ADD: @holiman's clearCommandBuffer in cmdlft55xx.c

[proxmark3-svn] / armsrc / iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index 860e96f13bb2972023fd360a0eee5a67a35ed5a2..7423a8ed335b60c9782e3f6e60cb122af5cc8334 100644 (file)
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -5,27 +5,22 @@
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------

-// Routines to support ISO 14443. This includes both the reader software and
-// the `fake tag' modes. At the moment only the Type B modulation is
-// supported.
+// Routines to support ISO 14443B. This includes both the reader software and
+// the `fake tag' modes.

 //-----------------------------------------------------------------------------
 
 #include "proxmark3.h"
 #include "apps.h"
 #include "util.h"
 #include "string.h"
 //-----------------------------------------------------------------------------
 
 #include "proxmark3.h"
 #include "apps.h"
 #include "util.h"
 #include "string.h"

-

 #include "iso14443crc.h"
 #include "iso14443crc.h"

+#include "common.h"
+#define RECEIVE_SAMPLES_TIMEOUT 800000
+#define ISO14443B_DMA_BUFFER_SIZE 256

 
 

-//static void GetSamplesFor14443(int weTx, int n);
-
-/*#define DEMOD_TRACE_SIZE 4096
-#define READER_TAG_BUFFER_SIZE 2048
-#define TAG_READER_BUFFER_SIZE 2048
-#define DEMOD_DMA_BUFFER_SIZE 1024
-*/

 
 

-#define RECEIVE_SAMPLES_TIMEOUT 2000
+// 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


@@ -104,7 +99,7 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
                ToSendStuffBit(1);
        }
 
                ToSendStuffBit(1);
        }
 

-       // Send SOF.
+       // Send EOF.

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


@@ -120,9 +115,6 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
 
        // Convert from last byte pos to length
        ToSendMax++;
 
        // Convert from last byte pos to length
        ToSendMax++;

-
-       // Add a few more for slop
-       ToSendMax += 2;

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


@@ -134,8 +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;


@@ -146,6 +137,9 @@ static struct {
 } Uart;
 
 /* Receive & handle a bit coming from the reader.
 } Uart;
 
 /* Receive & handle a bit coming from the reader.

+ *
+ * This function is called 4 times per bit (every 2 subcarrier cycles).
+ * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us

  *
  * LED handling:
  * LED A -> ON once we have received the SOF and are expecting the rest.
  *
  * LED handling:
  * LED A -> ON once we have received the SOF and are expecting the rest.


@@ -154,7 +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 Handle14443UartBit(int bit)
+static RAMFUNC int Handle14443bUartBit(uint8_t bit)

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


@@ -169,9 +163,9 @@ static int Handle14443UartBit(int bit)
 
                case STATE_GOT_FALLING_EDGE_OF_SOF:
                        Uart.posCnt++;
 
                case STATE_GOT_FALLING_EDGE_OF_SOF:
                        Uart.posCnt++;

-                       if(Uart.posCnt == 2) {
+                       if(Uart.posCnt == 2) {  // sample every 4 1/fs in the middle of a bit

                                if(bit) {
                                if(bit) {

-                                       if(Uart.bitCnt >= 10) {
+                                       if(Uart.bitCnt > 9) {

                                                // we've seen enough consecutive
                                                // zeros that it's a valid SOF
                                                Uart.posCnt = 0;
                                                // we've seen enough consecutive
                                                // zeros that it's a valid SOF
                                                Uart.posCnt = 0;


@@ -181,7 +175,7 @@ static int Handle14443UartBit(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


@@ -189,20 +183,21 @@ static int Handle14443UartBit(int bit)
                                Uart.bitCnt++;
                        }
                        if(Uart.posCnt >= 4) Uart.posCnt = 0;
                                Uart.bitCnt++;
                        }
                        if(Uart.posCnt >= 4) Uart.posCnt = 0;

-                       if(Uart.bitCnt > 14) {
+                       if(Uart.bitCnt > 12) {

                                // Give up if we see too many zeros without
                                // a one, too.
                                // 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;
 
                case STATE_AWAITING_START_BIT:
                        Uart.posCnt++;
                        if(bit) {
                        }
                        break;
 
                case STATE_AWAITING_START_BIT:
                        Uart.posCnt++;
                        if(bit) {

-                               if(Uart.posCnt > 25) {
+                               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
                                        // 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


