Mfp commands (#698)

[proxmark3-svn] / armsrc / iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index 75769859392c725453b4ede60ae9a5b3a60a3797..cb8567fa570533ae8cee27283ca0e37f22429b78 100644 (file)
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -1,5 +1,6 @@
 //-----------------------------------------------------------------------------
 // Jonathan Westhues, split Nov 2006
 //-----------------------------------------------------------------------------
 // Jonathan Westhues, split Nov 2006

+// piwi 2018

 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of
 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of


@@ -16,8 +17,8 @@
 
 #include "iso14443crc.h"
 
 
 #include "iso14443crc.h"
 

-#define RECEIVE_SAMPLES_TIMEOUT 2000
-#define ISO14443B_DMA_BUFFER_SIZE 256
+#define RECEIVE_SAMPLES_TIMEOUT 1000 // TR0 max is 256/fs = 256/(848kHz) = 302us or 64 samples from FPGA. 1000 seems to be much too high?
+#define ISO14443B_DMA_BUFFER_SIZE 128

 
 // PCB Block number for APDUs
 static uint8_t pcb_blocknum = 0;
 
 // PCB Block number for APDUs
 static uint8_t pcb_blocknum = 0;


@@ -374,7 +375,7 @@ void SimulateIso14443bTag(void)
 
        // We need to listen to the high-frequency, peak-detected path.
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // We need to listen to the high-frequency, peak-detected path.
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);

-       FpgaSetupSsc();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR);

 
        cmdsRecvd = 0;
 
 
        cmdsRecvd = 0;
 


@@ -440,7 +441,7 @@ void SimulateIso14443bTag(void)
                LED_D_OFF();
                FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
                AT91C_BASE_SSC->SSC_THR = 0xff;
                LED_D_OFF();
                FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
                AT91C_BASE_SSC->SSC_THR = 0xff;

-               FpgaSetupSsc();
+               FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR);

 
                // Transmit the response.
                uint16_t i = 0;
 
                // Transmit the response.
                uint16_t i = 0;


@@ -535,60 +536,11 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
 
 #define SUBCARRIER_DETECT_THRESHOLD    8
 
 
 #define SUBCARRIER_DETECT_THRESHOLD    8
 

-// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
-/* #define CHECK_FOR_SUBCARRIER() { \
-               v = ci; \
-               if(v < 0) v = -v; \
-               if(cq > 0) { \
-                       v += cq; \
-               } else { \
-                       v -= cq; \
-               } \
-       }
- */

 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))

-
-       //note: couldn't we just use MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2) from common.h - marshmellow
-#define CHECK_FOR_SUBCARRIER() { \
-               v = MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2); \
-       }
-               /*
-               if(ci < 0) { \
-                       if(cq < 0) { \ // ci < 0, cq < 0
-                               if (cq < ci) { \
-                                       v = -cq - (ci >> 1); \
-                               } else { \
-                                       v = -ci - (cq >> 1); \
-                               } \
-                       } else {        \ // ci < 0, cq >= 0
-                               if (cq < -ci) { \
-                                       v = -ci + (cq >> 1); \
-                               } else { \
-                                       v = cq - (ci >> 1); \
-                               } \
-                       } \
-               } else { \
-                       if(cq < 0) { \ // ci >= 0, cq < 0
-                               if (-cq < ci) { \
-                                       v = ci - (cq >> 1); \
-                               } else { \
-                                       v = -cq + (ci >> 1); \
-                               } \
-                       } else {        \ // ci >= 0, cq >= 0
-                               if (cq < ci) { \
-                                       v = ci + (cq >> 1); \
-                               } else { \
-                                       v = cq + (ci >> 1); \
-                               } \
-                       } \
-               } \
-       }
-               */
-
+#define AMPLITUDE(ci,cq) (MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2))

        switch(Demod.state) {
                case DEMOD_UNSYNCD:
        switch(Demod.state) {
                case DEMOD_UNSYNCD:

-                       CHECK_FOR_SUBCARRIER();
-                       if(v > SUBCARRIER_DETECT_THRESHOLD) {   // subcarrier detected
+                       if(AMPLITUDE(ci,cq) > SUBCARRIER_DETECT_THRESHOLD) {    // subcarrier detected

