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FIX EM Error

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missed two files for last push..  sorry
This commit is contained in:
marshmellow42 2015-03-16 08:39:18 -04:00
parent b41534d142
commit 2147c30778
2 changed files with 73 additions and 9 deletions
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79
common/lfdemod.c
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@ -55,7 +55,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
}
//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;
@ -78,7 +78,7 @@ uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_
//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
@ -120,6 +120,52 @@ uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx)
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
@ -151,6 +197,8 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
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;
@ -305,16 +353,29 @@ int manrawdecode(uint8_t * BitStream, size_t *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)){
@ -381,6 +442,8 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
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);

3
common/lfdemod.h
View file

@ -17,7 +17,8 @@
int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr);
int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr);
uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx);
uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo);
//uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx);
int ManchesterEncode(uint8_t *BitStream, size_t size);
int manrawdecode(uint8_t *BitStream, size_t *size);
int BiphaseRawDecode(uint8_t * BitStream, size_t *size, int offset, int invert);