small fix to please @dmaij's compiler (issue #703)

[proxmark3-svn] / armsrc / iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index 1ae1692b932270671298863365a1a033368a2171..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


@@ -16,7 +17,11 @@
 
 #include "iso14443crc.h"
 
 
 #include "iso14443crc.h"
 

-#define RECEIVE_SAMPLES_TIMEOUT 2000
+#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;

 
 //=============================================================================
 // An ISO 14443 Type B tag. We listen for commands from the reader, using
 
 //=============================================================================
 // An ISO 14443 Type B tag. We listen for commands from the reader, using


@@ -239,7 +244,7 @@ static RAMFUNC int Handle14443bUartBit(uint8_t bit)
                                        LED_A_OFF(); // Finished receiving
                                        Uart.state = STATE_UNSYNCD;
                                        if (Uart.byteCnt != 0) {
                                        LED_A_OFF(); // Finished receiving
                                        Uart.state = STATE_UNSYNCD;
                                        if (Uart.byteCnt != 0) {

-                                               return TRUE;
+                                               return true;

                                        }
                                } else {
                                        // this is an error
                                        }
                                } else {
                                        // this is an error


@@ -255,7 +260,7 @@ static RAMFUNC int Handle14443bUartBit(uint8_t bit)
                        break;
        }
 
                        break;
        }
 

-       return FALSE;
+       return false;

 }
 
 
 }
 
 


@@ -279,7 +284,7 @@ static void UartInit(uint8_t *data)
 // Receive a command (from the reader to us, where we are the simulated tag),
 // and store it in the given buffer, up to the given maximum length. Keeps
 // spinning, waiting for a well-framed command, until either we get one
 // Receive a command (from the reader to us, where we are the simulated tag),
 // and store it in the given buffer, up to the given maximum length. Keeps
 // spinning, waiting for a well-framed command, until either we get one

-// (returns TRUE) or someone presses the pushbutton on the board (FALSE).
+// (returns true) or someone presses the pushbutton on the board (false).

 //
 // Assume that we're called with the SSC (to the FPGA) and ADC path set
 // correctly.
 //
 // Assume that we're called with the SSC (to the FPGA) and ADC path set
 // correctly.


@@ -298,20 +303,20 @@ static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len)
        for(;;) {
                WDT_HIT();
 
        for(;;) {
                WDT_HIT();
 

-               if(BUTTON_PRESS()) return FALSE;
+               if(BUTTON_PRESS()) return false;

 
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
                        uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                        for(uint8_t mask = 0x80; mask != 0x00; mask >>= 1) {
                                if(Handle14443bUartBit(b & mask)) {
                                        *len = Uart.byteCnt;
 
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
                        uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                        for(uint8_t mask = 0x80; mask != 0x00; mask >>= 1) {
                                if(Handle14443bUartBit(b & mask)) {
                                        *len = Uart.byteCnt;

-                                       return TRUE;
+                                       return true;

                                }
                        }
                }
        }
                                }
                        }
                }
        }

-       
-       return FALSE;
+
+       return false;

 }
 
 //-----------------------------------------------------------------------------
 }
 
 //-----------------------------------------------------------------------------


@@ -320,10 +325,14 @@ static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len)
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {

-       // the only commands we understand is REQB, AFI=0, Select All, N=0:
-       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-       // ... and REQB, AFI=0, Normal Request, N=0:
-       static const uint8_t cmd2[] = { 0x05, 0x00, 0x00, 0x71, 0xFF };
+       // the only commands we understand is WUPB, AFI=0, Select All, N=1:
+       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 }; // WUPB
+       // ... and REQB, AFI=0, Normal Request, N=1:
+       static const uint8_t cmd2[] = { 0x05, 0x00, 0x00, 0x71, 0xFF }; // REQB
+       // ... and HLTB
+       static const uint8_t cmd3[] = { 0x50, 0xff, 0xff, 0xff, 0xff }; // HLTB
+       // ... and ATTRIB
+       static const uint8_t cmd4[] = { 0x1D, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; // ATTRIB

 
        // ... and we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
        // supports only 106kBit/s in both directions, max frame size = 32Bytes,
 
        // ... and we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
        // supports only 106kBit/s in both directions, max frame size = 32Bytes,


