CHG: @Marshmellow42 's fixes. ref: https://github.com/marshmellow42/proxmark3/commi...

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 910b2af4e65a1b2809819ff8d68d1db34bc6d7c2..ca126df32c696f7be98961c642dd0159397e07b7 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -7,22 +7,20 @@
 //-----------------------------------------------------------------------------
 // Low frequency demod/decode commands
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 // Low frequency demod/decode commands
 //-----------------------------------------------------------------------------

-
-#include <stdlib.h>

 #include "lfdemod.h"
 #include "lfdemod.h"

-#include <string.h>

 
 //un_comment to allow debug print calls when used not on device
 void dummy(char *fmt, ...){}
 
 
 //un_comment to allow debug print calls when used not on device
 void dummy(char *fmt, ...){}
 

+

 #ifndef ON_DEVICE
 #ifndef ON_DEVICE

-#include "ui.h"
-#include "cmdparser.h"
-#include "cmddata.h"
-#define prnt PrintAndLog
+# include "ui.h"
+# include "cmdparser.h"
+# include "cmddata.h"
+# define prnt PrintAndLog

 #else 
        uint8_t g_debugMode=0;
 #else 
        uint8_t g_debugMode=0;

-#define prnt dummy
+# define prnt dummy

 #endif
 
 //test samples are not just noise
 #endif
 
 //test samples are not just noise


@@ -60,7 +58,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
        for (uint8_t i = 0; i < bitLen; i++){
                ans ^= ((bits >> i) & 1);
        }
        for (uint8_t i = 0; i < bitLen; i++){
                ans ^= ((bits >> i) & 1);
        }

-       //prnt("DEBUG: ans: %d, ptype: %d",ans,pType);
+       if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);

        return (ans == pType);
 }
 
        return (ans == pType);
 }
 


@@ -76,6 +74,8 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
                        parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
                        BitStream[j++] = (BitStream[startIdx+word+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) {
                j--; // overwrite parity with next data
                // if parity fails then return 0
                switch (pType) {


@@ -141,68 +141,105 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
        return num;
 }
 
        return num;
 }
 

+//by marshmellow
+// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
+bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
+       return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
+}

 //by marshmellow
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
 //by marshmellow
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length

-uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
+// param @findone:  look for a repeating preamble or only the first.
+// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
+bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)

 {
        // Sanity check.  If preamble length is bigger than bitstream length.
 {
        // Sanity check.  If preamble length is bigger than bitstream length.

-       if ( *size <= pLen ) return 0;
+       if ( *size <= pLen ) return false;

        
        uint8_t foundCnt = 0;
        for (int idx = 0; idx < *size - pLen; idx++){
                if (memcmp(BitStream+idx, preamble, pLen) == 0){
        
        uint8_t foundCnt = 0;
        for (int idx = 0; idx < *size - pLen; idx++){
                if (memcmp(BitStream+idx, preamble, pLen) == 0){

+                       if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);

                        //first index found
                        foundCnt++;
                        if (foundCnt == 1){
                                *startIdx = idx;
                        //first index found
                        foundCnt++;
                        if (foundCnt == 1){
                                *startIdx = idx;

+                               if (findone) return true;

                        }
                        if (foundCnt == 2){
                                *size = idx - *startIdx;
                        }
                        if (foundCnt == 2){
                                *size = idx - *startIdx;

-                               return 1;
+                               return true;

                        }
                }
        }
                        }
                }
        }

-       return 0;
+       return false;
+}
+
+// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
+size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
+       size_t i = 0;
+       size_t waveSizeCnt = 0;
+       uint8_t thresholdCnt = 0;
+       bool isAboveThreshold = dest[i++] >= threshold_value;
+       for (; i < size-20; i++ ) {
+               if(dest[i] < threshold_value && isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;                     
+                       isAboveThreshold = false;
+                       waveSizeCnt = 0;
+               } else if (dest[i] >= threshold_value && !isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;                     
+                       isAboveThreshold = true;
+                       waveSizeCnt = 0;
+               } else {
+                       waveSizeCnt++;
+               }
+               if (thresholdCnt > 10) break;
+       }
+       if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
+       return i;

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

-int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
+// actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
+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
-       uint32_t i = 0;
-       if (BitStream[1]>1) return -1;  //allow only 1s and 0s
-
-       // 111111111 bit pattern represent start of frame
-       //  include 0 in front to help get start pos
-       uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
-       uint32_t idx = 0;
-       uint32_t parityBits = 0;
-       uint8_t errChk = 0;
-       uint8_t FmtLen = 10;
+       // sanity check
+       if (BitStream[1] > 1) return 0; 
+       
+       uint8_t fmtlen;