                                Demod.state = DEMOD_PHASE_REF_TRAINING;
                                Demod.sumI = ci;
                                Demod.sumQ = cq;
                                Demod.state = DEMOD_PHASE_REF_TRAINING;
                                Demod.sumI = ci;
                                Demod.sumQ = cq;


@@ -598,8 +550,7 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
 
                case DEMOD_PHASE_REF_TRAINING:
                        if(Demod.posCount < 8) {
 
                case DEMOD_PHASE_REF_TRAINING:
                        if(Demod.posCount < 8) {

-                               CHECK_FOR_SUBCARRIER();
-                               if (v > SUBCARRIER_DETECT_THRESHOLD) {
+                               if (AMPLITUDE(ci,cq) > 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;
                                        // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
                                        // note: synchronization time > 80 1/fs
                                        Demod.sumI += ci;


@@ -743,10 +694,11 @@ static void DemodInit(uint8_t *data)
  */
 static void GetSamplesFor14443bDemod(int n, bool quiet)
 {
  */
 static void GetSamplesFor14443bDemod(int n, bool quiet)
 {

-       int max = 0;
+       int maxBehindBy = 0;

        bool gotFrame = false;
        bool gotFrame = false;

-       int lastRxCounter, ci, cq, samples = 0;
-
+       int lastRxCounter, samples = 0;
+       int8_t ci, cq;
+       

        // Allocate memory from BigBuf for some buffers
        // free all previous allocations first
        BigBuf_free();
        // Allocate memory from BigBuf for some buffers
        // free all previous allocations first
        BigBuf_free();


@@ -755,15 +707,19 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
        uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
 
        // The DMA buffer, used to stream samples from the FPGA
        uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
 
        // The DMA buffer, used to stream samples from the FPGA

-       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
+       uint16_t *dmaBuf = (uint16_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE * sizeof(uint16_t));

 
        // Set up the demodulator for tag -> reader responses.
        DemodInit(receivedResponse);
 
 
        // Set up the demodulator for tag -> reader responses.
        DemodInit(receivedResponse);
 

+       // wait for last transfer to complete
+       while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY))
+

        // Setup and start DMA.
        // Setup and start DMA.

+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);

        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
 
        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
 

-       int8_t *upTo = dmaBuf;
+       uint16_t *upTo = dmaBuf;

        lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
 
        // Signal field is ON with the appropriate LED:
        lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
 
        // Signal field is ON with the appropriate LED:


@@ -772,39 +728,40 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
 
        for(;;) {
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
 
        for(;;) {

-               int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
-               if(behindBy > max) max = behindBy;
-
-               while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {
-                       ci = upTo[0];
-                       cq = upTo[1];
-                       upTo += 2;
-                       if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
-                               upTo = dmaBuf;
-                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
-                               AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
-                       }
-                       lastRxCounter -= 2;
-                       if(lastRxCounter <= 0) {
-                               lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
-                       }
+               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1);
+               if(behindBy > maxBehindBy) {
+                       maxBehindBy = behindBy;
+               }

 
 

-                       samples += 2;
+               if(behindBy < 1) continue;

 
 

-                       if(Handle14443bSamplesDemod(ci, cq)) {
-                               gotFrame = true;
-                               break;
-                       }
+               ci = *upTo >> 8;
+               cq = *upTo;
+               upTo++;
+               lastRxCounter--;
+               if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {               // we have read all of the DMA buffer content.
+                       upTo = dmaBuf;                                             // start reading the circular buffer from the beginning
+                       lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
+               }
+               if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+                       AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;  // DMA Next Counter registers
+               }
+               samples++;
+
+               if(Handle14443bSamplesDemod(ci, cq)) {
+                       gotFrame = true;
+                       break;

                }
 
                }
 

-               if(samples > n || gotFrame) {
+               if(samples > n) {

                        break;
                }
        }
 
                        break;
                }
        }
 

-       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
+       FpgaDisableSscDma();

 
 

-       if (!quiet) 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);
+       if (!quiet) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", maxBehindBy, samples, gotFrame, Demod.len, Demod.sumI, Demod.sumQ);