@@ -332,9 +341,14 @@ void SimulateIso14443bTag(void)
                0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
                0x00, 0x21, 0x85, 0x5e, 0xd7
        };
                0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
                0x00, 0x21, 0x85, 0x5e, 0xd7
        };

+       // response to HLTB and ATTRIB
+       static const uint8_t response2[] = {0x00, 0x78, 0xF0};
+
+
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);

 
        clear_trace();
 
        clear_trace();

-       set_tracing(TRUE);
+       set_tracing(true);

 
        const uint8_t *resp;
        uint8_t *respCode;
 
        const uint8_t *resp;
        uint8_t *respCode;


@@ -347,17 +361,21 @@ void SimulateIso14443bTag(void)
        uint16_t len;
        uint16_t cmdsRecvd = 0;
 
        uint16_t len;
        uint16_t cmdsRecvd = 0;
 

-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-

        // prepare the (only one) tag answer:
        CodeIso14443bAsTag(response1, sizeof(response1));
        uint8_t *resp1Code = BigBuf_malloc(ToSendMax);
        // prepare the (only one) tag answer:
        CodeIso14443bAsTag(response1, sizeof(response1));
        uint8_t *resp1Code = BigBuf_malloc(ToSendMax);

-       memcpy(resp1Code, ToSend, ToSendMax); 
+       memcpy(resp1Code, ToSend, ToSendMax);

        uint16_t resp1CodeLen = ToSendMax;
 
        uint16_t resp1CodeLen = ToSendMax;
 

+       // prepare the (other) tag answer:
+       CodeIso14443bAsTag(response2, sizeof(response2));
+       uint8_t *resp2Code = BigBuf_malloc(ToSendMax);
+       memcpy(resp2Code, ToSend, ToSendMax);
+       uint16_t resp2CodeLen = ToSendMax;
+

        // 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;
 


@@ -370,28 +388,43 @@ void SimulateIso14443bTag(void)
 
                if (tracing) {
                        uint8_t parity[MAX_PARITY_SIZE];
 
                if (tracing) {
                        uint8_t parity[MAX_PARITY_SIZE];

-                       LogTrace(receivedCmd, len, 0, 0, parity, TRUE);
+                       LogTrace(receivedCmd, len, 0, 0, parity, true);

                }
 
                // Good, look at the command now.
                if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
                        || (len == sizeof(cmd2) && memcmp(receivedCmd, cmd2, len) == 0) ) {
                }
 
                // Good, look at the command now.
                if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
                        || (len == sizeof(cmd2) && memcmp(receivedCmd, cmd2, len) == 0) ) {

-                       resp = response1; 
+                       resp = response1;

                        respLen = sizeof(response1);
                        respLen = sizeof(response1);

-                       respCode = resp1Code; 
+                       respCode = resp1Code;

                        respCodeLen = resp1CodeLen;
                        respCodeLen = resp1CodeLen;

+               } else if ( (len == sizeof(cmd3) && receivedCmd[0] == cmd3[0])
+                       || (len == sizeof(cmd4) && receivedCmd[0] == cmd4[0]) ) {
+                       resp = response2;
+                       respLen = sizeof(response2);
+                       respCode = resp2Code;
+                       respCodeLen = resp2CodeLen;

                } else {
                        Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
                        // And print whether the CRC fails, just for good measure
                        uint8_t b1, b2;
                } else {
                        Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
                        // And print whether the CRC fails, just for good measure
                        uint8_t b1, b2;

-                       ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
-                       if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
-                               // Not so good, try again.
-                               DbpString("+++CRC fail");
-                       } else {
-                               DbpString("CRC passes");
+                       if (len >= 3){ // if crc exists
+                               ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
+                               if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
+                                       // Not so good, try again.
+                                       DbpString("+++CRC fail");
+               
+                               } else {
+                                       DbpString("CRC passes");
+                               }

                        }
                        }

-                       break;
+                       //get rid of compiler warning
+                       respCodeLen = 0;
+                       resp = response1;
+                       respLen = 0;
+                       respCode = resp1Code;
+                       //don't crash at new command just wait and see if reader will send other new cmds.
+                       //break;

                }
 
                cmdsRecvd++;
                }
 
                cmdsRecvd++;