        *startIdx = 0;
        *startIdx = 0;

-       errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
-       if (errChk == 0 ) return -4;
-       if (*size < 64) return -3;
-       if (*size > 64) FmtLen = 22;
-       *startIdx += 1; //get rid of 0 from preamble
-       idx = *startIdx + 9;
-       for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
-               parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
-               //check even parity - quit if failed
-               if (parityTest(parityBits, 5, 0) == 0) return -5;
-               //set uint64 with ID from BitStream
-               for (uint8_t ii=0; ii<4; ii++){
-                       *hi = (*hi << 1) | (*lo >> 63);
-                       *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
-               }
+       
+       // preamble 0111111111
+       // include 0 in front to help get start pos
+       uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
+       if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx)) 
+               return 0;
+       if (*size < 64) return 0;
+       
+       fmtlen = (*size == 110) ? 22 : 10;
+
+       //skip last 4bit parity row for simplicity
+       *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);  
+       
+       switch (*size) {
+          case 40: { 
+           // std em410x format
+               *hi = 0;
+               *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
+               break;
+           } 
+           case 88:  { 
+           // long em format
+               *hi = (bytebits_to_byte(BitStream, 24)); 
+               *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
+               break;
+           } 
+           default: return 0;
+       

        }
        }

-       if (errChk != 0) return 1;
-       //skip last 5 bit parity test for simplicity.
-       // *size = 64 | 128;
-       return 0;
+       return 1;

 }
 
 //by marshmellow
 }
 
 //by marshmellow


@@ -278,6 +315,7 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
 {
        if (*size==0) return -1;
        int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
 {
        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 (*clk==0 || start < 0) return -3;
        if (*invert != 1) *invert = 0;
        if (amp==1) askAmp(BinStream, *size);


@@ -456,9 +494,11 @@ int gProxII_Demod(uint8_t BitStream[], size_t *size)
        size_t startIdx=0;
        uint8_t preamble[] = {1,1,1,1,1,0};
 
        size_t startIdx=0;
        uint8_t preamble[] = {1,1,1,1,1,0};
 

-       uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -3; //preamble not found
+       if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx)) 
+               return -3; //preamble not found
+

        if (*size != 96) return -2; //should have found 96 bits
        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
        //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


@@ -473,7 +513,6 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 {
        size_t last_transition = 0;
        size_t idx = 1;
 {
        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
        if (fchigh==0) fchigh=10;
        if (fclow==0) fclow=8;
        //set the threshold close to 0 (graph) or 128 std to avoid static


@@ -481,19 +520,22 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
        size_t preLastSample = 0;
        size_t LastSample = 0;
        size_t currSample = 0;
        size_t preLastSample = 0;
        size_t LastSample = 0;
        size_t currSample = 0;

-       // sync to first lo-hi transition, and threshold
+       if ( size < 1024 ) return 0; // not enough samples
+
+       //find start of modulating data in trace 
+       idx = findModStart(dest, size, threshold_value, fchigh);

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

-       // skip 160 samples to allow antenna/samples to settle
-       if(dest[160] < threshold_value) dest[0] = 0;
+       if(dest[idx] < threshold_value) dest[0] = 0;

        else dest[0] = 1;
        else dest[0] = 1;

+       idx++;

 
        size_t numBits = 0;
        // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
        // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
        // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
        //  (could also be fc/5 && fc/7 for fsk1 = 4-9)
 
        size_t numBits = 0;
        // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
        // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
        // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
        //  (could also be fc/5 && fc/7 for fsk1 = 4-9)

-       for(idx = 161; idx < size-20; idx++) {
+       for(; idx < size-20; idx++) {

                // threshold current value
 
                if (dest[idx] < threshold_value) dest[idx] = 0;
                // threshold current value
 
                if (dest[idx] < threshold_value) dest[idx] = 0;


@@ -508,13 +550,14 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
                                //do nothing with extra garbage
                        } else if (currSample < (fchigh-1)) {           //6-8 = 8 sample waves  (or 3-6 = 5)
                                //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
                                //do nothing with extra garbage
                        } else if (currSample < (fchigh-1)) {           //6-8 = 8 sample waves  (or 3-6 = 5)
                                //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)

-                               if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample     == 0 )){
+                               if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){

