X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/7bc95e2e43c0b00b72fc794b18c26a880ac19d1c..1929af0c9e70cbc2411628e14f70f86ef555dfed:/armsrc/iso14443a.c diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index ca888295..b105e792 100644 --- a/armsrc/iso14443a.c +++ b/armsrc/iso14443a.c @@ -236,6 +236,15 @@ bool RAMFUNC LogTrace(const uint8_t * btBytes, uint8_t iLen, uint32_t timestamp, //----------------------------------------------------------------------------- static tUart Uart; +// Lookup-Table to decide if 4 raw bits are a modulation. +// We accept two or three consecutive "0" in any position with the rest "1" +const bool Mod_Miller_LUT[] = { + TRUE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, + TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE +}; +#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4]) +#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)]) + void UartReset() { Uart.state = STATE_UNSYNCD; @@ -249,7 +258,7 @@ void UartReset() Uart.endTime = 0; } -inline RAMFUNC Modulation_t MillerModulation(uint8_t b) +/* inline RAMFUNC Modulation_t MillerModulation(uint8_t b) { // switch (b & 0x88) { // case 0x00: return MILLER_MOD_BOTH_HALVES; @@ -265,7 +274,7 @@ inline RAMFUNC Modulation_t MillerModulation(uint8_t b) default: return MOD_NOMOD; } } - + */ // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) { @@ -293,14 +302,18 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) if (Uart.syncBit != 0xFFFF) { Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8); Uart.startTime -= Uart.syncBit; + Uart.endTime = Uart.startTime; Uart.state = STATE_START_OF_COMMUNICATION; } } } else { - switch (MillerModulation(Uart.twoBits >> Uart.syncBit)) { - case MOD_FIRST_HALF: // Sequence Z = 0 + if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) { + if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) { // Modulation in both halves - error + UartReset(); + Uart.highCnt = 6; + } else { // Modulation in first half = Sequence Z = logic "0" if (Uart.state == STATE_MILLER_X) { // error - must not follow after X UartReset(); Uart.highCnt = 6; @@ -317,8 +330,9 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) Uart.shiftReg = 0; } } - break; - case MOD_SECOND_HALF: // Sequence X = 1 + } + } else { + if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) { // Modulation second half = Sequence X = logic "1" Uart.bitCount++; Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100; // add a 1 to the shiftreg Uart.state = STATE_MILLER_X; @@ -330,15 +344,14 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) Uart.bitCount = 0; Uart.shiftReg = 0; } - break; - case MOD_NOMOD: // no modulation in both halves - Sequence Y + } else { // no modulation in both halves - Sequence Y if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) { // Y after logic "0" - End of Communication Uart.state = STATE_UNSYNCD; if(Uart.len == 0 && Uart.bitCount > 0) { // if we decoded some bits Uart.shiftReg >>= (9 - Uart.bitCount); // add them to the output Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); Uart.parityBits <<= 1; // no parity bit - add "0" - Uart.bitCount--; // last "0" was part of the EOC sequence + Uart.bitCount--; // last "0" was part of the EOC sequence } return TRUE; } @@ -357,11 +370,7 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) Uart.shiftReg = 0; } } - break; - case MOD_BOTH_HALVES: // Error - UartReset(); - Uart.highCnt = 6; - return FALSE; + } } } @@ -388,9 +397,11 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) // Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only) static tDemod Demod; +// Lookup-Table to decide if 4 raw bits are a modulation. +// We accept three or four consecutive "1" in any position const bool Mod_Manchester_LUT[] = { - FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, TRUE, - FALSE, FALSE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE + FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, + FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, TRUE }; #define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4]) @@ -434,7 +445,7 @@ static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2; else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1; else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0; - if (Demod.syncBit < 8) { + if (Demod.syncBit != 0xFFFF) { Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8); Demod.startTime -= Demod.syncBit; Demod.bitCount = offset; // number of decoded data bits @@ -473,15 +484,17 @@ static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non } Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1); } else { // no modulation in both halves - End of communication - if(Demod.bitCount > 0) { // if we decoded bits - Demod.shiftReg >>= (9 - Demod.bitCount); // add the remaining decoded bits to the output - Demod.output[Demod.len++] = Demod.shiftReg & 0xff; - // No parity bit, so just shift a 0 - Demod.parityBits <<= 1; + if (Demod.len > 0 || Demod.bitCount > 0) { // received something + if(Demod.bitCount > 0) { // if we decoded bits + Demod.shiftReg >>= (9 - Demod.bitCount); // add the remaining decoded bits to the output + Demod.output[Demod.len++] = Demod.shiftReg & 0xff; + // No parity bit, so just shift a 0 + Demod.parityBits <<= 1; + } + return TRUE; // we are finished with decoding the raw data sequence + } else { // nothing received. Start over + DemodReset(); } - Demod.state = DEMOD_UNSYNCD; // start from the beginning - Demod.twoBits = 0; - return TRUE; // we are finished with decoding the raw data sequence } }