@@ -236,37 +231,30 @@ static int Handle14443UartBit(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;
                                        return TRUE;

+                                       }

                                } 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;
        }


@@ -274,6 +262,25 @@ static int Handle14443UartBit(int bit)
        return FALSE;
 }
 
        return FALSE;
 }
 

+
+static void UartReset()
+{
+       Uart.byteCntMax = MAX_FRAME_SIZE;
+       Uart.state = STATE_UNSYNCD;
+       Uart.byteCnt = 0;
+       Uart.bitCnt = 0;
+       Uart.posCnt = 0;
+       memset(Uart.output, 0x00, MAX_FRAME_SIZE);
+}
+
+
+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


@@ -283,76 +290,90 @@ static int Handle14443UartBit(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 GetIso14443CommandFromReader(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 14443 tag", no modulation (listen
+       // 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);
 
        // 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(Handle14443UartBit(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;

 }
 
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 // response to send, and send it.
 //-----------------------------------------------------------------------------
 }
 
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 // response to send, and send it.
 //-----------------------------------------------------------------------------

-void SimulateIso14443Tag(void)
+void SimulateIso14443bTag(void)

 {
 {

-       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
+       // 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
        };
        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};

 
 

-       uint8_t *resp;
-       int respLen;
+       uint8_t parity[MAX_PARITY_SIZE];
+                               
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);

 
 

-       uint8_t *resp1 = BigBuf_get_addr() + 800;
-       int resp1Len;
+       clear_trace();
+       set_tracing(TRUE);

 
 

-       uint8_t *receivedCmd = BigBuf_get_addr();
-       int len;
+       const uint8_t *resp;
+       uint8_t *respCode;
+       uint16_t respLen, respCodeLen;

 
 

-       int i;
+       // allocate command receive buffer
+       BigBuf_free();
+       uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);

 
 

-       int cmdsRecvd = 0;
-
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-       memset(receivedCmd, 0x44, 400);
+       uint16_t len;
+       uint16_t cmdsRecvd = 0;

 
 

+       // prepare the (only one) tag answer:

        CodeIso14443bAsTag(response1, sizeof(response1));
        CodeIso14443bAsTag(response1, sizeof(response1));

-       memcpy(resp1, ToSend, ToSendMax); 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);


@@ -361,32 +382,52 @@ void SimulateIso14443Tag(void)
        cmdsRecvd = 0;
 
        for(;;) {
        cmdsRecvd = 0;
 
        for(;;) {

-               uint8_t b1, b2;

 
 

-               if(!GetIso14443CommandFromReader(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) {
+                       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

+                       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");
                        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");
                        }
                        } 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;

                }
 
                }
 

-               memset(receivedCmd, 0x44, 32);
-

                cmdsRecvd++;
 
                if(cmdsRecvd > 0x30) {
                cmdsRecvd++;
 
                if(cmdsRecvd > 0x30) {


@@ -394,7 +435,7 @@ void SimulateIso14443Tag(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


@@ -403,25 +444,41 @@ void SimulateIso14443Tag(void)
                AT91C_BASE_SSC->SSC_THR = 0xff;
                FpgaSetupSsc();
 
                AT91C_BASE_SSC->SSC_THR = 0xff;
                FpgaSetupSsc();
 

+               uint8_t c;
+               // clear receiving shift register and holding register
+               while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+               c = AT91C_BASE_SSC->SSC_RHR; (void) c;
+               while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+               c = AT91C_BASE_SSC->SSC_RHR; (void) c;
+               
+               // Clear TXRDY:
+               AT91C_BASE_SSC->SSC_THR = 0x00;
+               

                // Transmit the response.
                // Transmit the response.

-               i = 0;
-               for(;;) {
+               uint16_t FpgaSendQueueDelay = 0;
+               uint16_t i = 0;
+               for(;i < respCodeLen; ) {

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

-                               uint8_t b = resp[i];
-
-                               AT91C_BASE_SSC->SSC_THR = b;
-
-                               i++;
-                               if(i > respLen) {
-                                       break;
-                               }
+                               AT91C_BASE_SSC->SSC_THR = respCode[i++];
+                               FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;

                        }
                        }

-                       if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                               volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                               (void)b;
+                               if(BUTTON_PRESS()) break;
+               }
+               
+               // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
+               uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;
+               for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
+                       if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                               AT91C_BASE_SSC->SSC_THR = 0x00;
+                               FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+                               i++;

