add: iceman1001's idea to reuse @pwpiwi's fast select without anticollision to speedu...

[proxmark3-svn] / armsrc / iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index 80f93678fb7840fae0927cefe943f8363e066cd7..22227e74bec96651d5c2620dd37f4bea210f27d2 100644 (file)
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -17,6 +17,10 @@
 #include "iso14443crc.h"
 
 #define RECEIVE_SAMPLES_TIMEOUT 2000
 #include "iso14443crc.h"
 
 #define RECEIVE_SAMPLES_TIMEOUT 2000

+#define ISO14443B_DMA_BUFFER_SIZE 256
+
+// 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


@@ -122,8 +126,7 @@ static struct {
                STATE_UNSYNCD,
                STATE_GOT_FALLING_EDGE_OF_SOF,
                STATE_AWAITING_START_BIT,
                STATE_UNSYNCD,
                STATE_GOT_FALLING_EDGE_OF_SOF,
                STATE_AWAITING_START_BIT,

-               STATE_RECEIVING_DATA,
-               STATE_ERROR_WAIT
+               STATE_RECEIVING_DATA

        }       state;
        uint16_t    shiftReg;
        int     bitCnt;
        }       state;
        uint16_t    shiftReg;
        int     bitCnt;


@@ -145,7 +148,7 @@ static struct {
  * Returns: true if we received a EOF
  *          false if we are still waiting for some more
  */
  * Returns: true if we received a EOF
  *          false if we are still waiting for some more
  */

-static int Handle14443bUartBit(int bit)
+static RAMFUNC int Handle14443bUartBit(uint8_t bit)

 {
        switch(Uart.state) {
                case STATE_UNSYNCD:
 {
        switch(Uart.state) {
                case STATE_UNSYNCD:


@@ -172,7 +175,7 @@ static int Handle14443bUartBit(int bit)
                                        } else {
                                                // didn't stay down long enough
                                                // before going high, error
                                        } else {
                                                // didn't stay down long enough
                                                // before going high, error

-                                               Uart.state = STATE_ERROR_WAIT;
+                                               Uart.state = STATE_UNSYNCD;

                                        }
                                } else {
                                        // do nothing, keep waiting
                                        }
                                } else {
                                        // do nothing, keep waiting


@@ -183,7 +186,8 @@ static int Handle14443bUartBit(int bit)
                        if(Uart.bitCnt > 12) {
                                // Give up if we see too many zeros without
                                // a one, too.
                        if(Uart.bitCnt > 12) {
                                // Give up if we see too many zeros without
                                // a one, too.

-                               Uart.state = STATE_ERROR_WAIT;
+                               LED_A_OFF();
+                               Uart.state = STATE_UNSYNCD;

                        }
                        break;
 
                        }
                        break;
 


@@ -193,7 +197,7 @@ static int Handle14443bUartBit(int bit)
                                if(Uart.posCnt > 50/2) {        // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
                                        // stayed high for too long between
                                        // characters, error
                                if(Uart.posCnt > 50/2) {        // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
                                        // stayed high for too long between
                                        // characters, error

-                                       Uart.state = STATE_ERROR_WAIT;
+                                       Uart.state = STATE_UNSYNCD;

                                }
                        } else {
                                // falling edge, this starts the data byte
                                }
                        } else {
                                // falling edge, this starts the data byte


@@ -227,41 +231,30 @@ static int Handle14443bUartBit(int bit)
 
                                        if(Uart.byteCnt >= Uart.byteCntMax) {
                                                // Buffer overflowed, give up
 
                                        if(Uart.byteCnt >= Uart.byteCntMax) {
                                                // Buffer overflowed, give up

-                                               Uart.posCnt = 0;
-                                               Uart.state = STATE_ERROR_WAIT;
+                                               LED_A_OFF();
+                                               Uart.state = STATE_UNSYNCD;

                                        } else {
                                                // so get the next byte now
                                                Uart.posCnt = 0;
                                                Uart.state = STATE_AWAITING_START_BIT;
                                        }
                                        } else {
                                                // so get the next byte now
                                                Uart.posCnt = 0;
                                                Uart.state = STATE_AWAITING_START_BIT;
                                        }

-                               } else if(Uart.shiftReg == 0x000) {
+                               } else if (Uart.shiftReg == 0x000) {

