github/proxmark3
1
0
Fork 0
mirror of https://github.com/Proxmark/proxmark3.git synced 2025-08-14 02:26:59 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions

fix: introduced a stupid error when refactoring the start bit detector in MillerDecoding()

Browse source 
chg: use -O2 instead of -Os when compiling ARM sources
chg: don't clear the Miller decoders input buffer on reset
chg: be more specific for the Miller decoders start bit pattern
add: new option c in hf list: mark CRC bytes (default is off)
This commit is contained in:
pwpiwi 2015-03-18 17:12:09 +01:00
commit 05ddb52c43
7 changed files with 197 additions and 86 deletions
Download patch file Download diff file Expand all files Collapse all files

49
armsrc/iso14443a.c
View file

@ -232,13 +232,19 @@ void AppendCrc14443a(uint8_t* data, int len)
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"
// We accept the following:
// 0001 - a 3 tick wide pause
// 0011 - a 2 tick wide pause, or a three tick wide pause shifted left
// 0111 - a 2 tick wide pause shifted left
// 1001 - a 2 tick wide pause shifted right
const bool Mod_Miller_LUT[] = {
TRUE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE,
TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE
// TRUE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE,
// TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE
FALSE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, TRUE,
FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE
};
#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4])
#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)])
#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x000000F0) >> 4])
#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x0000000F)])
void UartReset()
{
@ -248,7 +254,6 @@ void UartReset()
Uart.parityLen = 0; // number of decoded parity bytes
Uart.shiftReg = 0; // shiftreg to hold decoded data bits
Uart.parityBits = 0; // holds 8 parity bits
Uart.fourBits = 0x00000000; // buffer for 4 Bits
Uart.startTime = 0;
Uart.endTime = 0;
}
@ -257,6 +262,7 @@ void UartInit(uint8_t *data, uint8_t *parity)
{
Uart.output = data;
Uart.parity = parity;
Uart.fourBits = 0x00000000; // clear the buffer for 4 Bits
UartReset();
}
@ -269,18 +275,21 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
if (Uart.state == STATE_UNSYNCD) { // not yet synced
Uart.syncBit = 9999; // not set
// we look for a ...xxxx1111111100x11111xxxxxx pattern
// (unmodulated, followed by the start bit = 8 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
#define ISO14443A_STARTBIT_MASK 0x007FEF80 // mask is 00000000 01111111 11101111 10000000
#define ISO14443A_STARTBIT_PATTERN 0x007F8F80 // pattern is 00000000 01111111 10001111 10000000
if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 0 == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 1 == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 2 == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 3 == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 4 == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 5 == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 6 == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1;
else if ((Uart.fourBits & ISO14443A_STARTBIT_MASK) >> 7 == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0;
// The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from
// Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111)
// we therefore look for a ...xx11111111111100x11111xxxxxx... pattern
// (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
#define ISO14443A_STARTBIT_MASK 0x07FFEF80 // mask is 00000111 11111111 11101111 10000000
#define ISO14443A_STARTBIT_PATTERN 0x07FF8F80 // pattern is 00000111 11111111 10001111 10000000
if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 3)) == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 4)) == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 5)) == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 6)) == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1;
else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 7)) == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0;
if (Uart.syncBit != 9999) { // found a sync bit
Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
Uart.startTime -= Uart.syncBit;
@ -646,7 +655,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
TRUE)) break;
}
/* And ready to receive another command. */
UartReset();
UartInit(receivedCmd, receivedCmdPar);
/* And also reset the demod code, which might have been */
/* false-triggered by the commands from the reader. */
DemodReset();
@ -2798,7 +2807,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
if (MfSniffLogic(receivedCmd, Uart.len, Uart.parity, Uart.bitCount, TRUE)) break;
/* And ready to receive another command. */
UartReset();
UartInit(receivedCmd, receivedCmdPar);
/* And also reset the demod code */
DemodReset();