        //Tracing
        if (tracing && Demod.len > 0) {
                uint8_t parity[MAX_PARITY_SIZE];
        //Tracing
        if (tracing && Demod.len > 0) {
                uint8_t parity[MAX_PARITY_SIZE];


@@ -820,11 +777,7 @@ static void TransmitFor14443b(void)
 {
        int c;
 
 {
        int c;
 

-       FpgaSetupSsc();
-
-       while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-               AT91C_BASE_SSC->SSC_THR = 0xff;
-       }
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);

 
        // Signal field is ON with the appropriate Red LED
        LED_D_ON();
 
        // Signal field is ON with the appropriate Red LED
        LED_D_ON();


@@ -832,31 +785,15 @@ static void TransmitFor14443b(void)
        LED_B_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
 
        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)) {
        c = 0;
        for(;;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {

-                       AT91C_BASE_SSC->SSC_THR = ToSend[c];
+                       AT91C_BASE_SSC->SSC_THR = ~ToSend[c];

                        c++;
                        if(c >= ToSendMax) {
                                break;
                        }
                }
                        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(); // Finished sending
                WDT_HIT();
        }
        LED_B_OFF(); // Finished sending


@@ -874,19 +811,14 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 
        ToSendReset();
 
 
        ToSendReset();
 

-       // Establish initial reference level
-       for(i = 0; i < 40; i++) {
-               ToSendStuffBit(1);
-       }

        // Send SOF
        for(i = 0; i < 10; i++) {
                ToSendStuffBit(0);
        }
        // Send SOF
        for(i = 0; i < 10; i++) {
                ToSendStuffBit(0);
        }

+       ToSendStuffBit(1);
+       ToSendStuffBit(1);

 
        for(i = 0; i < len; i++) {
 
        for(i = 0; i < len; i++) {

-               // Stop bits/EGT
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);

                // Start bit
                ToSendStuffBit(0);
                // Data bits
                // Start bit
                ToSendStuffBit(0);
                // Data bits


@@ -899,19 +831,18 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
                        }
                        b >>= 1;
                }
                        }
                        b >>= 1;
                }

+               // Stop bit
+               ToSendStuffBit(1);

        }
        }

+

        // Send EOF
        // Send EOF

-       ToSendStuffBit(1);

        for(i = 0; i < 10; i++) {
                ToSendStuffBit(0);
        }
        for(i = 0; i < 10; i++) {
                ToSendStuffBit(0);
        }

-       for(i = 0; i < 8; i++) {
-               ToSendStuffBit(1);
-       }
+       ToSendStuffBit(1);

 
 

-       // And then a little more, to make sure that the last character makes
-       // it out before we switch to rx mode.
-       for(i = 0; i < 24; i++) {
+       // ensure that last byte is filled up
+       for(i = 0; i < 8; i++) {

                ToSendStuffBit(1);
        }
 
                ToSendStuffBit(1);
        }
 


@@ -951,7 +882,7 @@ int iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *respo
        // send
        CodeAndTransmit14443bAsReader(message_frame, message_length + 4);
        // get response
        // send
        CodeAndTransmit14443bAsReader(message_frame, message_length + 4);
        // get response

-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT*100, true);
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);

        if(Demod.len < 3)
        {
                return 0;
        if(Demod.len < 3)
        {
                return 0;


@@ -1011,7 +942,7 @@ int iso14443b_select_card()
 void iso14443b_setup() {
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        // Set up the synchronous serial port
 void iso14443b_setup() {
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        // Set up the synchronous serial port

-       FpgaSetupSsc();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);

        // connect Demodulated Signal to ADC:
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // connect Demodulated Signal to ADC:
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 


@@ -1019,9 +950,6 @@ void iso14443b_setup() {
     LED_D_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
 
     LED_D_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
 

-       // Start the timer
-       StartCountSspClk();
-

        DemodReset();
        UartReset();
 }
        DemodReset();
        UartReset();
 }


@@ -1047,7 +975,7 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        SpinDelay(200);
 
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        SpinDelay(200);
 
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);

-       FpgaSetupSsc();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);

 
        // Now give it time to spin up.
        // Signal field is on with the appropriate LED
 
        // Now give it time to spin up.
        // Signal field is on with the appropriate LED


@@ -1065,6 +993,8 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 
        if (Demod.len == 0) {
                DbpString("No response from tag");
 
        if (Demod.len == 0) {
                DbpString("No response from tag");

