CHG: added some comments when changing the HAS_512_FLASH macro directive.

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 4cf22d8667359942c30980e8fa62f14699d204d1..4b17c6fdaad5a245376b6a0c42ba57c2fa4a56a1 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);
        }

-       //PrintAndLog("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) {


@@ -220,7 +220,7 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
                        if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
 
                                if (smplCnt > clk-(clk/4)-1) { //full clock
                        if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
 
                                if (smplCnt > clk-(clk/4)-1) { //full clock

-                                       if (smplCnt > clk + (clk/4)+2) { //too many samples
+                                       if (smplCnt > clk + (clk/4)+1) { //too many samples

                                                errCnt++;
                                                if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
                                                BinStream[bitCnt++] = 7;
                                                errCnt++;
                                                if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
                                                BinStream[bitCnt++] = 7;


@@ -278,10 +278,11 @@ 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);

-       if (g_debugMode==2) prnt("DEBUG ASK: size %d, clk %d, beststart %d", *size, *clk, start);
+       if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);

 
        uint8_t initLoopMax = 255;
        if (initLoopMax > *size) initLoopMax = *size;
 
        uint8_t initLoopMax = 255;
        if (initLoopMax > *size) initLoopMax = *size;


@@ -350,9 +351,9 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
 //take 10 and 01 and manchester decode
 //run through 2 times and take least errCnt
 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){
 //take 10 and 01 and manchester decode
 //run through 2 times and take least errCnt
 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){

-       uint16_t bitnum = 0, MaxBits = 512, errCnt = 0;
+       int errCnt = 0, bestErr = 1000;
+       uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;

        size_t i, k;
        size_t i, k;

-       uint16_t bestErr = 1000, bestRun = 0;

        if (*size < 16) return -1;
        //find correct start position [alignment]
        for (k=0; k < 2; ++k){
        if (*size < 16) return -1;
        //find correct start position [alignment]
        for (k=0; k < 2; ++k){


@@ -481,19 +482,42 @@ 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
+
+       // jump to modulating data by finding the first 4 threshold crossings (or first 2 waves)
+       // in case you have junk or noise at the beginning of the trace...
+       uint8_t thresholdCnt = 0;
+       size_t waveSizeCnt = 0;
+       bool isAboveThreshold = dest[idx++] >= threshold_value;
+       for (; idx < size-20; idx++ ) {
+               if(dest[idx] < threshold_value && isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;                  
+                       isAboveThreshold = false;
+                       waveSizeCnt = 0;
+               } else if (dest[idx] >= threshold_value && !isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;                  
+                       isAboveThreshold = true;
+                       waveSizeCnt = 0;
+               } else {
+                       waveSizeCnt++;
+               }
+               if (thresholdCnt > 10) break;
+       }
+       if (g_debugMode == 2) prnt("threshold Count reached at %u",idx);

 
        // 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 +532,14 @@ 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)


@@ -537,7 +562,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
        uint32_t n=1;
        for( idx=1; idx < size; idx++) {
                n++;
        uint32_t n=1;
        for( idx=1; idx < size; idx++) {
                n++;

-               if (dest[idx]==lastval) continue; 
+               if (dest[idx]==lastval) continue; //skip until we hit a transition

                
                //find out how many bits (n) we collected
                //if lastval was 1, we have a 1->0 crossing
                
                //find out how many bits (n) we collected
                //if lastval was 1, we have a 1->0 crossing


@@ -698,7 +723,7 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
 // by iceman
 // find Visa2000 preamble in already demoded data
 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
 // by iceman
 // find Visa2000 preamble in already demoded data
 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {

-       if (*size < 96*2) return -1; //make sure buffer has data
+       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);
        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);


@@ -710,7 +735,7 @@ int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
 // by iceman
 // find Noralsy preamble in already demoded data
 int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
 // by iceman
 // find Noralsy preamble in already demoded data
 int NoralsyDemod_AM(uint8_t *dest, size_t *size) {

-       if (*size < 96*2) return -1; //make sure buffer has data
+       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);
        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);