                        }
                }
                        }
                }

+               
+               // trace the response:
+               if (tracing) LogTrace(resp, respLen, 0, 0, parity, FALSE);                      

        }
        }

+       FpgaDisableSscDma();

 }
 
 //=============================================================================
 }
 
 //=============================================================================


@@ -438,14 +495,15 @@ 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;
        int     thisBit;
        }       state;
        int     bitCount;
        int     posCount;
        int     thisBit;

+/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.

        int     metric;
        int     metricN;
        int     metric;
        int     metricN;

+*/

        uint16_t    shiftReg;
        uint8_t   *output;
        int     len;
        uint16_t    shiftReg;
        uint8_t   *output;
        int     len;


@@ -456,6 +514,9 @@ static struct {
 /*
  * Handles reception of a bit from the tag
  *
 /*
  * Handles reception of a bit from the tag
  *

+ * This function is called 2 times per bit (every 4 subcarrier cycles).
+ * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us
+ *

  * LED handling:
  * LED C -> ON once we have received the SOF and are expecting the rest.
  * LED C -> OFF once we have received EOF or are unsynced
  * LED handling:
  * LED C -> ON once we have received the SOF and are expecting the rest.
  * LED C -> OFF once we have received EOF or are unsynced


@@ -464,18 +525,15 @@ static struct {
  *          false if we are still waiting for some more
  *
  */
  *          false if we are still waiting for some more
  *
  */

-static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
+static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)

 {
        int v;
 {
        int v;

+       int ai, aq;

 
 

-       // The soft decision on the bit uses an estimate of just the
-       // quadrant of the reference angle, not the exact angle.
+// The soft decision on the bit uses an estimate of just the
+// quadrant of the reference angle, not the exact angle.

 #define MAKE_SOFT_DECISION() { \
 #define MAKE_SOFT_DECISION() { \

-               if(Demod.sumI > 0) { \
-                       v = ci; \
-               } else { \
-                       v = -ci; \
-               } \
+               v = (Demod.sumI > 0) ? ci : -ci;\

                if(Demod.sumQ > 0) { \
                        v += cq; \
                } else { \
                if(Demod.sumQ > 0) { \
                        v += cq; \
                } else { \


@@ -483,47 +541,64 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
                } \
        }
 
                } \
        }
 

+#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)))
+#define CHECK_FOR_SUBCARRIER() { \
+               ai = (abs(ci) >> 1); \
+               aq = (abs(cq) >> 1); \
+               v = MAX(abs(ci), abs(cq)) + MIN(ai, aq); \
+}
+
+

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

-                       v = ci;
-                       if(v < 0) v = -v;
-                       if(cq > 0) {
-                               v += cq;
-                       } else {
-                               v -= cq;
-                       }
-                       if(v > 40) {
-                               Demod.posCount = 0;
+                       CHECK_FOR_SUBCARRIER();
+                       if(v > SUBCARRIER_DETECT_THRESHOLD) {   // subcarrier detected

                                Demod.state = DEMOD_PHASE_REF_TRAINING;
                                Demod.state = DEMOD_PHASE_REF_TRAINING;

-                               Demod.sumI = 0;
-                               Demod.sumQ = 0;
+                               Demod.sumI = ci;
+                               Demod.sumQ = cq;
+                               Demod.posCount = 1;

                        }
                        break;
 
                case DEMOD_PHASE_REF_TRAINING:
                        }
                        break;
 
                case DEMOD_PHASE_REF_TRAINING:

-                       if(Demod.posCount < 8) {
-                               Demod.sumI += ci;
-                               Demod.sumQ += cq;
-                       } else if(Demod.posCount > 100) {
-                               // error, waited too long
-                               Demod.state = DEMOD_UNSYNCD;
-                       } else {
-                               MAKE_SOFT_DECISION();
-                               if(v < 0) {
-                                       Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
-                                       Demod.posCount = 0;
+                       if(Demod.posCount < 10*2) {
+                               CHECK_FOR_SUBCARRIER();
+                               if (v > SUBCARRIER_DETECT_THRESHOLD) {
+                                       // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
+                                       // note: synchronization time > 80 1/fs
+                                       Demod.sumI += ci;
+                                       Demod.sumQ += cq;
+                                       Demod.posCount++;
+                               } else {                // subcarrier lost
+                                       Demod.state = DEMOD_UNSYNCD;

                                }
                                }

+                       } else {
+                               Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;

                        }
                        }

-                       Demod.posCount++;

