X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/0422e2a47109a7845998c2130ae40c6d04e56d09..8652988d62b19631e498b62a3800f0decb5e743a:/armsrc/lfops.c diff --git a/armsrc/lfops.c b/armsrc/lfops.c index 6ac4e725..f9aee43e 100644 --- a/armsrc/lfops.c +++ b/armsrc/lfops.c @@ -115,15 +115,181 @@ void ModThenAcquireRawAdcSamples125k(int delay_off,int period_0,int period_1,BYT DoAcquisition125k(at134khz); } +/* blank r/w tag data stream +...0000000000000000 01111111 +1010101010101010101010101010101010101010101010101010101010101010 +0011010010100001 +01111111 +101010101010101[0]000... + +[5555fe852c5555555555555555fe0000] +*/ +void ReadTItag() +{ + // some hardcoded initial params + // when we read a TI tag we sample the zerocross line at 2Mhz + // TI tags modulate a 1 as 16 cycles of 123.2Khz + // TI tags modulate a 0 as 16 cycles of 134.2Khz + #define FSAMPLE 2000000 + #define FREQLO 123200 + #define FREQHI 134200 + + signed char *dest = (signed char *)BigBuf; + int n = sizeof(BigBuf); +// int *dest = GraphBuffer; +// int n = GraphTraceLen; + + // 128 bit shift register [shift3:shift2:shift1:shift0] + DWORD shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0; + + int i, cycles=0, samples=0; + // how many sample points fit in 16 cycles of each frequency + DWORD sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI; + // when to tell if we're close enough to one freq or another + DWORD threshold = (sampleslo - sampleshi + 1)>>1; + + // TI tags charge at 134.2Khz + FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz + + // Place FPGA in passthrough mode, in this mode the CROSS_LO line + // connects to SSP_DIN and the SSP_DOUT logic level controls + // whether we're modulating the antenna (high) + // or listening to the antenna (low) + FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU); + + // get TI tag data into the buffer + AcquireTiType(); + + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + + for (i=0; i0) ) { + cycles++; + // after 16 cycles, measure the frequency + if (cycles>15) { + cycles=0; + samples=i-samples; // number of samples in these 16 cycles + + // TI bits are coming to us lsb first so shift them + // right through our 128 bit right shift register + shift0 = (shift0>>1) | (shift1 << 31); + shift1 = (shift1>>1) | (shift2 << 31); + shift2 = (shift2>>1) | (shift3 << 31); + shift3 >>= 1; + + // check if the cycles fall close to the number + // expected for either the low or high frequency + if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) { + // low frequency represents a 1 + shift3 |= (1<<31); + } else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) { + // high frequency represents a 0 + } else { + // probably detected a gay waveform or noise + // use this as gaydar or discard shift register and start again + shift3 = shift2 = shift1 = shift0 = 0; + } + samples = i; + + // for each bit we receive, test if we've detected a valid tag + + // if we see 17 zeroes followed by 6 ones, we might have a tag + // remember the bits are backwards + if ( ((shift0 & 0x7fffff) == 0x7e0000) ) { + // if start and end bytes match, we have a tag so break out of the loop + if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) { + cycles = 0xF0B; //use this as a flag (ugly but whatever) + break; + } + } + } + } + } + + // if flag is set we have a tag + if (cycles!=0xF0B) { + DbpString("Info: No valid tag detected."); + } else { + // put 64 bit data into shift1 and shift0 + shift0 = (shift0>>24) | (shift1 << 8); + shift1 = (shift1>>24) | (shift2 << 8); + + // align 16 bit crc into lower half of shift2 + shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff; + + // if r/w tag, check ident match + if ( shift3&(1<<15) ) { + DbpString("Info: TI tag is rewriteable"); + // only 15 bits compare, last bit of ident is not valid + if ( ((shift3>>16)^shift0)&0x7fff ) { + DbpString("Error: Ident mismatch!"); + } else { + DbpString("Info: TI tag ident is valid"); + } + } else { + DbpString("Info: TI tag is readonly"); + } + + // WARNING the order of the bytes in which we calc crc below needs checking + // i'm 99% sure the crc algorithm is correct, but it may need to eat the + // bytes in reverse or something + // calculate CRC + DWORD crc=0; + + crc = update_crc16(crc, (shift0)&0xff); + crc = update_crc16(crc, (shift0>>8)&0xff); + crc = update_crc16(crc, (shift0>>16)&0xff); + crc = update_crc16(crc, (shift0>>24)&0xff); + crc = update_crc16(crc, (shift1)&0xff); + crc = update_crc16(crc, (shift1>>8)&0xff); + crc = update_crc16(crc, (shift1>>16)&0xff); + crc = update_crc16(crc, (shift1>>24)&0xff); + + DbpString("Info: Tag data_hi, data_lo, crc = "); + DbpIntegers(shift1, shift0, shift2&0xffff); + if (crc != (shift2&0xffff)) { + DbpString("Error: CRC mismatch, expected"); + DbpIntegers(0, 0, crc); + } else { + DbpString("Info: CRC is good"); + } + } +} + +void WriteTIbyte(BYTE b) +{ + int i = 0; + + // modulate 8 bits out to the antenna + for (i=0; i<8; i++) + { + if (b&(1<= n) return; + i++; if(i >= TIBUFLEN) break; } WDT_HIT(); } @@ -171,54 +337,22 @@ void AcquireTiType(void) // return stolen pin to SSP PIO_DISABLE = (1<=0; i--) { +// DbpIntegers(0, 0, BigBuf[i]); + for (j=0; j<32; j++) { + if(BigBuf[i] & (1 << j)) { + dest[--n] = 1; + } else { + dest[--n] = -1; + } } } } -void AcquireRawBitsTI(void) -{ - // TI tags charge at 134.2Khz - FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz - - // Place FPGA in passthrough mode, in this mode the CROSS_LO line - // connects to SSP_DIN and the SSP_DOUT logic level controls - // whether we're modulating the antenna (high) - // or listening to the antenna (low) - FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU); - - // get TI tag data into the buffer - AcquireTiType(); - - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); -} - // arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc // if crc provided, it will be written with the data verbatim (even if bogus) // if not provided a valid crc will be computed from the data and written. @@ -292,7 +426,7 @@ void WriteTItag(DWORD idhi, DWORD idlo, WORD crc) AcquireTiType(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - DbpString("Now use tibits and tidemod"); + DbpString("Now use tiread to check"); } void SimulateTagLowFrequency(int period, int ledcontrol)