                                        // this is an EOF byte
                                        LED_A_OFF(); // Finished receiving
                                        // this is an EOF byte
                                        LED_A_OFF(); // Finished receiving

+                                       Uart.state = STATE_UNSYNCD;

                                        if (Uart.byteCnt != 0) {
                                                return TRUE;
                                        }
                                        if (Uart.byteCnt != 0) {
                                                return TRUE;
                                        }

-                                       Uart.posCnt = 0;
-                                       Uart.state = STATE_ERROR_WAIT;

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

-                                       Uart.posCnt = 0;
-                                       Uart.state = STATE_ERROR_WAIT;
+                                       LED_A_OFF();
+                                       Uart.state = STATE_UNSYNCD;

                                }
                        }
                        break;
 
                                }
                        }
                        break;
 

-               case STATE_ERROR_WAIT:
-                       // We're all screwed up, so wait a little while
-                       // for whatever went wrong to finish, and then
-                       // start over.
-                       Uart.posCnt++;
-                       if(Uart.posCnt > 10) {
-                               Uart.state = STATE_UNSYNCD;
-                               LED_A_OFF();
-                       }
-                       break;
-

                default:
                default:

+                       LED_A_OFF();

                        Uart.state = STATE_UNSYNCD;
                        break;
        }
                        Uart.state = STATE_UNSYNCD;
                        break;
        }


@@ -269,6 +262,23 @@ static int Handle14443bUartBit(int bit)
        return FALSE;
 }
 
        return FALSE;
 }
 

+
+static void UartReset()
+{
+       Uart.byteCntMax = MAX_FRAME_SIZE;
+       Uart.state = STATE_UNSYNCD;
+       Uart.byteCnt = 0;
+       Uart.bitCnt = 0;
+}
+
+
+static void UartInit(uint8_t *data)
+{
+       Uart.output = data;
+       UartReset();
+}
+
+

 //-----------------------------------------------------------------------------
 // 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
 //-----------------------------------------------------------------------------
 // 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


@@ -278,44 +288,34 @@ static int Handle14443bUartBit(int bit)
 // 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.
 //-----------------------------------------------------------------------------

-static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen)
+static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len)

 {
 {

-       uint8_t mask;
-       int i, bit;
-

        // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
        // only, since we are receiving, not transmitting).
        // Signal field is off with the appropriate LED
        LED_D_OFF();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
 
        // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
        // only, since we are receiving, not transmitting).
        // Signal field is off with the appropriate LED
        LED_D_OFF();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
 

-

        // Now run a `software UART' on the stream of incoming samples.
        // Now run a `software UART' on the stream of incoming samples.

-       Uart.output = received;
-       Uart.byteCntMax = maxLen;
-       Uart.state = STATE_UNSYNCD;
+       UartInit(received);

 
        for(;;) {
                WDT_HIT();
 
                if(BUTTON_PRESS()) return FALSE;
 
 
        for(;;) {
                WDT_HIT();
 
                if(BUTTON_PRESS()) return FALSE;
 

-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = 0x00;
-               }

                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
                        uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
                        uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;

-
-                       mask = 0x80;
-                       for(i = 0; i < 8; i++, mask >>= 1) {
-                               bit = (b & mask);
-                               if(Handle14443bUartBit(bit)) {
+                       for(uint8_t mask = 0x80; mask != 0x00; mask >>= 1) {
+                               if(Handle14443bUartBit(b & mask)) {

                                        *len = Uart.byteCnt;
                                        return TRUE;
                                }
                        }
                }
        }
                                        *len = Uart.byteCnt;
                                        return TRUE;
                                }
                        }
                }
        }

+
+       return FALSE;

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


@@ -324,35 +324,53 @@ static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {

-       // the only command we understand is REQB, AFI=0, Select All, N=0:
-       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-       // ... and we respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
+       // 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,
        // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
        static const uint8_t response1[] = {
                0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
                0x00, 0x21, 0x85, 0x5e, 0xd7
        };
        // supports only 106kBit/s in both directions, max frame size = 32Bytes,
        // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
        static const uint8_t response1[] = {
                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();
+       set_tracing(TRUE);

 
 

-       uint8_t *resp;
-       int respLen;
+       const uint8_t *resp;
+       uint8_t *respCode;
+       uint16_t respLen, respCodeLen;