                        break;
 
                case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
                        MAKE_SOFT_DECISION();
                        break;
 
                case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
                        MAKE_SOFT_DECISION();

-                       if(v < 0) {
+                       //Dbprintf("ICE: %d %d %d %d %d", v, Demod.sumI, Demod.sumQ, ci, cq );
+                       if(v < 0) {     // logic '0' detected

                                Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
                                Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;

-                               Demod.posCount = 0;
+                               Demod.posCount = 0;     // start of SOF sequence

                        } else {
                        } else {

-                               if(Demod.posCount > 100) {
+                               if(Demod.posCount > 25*2) {     // maximum length of TR1 = 200 1/fs

                                        Demod.state = DEMOD_UNSYNCD;
                                }
                        }
                                        Demod.state = DEMOD_UNSYNCD;
                                }
                        }


@@ -531,37 +606,40 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
                        break;
 
                case DEMOD_GOT_FALLING_EDGE_OF_SOF:
                        break;
 
                case DEMOD_GOT_FALLING_EDGE_OF_SOF:

+                       Demod.posCount++;

                        MAKE_SOFT_DECISION();
                        if(v > 0) {
                        MAKE_SOFT_DECISION();
                        if(v > 0) {

-                               if(Demod.posCount < 12) {
+                               if(Demod.posCount < 10*2) { // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges

                                        Demod.state = DEMOD_UNSYNCD;
                                } else {
                                        LED_C_ON(); // Got SOF
                                        Demod.state = DEMOD_AWAITING_START_BIT;
                                        Demod.posCount = 0;
                                        Demod.len = 0;
                                        Demod.state = DEMOD_UNSYNCD;
                                } else {
                                        LED_C_ON(); // Got SOF
                                        Demod.state = DEMOD_AWAITING_START_BIT;
                                        Demod.posCount = 0;
                                        Demod.len = 0;

+/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.

                                        Demod.metricN = 0;
                                        Demod.metric = 0;
                                        Demod.metricN = 0;
                                        Demod.metric = 0;

+*/

                                }
                        } else {
                                }
                        } else {

-                               if(Demod.posCount > 100) {
+                               if(Demod.posCount > 13*2) { // low phase of SOF too long (> 12 etu)

                                        Demod.state = DEMOD_UNSYNCD;
                                        LED_C_OFF();
                                }
                        }
                                        Demod.state = DEMOD_UNSYNCD;
                                        LED_C_OFF();
                                }
                        }

-                       Demod.posCount++;

                        break;
 
                case DEMOD_AWAITING_START_BIT:
                        break;
 
                case DEMOD_AWAITING_START_BIT:

+                       Demod.posCount++;

                        MAKE_SOFT_DECISION();
                        if(v > 0) {
                        MAKE_SOFT_DECISION();
                        if(v > 0) {

-                               if(Demod.posCount > 10) {
+                               if(Demod.posCount > 3*2) {              // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs

                                        Demod.state = DEMOD_UNSYNCD;
                                        LED_C_OFF();
                                }
                                        Demod.state = DEMOD_UNSYNCD;
                                        LED_C_OFF();
                                }

-                       } else {
+                       } else {                                                        // start bit detected

                                Demod.bitCount = 0;
                                Demod.bitCount = 0;

-                               Demod.posCount = 1;
+                               Demod.posCount = 1;                             // this was the first half

                                Demod.thisBit = v;
                                Demod.shiftReg = 0;
                                Demod.state = DEMOD_RECEIVING_DATA;
                                Demod.thisBit = v;
                                Demod.shiftReg = 0;
                                Demod.state = DEMOD_RECEIVING_DATA;


@@ -570,28 +648,30 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
 
                case DEMOD_RECEIVING_DATA:
                        MAKE_SOFT_DECISION();
 
                case DEMOD_RECEIVING_DATA:
                        MAKE_SOFT_DECISION();

-                       if(Demod.posCount == 0) {
+                       if(Demod.posCount == 0) {                       // first half of bit

                                Demod.thisBit = v;
                                Demod.posCount = 1;
                                Demod.thisBit = v;
                                Demod.posCount = 1;

-                       } else {
+                       } else {                                                        // second half of bit

                                Demod.thisBit += v;
 
                                Demod.thisBit += v;
 

+/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.

