j--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
- case 3: if (BitStream[j]==1) return 0; break; //should be 0 spacer bit
- case 2: if (BitStream[j]==0) return 0; break; //should be 1 spacer bit
- default: //test parity
- if (parityTest(parityWd, pLen, pType) == 0) return 0; break;
+ case 3: if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
+ case 2: if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
+ default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
}
bitCnt+=(pLen-1);
parityWd = 0;
//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;
- for (int idx=0; idx < *size - pLen; idx++){
+ // Sanity check. If preamble length is bigger than bitstream length.
+ if ( *size <= pLen ) return 0;
+
+ uint8_t foundCnt = 0;
+ for (int idx = 0; idx < *size - pLen; idx++){
if (memcmp(BitStream+idx, preamble, pLen) == 0){
//first index found
foundCnt++;
//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)
+int 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 0; //allow only 1s and 0s
+ 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 FmtLen = 10;
*startIdx = 0;
errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
- if (errChk == 0 || *size < 64) return 0;
+ 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 0;
+ 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);
//by marshmellow
void askAmp(uint8_t *BitStream, size_t size)
{
- for(size_t i = 1; i<size; i++){
- if (BitStream[i]-BitStream[i-1]>=30) //large jump up
- BitStream[i]=255;
- else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
- BitStream[i]=0;
+ uint8_t last = 128;
+ for(size_t i = 1; i < size; ++i){
+ if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
+ last = 255;
+ else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
+ last = 0;
+
+ BitStream[i] = last;
}
- return;
}
//by marshmellow
{
if (justNoise(dest, *size)) return -1;
- size_t numStart=0, size2=*size, startIdx=0;
+ size_t numStart=0, size2 = *size, startIdx=0;
// FSK demodulator
*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
if (*size < 96*2) return -2;
{
if (justNoise(dest, *size)) return -1;
- size_t numStart=0, size2=*size, startIdx=0;
+ size_t numStart=0, size2 = *size, startIdx=0;
// FSK demodulator
*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
if (*size < 96) return -2;
return (int)startIdx;
}
+// ASK/Diphase fc/64 (inverted Biphase)
+// Note: this i s not a demod, this is only a detection
+// the parameter *dest needs to be demoded before call
+int JablotronDemod(uint8_t *dest, size_t *size){
+ //make sure buffer has enough data
+ if (*size < 64) return -1;
+
+ size_t startIdx = 0;
+ // 0xFFFF preamble, 64bits
+ 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 -4; //preamble not found
+ if (*size != 64) return -3;
+
+ uint8_t checkchksum = 0;
+ for (int i=16; i < 56; i += 8) {
+ checkchksum += bytebits_to_byte(dest+startIdx+i,8);
+ }
+ checkchksum ^= 0x3A;
+
+ uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
+
+ if ( checkchksum != crc ) return -5;
+ return (int)startIdx;
+}
+
// by marshmellow
// FSK Demod then try to locate an AWID ID
int AWIDdemodFSK(uint8_t *dest, size_t *size)
return (int)startIdx;
}
-// find presco preamble 0x10D in already demoded data
+// find nedap preamble in already demoded data
int NedapDemod(uint8_t *dest, size_t *size) {
//make sure buffer has data
if (*size < 128) return -3;
size_t startIdx = 0;
- uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
+ //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
+ 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
- //return start position
return (int) startIdx;
}
projects / proxmark3-svn / blobdiff