                                        dest[numBits-1]=1;
                                }
                                dest[numBits++]=1;
 
                                        dest[numBits-1]=1;
                                }
                                dest[numBits++]=1;
 

-                       } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage 
-                               //do nothing with beginning garbage
+                       } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
+                               //do nothing with beginning garbage and reset..  should be rare..
+                               numBits = 0; 

                        } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
                                dest[numBits++]=1;
                        } else {                                        //9+ = 10 sample waves (or 6+ = 7)
                        } 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)


@@ -588,9 +631,8 @@ int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32
        if (*size < 96*2) return -2;
        // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
        uint8_t preamble[] = {0,0,0,1,1,1,0,1};
        if (*size < 96*2) return -2;
        // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
        uint8_t preamble[] = {0,0,0,1,1,1,0,1};

-       // find bitstring in array  
-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -3; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+               return -3; //preamble not found

 
        numStart = startIdx + sizeof(preamble);
        // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
 
        numStart = startIdx + sizeof(preamble);
        // final loop, go over previously decoded FSK data and manchester decode into usable tag ID


@@ -622,9 +664,8 @@ int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, ui
 
        // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
        uint8_t preamble[] = {0,0,0,0,1,1,1,1};
 
        // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
        uint8_t preamble[] = {0,0,0,0,1,1,1,1};

-
-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -3; //preamble not found
+       if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+               return -3; //preamble not found

 
        numStart = startIdx + sizeof(preamble);
        // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
 
        numStart = startIdx + sizeof(preamble);
        // final loop, go over previously decoded FSK data and manchester decode into usable tag ID


@@ -661,8 +702,8 @@ int IOdemodFSK(uint8_t *dest, size_t size)
        //Handle the data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
        //Handle the data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
-       if (errChk == 0) return -4; //preamble not found
+       if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
+               return -4; //preamble not found

 
        if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
                //confirmed proper separator bits found
 
        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


@@ -679,8 +720,9 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
        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};
        if (*size < 64*2) return -2;
        size_t startIdx = 0;
        uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -4; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+               return -4; //preamble not found
+       

        uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ 
                                                 bytebits_to_byte(dest+startIdx+8,8) ^ 
                                                 bytebits_to_byte(dest+startIdx+16,8) ^ 
        uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ 
                                                 bytebits_to_byte(dest+startIdx+8,8) ^ 
                                                 bytebits_to_byte(dest+startIdx+16,8) ^ 


@@ -701,8 +743,8 @@ 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 (*size < 96) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -2; //preamble not found

        if (*size != 96) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;
        if (*size != 96) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;


@@ -713,8 +755,8 @@ int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
        if (*size < 96) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
        if (*size < 96) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -2; //preamble not found

        if (*size != 96) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;
        if (*size != 96) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;


@@ -724,8 +766,8 @@ int PrescoDemod(uint8_t *dest, size_t *size) {
        if (*size < 128*2) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
        if (*size < 128*2) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -2; //preamble not found

        if (*size != 128) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;
        if (*size != 128) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;


@@ -737,8 +779,8 @@ int FDXBdemodBI(uint8_t *dest, size_t *size) {
        if (*size < 128*2) return -1;   //make sure buffer has enough data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
        if (*size < 128*2) return -1;   //make sure buffer has enough data
        size_t startIdx = 0;
        uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -2; //preamble not found

        if (*size != 128) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;
        if (*size != 128) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;


@@ -752,8 +794,8 @@ int JablotronDemod(uint8_t *dest, size_t *size){
        if (*size < 64*2) return -1;    //make sure buffer has enough data
        size_t startIdx = 0;
        uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
        if (*size < 64*2) return -1;    //make sure buffer has enough data
        size_t startIdx = 0;
        uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx)) 
+               return -2; //preamble not found

        if (*size != 64) return -3; // wrong demoded size
        
        uint8_t checkchksum = 0;
        if (*size != 64) return -3; // wrong demoded size
        
        uint8_t checkchksum = 0;


@@ -781,8 +823,8 @@ int AWIDdemodFSK(uint8_t *dest, size_t *size)
 
        uint8_t preamble[] = {0,0,0,0,0,0,0,1};
        size_t startIdx = 0;
 
        uint8_t preamble[] = {0,0,0,0,0,0,0,1};
        size_t startIdx = 0;

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -4; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -4; //preamble not found

        if (*size != 96) return -5;
        return (int)startIdx;
 }
        if (*size != 96) return -5;
        return (int)startIdx;
 }


@@ -800,11 +842,10 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
        // FSK demodulator
        *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
        if (*size < 128) return -2;  //did we get a good demod?
        // FSK demodulator
        *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
        if (*size < 128) return -2;  //did we get a good demod?

