mirror of
https://github.com/Proxmark/proxmark3.git
synced 2024-09-21 15:26:35 +08:00
Fixed thresholding of io fskdemod
This commit is contained in:
parent
6f101995b6
commit
e47e52a2c8
|
@ -592,41 +592,40 @@ uint32_t bytebits_to_byte(uint8_t* src, int numbits)
|
|||
|
||||
int IOdemodFSK(uint8_t *dest, size_t size)
|
||||
{
|
||||
static const uint8_t THRESHOLD = 170;
|
||||
uint32_t idx=0;
|
||||
//make sure buffer has data
|
||||
if (size < 66) return -1;
|
||||
//test samples are not just noise
|
||||
uint8_t testMax=0;
|
||||
for(idx=0;idx<65;idx++){
|
||||
if (testMax<dest[idx]) testMax=dest[idx];
|
||||
}
|
||||
idx=0;
|
||||
//if not just noise
|
||||
if (testMax>20){
|
||||
// FSK demodulator
|
||||
size = fskdemod(dest, size,64,1,10,8); // RF/64 and invert
|
||||
if (size < 65) return -1; //did we get a good demod?
|
||||
//Index map
|
||||
//0 10 20 30 40 50 60
|
||||
//| | | | | | |
|
||||
//01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
|
||||
//-----------------------------------------------------------------------------
|
||||
//00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
|
||||
//
|
||||
//XSF(version)facility:codeone+codetwo
|
||||
//Handle the data
|
||||
uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
|
||||
for( idx=0; idx < (size - 65); idx++) {
|
||||
if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
|
||||
//frame marker found
|
||||
if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){
|
||||
//confirmed proper separator bits found
|
||||
//return start position
|
||||
return (int) idx;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
uint8_t justNoise = 1;
|
||||
for(idx=0;idx< size && justNoise ;idx++){
|
||||
justNoise = dest[idx] > THRESHOLD;
|
||||
}
|
||||
if(justNoise) return 0;
|
||||
|
||||
// FSK demodulator
|
||||
size = fskdemod(dest, size,64,1,10,8); // RF/64 and invert
|
||||
if (size < 65) return -1; //did we get a good demod?
|
||||
//Index map
|
||||
//0 10 20 30 40 50 60
|
||||
//| | | | | | |
|
||||
//01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
|
||||
//-----------------------------------------------------------------------------
|
||||
//00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
|
||||
//
|
||||
//XSF(version)facility:codeone+codetwo
|
||||
//Handle the data
|
||||
uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
|
||||
for( idx=0; idx < (size - 65); idx++) {
|
||||
if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
|
||||
//frame marker found
|
||||
if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){
|
||||
//confirmed proper separator bits found
|
||||
//return start position
|
||||
return (int) idx;
|
||||
}
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue