } else if (dest[i] < high && dest[i] > low){
+                       if (ignoreCnt == 0){
+                               bitHigh = 0;
+                               if (errBitHigh == 1){
+                                       dest[bitnum++] = 7;
+                                       errCnt++;

                                }
                                }

-                               else 
-                                       errCnt[cnt]++; //error no peak detected
+                               errBitHigh=0;
+                       } else {
+                               ignoreCnt--;

                        }
                        }

+               } else if ((dest[i] >= high || dest[i] <= low) && (bitHigh == 0)) {
+                       //error bar found no clock...
+                       errBitHigh=1;
+               }
+               if (bitnum >= MaxBits) break;
+       }
+       *size = bitnum;
+       return bestErrCnt;
+}

 
 

-                       //if we found no errors this is correct one - return this clock
-                       if ( errCnt[cnt] == 0 )
-                               return clk[cnt];
+//by marshmellow
+//detects the bit clock for FSK given the high and low Field Clocks
+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
+{
+       uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
+       uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+       uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+       uint8_t rfLensFnd = 0;
+       uint8_t lastFCcnt = 0;
+       uint16_t fcCounter = 0;
+       uint16_t rfCounter = 0;
+       uint8_t firstBitFnd = 0;
+       size_t i;
+       if (size == 0) return 0;
+
+       uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+       rfLensFnd=0;
+       fcCounter=0;
+       rfCounter=0;
+       firstBitFnd=0;
+       //PrintAndLog("DEBUG: fcTol: %d",fcTol);
+       // prime i to first up transition
+       for (i = 1; i < size-1; i++)
+               if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
+                       break;
+
+       for (; i < size-1; i++){
+               fcCounter++;
+               rfCounter++;

 
 

-                       if ( errCnt[cnt] < bestErr) 
-                               bestErr = errCnt[cnt];
+               if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) 
+                       continue;               
+               // else new peak 
+               // if we got less than the small fc + tolerance then set it to the small fc
+               if (fcCounter < fcLow+fcTol) 
+                       fcCounter = fcLow;
+               else //set it to the large fc
+                       fcCounter = fcHigh;
+
+               //look for bit clock  (rf/xx)
+               if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
+                       //not the same size as the last wave - start of new bit sequence
+                       if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
+                               for (int ii=0; ii<15; ii++){
+                                       if (rfLens[ii] == rfCounter){
+                                               rfCnts[ii]++;
+                                               rfCounter = 0;
+                                               break;
+                                       }
+                               }
+                               if (rfCounter > 0 && rfLensFnd < 15){
+                                       //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+                                       rfCnts[rfLensFnd]++;
+                                       rfLens[rfLensFnd++] = rfCounter;
+                               }
+                       } else {
+                               firstBitFnd++;
+                       }
+                       rfCounter=0;
+                       lastFCcnt=fcCounter;

                }
                }

-               // save the least error.
-               errCnt[cnt] = bestErr;
+               fcCounter=0;

        }
        }

-       // find best clock which has lowest number of errors
-       int j = 0, bestIndex = 0;
-       for (; j < clkLen; ++j){
-               if ( errCnt[j] < errCnt[bestIndex] )
-                       bestIndex = j;
+       uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
+
+       for (i=0; i<15; i++){
+               //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
+               //get highest 2 RF values  (might need to get more values to compare or compare all?)
+               if (rfCnts[i]>rfCnts[rfHighest]){
+                       rfHighest3=rfHighest2;
+                       rfHighest2=rfHighest;
+                       rfHighest=i;
+               } else if(rfCnts[i]>rfCnts[rfHighest2]){
+                       rfHighest3=rfHighest2;
+                       rfHighest2=i;
+               } else if(rfCnts[i]>rfCnts[rfHighest3]){
+                       rfHighest3=i;
+               }
+       }  
+       // set allowed clock remainder tolerance to be 1 large field clock length+1 
+       //   we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off  
+       uint8_t tol1 = fcHigh+1; 
+       
+       //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
+
+       // 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;
+                               }
+                       }
+               }

