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CHG: according to measureement by @wilrn the actual timing for receiving tag data, is 90us (ONE) and 100us (ZERO) which is not mentioned anywhere before. What a find!

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iceman1001 2016-09-24 15:15:24 +02:00
parent d5bded10e2
commit 25d52dd261
1 changed files with 23 additions and 17 deletions
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40
armsrc/legicrf.c
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@ -89,11 +89,9 @@ static void setup_timer(void) {
#define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
#ifndef SHORT_COIL
//#define LOW(x) AT91C_BASE_PIOA->PIO_CODR = (x)
# define SHORT_COIL LOW(GPIO_SSC_DOUT);
#endif
#ifndef OPEN_COIL
//#define HIGH(x) AT91C_BASE_PIOA->PIO_SODR = (x)
# define OPEN_COIL HIGH(GPIO_SSC_DOUT);
#endif
@ -104,12 +102,13 @@ uint32_t sendFrameStop = 0;
// one == 80us / 120ticks
// zero == 40us / 60ticks
#ifndef COIL_PULSE
# define COIL_PULSE(x) { \
# define COIL_PULSE(x) \
do { \
SHORT_COIL; \
WaitTicks(RWD_TIME_PAUSE); \
WaitTicks( (RWD_TIME_PAUSE) ); \
OPEN_COIL; \
WaitTicks((x)); \
}
} while (0)
#endif
// ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces.
@ -282,8 +281,9 @@ static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
uint8_t i = bits, edges = 0;
uint16_t lsfr = 0;
uint32_t the_bit = 1, next_bit_at = 0, data;
int old_level = 0, level = 0;
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
@ -298,15 +298,15 @@ static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
data = lsfr;
//FIXED time between sending frame and now listening frame. 330us
//WaitTicks( GET_TICKS - sendFrameStop - TAG_FRAME_WAIT);
WaitTicks( 490 );
//WaitTicks( TAG_FRAME_WAIT - (GET_TICKS - sendFrameStop ) );
WaitTicks( 495 );
uint32_t starttime = GET_TICKS;
next_bit_at = GET_TICKS + TAG_BIT_PERIOD;
while ( i-- ){
edges = 0;
uint8_t adjust = 0;
while ( GET_TICKS < next_bit_at) {
level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
@ -315,11 +315,17 @@ static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
++edges;
old_level = level;
}
if(edges > 20 && adjust == 0) {
next_bit_at -= 15;
adjust = 1;
}
}
next_bit_at += TAG_BIT_PERIOD;
// We expect 42 edges == ONE
if(edges > 30 && edges < 64)
if(edges > 20 && edges < 64)
data ^= the_bit;
the_bit <<= 1;
@ -351,7 +357,7 @@ static uint32_t setup_phase_reader(uint8_t iv) {
// Switch on carrier and let the tag charge for 1ms
HIGH(GPIO_SSC_DOUT);
WaitUS(300);
WaitUS(1000);
ResetTicks();
@ -367,8 +373,8 @@ static uint32_t setup_phase_reader(uint8_t iv) {
frame_receiveAsReader(&current_frame, 6);
// fixed delay before sending ack.
WaitTicks(387); // 244us
legic_prng_forward(3); //240us / 100 == 2.4 iterations
WaitTicks(366); // 244us
legic_prng_forward(1); //240us / 100 == 2.4 iterations
// Send obsfuscated acknowledgment frame.
// 0x19 = 0x18 MIM22, 0x01 LSB READCMD
@ -432,8 +438,8 @@ int legic_read_byte(int byte_index, int cmd_sz) {
// 460 | 690
// 258 | 387
// 244 | 366
WaitTicks(332);
legic_prng_forward(2); // 460 / 100 = 4.6 iterations
WaitTicks(366);
legic_prng_forward(3); // 460 / 100 = 4.6 iterations
uint8_t byte = 0, crc = 0, calcCrc = 0;
uint32_t cmd = (byte_index << 1) | LEGIC_READ;