-
-       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};

        size_t startIdx = 0;
        size_t startIdx = 0;

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -4; //preamble not found
+       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -4; //preamble not found

        if (*size != 128) return -3;
        return (int)startIdx;
 }
        if (*size != 128) return -3;
        return (int)startIdx;
 }


@@ -817,8 +858,8 @@ int NedapDemod(uint8_t *dest, size_t *size) {
        size_t startIdx = 0;
        //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
        uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
        size_t startIdx = 0;
        //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
        uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -4; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -4; //preamble not found

        return (int) startIdx;
 }
 
        return (int) startIdx;
 }
 


@@ -829,8 +870,8 @@ int IdteckDemodPSK(uint8_t *dest, size_t *size) {
        if (*size < 64*2) return -1;    
        size_t startIdx = 0;
        uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};
        if (*size < 64*2) return -1;    
        size_t startIdx = 0;
        uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};

-       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
-       if (errChk == 0) return -2; //preamble not found
+       if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
+               return -2; //preamble not found

        if (*size != 64) return -3; // wrong demoded size
        return (int) startIdx;
 }
        if (*size != 64) return -3; // wrong demoded size
        return (int) startIdx;
 }


@@ -1249,36 +1290,32 @@ int DetectNRZClock(uint8_t dest[], size_t size, int clock)
 // by marshmellow
 // convert psk1 demod to psk2 demod
 // only transition waves are 1s
 // by marshmellow
 // convert psk1 demod to psk2 demod
 // only transition waves are 1s

-void psk1TOpsk2(uint8_t *BitStream, size_t size)
-{
-       size_t i=1;
-       uint8_t lastBit=BitStream[0];
-       for (; i<size; i++){
-               if (BitStream[i]==7){
-                       //ignore errors
-               } else if (lastBit!=BitStream[i]){
-                       lastBit=BitStream[i];
-                       BitStream[i]=1;
+void psk1TOpsk2(uint8_t *bits, size_t size) {
+       uint8_t lastBit = bits[0];
+       for (size_t i = 1; i < size; i++){
+               //ignore errors         
+               if (bits[i] == 7) continue;
+                       
+               if (lastBit != bits[i]){
+                       lastBit = bits[i];
+                       bits[i] = 1;

                } else {
                } else {

-                       BitStream[i]=0;
+                       bits[i] = 0;

                }
        }
                }
        }

-       return;

 }
 
 // by marshmellow
 // convert psk2 demod to psk1 demod
 // from only transition waves are 1s to phase shifts change bit
 }
 
 // by marshmellow
 // convert psk2 demod to psk1 demod
 // from only transition waves are 1s to phase shifts change bit

-void psk2TOpsk1(uint8_t *BitStream, size_t size)
-{
-       uint8_t phase=0;
-       for (size_t i=0; i<size; i++){
-               if (BitStream[i]==1){
-                       phase ^=1;
+void psk2TOpsk1(uint8_t *bits, size_t size) {
+       uint8_t phase = 0;
+       for (size_t i = 0; i < size; i++){
+               if (bits[i] == 1){
+                       phase ^= 1;

                }
                }

-               BitStream[i]=phase;
+               bits[i] = phase;

        }
        }

-       return;

 }
 
 // redesigned by marshmellow adjusted from existing decode functions
 }
 
 // redesigned by marshmellow adjusted from existing decode functions


@@ -1369,7 +1406,10 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
                        continue;               
                // else new peak 
                // if we got less than the small fc + tolerance then set it to the small fc
                        continue;               
                // else new peak 
                // if we got less than the small fc + tolerance then set it to the small fc

-               if (fcCounter < fcLow+fcTol) 
+               // if it is inbetween set it to the last counter
+               if (fcCounter < fcHigh && fcCounter > fcLow)
+                       fcCounter = lastFCcnt;
+               else if (fcCounter < fcLow+fcTol) 

                        fcCounter = fcLow;
                else //set it to the large fc
                        fcCounter = fcHigh;
                        fcCounter = fcLow;
                else //set it to the large fc
                        fcCounter = fcHigh;


@@ -1435,7 +1475,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
                }
        }
 