 
        // allocate command receive buffer
        BigBuf_free();
        uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
 
        // allocate command receive buffer
        BigBuf_free();
        uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);

-       int len;

 
 

-       int i;
-
-       int cmdsRecvd = 0;
-
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+       uint16_t len;
+       uint16_t cmdsRecvd = 0;

 
        // prepare the (only one) tag answer:
        CodeIso14443bAsTag(response1, sizeof(response1));
 
        // prepare the (only one) tag answer:
        CodeIso14443bAsTag(response1, sizeof(response1));

-       uint8_t *resp1 = BigBuf_malloc(ToSendMax);
-       memcpy(resp1, ToSend, ToSendMax); 
-       uint16_t resp1Len = ToSendMax;
+       uint8_t *resp1Code = BigBuf_malloc(ToSendMax);
+       memcpy(resp1Code, ToSend, 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);


@@ -361,28 +379,51 @@ void SimulateIso14443bTag(void)
        cmdsRecvd = 0;
 
        for(;;) {
        cmdsRecvd = 0;
 
        for(;;) {

-               uint8_t b1, b2;

 
 

-               if(!GetIso14443bCommandFromReader(receivedCmd, &len, 100)) {
+               if(!GetIso14443bCommandFromReader(receivedCmd, &len)) {

                        Dbprintf("button pressed, received %d commands", cmdsRecvd);
                        break;
                        Dbprintf("button pressed, received %d commands", cmdsRecvd);
                        break;

-                       }
+               }

 
 

-               // Good, look at the command now.
+               if (tracing) {
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       LogTrace(receivedCmd, len, 0, 0, parity, TRUE);
+               }

 
 

-               if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0) {
-                       resp = resp1; respLen = resp1Len;
+               // 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;
+                       respLen = sizeof(response1);
+                       respCode = resp1Code;
+                       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
                } else {
                        Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
                        // And print whether the CRC fails, just for good measure

-                       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");
+                       uint8_t b1, b2;
+                       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++;


@@ -392,7 +433,7 @@ void SimulateIso14443bTag(void)
                        break;
                }
 
                        break;
                }
 

-               if(respLen <= 0) continue;
+               if(respCodeLen <= 0) continue;

 
                // Modulate BPSK
                // Signal field is off with the appropriate LED
 
                // Modulate BPSK
                // Signal field is off with the appropriate LED


@@ -402,15 +443,15 @@ void SimulateIso14443bTag(void)
                FpgaSetupSsc();
 
                // Transmit the response.
                FpgaSetupSsc();
 
                // Transmit the response.

-               i = 0;
+               uint16_t i = 0;

                for(;;) {
                        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                for(;;) {
                        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {

-                               uint8_t b = resp[i];
+                               uint8_t b = respCode[i];

 
                                AT91C_BASE_SSC->SSC_THR = b;
 
                                i++;
 
                                AT91C_BASE_SSC->SSC_THR = b;
 
                                i++;

-                               if(i > respLen) {
+                               if(i > respCodeLen) {

                                        break;
                                }
                        }
                                        break;
                                }
                        }


@@ -419,6 +460,13 @@ void SimulateIso14443bTag(void)
                                (void)b;
                        }
                }
                                (void)b;
                        }
                }

+
+               // trace the response:
+               if (tracing) {
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       LogTrace(resp, respLen, 0, 0, parity, FALSE);
+               }
+

        }
 }
 
        }
 }
 


@@ -436,8 +484,7 @@ static struct {
                DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
                DEMOD_GOT_FALLING_EDGE_OF_SOF,
                DEMOD_AWAITING_START_BIT,
                DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
                DEMOD_GOT_FALLING_EDGE_OF_SOF,
                DEMOD_AWAITING_START_BIT,

-               DEMOD_RECEIVING_DATA,
-               DEMOD_ERROR_WAIT
+               DEMOD_RECEIVING_DATA

        }       state;
        int     bitCount;
        int     posCount;
        }       state;
        int     bitCount;
        int     posCount;


@@ -497,18 +544,23 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                } else { \
                        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() { \
 #define CHECK_FOR_SUBCARRIER() { \

+               v = MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2); \
+       }
+               /*

                if(ci < 0) { \
                if(ci < 0) { \

-                       if(cq < 0) { /* ci < 0, cq < 0 */ \
+                       if(cq < 0) { \ // ci < 0, cq < 0