                                if(Demod.thisBit > 0) {
                                        Demod.metric += Demod.thisBit;
                                } else {
                                        Demod.metric -= Demod.thisBit;
                                }
                                (Demod.metricN)++;
                                if(Demod.thisBit > 0) {
                                        Demod.metric += Demod.thisBit;
                                } else {
                                        Demod.metric -= Demod.thisBit;
                                }
                                (Demod.metricN)++;

+*/                             

 
                                Demod.shiftReg >>= 1;
 
                                Demod.shiftReg >>= 1;

-                               if(Demod.thisBit > 0) {
+                               if(Demod.thisBit > 0) { // logic '1'

                                        Demod.shiftReg |= 0x200;
                                }
 
                                Demod.bitCount++;
                                if(Demod.bitCount == 10) {
                                        uint16_t s = Demod.shiftReg;
                                        Demod.shiftReg |= 0x200;
                                }
 
                                Demod.bitCount++;
                                if(Demod.bitCount == 10) {
                                        uint16_t s = Demod.shiftReg;

-                                       if((s & 0x200) && !(s & 0x001)) {
+                                       if((s & 0x200) && !(s & 0x001)) { // stop bit == '1', start bit == '0'

                                                uint8_t b = (s >> 1);
                                                Demod.output[Demod.len] = b;
                                                Demod.len++;
                                                uint8_t b = (s >> 1);
                                                Demod.output[Demod.len] = b;
                                                Demod.len++;


@@ -600,8 +680,8 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
                                                Demod.state = DEMOD_UNSYNCD;
                                                LED_C_OFF();
                                                if(s == 0x000) {
                                                Demod.state = DEMOD_UNSYNCD;
                                                LED_C_OFF();
                                                if(s == 0x000) {

-                                               // This is EOF
-                                               return TRUE;
+                                                       // This is EOF (start, stop and all data bits == '0'
+                                                       return TRUE;

                                                }
                                        }
                                }
                                                }
                                        }
                                }


@@ -614,7 +694,6 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
                        LED_C_OFF();
                        break;
        }
                        LED_C_OFF();
                        break;
        }

-

        return FALSE;
 }
 
        return FALSE;
 }
 


@@ -624,6 +703,12 @@ static void DemodReset()
        // Clear out the state of the "UART" that receives from the tag.
        Demod.len = 0;
        Demod.state = DEMOD_UNSYNCD;
        // Clear out the state of the "UART" that receives from the tag.
        Demod.len = 0;
        Demod.state = DEMOD_UNSYNCD;

+       Demod.posCount = 0;
+       Demod.sumI = 0;
+       Demod.sumQ = 0;
+       Demod.bitCount = 0;
+       Demod.thisBit = 0;
+       Demod.shiftReg = 0;

        memset(Demod.output, 0x00, MAX_FRAME_SIZE);
 }
 
        memset(Demod.output, 0x00, MAX_FRAME_SIZE);
 }
 


@@ -635,144 +720,99 @@ 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
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer

- *  weTx: set to 'TRUE' if we behave like a reader
- *        set to 'FALSE' if we behave like a snooper

  *  quiet: set to 'TRUE' to disable debug output
  */
  *  quiet: set to 'TRUE' to disable debug output
  */

-static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
+static void GetSamplesFor14443bDemod(int n, bool quiet)

 {
        int max = 0;
 {
        int max = 0;

-       int gotFrame = FALSE;
+       bool gotFrame = FALSE;

        int lastRxCounter, ci, cq, samples = 0;
 
        // Allocate memory from BigBuf for some buffers
        // free all previous allocations first
        BigBuf_free();
        int lastRxCounter, ci, cq, samples = 0;
 
        // Allocate memory from BigBuf for some buffers
        // free all previous allocations first
        BigBuf_free();

-       
+
+       // And put the FPGA in the appropriate mode
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
+

        // The response (tag -> reader) that we're receiving.
        // The response (tag -> reader) that we're receiving.

-       uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
+       // Set up the demodulator for tag -> reader responses.
+       DemodInit(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);
-
-       // Set up the demodulator for tag -> reader responses.
-       DemodInit(receivedResponse);
+       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);

 
        // Setup and start DMA.
 