        }
        }

-       return clk[bestIndex];
+
+       if (ii<0) return 0; // oops we went too far
+
+       return clk[ii];
+}
+
+//by marshmellow
+//countFC is to detect the field clock lengths.
+//counts and returns the 2 most common wave lengths
+//mainly used for FSK field clock detection
+uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
+{
+       uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
+       uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
+       uint8_t fcLensFnd = 0;
+       uint8_t lastFCcnt=0;
+       uint8_t fcCounter = 0;
+       size_t i;
+       if (size == 0) return 0;
+
+       // prime i to first up transition
+       for (i = 1; i < size-1; i++)
+               if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
+                       break;
+
+       for (; i < size-1; 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<10; ii++){
+                               if (fcLens[ii]==fcCounter){
+                                       fcCnts[ii]++;
+                                       fcCounter=0;
+                                       break;
+                               }
+                       }
+                       if (fcCounter>0 && fcLensFnd<10){
+                               //add new fc length 
+                               fcCnts[fcLensFnd]++;
+                               fcLens[fcLensFnd++]=fcCounter;
+                       }
+                       fcCounter=0;
+               } else {
+                       // count sample
+                       fcCounter++;
+               }
+       }
+       
+       uint8_t best1=9, best2=9, best3=9;
+       uint16_t maxCnt1=0;
+       // go through fclens and find which ones are bigest 2  
+       for (i=0; i<10; i++){
+               // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);    
+               // 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;
+               }
+       }
+       uint8_t fcH=0, fcL=0;
+       if (fcLens[best1]>fcLens[best2]){
+               fcH=fcLens[best1];
+               fcL=fcLens[best2];
+       } else{
+               fcH=fcLens[best2];
+               fcL=fcLens[best1];
+       }
+
+       // TODO: take top 3 answers and compare to known Field clocks to get top 2
+
+       uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+       // PrintAndLog("DEBUG: Best %d  best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
+       if (fskAdj) return fcs; 
+       return fcLens[best1];
+}
+
+//by marshmellow - demodulate PSK1 wave 
+//uses wave lengths (# Samples) 
+int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
+{
+       if (size == 0) return -1;
+       uint16_t loopCnt = 4096;  //don't need to loop through entire array...
+       if (*size<loopCnt) loopCnt = *size;
+
+       uint8_t curPhase = *invert;
+       size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
+       uint8_t fc=0, fullWaveLen=0, tol=1;
+       uint16_t errCnt=0, waveLenCnt=0;
+       fc = countFC(dest, *size, 0);
+       if (fc!=2 && fc!=4 && fc!=8) return -1;
+       //PrintAndLog("DEBUG: FC: %d",fc);
+       *clock = DetectPSKClock(dest, *size, *clock);
+       if (*clock == 0) return -1;
+       int avgWaveVal=0, lastAvgWaveVal=0;
+       //find first phase shift
+       for (i=0; i<loopCnt; i++){
+               if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
+                       waveEnd = i+1;
+                       //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
+                       waveLenCnt = waveEnd-waveStart;
+                       if (waveLenCnt > fc && waveStart > fc){ //not first peak and is a large wave 
+                               lastAvgWaveVal = avgWaveVal/(waveLenCnt);
+                               firstFullWave = waveStart;
+                               fullWaveLen=waveLenCnt;
+                               //if average wave value is > graph 0 then it is an up wave or a 1
+                               if (lastAvgWaveVal > 123) curPhase ^= 1;  //fudge graph 0 a little 123 vs 128
+                               break;
+                       } 
+                       waveStart = i+1;
+                       avgWaveVal = 0;
+               }
+               avgWaveVal += dest[i+2];
+       }
+       //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);  
+       lastClkBit = firstFullWave; //set start of wave as clock align
+       //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
+       waveStart = 0;
+       size_t numBits=0;
+       //set skipped bits
+       memset(dest, curPhase^1, firstFullWave / *clock);
+       numBits += (firstFullWave / *clock);
+       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 (i+1 > lastClkBit + *clock + tol + fc){
+                                       lastClkBit += *clock; //no phase shift but clock bit
+                                       dest[numBits++] = curPhase;
+                               }
+                               avgWaveVal = 0;
+                               waveStart = i+1;
+                       }
+               }
+               avgWaveVal += dest[i+1];
+       }
+       *size = numBits;
+       return errCnt;

 }
 }