@@ -1249,36 +1274,32 @@ 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


@@ -1355,7 +1376,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
        fcCounter=0;
        rfCounter=0;
        firstBitFnd=0;
        fcCounter=0;
        rfCounter=0;
        firstBitFnd=0;

-       //PrintAndLog("DEBUG: fcTol: %d",fcTol);
+       //prnt("DEBUG: fcTol: %d",fcTol);

        // prime i to first peak / up transition
        for (i = 160; i < size-20; i++)
                if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
        // prime i to first peak / up transition
        for (i = 160; i < size-20; i++)
                if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])


@@ -1386,7 +1407,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc
                                        }
                                }
                                if (rfCounter > 0 && rfLensFnd < 15){
                                        }
                                }
                                if (rfCounter > 0 && rfLensFnd < 15){

-                                       //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+                                       //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);

                                        rfCnts[rfLensFnd]++;
                                        rfLens[rfLensFnd++] = rfCounter;
                                }
                                        rfCnts[rfLensFnd]++;
                                        rfLens[rfLensFnd++] = rfCounter;
                                }


@@ -1449,10 +1470,10 @@ 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 +1560,53 @@ 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;
+       size_t i=0, 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;
        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);
+       //prnt("DEBUG: FC: %d",fc);

        *clock = DetectPSKClock(dest, *size, *clock);
        if (*clock == 0) return -1;
        *clock = DetectPSKClock(dest, *size, *clock);
        if (*clock == 0) return -1;

+       // jump to modulating data by finding the first 2 threshold crossings (or first 1 waves)
+       // in case you have junk or noise at the beginning of the trace...
+       uint8_t thresholdCnt = 0;
+       size_t waveSizeCnt = 0;
+       uint8_t threshold_value = 123; //-5
+       bool isAboveThreshold = dest[i++] >= threshold_value;
+       for (; i < *size-20; i++ ) {
+               if(dest[i] < threshold_value && isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;                      
+                       isAboveThreshold = false;
+                       waveSizeCnt = 0;
+               } else if (dest[i] >= threshold_value && !isAboveThreshold) {
+                       thresholdCnt++;
+                       if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;                      
+                       isAboveThreshold = true;
+                       waveSizeCnt = 0;
+               } else {
+                       waveSizeCnt++;
+               }
+               if (thresholdCnt > 10) break;
+       }
+       if (g_debugMode == 2) prnt("DEBUG PSK: threshold Count reached at %u, count: %u",i, thresholdCnt);
+
+

        int avgWaveVal=0, lastAvgWaveVal=0;
        int avgWaveVal=0, lastAvgWaveVal=0;

+       waveStart = i+1;

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

-       for (i=0; i<loopCnt; i++){
+       for (; i<loopCnt; i++){

                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;

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

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


@@ -1595,9 +1642,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
                                waveLenCnt = waveEnd-waveStart;
                                lastAvgWaveVal = avgWaveVal/waveLenCnt;
                                if (waveLenCnt > fc){  
                                waveLenCnt = waveEnd-waveStart;
                                lastAvgWaveVal = avgWaveVal/waveLenCnt;
                                if (waveLenCnt > fc){  

-                                       //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
+                                       //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);

                                        //this wave is a phase shift
                                        //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);
+                                       //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);

                                        if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
                                                curPhase ^= 1;
                                                dest[numBits++] = curPhase;
                                        if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
                                                curPhase ^= 1;
                                                dest[numBits++] = curPhase;


@@ -1632,13 +1679,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        int tol = 0;
        int i, j, skip, start, end, low, high, minClk, waveStart;
        bool complete = false;
        int tol = 0;
        int i, j, skip, start, end, low, high, minClk, waveStart;
        bool complete = false;

-       int tmpbuff[bufsize / 64];
-       int waveLen[bufsize / 64];
+       int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
+       int waveLen[bufsize / 32]; //  if clock is larger then we waste memory in array size that is not needed...

        size_t testsize = (bufsize < 512) ? bufsize : 512;
        int phaseoff = 0;
        high = low = 128;
        memset(tmpbuff, 0, sizeof(tmpbuff));
        size_t testsize = (bufsize < 512) ? bufsize : 512;
        int phaseoff = 0;
        high = low = 128;
        memset(tmpbuff, 0, sizeof(tmpbuff));

+       memset(waveLen, 0, sizeof(waveLen));

 
 

+       

        if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
                if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
                return false; //just noise
        if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
                if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
                return false; //just noise


@@ -1665,7 +1714,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
                waveStart = i;
                while ((buffer[i] > low) && (i < bufsize))
                        ++i;
                waveStart = i;
                while ((buffer[i] > low) && (i < bufsize))
                        ++i;

-               if (j >= (bufsize/64)) {
+               if (j >= (bufsize/32)) {

                        break;
                }
                waveLen[j] = i - waveStart; //first high to first low
                        break;
                }
                waveLen[j] = i - waveStart; //first high to first low


@@ -1711,6 +1760,8 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        if (start < 0) {
                if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
                return false;
        if (start < 0) {
                if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
                return false;

+       } else {
+               if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);

        }
        if (waveLen[i+2] > clk*1+tol)
                phaseoff = 0;
        }
        if (waveLen[i+2] > clk*1+tol)
                phaseoff = 0;


@@ -1724,7 +1775,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        end = skip;
        for (i += 3; i < j - 4; ++i) {
                end += tmpbuff[i];
        end = skip;
        for (i += 3; i < j - 4; ++i) {
                end += tmpbuff[i];

-               if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) {           //1 to 2 clocks depending on 2 bits prior
+               if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) {           //1 to 2 clocks depending on 2 bits prior

                        if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) {       //2 clocks and wave size is 1 1/2
                                if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
                                        if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
                        if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) {       //2 clocks and wave size is 1 1/2
                                if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
                                        if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit


@@ -1746,12 +1797,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
        start = skip;
        size_t datalen = end - start;
        // check validity of datalen (should be even clock increments)  - use a tolerance of up to 1/8th a clock
        start = skip;
        size_t datalen = end - start;
        // check validity of datalen (should be even clock increments)  - use a tolerance of up to 1/8th a clock

-       if (datalen % clk > clk/8) {
+       if ( clk - (datalen % clk) <= clk/8) {
+               // padd the amount off - could be problematic...  but shouldn't happen often
+               datalen += clk - (datalen % clk);
+       } else if ( (datalen % clk) <= clk/8 ) {
+               // padd the amount off - could be problematic...  but shouldn't happen often
+               datalen -= datalen % clk;
+       } else {

                if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
                return false;
                if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
                return false;

-       } else {
-               // padd the amount off - could be problematic...  but shouldn't happen often
-               datalen += datalen % clk;

        }
        // if datalen is less than one t55xx block - ERROR
        if (datalen/clk < 8*4) {
        }
        // if datalen is less than one t55xx block - ERROR
        if (datalen/clk < 8*4) {


@@ -1759,8 +1813,20 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
                return false;
        }
        size_t dataloc = start;
                return false;
        }
        size_t dataloc = start;

+       if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
+               //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start 
+               for ( i=0; i <= (clk/8); ++i ) {
+                       if ( buffer[dataloc - (clk*4) - i] <= low ) {
+                               dataloc -= i;
+                               break;
+                       }
+               }
+       }
+       

        size_t newloc = 0;
        i=0;
        size_t newloc = 0;
        i=0;

+       if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);            
+

        // warning - overwriting buffer given with raw wave data with ST removed...
        while ( dataloc < bufsize-(clk/2) ) {
                //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
        // warning - overwriting buffer given with raw wave data with ST removed...
        while ( dataloc < bufsize-(clk/2) ) {
                //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)


@@ -1779,6 +1845,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
                }
                newloc += i;
                //skip next ST  -  we just assume it will be there from now on...
                }
                newloc += i;
                //skip next ST  -  we just assume it will be there from now on...

+               if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));

                dataloc += clk*4;
        }
        *size = newloc;
                dataloc += clk*4;
        }
        *size = newloc;