        // 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:
 
        // Signal field is ON with the appropriate LED:

-       if (weTx) LED_D_ON(); else LED_D_OFF();
-       // And put the FPGA in the appropriate mode
-       FpgaWriteConfWord(
-               FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
-               (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
-
+       LED_D_ON();

        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;
 

-                       if(Handle14443SamplesDemod(ci, cq)) {
-                               gotFrame = 1;
-                       }
+                       //
+                       gotFrame = Handle14443bSamplesDemod(ci , cq );
+                       if ( gotFrame )
+                               break;

                }
 
                }
 

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

                        break;
                }
        }
                        break;
                }
        }

+

        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;

-       if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
+
+       if (!quiet && Demod.len == 0) {
+               Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d",
+                       max,
+                       samples, 
+                       gotFrame, 
+                       Demod.len, 
+                       Demod.sumI, 
+                       Demod.sumQ
+               );
+       }
+

        //Tracing
        if (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);
        }
 }
 
 

-//-----------------------------------------------------------------------------
-// Read the tag's response. We just receive a stream of slightly-processed
-// samples from the FPGA, which we will later do some signal processing on,
-// to get the bits.
-//-----------------------------------------------------------------------------
-/*static void GetSamplesFor14443(int weTx, int n)
-{
-       uint8_t *dest = (uint8_t *)BigBuf;
-       int c;
-
-       FpgaWriteConfWord(
-               FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
-               (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
-
-       c = 0;
-       for(;;) {
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = 0x43;
-               }
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       int8_t b;
-                       b = (int8_t)AT91C_BASE_SSC->SSC_RHR;
-
-                       dest[c++] = (uint8_t)b;
-
-                       if(c >= n) {
-                               break;
-                       }
-               }
-       }
-}*/
-
-

 //-----------------------------------------------------------------------------
 // Transmit the command (to the tag) that was placed in ToSend[].
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 // Transmit the command (to the tag) that was placed in ToSend[].
 //-----------------------------------------------------------------------------

-static void TransmitFor14443(void)
+static void TransmitFor14443b(void)

 {
        int c;
 
        FpgaSetupSsc();
 {
        int c;
 
        FpgaSetupSsc();

-
+       

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


@@ -781,9 +821,8 @@ static void TransmitFor14443(void)
        LED_D_ON();
        // Signal we are transmitting with the Green LED
        LED_B_ON();
        LED_D_ON();
        // Signal we are transmitting with the Green LED
        LED_B_ON();

-       FpgaWriteConfWord(
-               FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
-
+       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;
        for(c = 0; c < 10;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = 0xff;


@@ -817,7 +856,7 @@ static void TransmitFor14443(void)
 
 //-----------------------------------------------------------------------------
 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
 
 //-----------------------------------------------------------------------------
 // Code a layer 2 command (string of octets, including CRC) into ToSend[],

-// so that it is ready to transmit to the tag using TransmitFor14443().
+// so that it is ready to transmit to the tag using TransmitFor14443b().

 //-----------------------------------------------------------------------------
 static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 {
 //-----------------------------------------------------------------------------
 static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 {


@@ -831,7 +870,7 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
                ToSendStuffBit(1);
        }
        // Send SOF
                ToSendStuffBit(1);
        }
        // Send SOF

-       for(i = 0; i < 10; i++) {
+       for(i = 0; i < 11; i++) {

                ToSendStuffBit(0);
        }
 
                ToSendStuffBit(0);
        }
 


@@ -854,7 +893,7 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
        }
        // Send EOF
        ToSendStuffBit(1);
        }
        // Send EOF
        ToSendStuffBit(1);

-       for(i = 0; i < 10; i++) {
+       for(i = 0; i < 11; i++) {

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


@@ -863,7 +902,7 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 
        // And then a little more, to make sure that the last character makes
        // it out before we switch to rx mode.
 
        // 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++) {
+       for(i = 0; i < 10; i++) {

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


@@ -872,39 +911,117 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 }
 
 
 }
 
 

-//-----------------------------------------------------------------------------
-// Read an ISO 14443 tag. We send it some set of commands, and record the
-// responses.
-// The command name is misleading, it actually decodes the reponse in HEX
-// into the output buffer (read the result using hexsamples, not hisamples)
-//
-// obsolete function only for test
-//-----------------------------------------------------------------------------
-void AcquireRawAdcSamplesIso14443(uint32_t parameter)
-{
-       uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-
-       SendRawCommand14443B(sizeof(cmd1),1,1,cmd1);
-}
-
-

 /**
   Convenience function to encode, transmit and trace iso 14443b comms
   **/
 static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 {
        CodeIso14443bAsReader(cmd, len);
 /**
   Convenience function to encode, transmit and trace iso 14443b comms
   **/
 static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 {
        CodeIso14443bAsReader(cmd, len);

-       TransmitFor14443();
+       TransmitFor14443b();

        if (tracing) {
                uint8_t parity[MAX_PARITY_SIZE];
        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);
+
+       BigBuf_free();
+       // 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 14443 tag.
+// Read a SRI512 ISO 14443B tag.

