+// static void UartInit(uint8_t *data) {
+ // Uart.output = data;
+ // UartReset();
+// }
+
+//=============================================================================
+// An LEGIC reader. We take layer two commands, code them
+// appropriately, and then send them to the tag. We then listen for the
+// tag's response, which we leave in the buffer to be demodulated on the
+// PC side.
+//=============================================================================
+
+static struct {
+ enum {
+ DEMOD_UNSYNCD,
+ DEMOD_PHASE_REF_TRAINING,
+ DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
+ DEMOD_GOT_FALLING_EDGE_OF_SOF,
+ DEMOD_AWAITING_START_BIT,
+ DEMOD_RECEIVING_DATA
+ } state;
+ int bitCount;
+ int posCount;
+ int thisBit;
+ uint16_t shiftReg;
+ uint8_t *output;
+ int len;
+ int sumI;
+ int sumQ;
+} Demod;
+
+/*
+ * Handles reception of a bit from the tag
+ *
+ * This function is called 2 times per bit (every 4 subcarrier cycles).
+ * Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
+ *
+ * LED handling:
+ * LED C -> ON once we have received the SOF and are expecting the rest.
+ * LED C -> OFF once we have received EOF or are unsynced
+ *
+ * Returns: true if we received a EOF
+ * false if we are still waiting for some more
+ *
+ */
+
+ #ifndef SUBCARRIER_DETECT_THRESHOLD
+ # define SUBCARRIER_DETECT_THRESHOLD 8
+ #endif
+
+ // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
+#ifndef CHECK_FOR_SUBCARRIER
+# define CHECK_FOR_SUBCARRIER() { v = MAX(ai, aq) + MIN(halfci, halfcq); }
+#endif
+
+// The soft decision on the bit uses an estimate of just the
+// quadrant of the reference angle, not the exact angle.
+// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
+#define MAKE_SOFT_DECISION() { \
+ if(Demod.sumI > 0) \
+ v = ci; \
+ else \
+ v = -ci; \
+ \
+ if(Demod.sumQ > 0) \
+ v += cq; \
+ else \
+ v -= cq; \
+ \
+ }
+
+static RAMFUNC int HandleLegicSamplesDemod(int ci, int cq)
+{
+ int v = 0;
+ int ai = ABS(ci);
+ int aq = ABS(cq);
+ int halfci = (ai >> 1);
+ int halfcq = (aq >> 1);
+
+ switch(Demod.state) {
+ case DEMOD_UNSYNCD:
+
+ CHECK_FOR_SUBCARRIER()
+
+ if(v > SUBCARRIER_DETECT_THRESHOLD) { // subcarrier detected
+ Demod.state = DEMOD_PHASE_REF_TRAINING;
+ Demod.sumI = ci;
+ Demod.sumQ = cq;
+ Demod.posCount = 1;
+ }
+ break;
+
+ case DEMOD_PHASE_REF_TRAINING:
+ if(Demod.posCount < 8) {
+
+ CHECK_FOR_SUBCARRIER()
+
+ if (v > SUBCARRIER_DETECT_THRESHOLD) {
+ // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
+ // note: synchronization time > 80 1/fs
+ Demod.sumI += ci;
+ Demod.sumQ += cq;
+ ++Demod.posCount;
+ } else {
+ // subcarrier lost
+ Demod.state = DEMOD_UNSYNCD;
+ }
+ } else {
+ Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
+ }
+ break;
+
+ case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
+
+ MAKE_SOFT_DECISION()
+
+ //Dbprintf("ICE: %d %d %d %d %d", v, Demod.sumI, Demod.sumQ, ci, cq );
+ // logic '0' detected
+ if (v <= 0) {
+
+ Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
+
+ // start of SOF sequence
+ Demod.posCount = 0;
+ } else {
+ // maximum length of TR1 = 200 1/fs
+ if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
+ }
+ ++Demod.posCount;
+ break;
+
+ case DEMOD_GOT_FALLING_EDGE_OF_SOF:
+ ++Demod.posCount;
+
+ MAKE_SOFT_DECISION()
+
+ if(v > 0) {
+ // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
+ if(Demod.posCount < 10*2) {
+ Demod.state = DEMOD_UNSYNCD;
+ } else {
+ LED_C_ON(); // Got SOF
+ Demod.state = DEMOD_AWAITING_START_BIT;
+ Demod.posCount = 0;
+ Demod.len = 0;
+ }
+ } else {
+ // low phase of SOF too long (> 12 etu)
+ if(Demod.posCount > 13*2) {
+ Demod.state = DEMOD_UNSYNCD;
+ LED_C_OFF();
+ }
+ }
+ break;
+
+ case DEMOD_AWAITING_START_BIT:
+ ++Demod.posCount;
+
+ MAKE_SOFT_DECISION()
+
+ if(v > 0) {
+ // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
+ if(Demod.posCount > 3*2) {
+ Demod.state = DEMOD_UNSYNCD;
+ LED_C_OFF();
+ }
+ } else {
+ // start bit detected
+ Demod.bitCount = 0;
+ Demod.posCount = 1; // this was the first half
+ Demod.thisBit = v;
+ Demod.shiftReg = 0;
+ Demod.state = DEMOD_RECEIVING_DATA;
+ }
+ break;
+
+ case DEMOD_RECEIVING_DATA:
+
+ MAKE_SOFT_DECISION()
+
+ if(Demod.posCount == 0) {
+ // first half of bit
+ Demod.thisBit = v;
+ Demod.posCount = 1;
+ } else {
+ // second half of bit
+ Demod.thisBit += v;
+ Demod.shiftReg >>= 1;
+ // logic '1'
+ if(Demod.thisBit > 0)
+ Demod.shiftReg |= 0x200;
+
+ ++Demod.bitCount;
+
+ if(Demod.bitCount == 10) {
+
+ uint16_t s = Demod.shiftReg;
+
+ if((s & 0x200) && !(s & 0x001)) {
+ // stop bit == '1', start bit == '0'
+ uint8_t b = (s >> 1);
+ Demod.output[Demod.len] = b;
+ ++Demod.len;
+ Demod.state = DEMOD_AWAITING_START_BIT;
+ } else {
+ Demod.state = DEMOD_UNSYNCD;
+ LED_C_OFF();
+
+ if(s == 0x000) {
+ // This is EOF (start, stop and all data bits == '0'
+ return TRUE;
+ }
+ }
+ }
+ Demod.posCount = 0;
+ }
+ break;
+
+ default:
+ Demod.state = DEMOD_UNSYNCD;
+ LED_C_OFF();
+ break;
+ }
+ return FALSE;
+}
+
+// Clear out the state of the "UART" that receives from the tag.
+static void DemodReset() {
+ Demod.len = 0;
+ Demod.state = DEMOD_UNSYNCD;
+ Demod.posCount = 0;
+ Demod.sumI = 0;
+ Demod.sumQ = 0;
+ Demod.bitCount = 0;
+ Demod.thisBit = 0;
+ Demod.shiftReg = 0;
+ memset(Demod.output, 0x00, 3);
+}
+
+static void DemodInit(uint8_t *data) {
+ Demod.output = data;
+ DemodReset();
+}
+
+/*
+ * Demodulate the samples we received from the tag, also log to tracebuffer
+ * quiet: set to 'TRUE' to disable debug output
+ */
+ #define LEGIC_DMA_BUFFER_SIZE 256
+static void GetSamplesForLegicDemod(int n, bool quiet)
+{
+ int max = 0;
+ bool gotFrame = FALSE;
+ int lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
+ int ci, cq, samples = 0;
+
+ BigBuf_free();
+
+ // And put the FPGA in the appropriate mode
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_QUARTER_FREQ);
+
+ // The response (tag -> reader) that we're receiving.
+ // Set up the demodulator for tag -> reader responses.
+ DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
+
+ // The DMA buffer, used to stream samples from the FPGA
+ int8_t *dmaBuf = (int8_t*) BigBuf_malloc(LEGIC_DMA_BUFFER_SIZE);
+ int8_t *upTo = dmaBuf;
+
+ // Setup and start DMA.
+ if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, LEGIC_DMA_BUFFER_SIZE) ){
+ if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
+ return;
+ }
+
+ // Signal field is ON with the appropriate LED:
+ LED_D_ON();
+ for(;;) {
+ int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
+ if(behindBy > max) max = behindBy;
+
+ while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (LEGIC_DMA_BUFFER_SIZE-1)) > 2) {
+ ci = upTo[0];
+ cq = upTo[1];
+ upTo += 2;
+ if(upTo >= dmaBuf + LEGIC_DMA_BUFFER_SIZE) {
+ upTo = dmaBuf;
+ AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
+ AT91C_BASE_PDC_SSC->PDC_RNCR = LEGIC_DMA_BUFFER_SIZE;
+ }
+ lastRxCounter -= 2;
+ if(lastRxCounter <= 0)
+ lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
+
+ samples += 2;
+
+ gotFrame = HandleLegicSamplesDemod(ci , cq );
+ if ( gotFrame )
+ break;
+ }
+
+ if(samples > n || gotFrame)
+ break;
+ }
+
+ FpgaDisableSscDma();
+
+ if (!quiet && Demod.len == 0) {
+ Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d",
+ max,
+ samples,
+ gotFrame,
+ Demod.len,
+ Demod.sumI,
+ Demod.sumQ
+ );
+ }
+
+ //Tracing
+ if (Demod.len > 0) {
+ uint8_t parity[MAX_PARITY_SIZE] = {0x00};
+ LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
+ }
+}
+//-----------------------------------------------------------------------------
+// Transmit the command (to the tag) that was placed in ToSend[].