@@ -408,7 +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;


@@ -428,13 +461,13 @@ void SimulateIso14443bTag(void)
                                (void)b;
                        }
                }
                                (void)b;
                        }
                }

-               
+

                // trace the response:
                if (tracing) {
                        uint8_t parity[MAX_PARITY_SIZE];
                // trace the response:
                if (tracing) {
                        uint8_t parity[MAX_PARITY_SIZE];

-                       LogTrace(resp, respLen, 0, 0, parity, FALSE);
+                       LogTrace(resp, respLen, 0, 0, parity, false);

                }
                }

-                       
+

        }
 }
 
        }
 }
 


@@ -503,54 +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)))

-#define CHECK_FOR_SUBCARRIER() { \
-               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;


@@ -560,8 +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;


@@ -644,7 +633,7 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                                        Demod.metric -= Demod.thisBit;
                                }
                                (Demod.metricN)++;
                                        Demod.metric -= Demod.thisBit;
                                }
                                (Demod.metricN)++;

-*/                             
+*/

 
                                Demod.shiftReg >>= 1;
                                if(Demod.thisBit > 0) { // logic '1'
 
                                Demod.shiftReg >>= 1;
                                if(Demod.thisBit > 0) { // logic '1'


@@ -664,7 +653,7 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                                                LED_C_OFF();
                                                if(s == 0x000) {
                                                        // This is EOF (start, stop and all data bits == '0'
                                                LED_C_OFF();
                                                if(s == 0x000) {
                                                        // This is EOF (start, stop and all data bits == '0'

-                                                       return TRUE;
+                                                       return true;

                                                }
                                        }
                                }
                                                }
                                        }
                                }


@@ -678,7 +667,7 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                        break;
        }
 
                        break;
        }
 

-       return FALSE;
+       return false;

 }
 
 
 }
 
 


@@ -701,32 +690,37 @@ static void DemodInit(uint8_t *data)
 
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer
 
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer

- *  quiet: set to 'TRUE' to disable debug output
+ *  quiet: set to 'true' to disable debug output

  */
 static void GetSamplesFor14443bDemod(int n, bool quiet)
 {
  */
 static void GetSamplesFor14443bDemod(int n, bool quiet)
 {

-       int max = 0;
-       bool gotFrame = FALSE;
-       int lastRxCounter, ci, cq, samples = 0;
-
+       int maxBehindBy = 0;
+       bool gotFrame = false;
+       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();

-       
+

        // The response (tag -> reader) that we're receiving.
        uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
        // The response (tag -> reader) that we're receiving.
        uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);

-       
+

        // The DMA buffer, used to stream samples from the FPGA
        // The DMA buffer, used to stream samples from the FPGA

-       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(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.

-       FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);

 
 

-       int8_t *upTo = dmaBuf;
-       lastRxCounter = DMA_BUFFER_SIZE;
+       uint16_t *upTo = dmaBuf;
+       lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;

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


@@ -734,44 +728,44 @@ 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) & (DMA_BUFFER_SIZE-1)) > 2) {
-                       ci = upTo[0];
-                       cq = upTo[1];
-                       upTo += 2;
-                       if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
-                               upTo = dmaBuf;
-                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
-                               AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
-                       }
-                       lastRxCounter -= 2;
-                       if(lastRxCounter <= 0) {
-                               lastRxCounter += 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];

-               //GetParity(Demod.output, Demod.len, parity);
-               LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
+               LogTrace(Demod.output, Demod.len, 0, 0, parity, false);

        }
 }
 
        }
 }
 


@@ -783,11 +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();


@@ -795,31 +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


@@ -837,19 +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


@@ -862,19 +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);
        }
 


@@ -892,11 +860,99 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
        TransmitFor14443b();
        if (tracing) {
                uint8_t parity[MAX_PARITY_SIZE];
        TransmitFor14443b();
        if (tracing) {
                uint8_t parity[MAX_PARITY_SIZE];

-               GetParity(cmd, len, parity);
-               LogTrace(cmd,len, 0, 0, parity, TRUE);
+               LogTrace(cmd,len, 0, 0, parity, true);
+       }
+}
+
+/* Sends an APDU to the tag
+ * TODO: check CRC and preamble
+ */
+int iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response)
+{
+       uint8_t message_frame[message_length + 4];
+       // PCB
+       message_frame[0] = 0x0A | pcb_blocknum;
+       pcb_blocknum ^= 1;
+       // CID
+       message_frame[1] = 0;
+       // INF
+       memcpy(message_frame + 2, message, message_length);
+       // EDC (CRC)
+       ComputeCrc14443(CRC_14443_B, message_frame, message_length + 2, &message_frame[message_length + 2], &message_frame[message_length + 3]);
+       // send
+       CodeAndTransmit14443bAsReader(message_frame, message_length + 4);
+       // get response
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       if(Demod.len < 3)
+       {
+               return 0;

        }
        }

+       // TODO: Check CRC
+       // copy response contents
+       if(response != NULL)
+       {
+               memcpy(response, Demod.output, Demod.len);
+       }
+       return Demod.len;

 }
 
 }
 

+/* Perform the ISO 14443 B Card Selection procedure
+ * Currently does NOT do any collision handling.
+ * It expects 0-1 cards in the device's range.
+ * TODO: Support multiple cards (perform anticollision)
+ * TODO: Verify CRC checksums
+ */
+int iso14443b_select_card()
+{
+       // WUPB command (including CRC)
+       // Note: WUPB wakes up all tags, REQB doesn't wake up tags in HALT state
+       static const uint8_t wupb[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
+       // ATTRIB command (with space for CRC)
+       uint8_t attrib[] = { 0x1D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00};
+
+       // first, wake up the tag
+       CodeAndTransmit14443bAsReader(wupb, sizeof(wupb));
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       // ATQB too short?
+       if (Demod.len < 14)
+       {
+               return 2;
+       }
+
+    // select the tag
+    // copy the PUPI to ATTRIB
+    memcpy(attrib + 1, Demod.output + 1, 4);
+    /* copy the protocol info from ATQB (Protocol Info -> Protocol_Type) into
+    ATTRIB (Param 3) */
+    attrib[7] = Demod.output[10] & 0x0F;
+    ComputeCrc14443(CRC_14443_B, attrib, 9, attrib + 9, attrib + 10);
+    CodeAndTransmit14443bAsReader(attrib, sizeof(attrib));
+    GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+    // Answer to ATTRIB too short?
+    if(Demod.len < 3)
+       {
+               return 2;
+       }
+       // reset PCB block number
+       pcb_blocknum = 0;
+       return 1;
+}
+
+// Set up ISO 14443 Type B communication (similar to iso14443a_setup)
+void iso14443b_setup() {
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+       // Set up the synchronous serial port
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
+       // 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);
+
+       DemodReset();
+       UartReset();
+}

 
 //-----------------------------------------------------------------------------
 // Read a SRI512 ISO 14443B tag.
 
 //-----------------------------------------------------------------------------
 // Read a SRI512 ISO 14443B tag.


@@ -909,9 +965,6 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 //-----------------------------------------------------------------------------
 void ReadSTMemoryIso14443b(uint32_t dwLast)
 {
 //-----------------------------------------------------------------------------
 void ReadSTMemoryIso14443b(uint32_t dwLast)
 {

-       clear_trace();
-       set_tracing(TRUE);
-

        uint8_t i = 0x00;
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        uint8_t i = 0x00;
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);


@@ -922,78 +975,83 @@ 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
        LED_D_ON();
 
        // Now give it time to spin up.
        // Signal field is on with the appropriate LED
        LED_D_ON();

-       FpgaWriteConfWord(
-               FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);

        SpinDelay(200);
 
        SpinDelay(200);
 

+       clear_trace();
+       set_tracing(true);
+

        // First command: wake up the tag using the INITIATE command
        uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};
        // First command: wake up the tag using the INITIATE command
        uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};

-

        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));

-//    LED_A_ON();
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);

 
        if (Demod.len == 0) {
 
        if (Demod.len == 0) {

-       DbpString("No response from tag");
-       return;
+               DbpString("No response from tag");
+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+               return;

        } else {
        } else {

-       Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %02x %02x %02x",
-               Demod.output[0], Demod.output[1], Demod.output[2]);
+               Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",
+                               Demod.output[0], Demod.output[1], Demod.output[2]);