                }
        }
 

-       if (ii<0) return 0; // oops we went too far
+       if (ii<2) return 0; // oops we went too far

 
        return clk[ii];
 }
 
        return clk[ii];
 }


@@ -1449,10 +1489,10 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
        uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint8_t fcLensFnd = 0;
        uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint8_t fcLensFnd = 0;

-       uint8_t lastFCcnt=0;
+       uint8_t lastFCcnt = 0;

        uint8_t fcCounter = 0;
        size_t i;
        uint8_t fcCounter = 0;
        size_t i;

-       if (size == 0) return 0;
+       if (size < 180) return 0;

 
        // prime i to first up transition
        for (i = 160; i < size-20; i++)
 
        // prime i to first up transition
        for (i = 160; i < size-20; i++)


@@ -1539,27 +1579,37 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 
        size_t numBits=0;
        uint8_t curPhase = *invert;
 
        size_t numBits=0;
        uint8_t curPhase = *invert;

-       size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
-       uint8_t fc=0, fullWaveLen=0, tol=1;
-       uint16_t errCnt=0, waveLenCnt=0;
-       fc = countFC(dest, *size, 0);
+       size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
+       uint16_t fc=0, fullWaveLen=0, tol=1;
+       uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
+       fc = countFC(dest, *size, 1);
+       uint8_t fc2 = fc >> 8;
+       if (fc2 == 10) return -1; //fsk found - quit
+       fc = fc & 0xFF;

        if (fc!=2 && fc!=4 && fc!=8) return -1;
        //prnt("DEBUG: FC: %d",fc);
        *clock = DetectPSKClock(dest, *size, *clock);
        if (*clock == 0) return -1;
        if (fc!=2 && fc!=4 && fc!=8) return -1;
        //prnt("DEBUG: FC: %d",fc);
        *clock = DetectPSKClock(dest, *size, *clock);
        if (*clock == 0) return -1;

-       int avgWaveVal=0, lastAvgWaveVal=0;
+
+       //find start of modulating data in trace 
+       uint8_t threshold_value = 123; //-5
+       i = findModStart(dest, *size, threshold_value, fc);
+

        //find first phase shift
        //find first phase shift

-       for (i=0; i<loopCnt; i++){
+       int avgWaveVal=0, lastAvgWaveVal=0;
+       waveStart = i;
+       for (; i<loopCnt; i++){
+               // find peak 

                if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
                        waveEnd = i+1;
                if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
                        waveEnd = i+1;

-                       //prnt("DEBUG: waveEnd: %d",waveEnd);
+                       if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);

                        waveLenCnt = waveEnd-waveStart;
                        waveLenCnt = waveEnd-waveStart;

-                       if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
+                       if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack

                                lastAvgWaveVal = avgWaveVal/(waveLenCnt);
                                firstFullWave = waveStart;
                                fullWaveLen=waveLenCnt;
                                lastAvgWaveVal = avgWaveVal/(waveLenCnt);
                                firstFullWave = waveStart;
                                fullWaveLen=waveLenCnt;

-                               //if average wave value is > graph 0 then it is an up wave or a 1
-                               if (lastAvgWaveVal > 123) curPhase ^= 1;  //fudge graph 0 a little 123 vs 128
+                               //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
+                               if (lastAvgWaveVal > threshold_value) curPhase ^= 1;

                                break;
                        } 
                        waveStart = i+1;
                                break;
                        } 
                        waveStart = i+1;


@@ -1580,7 +1630,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
        //set start of wave as clock align
        lastClkBit = firstFullWave;
        if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);  
        //set start of wave as clock align
        lastClkBit = firstFullWave;
        if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);  

-       if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
+       if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);

        waveStart = 0;
        dest[numBits++] = curPhase; //set first read bit
        for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
        waveStart = 0;
        dest[numBits++] = curPhase; //set first read bit
        for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){


@@ -1611,6 +1661,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
                                } else if (i+1 > lastClkBit + *clock + tol + fc){
                                        lastClkBit += *clock; //no phase shift but clock bit
                                        dest[numBits++] = curPhase;
                                } else if (i+1 > lastClkBit + *clock + tol + fc){
                                        lastClkBit += *clock; //no phase shift but clock bit
                                        dest[numBits++] = curPhase;

+                               } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
+                                       errCnt2++;
+                                       if(errCnt2 > 101) return errCnt2;

                                }
                                avgWaveVal = 0;
                                waveStart = i+1;
                                }
                                avgWaveVal = 0;
                                waveStart = i+1;