#include "apps.h"
#include "legicrf.h"
+#include "unistd.h"
+#include "stdint.h"
static struct legic_frame {
- int num_bytes;
- int num_bits;
- char data[10];
+ int bits;
+ uint16_t data;
} current_frame;
-static char response = 0x2b; /* 1101 01 */
+AT91PS_TC timer;
-static void frame_send(char *response, int num_bytes, int num_bits)
+static void setup_timer(void)
+{
+ /* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
+ * this it won't be terribly accurate but should be good enough.
+ */
+ AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
+ timer = AT91C_BASE_TC1;
+ timer->TC_CCR = AT91C_TC_CLKDIS;
+ timer->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
+ timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+
+/* At TIMER_CLOCK3 (MCK/32) */
+#define RWD_TIME_1 150 /* RWD_TIME_PAUSE off, 80us on = 100us */
+#define RWD_TIME_0 90 /* RWD_TIME_PAUSE off, 40us on = 60us */
+#define RWD_TIME_PAUSE 30 /* 20us */
+#define RWD_TIME_FUZZ 20 /* rather generous 13us, since the peak detector + hysteresis fuzz quite a bit */
+#define TAG_TIME_BIT 150 /* 100us for every bit */
+#define TAG_TIME_WAIT 490 /* time from RWD frame end to tag frame start, experimentally determined */
+
+}
+
+#define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
+
+static const struct legic_frame queries[] = {
+ {7, 0x55}, /* 1010 101 */
+};
+
+static const struct legic_frame responses[] = {
+ {6, 0x3b}, /* 1101 11 */
+};
+
+/* Send a frame in tag mode, the FPGA must have been set up by
+ * LegicRfSimulate
+ */
+static void frame_send_tag(uint16_t response, int bits)
{
#if 0
/* Use the SSC to send a response. 8-bit transfers, LSBit first, 100us per bit */
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
/* Wait for the frame start */
- while(AT91C_BASE_TC1->TC_CV < 490) ;
+ while(timer->TC_CV < TAG_TIME_WAIT) ;
int i;
- for(i=0; i<(num_bytes*8+num_bits); i++) {
- int nextbit = AT91C_BASE_TC1->TC_CV + 150;
- int bit = response[i/8] & (1<<(i%8));
+ for(i=0; i<bits; i++) {
+ int nextbit = timer->TC_CV + TAG_TIME_BIT;
+ int bit = response & 1;
+ response = response >> 1;
if(bit)
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
else
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
- while(AT91C_BASE_TC1->TC_CV < nextbit) ;
+ while(timer->TC_CV < nextbit) ;
}
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
#endif
}
-static void frame_respond(struct legic_frame *f)
+/* Figure out a response to a frame in tag mode */
+static void frame_respond_tag(struct legic_frame const * const f)
{
LED_D_ON();
- if(f->num_bytes == 0 && f->num_bits == 7) {
- /* This seems to be the initial dialogue, just send 6 bits of static data */
- frame_send(&response, 0, 6);
+ int i, r_size;
+ uint16_t r_data;
+
+ for(i=0; i<sizeof(queries)/sizeof(queries[0]); i++) {
+ if(f->bits == queries[i].bits && f->data == queries[i].data) {
+ r_data = responses[i].data;
+ r_size = responses[i].bits;
+ break;
+ }
}
+
+ if(r_size != 0) {
+ frame_send_tag(r_data, r_size);
+ LED_A_ON();
+ } else {
+ LED_A_OFF();
+ }
+
LED_D_OFF();
}
-static void frame_append_bit(struct legic_frame *f, int bit)
+static void frame_append_bit(struct legic_frame * const f, int bit)
{
- if(f->num_bytes >= (int)sizeof(f->data))
+ if(f->bits >= 15)
return; /* Overflow, won't happen */
- f->data[f->num_bytes] |= (bit<<f->num_bits);
- f->num_bits++;
- if(f->num_bits > 7) {
- f->num_bits = 0;
- f->num_bytes++;
- }
+ f->data |= (bit<<f->bits);
+ f->bits++;
}
-static int frame_is_empty(struct legic_frame *f)
+static int frame_is_empty(struct legic_frame const * const f)
{
- return( (f->num_bytes + f->num_bits) <= 4 );
+ return( f->bits <= 4 );
}
-static void frame_handle(struct legic_frame *f)
+/* Handle (whether to respond) a frame in tag mode */
+static void frame_handle_tag(struct legic_frame const * const f)
{
+ if(f->bits == 6) {
+ /* Short path */
+ return;
+ }
if( !frame_is_empty(f) ) {
- frame_respond(f);
+ frame_respond_tag(f);
}
}
-static void frame_clean(struct legic_frame *f)
+static void frame_clean(struct legic_frame * const f)
{
- if(!frame_is_empty(f))
- memset(f->data, 0, sizeof(f->data));
- f->num_bits = 0;
- f->num_bytes = 0;
+ f->data = 0;
+ f->bits = 0;
}
-static void emit(int bit)
+enum emit_mode {
+ EMIT_RWD, /* Emit in tag simulation mode, e.g. the source is the RWD */
+ EMIT_TAG /* Emit in reader simulation mode, e.g. the source is the TAG */
+};
+static void emit(enum emit_mode mode, int bit)
{
if(bit == -1) {
- frame_handle(¤t_frame);
+ if(mode == EMIT_RWD) {
+ frame_handle_tag(¤t_frame);
+ }
frame_clean(¤t_frame);
} else if(bit == 0) {
frame_append_bit(¤t_frame, 0);
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
- /* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
- * this it won't be terribly accurate but should be good enough.
- */
- AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
- AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
- AT91C_BASE_TC1->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
- AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
- int old_level = 0;
-
-/* At TIMER_CLOCK3 (MCK/32) */
-#define BIT_TIME_1 150
-#define BIT_TIME_0 90
-#define BIT_TIME_FUZZ 20
+ setup_timer();
+ int old_level = 0;
int active = 0;
+
while(!BUTTON_PRESS()) {
int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
- int time = AT91C_BASE_TC1->TC_CV;
+ int time = timer->TC_CV;
if(level != old_level) {
if(level == 1) {
- AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
- if(time > (BIT_TIME_1-BIT_TIME_FUZZ) && time < (BIT_TIME_1+BIT_TIME_FUZZ)) {
+ timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+ if(FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
/* 1 bit */
- emit(1);
+ emit(EMIT_RWD, 1);
active = 1;
- } else if(time > (BIT_TIME_0-BIT_TIME_FUZZ) && time < (BIT_TIME_0+BIT_TIME_FUZZ)) {
+ LED_B_ON();
+ } else if(FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
/* 0 bit */
- emit(0);
- active = 0;
- } else {
+ emit(EMIT_RWD, 0);
+ active = 1;
+ LED_B_ON();
+ } else if(active) {
/* invalid */
- emit(-1);
+ emit(EMIT_RWD, -1);
active = 0;
+ LED_B_OFF();
}
}
}
- if(time >= (BIT_TIME_1+2*BIT_TIME_FUZZ) && active) {
+ if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
/* Frame end */
- emit(-1);
+ emit(EMIT_RWD, -1);
active = 0;
+ LED_B_OFF();
}
- if(time >= (20*BIT_TIME_1) && (AT91C_BASE_TC1->TC_SR & AT91C_TC_CLKSTA)) {
- AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+ if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA)) {
+ timer->TC_CCR = AT91C_TC_CLKDIS;
}
projects / proxmark3-svn / blobdiff