+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                return;
        } else {
                Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",
                return;
        } else {
                Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",


@@ -1080,17 +1010,23 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        if (Demod.len != 3) {
                Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        if (Demod.len != 3) {
                Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);

+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                return;
        }
        // Check the CRC of the answer:
        ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
        if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
                DbpString("CRC Error reading select response.");
                return;
        }
        // Check the CRC of the answer:
        ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
        if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
                DbpString("CRC Error reading select response.");

+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                return;
        }
        // Check response from the tag: should be the same UID as the command we just sent:
        if (cmd1[1] != Demod.output[0]) {
                Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
                return;
        }
        // Check response from the tag: should be the same UID as the command we just sent:
        if (cmd1[1] != Demod.output[0]) {
                Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);

+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                return;
        }
 
                return;
        }
 


@@ -1102,6 +1038,8 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        if (Demod.len != 10) {
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        if (Demod.len != 10) {
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);

+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                return;
        }
        // The check the CRC of the answer (use cmd1 as temporary variable):
                return;
        }
        // The check the CRC of the answer (use cmd1 as temporary variable):


@@ -1131,6 +1069,8 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
                if (Demod.len != 6) { // Check if we got an answer from the tag
                        DbpString("Expected 6 bytes from tag, got less...");
                GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
                if (Demod.len != 6) { // Check if we got an answer from the tag
                        DbpString("Expected 6 bytes from tag, got less...");

+                       LED_D_OFF();
+                       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

                        return;
                }
                // The check the CRC of the answer (use cmd1 as temporary variable):
                        return;
                }
                // The check the CRC of the answer (use cmd1 as temporary variable):


@@ -1149,6 +1089,9 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                }
                i++;
        }
                }
                i++;
        }

+       
+       LED_D_OFF();
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

 }
 
 
 }
 
 


@@ -1171,11 +1114,6 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
  */
 void RAMFUNC SnoopIso14443b(void)
 {
  */
 void RAMFUNC SnoopIso14443b(void)
 {

-       // We won't start recording the frames that we acquire until we trigger;
-       // a good trigger condition to get started is probably when we see a
-       // response from the tag.
-       int triggered = true;                   // TODO: set and evaluate trigger condition
-

        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        BigBuf_free();
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        BigBuf_free();
 


@@ -1183,10 +1121,10 @@ void RAMFUNC SnoopIso14443b(void)
        set_tracing(true);
 
        // The DMA buffer, used to stream samples from the FPGA
        set_tracing(true);
 
        // The DMA buffer, used to stream samples from the FPGA

-       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
+       uint16_t *dmaBuf = (uint16_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE * sizeof(uint16_t));

        int lastRxCounter;
        int lastRxCounter;

-       int8_t *upTo;
-       int ci, cq;
+       uint16_t *upTo;
+       int8_t ci, cq;

        int maxBehindBy = 0;
 
        // Count of samples received so far, so that we can include timing
        int maxBehindBy = 0;
 
        // Count of samples received so far, so that we can include timing


@@ -1211,7 +1149,7 @@ void RAMFUNC SnoopIso14443b(void)
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // Setup for the DMA.
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // Setup for the DMA.

-       FpgaSetupSsc();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);

        upTo = dmaBuf;
        lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
        upTo = dmaBuf;
        lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);


@@ -1219,46 +1157,48 @@ void RAMFUNC SnoopIso14443b(void)
 
        bool TagIsActive = false;
        bool ReaderIsActive = false;
 
        bool TagIsActive = false;
        bool ReaderIsActive = false;

+       // We won't start recording the frames that we acquire until we trigger.
+       // A good trigger condition to get started is probably when we see a
+       // reader command
+       bool triggered = false;

 
        // And now we loop, receiving samples.
        for(;;) {
 
        // And now we loop, receiving samples.
        for(;;) {

-               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
-                                                               (ISO14443B_DMA_BUFFER_SIZE-1);
+               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1);

                if(behindBy > maxBehindBy) {
                        maxBehindBy = behindBy;
                }
 
                if(behindBy > maxBehindBy) {
                        maxBehindBy = behindBy;
                }
 

-               if(behindBy < 2) continue;
+               if(behindBy < 1) continue;