        }
        }

+

        // There is a response, SELECT the uid
        DbpString("Now SELECT tag:");
        cmd1[0] = 0x0E; // 0x0E is SELECT
        cmd1[1] = Demod.output[0];
        ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
        // There is a response, SELECT the uid
        DbpString("Now SELECT tag:");
        cmd1[0] = 0x0E; // 0x0E is SELECT
        cmd1[1] = Demod.output[0];
        ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));

-
-//    LED_A_ON();
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);

        if (Demod.len != 3) {
                Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
        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;
        }

+

        // Tag is now selected,
        // First get the tag's UID:
        cmd1[0] = 0x0B;
        ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
        CodeAndTransmit14443bAsReader(cmd1, 3); // Only first three bytes for this one
        // Tag is now selected,
        // First get the tag's UID:
        cmd1[0] = 0x0B;
        ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
        CodeAndTransmit14443bAsReader(cmd1, 3); // Only first three bytes for this one

-
-//    LED_A_ON();
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);

        if (Demod.len != 10) {
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
        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):
        ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
        if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
                Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
                return;
        }
        // The check the CRC of the answer (use cmd1 as temporary variable):
        ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
        if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
                Dbprintf("CRC Error reading block! Expected: %04x got: %04x",

-                       (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
+                               (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);

                // Do not return;, let's go on... (we should retry, maybe ?)
        }
        Dbprintf("Tag UID (64 bits): %08x %08x",
                // Do not return;, let's go on... (we should retry, maybe ?)
        }
        Dbprintf("Tag UID (64 bits): %08x %08x",

-               (Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
-               (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
+                       (Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
+                       (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);

 
        // Now loop to read all 16 blocks, address from 0 to last block
        Dbprintf("Tag memory dump, block 0 to %d", dwLast);
 
        // Now loop to read all 16 blocks, address from 0 to last block
        Dbprintf("Tag memory dump, block 0 to %d", dwLast);


@@ -1008,30 +1066,32 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                cmd1[1] = i;
                ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
                CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
                cmd1[1] = i;
                ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
                CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));

-
-//         LED_A_ON();
-               GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//         LED_A_OFF();
+               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...");
                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):
                ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
                if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
                        Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
                        return;
                }
                // The check the CRC of the answer (use cmd1 as temporary variable):
                ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
                if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
                        Dbprintf("CRC Error reading block! Expected: %04x got: %04x",

-                               (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
+                                       (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);

                        // Do not return;, let's go on... (we should retry, maybe ?)
                }
                // Now print out the memory location:
                Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i,
                        // Do not return;, let's go on... (we should retry, maybe ?)
                }
                // Now print out the memory location:
                Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i,

-                       (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
-                       (Demod.output[4]<<8)+Demod.output[5]);
+                               (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
+                               (Demod.output[4]<<8)+Demod.output[5]);

                if (i == 0xff) {
                        break;
                }
                i++;
        }
                if (i == 0xff) {
                        break;
                }
                i++;
        }

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

 }
 
 
 }
 
 


@@ -1049,27 +1109,22 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
  * Memory usage for this function, (within BigBuf)
  * Last Received command (reader->tag) - MAX_FRAME_SIZE
  * Last Received command (tag->reader) - MAX_FRAME_SIZE
  * Memory usage for this function, (within BigBuf)
  * Last Received command (reader->tag) - MAX_FRAME_SIZE
  * Last Received command (tag->reader) - MAX_FRAME_SIZE

- * DMA Buffer - DMA_BUFFER_SIZE
+ * DMA Buffer - ISO14443B_DMA_BUFFER_SIZE

  * Demodulated samples received - all the rest
  */
 void RAMFUNC SnoopIso14443b(void)
 {
  * Demodulated samples received - all the rest
  */
 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();
 
        clear_trace();
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
        BigBuf_free();
 
        clear_trace();

-       set_tracing(TRUE);
+       set_tracing(true);

 
        // The DMA buffer, used to stream samples from the FPGA
 
        // The DMA buffer, used to stream samples from the FPGA

-       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(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