                                if (cq < ci) { \
                                        v = -cq - (ci >> 1); \
                                } else { \
                                        v = -ci - (cq >> 1); \
                                } \
                                if (cq < ci) { \
                                        v = -cq - (ci >> 1); \
                                } else { \
                                        v = -ci - (cq >> 1); \
                                } \

-                       } else {        /* ci < 0, cq >= 0 */ \
+                       } else {        \ // ci < 0, cq >= 0

                                if (cq < -ci) { \
                                        v = -ci + (cq >> 1); \
                                } else { \
                                if (cq < -ci) { \
                                        v = -ci + (cq >> 1); \
                                } else { \


@@ -516,13 +568,13 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                                } \
                        } \
                } else { \
                                } \
                        } \
                } else { \

-                       if(cq < 0) { /* ci >= 0, cq < 0 */ \
+                       if(cq < 0) { \ // ci >= 0, cq < 0

                                if (-cq < ci) { \
                                        v = ci - (cq >> 1); \
                                } else { \
                                        v = -cq + (ci >> 1); \
                                } \
                                if (-cq < ci) { \
                                        v = ci - (cq >> 1); \
                                } else { \
                                        v = -cq + (ci >> 1); \
                                } \

-                       } else {        /* ci >= 0, cq >= 0 */ \
+                       } else {        \ // ci >= 0, cq >= 0

                                if (cq < ci) { \
                                        v = ci + (cq >> 1); \
                                } else { \
                                if (cq < ci) { \
                                        v = ci + (cq >> 1); \
                                } else { \


@@ -531,7 +583,8 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                        } \
                } \
        }
                        } \
                } \
        }

-       
+               */
+

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


@@ -629,7 +682,7 @@ 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'


@@ -684,22 +737,6 @@ static void DemodInit(uint8_t *data)
 }
 
 
 }
 
 

-static void UartReset()
-{
-       Uart.byteCntMax = MAX_FRAME_SIZE;
-       Uart.state = STATE_UNSYNCD;
-       Uart.byteCnt = 0;
-       Uart.bitCnt = 0;
-}
-
-
-static void UartInit(uint8_t *data)
-{
-       Uart.output = data;
-       UartReset();
-}
-
-

 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer
  *  quiet: set to 'TRUE' to disable debug output
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer
  *  quiet: set to 'TRUE' to disable debug output


@@ -713,43 +750,43 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
        // 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);
+       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);

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

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

 
        int8_t *upTo = dmaBuf;
 
        int8_t *upTo = dmaBuf;

-       lastRxCounter = DMA_BUFFER_SIZE;
+       lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;

 
        // Signal field is ON with the appropriate LED:
        LED_D_ON();
        // And put the FPGA in the appropriate mode
 
        // Signal field is ON with the appropriate LED:
        LED_D_ON();
        // And put the FPGA in the appropriate mode

-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       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;
 
 
        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) {
+               while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {

                        ci = upTo[0];
                        cq = upTo[1];
                        upTo += 2;
                        ci = upTo[0];
                        cq = upTo[1];
                        upTo += 2;

-                       if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
+                       if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {

                                upTo = dmaBuf;
                                AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
                                upTo = dmaBuf;
                                AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;

-                               AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
+                               AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;

                        }
                        lastRxCounter -= 2;
                        if(lastRxCounter <= 0) {
                        }
                        lastRxCounter -= 2;
                        if(lastRxCounter <= 0) {

-                               lastRxCounter += DMA_BUFFER_SIZE;
+                               lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;

                        }
 
                        samples += 2;
                        }
 
                        samples += 2;


@@ -771,7 +808,6 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
        //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);
        }
 }


@@ -893,11 +929,102 @@ 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*100, 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();
+       // 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);
+
+       // Start the timer
+       StartCountSspClk();
+
+       DemodReset();
+       UartReset();
+}

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


@@ -910,9 +1037,6 @@ 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);


@@ -928,35 +1052,32 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        // 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);
+       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);
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

-//    LED_A_OFF();

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

-       DbpString("No response from tag");
-       return;
+               DbpString("No response from tag");
+               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);
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

-//    LED_A_OFF();

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


@@ -972,15 +1093,13 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
                return;
        }
                Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
                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);
        GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

