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add first attempt at lf miller decoding

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don't have any tags capable to test and not yet hooked up to data
rawdemod...
This commit is contained in:
marshmellow42 2017-03-14 13:16:30 -04:00
commit 127f149075
2 changed files with 35 additions and 12 deletions
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29
common/lfdemod.c
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@ -1074,17 +1074,18 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
}
//by marshmellow
//take 11 10 01 11 00 and make 01100 ... miller decoding
//take 11 10 01 11 00 and make 01100 ... miller decoding
//check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
//decodes miller encoded binary
//NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
/*int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
if (*size < 16) return -1;
uint16_t MaxBits = 512, errCnt = 0, bestErr = 1000, bestRun = 0;
size_t i, ii, bitCnt=0;
uint8_t alignCnt = 0, curBit = BitStream[0];
uint16_t MaxBits = 512, errCnt = 0;
size_t i, bitCnt=0;
uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
uint8_t halfClkErr = 0;
//find alignment, needs 4 1s or 0s to properly align
for (i=1; i < *size; i++) {
for (i=1; i < *size-1; i++) {
alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
curBit = BitStream[i];
if (alignCnt == 4) break;
@ -1094,8 +1095,21 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
if (g_debugMode) prnt("ERROR MillerDecode: alignment not found so either your bitstream is not miller or your data does not have a 101 in it");
return -1;
}
alignedIdx = (i-1) % 2;
for (i=alignedIdx; i < *size-3; i+=2) {
halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
errCnt++;
BitStream[bitCnt++] = 7;
continue;
}
BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
}*/
if (bitCnt > MaxBits) break;
}
*size = bitCnt;
return errCnt;
}
//by marshmellow
//take 01 or 10 = 1 and 11 or 00 = 0
@ -1876,7 +1890,6 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
return (int) startIdx;
}
// by iceman
// find Visa2000 preamble in already demoded data
int Visa2kDemod_AM(uint8_t *dest, size_t *size) {