@@ -1084,7 +1139,7 @@ void RAMFUNC SnoopIso14443b(void)
        Dbprintf("  Trace: %i bytes", BigBuf_max_traceLen());
        Dbprintf("  Reader -> tag: %i bytes", MAX_FRAME_SIZE);
        Dbprintf("  tag -> Reader: %i bytes", MAX_FRAME_SIZE);
        Dbprintf("  Trace: %i bytes", BigBuf_max_traceLen());
        Dbprintf("  Reader -> tag: %i bytes", MAX_FRAME_SIZE);
        Dbprintf("  tag -> Reader: %i bytes", MAX_FRAME_SIZE);

-       Dbprintf("  DMA: %i bytes", DMA_BUFFER_SIZE);
+       Dbprintf("  DMA: %i bytes", ISO14443B_DMA_BUFFER_SIZE);

 
        // Signal field is off, no reader signal, no tag signal
        LEDsoff();
 
        // Signal field is off, no reader signal, no tag signal
        LEDsoff();


@@ -1094,56 +1149,57 @@ 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;
        upTo = dmaBuf;

-       lastRxCounter = DMA_BUFFER_SIZE;
-       FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
+       lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
+       FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);

        uint8_t parity[MAX_PARITY_SIZE];
 
        uint8_t parity[MAX_PARITY_SIZE];
 

-       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) &
-                                                               (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;
-
-               ci = upTo[0];
-               cq = upTo[1];
-               upTo += 2;
-               lastRxCounter -= 2;
-               if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
-                       upTo = dmaBuf;
-                       lastRxCounter += DMA_BUFFER_SIZE;
-                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
-                       AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
-                       WDT_HIT();
-                       if(behindBy > (9*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 < 1) continue;
+
+               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;
+                       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) {
-                                       //GetParity(Uart.output, Uart.byteCnt, parity);
-                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
+                               triggered = true;
+                               if(tracing) {
+                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);

                                }
                                /* And ready to receive another command. */
                                UartReset();
                                }
                                /* And ready to receive another command. */
                                UartReset();


@@ -1152,9 +1208,9 @@ void RAMFUNC SnoopIso14443b(void)
                                DemodReset();
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {
                                DemodReset();
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {

-                               if(triggered && tracing) {
-                                       //GetParity(Uart.output, Uart.byteCnt, parity);
-                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
+                               triggered = true;
+                               if(tracing) {
+                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);

                                }
                                /* And ready to receive another command. */
                                UartReset();
                                }
                                /* And ready to receive another command. */
                                UartReset();


@@ -1165,18 +1221,15 @@ 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)
                                {
                                        uint8_t parity[MAX_PARITY_SIZE];
 
                                //Use samples as a time measurement
                                if(tracing)
                                {
                                        uint8_t parity[MAX_PARITY_SIZE];

-                                       //GetParity(Demod.output, Demod.len, parity);
-                                       LogTrace(Demod.output, Demod.len, samples, samples, parity, FALSE);
+                                       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();
                        }


@@ -1187,7 +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);


@@ -1213,34 +1265,24 @@ 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();

 
 

-       set_tracing(TRUE);
-       
-/*     if(!powerfield) {
-               // Make sure that we start from off, since the tags are stateful;
-               // confusing things will happen if we don't reset them between reads.
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-               LED_D_OFF();
-               SpinDelay(200);
-       }
- */
-
-       // if(!GETBIT(GPIO_LED_D))      {       // if field is off
-               // FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
-               // // Signal field is on with the appropriate LED
-               // LED_D_ON();
-               // SpinDelay(200);
-       // }
+       // switch field on and give tag some time to power up
+       LED_D_ON();
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
+       SpinDelay(10);

 
 

-       CodeAndTransmit14443bAsReader(data, datalen);
+       if (datalen){
+               set_tracing(true);
+               
+               CodeAndTransmit14443bAsReader(data, datalen);

 
 

-       if(recv) {
-               GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-               uint16_t iLen = MIN(Demod.len, USB_CMD_DATA_SIZE);
-               cmd_send(CMD_ACK, iLen, 0, 0, Demod.output, iLen);
+               if(recv) {
+                       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+                       uint16_t iLen = MIN(Demod.len, USB_CMD_DATA_SIZE);
+                       cmd_send(CMD_ACK, iLen, 0, 0, Demod.output, iLen);
+               }

        }
        }

-       
+

        if(!powerfield) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                LED_D_OFF();
        if(!powerfield) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                LED_D_OFF();