From: Martin Holst Swende Date: Tue, 6 Jan 2015 17:43:37 +0000 (+0100) Subject: Fixed thresholding of io fskdemod X-Git-Tag: v2.0.0-rc1~62^2~1 X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/commitdiff_plain/e47e52a2c8f2d925cefe2f5f1a55ceceb7ca0813?ds=sidebyside Fixed thresholding of io fskdemod --- diff --git a/common/lfdemod.c b/common/lfdemod.c index 79c99f73..e0d20464 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -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 (testMax20){ - // 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; }