}
//by marshmellow
-//search for given preamble in given BitStream and return startIndex and length
+//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;
//by marshmellow
//takes 1s and 0s and searches for EM410x format - output EM ID
-uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx)
+uint64_t Em410xDecodeOld(uint8_t *BitStream, size_t *size, size_t *startIdx)
{
//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
return 0;
}
+//by marshmellow
+//takes 1s and 0s and searches for EM410x format - output EM ID
+uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
+{
+ //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){ //allow only 1s and 0s
+ // PrintAndLog("no data found");
+ return 0;
+ }
+ // 111111111 bit pattern represent start of frame
+ uint8_t preamble[] = {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;
+ *startIdx = 0;
+ for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
+ errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
+ if (errChk == 0) return 0;
+ if (*size>64) FmtLen = 22;
+ 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
+ if (parityTest(parityBits, 5, 0) == 0){
+ //parity failed try next bit (in the case of 1111111111) but last 9 = preamble
+ startIdx++;
+ errChk = 0;
+ break;
+ }
+ //set uint64 with ID from BitStream
+ for (uint8_t ii=0; ii<4; ii++){
+ *hi = (*hi << 1) | (*lo >> 63);
+ *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
+ }
+ }
+ if (errChk != 0) return 1;
+ //skip last 5 bit parity test for simplicity.
+ // *size = 64 | 128;
+ }
+ return 0;
+}
+
//by marshmellow
//takes 3 arguments - clock, invert, maxErr as integers
//attempts to demodulate ask while decoding manchester
int iii = 0;
uint32_t gLen = *size;
if (gLen > 3000) gLen=3000;
+ //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
+ if (!maxErr) gLen=*clk*2;
uint8_t errCnt =0;
uint16_t MaxBits = 500;
uint32_t bestStart = *size;
}
//by marshmellow
-//take 01 or 10 = 0 and 11 or 00 = 1
+//take 01 or 10 = 1 and 11 or 00 = 0
+//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
{
uint16_t bitnum=0;
uint32_t errCnt =0;
- uint32_t i;
- uint16_t MaxBits=500;
- i=offset;
- if (size == 0) return -1;
- for (;i<*size-2; i+=2){
+ 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 (i<*size-3 && BitStream[i+1]==BitStream[i+2]) {
+ BitStream[bitnum++]=77;
+ 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)){
uint32_t iii = 0;
uint32_t gLen = *size;
if (gLen > 500) gLen=500;
+ //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
+ if (!maxErr) gLen=*clk*2;
uint8_t errCnt =0;
uint32_t bestStart = *size;
uint32_t bestErrCnt = maxErr; //(*size/1000);
size_t i=1;
uint8_t lastBit=BitStream[0];
for (; i<size; i++){
- if (lastBit!=BitStream[i]){
+ if (BitStream[i]==77){
+ //ignore errors
+ } else if (lastBit!=BitStream[i]){
lastBit=BitStream[i];
BitStream[i]=1;
} else {
//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;
+ 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
+ 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;
- }
+ 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;
errCnt=0;
size_t numBits=0;
- //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
+ //set skipped bits
+ memset(dest+numBits,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
waveEnd = i+1;
waveLenCnt = waveEnd-waveStart;
lastAvgWaveVal = avgWaveVal/waveLenCnt;
- if (waveLenCnt > fc){
+ if (waveLenCnt > fc){
//PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
//if 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);
projects / proxmark3-svn / blobdiff