 
 

-               ci = upTo[0];
-               cq = upTo[1];
-               upTo += 2;
-               lastRxCounter -= 2;
-               if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
-                       upTo = dmaBuf;
+               ci = *upTo>>8;
+               cq = *upTo;
+               upTo++;
+               lastRxCounter--;
+               if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {               // we have read all of the DMA buffer content.
+                       upTo = dmaBuf;                                             // start reading the circular buffer from the beginning again

                        lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
                        lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;

-                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
-                       AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
-                       WDT_HIT();
-                       if(behindBy > (9*ISO14443B_DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
-                               Dbprintf("blew circular buffer! behindBy=%d", behindBy);
-                               break;
-                       }
-                       if(!tracing) {
-                               DbpString("Reached trace limit");
+                       if(behindBy > (9*ISO14443B_DMA_BUFFER_SIZE/10)) { 
+                               Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy);

                                break;
                        }
                                break;
                        }

+               }
+               if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+                       AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;  // DMA Next Counter registers
+                       WDT_HIT();

                        if(BUTTON_PRESS()) {
                                DbpString("cancelled");
                                break;
                        }
                }
 
                        if(BUTTON_PRESS()) {
                                DbpString("cancelled");
                                break;
                        }
                }
 

-               samples += 2;
+               samples++;

 
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending
                        if(Handle14443bUartBit(ci & 0x01)) {
 
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending
                        if(Handle14443bUartBit(ci & 0x01)) {

-                               if(triggered && tracing) {
+                               triggered = true;
+                               if(tracing) {

                                        LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
                                }
                                /* And ready to receive another command. */
                                        LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
                                }
                                /* And ready to receive another command. */


@@ -1268,7 +1208,8 @@ void RAMFUNC SnoopIso14443b(void)
                                DemodReset();
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {
                                DemodReset();
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {

-                               if(triggered && tracing) {
+                               triggered = true;
+                               if(tracing) {

                                        LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
                                }
                                /* And ready to receive another command. */
                                        LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
                                }
                                /* And ready to receive another command. */


@@ -1280,8 +1221,8 @@ void RAMFUNC SnoopIso14443b(void)
                        ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                }
 
                        ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                }
 

-               if(!ReaderIsActive) {                                           // no need to try decoding tag data if the reader is sending - and we cannot afford the time
-                       if(Handle14443bSamplesDemod(ci | 0x01, cq | 0x01)) {
+               if(!ReaderIsActive && triggered) {                                              // no need to try decoding tag data if the reader is sending or not yet triggered
+                       if(Handle14443bSamplesDemod(ci/2, cq/2)) {

 
                                //Use samples as a time measurement
                                if(tracing)
 
                                //Use samples as a time measurement
                                if(tracing)


@@ -1289,8 +1230,6 @@ void RAMFUNC SnoopIso14443b(void)
                                        uint8_t parity[MAX_PARITY_SIZE];
                                        LogTrace(Demod.output, Demod.len, samples, samples, parity, false);
                                }
                                        uint8_t parity[MAX_PARITY_SIZE];
                                        LogTrace(Demod.output, Demod.len, samples, samples, parity, false);
                                }

-                               triggered = true;
-

                                // And ready to receive another response.
                                DemodReset();
                        }
                                // And ready to receive another response.
                                DemodReset();
                        }


@@ -1301,7 +1240,6 @@ void RAMFUNC SnoopIso14443b(void)
 
        FpgaDisableSscDma();
        LEDsoff();
 
        FpgaDisableSscDma();
        LEDsoff();

-       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;

        DbpString("Snoop statistics:");
        Dbprintf("  Max behind by: %i", maxBehindBy);
        Dbprintf("  Uart State: %x", Uart.state);
        DbpString("Snoop statistics:");
        Dbprintf("  Max behind by: %i", maxBehindBy);
        Dbprintf("  Uart State: %x", Uart.state);


@@ -1327,7 +1265,11 @@ void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, u
 {
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 {
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);

-       FpgaSetupSsc();
+
+       // switch field on and give tag some time to power up
+       LED_D_ON();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
+       SpinDelay(10);

 
        if (datalen){
                set_tracing(true);
 
        if (datalen){
                set_tracing(true);