+//-----------------------------------------------------------------------------
+static void TransmitForLegic(void)
+{
+ int c;
+
+ FpgaSetupSsc();
+
+ while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))
+ AT91C_BASE_SSC->SSC_THR = 0xff;
+
+ // Signal field is ON with the appropriate Red LED
+ LED_D_ON();
+
+ // Signal we are transmitting with the Green LED
+ LED_B_ON();
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
+
+ for(c = 0; c < 10;) {
+ if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+ AT91C_BASE_SSC->SSC_THR = 0xff;
+ c++;
+ }
+ if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+ volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
+ (void)r;
+ }
+ WDT_HIT();
+ }
+
+ c = 0;
+ for(;;) {
+ if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+ AT91C_BASE_SSC->SSC_THR = ToSend[c];
+ legic_prng_forward(1); // forward the lfsr
+ c++;
+ if(c >= ToSendMax) {
+ break;
+ }
+ }
+ if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+ volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
+ (void)r;
+ }
+ WDT_HIT();
+ }
+ LED_B_OFF();
+}
+
+
+//-----------------------------------------------------------------------------
+// Code a layer 2 command (string of octets, including CRC) into ToSend[],
+// so that it is ready to transmit to the tag using TransmitForLegic().
+//-----------------------------------------------------------------------------
+static void CodeLegicBitsAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
+{
+ int i, j;
+ uint8_t b;
+
+ ToSendReset();
+
+ // Send SOF
+ for(i = 0; i < 7; i++)
+ ToSendStuffBit(1);
+
+
+ for(i = 0; i < cmdlen; i++) {
+ // Start bit
+ ToSendStuffBit(0);
+
+ // Data bits
+ b = cmd[i];
+ for(j = 0; j < bits; j++) {
+ if(b & 1) {
+ ToSendStuffBit(1);
+ } else {
+ ToSendStuffBit(0);
+ }
+ b >>= 1;
+ }
+ }
+
+ // Convert from last character reference to length
+ ++ToSendMax;
+}
+
+/**
+ Convenience function to encode, transmit and trace Legic comms
+ **/
+static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
+{
+ CodeLegicBitsAsReader(cmd, cmdlen, bits);
+ TransmitForLegic();
+ if (tracing) {
+ uint8_t parity[1] = {0x00};
+ LogTrace(cmd, cmdlen, 0, 0, parity, TRUE);
+ }
+}
+
+int ice_legic_select_card()
+{
+ //int cmd_size=0, card_size=0;
+ uint8_t wakeup[] = { 0x7F };
+ uint8_t getid[] = {0x19};
+
+ legic_prng_init(SESSION_IV);
+
+ // first, wake up the tag, 7bits
+ CodeAndTransmitLegicAsReader(wakeup, sizeof(wakeup), 7);
+
+ GetSamplesForLegicDemod(1000, TRUE);
+
+ // frame_clean(¤t_frame);
+ //frame_receive_rwd(¤t_frame, 6, 1);
+
+ legic_prng_forward(1); /* we wait anyways */
+
+ //while(timer->TC_CV < 387) ; /* ~ 258us */
+ //frame_send_rwd(0x19, 6);
+ CodeAndTransmitLegicAsReader(getid, sizeof(getid), 8);
+ GetSamplesForLegicDemod(1000, TRUE);
+
+ //if (Demod.len < 14) return 2;
+ Dbprintf("CARD TYPE: %02x LEN: %d", Demod.output[0], Demod.len);
+
+ switch(Demod.output[0]) {
+ case 0x1d:
+ DbpString("MIM 256 card found");
+ // cmd_size = 9;
+ // card_size = 256;
+ break;
+ case 0x3d:
+ DbpString("MIM 1024 card found");
+ // cmd_size = 11;
+ // card_size = 1024;
+ break;
+ default:
+ return -1;
+ }
+
+ // if(bytes == -1)
+ // bytes = card_size;
+
+ // if(bytes + offset >= card_size)
+ // bytes = card_size - offset;
+
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+ set_tracing(FALSE);
+ return 1;
+}
+
+// Set up LEGIC communication
+void ice_legic_setup() {
+
+ // standard things.
+ FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+ BigBuf_free(); BigBuf_Clear_ext(false);
+ clear_trace();
+ set_tracing(TRUE);
+ DemodReset();
+ UartReset();
+
+ // Set up the synchronous serial port
+ FpgaSetupSsc();
+
+ // connect Demodulated Signal to ADC:
+ SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+
+ // Signal field is on with the appropriate LED
+ LED_D_ON();
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
+ SpinDelay(20);
+ // Start the timer
+ //StartCountSspClk();
+
+ // initalize CRC
+ crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
+
+ // initalize prng
+ legic_prng_init(0);
+}
\ No newline at end of file
projects / proxmark3-svn / blobdiff