+ // TC0: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers
+ AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK;
+
+ // TC1: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
+ // external trigger rising edge, load RA on falling edge of TIOA.
+ AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
+
+ // Enable and reset counters
+ AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+
+ // Reset the received frame, frame count and timing info
+ // frame_count = 0;
+ response = 0;
+ lastbit = 1;
+ bStop = false;
+
+ // Tag specific configuration settings (sof, timings, etc.)
+ if (htf < 10) {
+ // hitagS settings
+ reset_sof = 1;
+ t_wait = 200;
+ //DbpString("Configured for hitagS reader");
+ } else if (htf < 20) {
+ // hitag1 settings
+ reset_sof = 1;
+ t_wait = 200;
+ //DbpString("Configured for hitag1 reader");
+ } else if (htf < 30) {
+ // hitag2 settings
+ reset_sof = 4;
+ t_wait = HITAG_T_WAIT_2;
+ //DbpString("Configured for hitag2 reader");
+ } else {
+ Dbprintf("Error, unknown hitag reader type: %d", htf);
+ return;
+ }
+ while (!bStop && !BUTTON_PRESS()) {
+
+ WDT_HIT();
+
+ // Check if frame was captured and store it
+ if (rxlen > 0) {
+ // frame_count++;
+ if (!bQuiet) {
+ if (!LogTraceHitag(rx, rxlen, response, 0, false)) {
+ DbpString("Trace full");
+ if (bQuitTraceFull) {
+ break;
+ } else {
+ bQuiet = true;
+ }
+ }
+ }
+ }
+
+ // By default reset the transmission buffer
+ tx = txbuf;
+ switch (htf) {
+ case WHT2F_CRYPTO: {
+ bStop = !hitag2_crypto(rx, rxlen, tx, &txlen, true);
+ }
+ break;
+ case WHT2F_PASSWORD: {
+ bStop = !hitag2_password(rx, rxlen, tx, &txlen, true);
+ }
+ break;
+ default: {
+ Dbprintf("Error, unknown function: %d", htf);
+ return;
+ }
+ break;
+ }
+
+ // Send and store the reader command
+ // Disable timer 1 with external trigger to avoid triggers during our own modulation
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+
+ // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
+ // Since the clock counts since the last falling edge, a 'one' means that the
+ // falling edge occured halfway the period. with respect to this falling edge,
+ // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
+ // All timer values are in terms of T0 units
+ while (AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
+
+ //Dbprintf("DEBUG: Sending reader frame");
+
+ // Transmit the reader frame
+ hitag_reader_send_frame(tx, txlen);
+
+ // Enable and reset external trigger in timer for capturing future frames
+ AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+
+ // Add transmitted frame to total count
+ if (txlen > 0) {
+ // frame_count++;
+ if (!bQuiet) {
+ // Store the frame in the trace
+ if (!LogTraceHitag(tx, txlen, HITAG_T_WAIT_2, 0, true)) {
+ if (bQuitTraceFull) {
+ break;
+ } else {
+ bQuiet = true;
+ }
+ }
+ }
+ }
+
+ // Reset values for receiving frames
+ memset(rx, 0x00, sizeof(rx));
+ rxlen = 0;
+ lastbit = 1;
+ bSkip = true;
+ tag_sof = reset_sof;
+ response = 0;
+ //Dbprintf("DEBUG: Waiting to receive frame");
+ uint32_t errorCount = 0;
+
+ // Receive frame, watch for at most T0*EOF periods
+ while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
+ // Check if falling edge in tag modulation is detected
+ if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
+ // Retrieve the new timing values
+ int ra = (AT91C_BASE_TC1->TC_RA/T0);
+
+ // Reset timer every frame, we have to capture the last edge for timing
+ AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
+
+ LED_B_ON();
+
+ // Capture tag frame (manchester decoding using only falling edges)
+ if (ra >= HITAG_T_EOF) {
+ if (rxlen != 0) {
+ //Dbprintf("DEBUG: Wierd1");
+ }
+ // Capture the T0 periods that have passed since last communication or field drop (reset)
+ // We always recieve a 'one' first, which has the falling edge after a half period |-_|
+ response = ra - HITAG_T_TAG_HALF_PERIOD;
+ } else if (ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
+ // Manchester coding example |-_|_-|-_| (101)
+
+ // need to test to verify we don't exceed memory...
+ // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
+ // break;
+ // }
+ rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+ rxlen++;
+ rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+ rxlen++;
+ } else if (ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
+ // Manchester coding example |_-|...|_-|-_| (0...01)
+
+ // need to test to verify we don't exceed memory...
+ // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
+ // break;
+ // }
+ rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+ rxlen++;
+ // We have to skip this half period at start and add the 'one' the second time
+ if (!bSkip) {
+ rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+ rxlen++;
+ }
+ lastbit = !lastbit;
+ bSkip = !bSkip;
+ } else if (ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
+ // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
+
+ // need to test to verify we don't exceed memory...
+ // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
+ // break;
+ // }
+ if (tag_sof) {
+ // Ignore bits that are transmitted during SOF
+ tag_sof--;
+ } else {
+ // bit is same as last bit
+ rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
+ rxlen++;
+ }
+ } else {
+ // Dbprintf("DEBUG: Wierd2");
+ errorCount++;
+ // Ignore wierd value, it is too small to mean anything
+ }
+ }
+ // if we saw over 100 wierd values break it probably isn't hitag...
+ if (errorCount > 100) break;