+/*
+ * LEGIC RF simulation code
+ *
+ * (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+ */
+
+#include <proxmark3.h>
+
+#include "apps.h"
+#include "legicrf.h"
+
+static struct legic_frame {
+ int num_bytes;
+ int num_bits;
+ char data[10];
+} current_frame;
+static char response = 0x2b; /* 1101 01 */
+
+static void frame_send(char *response, int num_bytes, int num_bits)
+{
+#if 0
+ /* Use the SSC to send a response. 8-bit transfers, LSBit first, 100us per bit */
+#else
+ /* Bitbang the response */
+ AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
+ AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+ AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+
+ /* Wait for the frame start */
+ while(AT91C_BASE_TC1->TC_CV < 490) ;
+
+ 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));
+ 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) ;
+ }
+ AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
+#endif
+}
+
+static void frame_respond(struct legic_frame *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);
+ }
+ LED_D_OFF();
+}
+
+static void frame_append_bit(struct legic_frame *f, int bit)
+{
+ if(f->num_bytes >= (int)sizeof(f->data))
+ 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++;
+ }
+}
+
+static int frame_is_empty(struct legic_frame *f)
+{
+ return( (f->num_bytes + f->num_bits) <= 4 );
+}
+
+static void frame_handle(struct legic_frame *f)
+{
+ if( !frame_is_empty(f) ) {
+ frame_respond(f);
+ }
+}
+
+static void frame_clean(struct legic_frame *f)
+{
+ if(!frame_is_empty(f))
+ memset(f->data, 0, sizeof(f->data));
+ f->num_bits = 0;
+ f->num_bytes = 0;
+}
+
+static void emit(int bit)
+{
+ if(bit == -1) {
+ frame_handle(¤t_frame);
+ frame_clean(¤t_frame);
+ } else if(bit == 0) {
+ frame_append_bit(¤t_frame, 0);
+ } else if(bit == 1) {
+ frame_append_bit(¤t_frame, 1);
+ }
+}
+
+void LegicRfSimulate(void)
+{
+ /* ADC path high-frequency peak detector, FPGA in high-frequency simulator mode,
+ * modulation mode set to 212kHz subcarrier. We are getting the incoming raw
+ * envelope waveform on DIN and should send our response on DOUT.
+ *
+ * The LEGIC RF protocol is pulse-pause-encoding from reader to card, so we'll
+ * measure the time between two rising edges on DIN, and no encoding on the
+ * subcarrier from card to reader, so we'll just shift out our verbatim data
+ * on DOUT, 1 bit is 100us. The time from reader to card frame is still unclear,
+ * seems to be 300us-ish.
+ */
+ SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+ FpgaSetupSsc();
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_212K);
+
+ /* Bitbang the receiver */
+ 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
+
+ int active = 0;
+ while(!BUTTON_PRESS()) {
+ int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
+ int time = AT91C_BASE_TC1->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)) {
+ /* 1 bit */
+ emit(1);
+ active = 1;
+ } else if(time > (BIT_TIME_0-BIT_TIME_FUZZ) && time < (BIT_TIME_0+BIT_TIME_FUZZ)) {
+ /* 0 bit */
+ emit(0);
+ active = 0;
+ } else {
+ /* invalid */
+ emit(-1);
+ active = 0;
+ }
+ }
+ }
+
+ if(time >= (BIT_TIME_1+2*BIT_TIME_FUZZ) && active) {
+ /* Frame end */
+ emit(-1);
+ active = 0;
+ }
+
+ if(time >= (20*BIT_TIME_1) && (AT91C_BASE_TC1->TC_SR & AT91C_TC_CLKSTA)) {
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+ }
+
+
+ old_level = level;
+ WDT_HIT();
+ }
+}
projects / proxmark3-svn / commitdiff