-//    LED_A_OFF();

        if (Demod.len != 10) {
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
                return;
        if (Demod.len != 10) {
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
                return;


@@ -989,12 +1108,12 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        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",
        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);


@@ -1009,10 +1128,7 @@ 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);
                GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

-//         LED_A_OFF();

                if (Demod.len != 6) { // Check if we got an answer from the tag
                        DbpString("Expected 6 bytes from tag, got less...");
                        return;
                if (Demod.len != 6) { // Check if we got an answer from the tag
                        DbpString("Expected 6 bytes from tag, got less...");
                        return;


@@ -1021,13 +1137,13 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                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",
                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;
                }
                if (i == 0xff) {
                        break;
                }


@@ -1050,7 +1166,7 @@ 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)


@@ -1067,7 +1183,7 @@ 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(DMA_BUFFER_SIZE);
+       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);

        int lastRxCounter;
        int8_t *upTo;
        int ci, cq;
        int lastRxCounter;
        int8_t *upTo;
        int ci, cq;


@@ -1085,29 +1201,29 @@ 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();
 
        // And put the FPGA in the appropriate mode
 
        // Signal field is off, no reader signal, no tag signal
        LEDsoff();
 
        // And put the FPGA in the appropriate mode

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

        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // Setup for the DMA.
        FpgaSetupSsc();
        upTo = dmaBuf;
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
        // Setup for the DMA.
        FpgaSetupSsc();
        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];
 
        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;
        uint8_t parity[MAX_PARITY_SIZE];
 
        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;

-       
+

        // And now we loop, receiving samples.
        for(;;) {
                int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
        // And now we loop, receiving samples.
        for(;;) {
                int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &

-                                                               (DMA_BUFFER_SIZE-1);
+                                                               (ISO14443B_DMA_BUFFER_SIZE-1);

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


@@ -1118,13 +1234,13 @@ void RAMFUNC SnoopIso14443b(void)
                cq = upTo[1];
                upTo += 2;
                lastRxCounter -= 2;
                cq = upTo[1];
                upTo += 2;
                lastRxCounter -= 2;

-               if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
+               if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {

                        upTo = dmaBuf;
                        upTo = dmaBuf;

-                       lastRxCounter += DMA_BUFFER_SIZE;
+                       lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;

                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;

-                       AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
+                       AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;

                        WDT_HIT();
                        WDT_HIT();

-                       if(behindBy > (9*DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
+                       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;
                        }
                                Dbprintf("blew circular buffer! behindBy=%d", behindBy);
                                break;
                        }


@@ -1143,7 +1259,6 @@ void RAMFUNC SnoopIso14443b(void)
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending
                        if(Handle14443bUartBit(ci & 0x01)) {
                                if(triggered && tracing) {
                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);
                                }
                                /* And ready to receive another command. */
                                        LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
                                }
                                /* And ready to receive another command. */


@@ -1154,7 +1269,6 @@ void RAMFUNC SnoopIso14443b(void)
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {
                                if(triggered && tracing) {
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {
                                if(triggered && tracing) {

-                                       //GetParity(Uart.output, Uart.byteCnt, parity);

                                        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. */


@@ -1163,17 +1277,16 @@ void RAMFUNC SnoopIso14443b(void)
                                /* false-triggered by the commands from the reader. */
                                DemodReset();
                        }
                                /* false-triggered by the commands from the reader. */
                                DemodReset();
                        }

-                       ReaderIsActive = (Uart.state != STATE_UNSYNCD);
+                       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(!ReaderIsActive) {                                           // no need to try decoding tag data if the reader is sending - and we cannot afford the time

-                       if(Handle14443bSamplesDemod(ci & 0xFE, cq & 0xFE)) {
+                       if(Handle14443bSamplesDemod(ci | 0x01, cq | 0x01)) {

 
                                //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);
                                }
                                triggered = TRUE;
                                        LogTrace(Demod.output, Demod.len, samples, samples, parity, FALSE);
                                }
                                triggered = TRUE;


@@ -1216,32 +1329,18 @@ void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, u
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        FpgaSetupSsc();
 
        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);
-               // // Signal field is on with the appropriate LED
-               // LED_D_ON();
-               // SpinDelay(200);
-       // }
+       if (datalen){
+               set_tracing(TRUE);
+               
+               CodeAndTransmit14443bAsReader(data, datalen);

 
 

-       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();