 //
 // SRI512 tags are just simple memory tags, here we're looking at making a dump
 // of the contents of the memory. No anticollision algorithm is done, we assume
 //
 // SRI512 tags are just simple memory tags, here we're looking at making a dump
 // of the contents of the memory. No anticollision algorithm is done, we assume


@@ -912,14 +1029,16 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 //
 // I tried to be systematic and check every answer of the tag, every CRC, etc...
 //-----------------------------------------------------------------------------
 //
 // I tried to be systematic and check every answer of the tag, every CRC, etc...
 //-----------------------------------------------------------------------------

-void ReadSTMemoryIso14443(uint32_t dwLast)
+void ReadSTMemoryIso14443b(uint32_t dwLast)

 {
 {

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

        clear_trace();
        set_tracing(TRUE);
 
        uint8_t i = 0x00;
 
        clear_trace();
        set_tracing(TRUE);
 
        uint8_t i = 0x00;
 

-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);

        // Make sure that we start from off, since the tags are stateful;
        // confusing things will happen if we don't reset them between reads.
        LED_D_OFF();
        // Make sure that we start from off, since the tags are stateful;
        // confusing things will happen if we don't reset them between reads.
        LED_D_OFF();


@@ -932,76 +1051,68 @@ void ReadSTMemoryIso14443(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 | FPGA_HF_READER_RX_XCORR_848_KHZ);
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);

        SpinDelay(200);
 
        // First command: wake up the tag using the INITIATE command
        SpinDelay(200);
 
        // First command: wake up the tag using the INITIATE command

-       uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
-
+       uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};

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

-//    LED_A_ON();
-       GetSamplesFor14443Demod(TRUE, 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");
+               return;

        } else {
        } else {

-       Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
-               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();
-       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

        if (Demod.len != 3) {
        if (Demod.len != 3) {

-       Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
-       return;
+               Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
+               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]) {
        }
        // 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;
+               DbpString("CRC Error reading select response.");
+               return;

        }
        // Check response from the tag: should be the same UID as the command we just sent:
        if (cmd1[1] != Demod.output[0]) {
        }
        // 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: %x %x", 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();
-       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
+       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);

        if (Demod.len != 10) {
        if (Demod.len != 10) {

-       Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
-       return;
+               Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
+               return;

        }
        // The check the CRC of the answer (use cmd1 as temporary variable):
        ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
        }
        // 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! - Below: expected, got %x %x",
-               (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
+       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]);

        // 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
 
        // Now loop to read all 16 blocks, address from 0 to last block

-       Dbprintf("Tag memory dump, block 0 to %d",dwLast);
+       Dbprintf("Tag memory dump, block 0 to %d", dwLast);

        cmd1[0] = 0x08;
        i = 0x00;
        dwLast++;
        cmd1[0] = 0x08;
        i = 0x00;
        dwLast++;


@@ -1013,10 +1124,7 @@ void ReadSTMemoryIso14443(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();
-               GetSamplesFor14443Demod(TRUE, 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...");
                return;
                if (Demod.len != 6) { // Check if we got an answer from the tag
                DbpString("Expected 6 bytes from tag, got less...");
                return;


@@ -1024,16 +1132,16 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
                // 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]) {
                // 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! - Below: expected, got %x %x",
-                       (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
+                       Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
+                                       (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:
                // Do not return;, let's go on... (we should retry, maybe ?)
                }
                // Now print out the memory location:

-               Dbprintf("Address=%x, Contents=%x, CRC=%x", i,
-               (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
-               (Demod.output[4]<<8)+Demod.output[5]);
+               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]);

                if (i == 0xff) {
                if (i == 0xff) {

-               break;
+                       break;

                }
                i++;
        }
                }
                i++;
        }


@@ -1054,10 +1162,10 @@ void ReadSTMemoryIso14443(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, 1024 bytes (samples) - DMA_BUFFER_SIZE
+ * DMA Buffer - ISO14443B_DMA_BUFFER_SIZE

  * Demodulated samples received - all the rest
  */
  * Demodulated samples received - all the rest
  */

-void RAMFUNC SnoopIso14443(void)
+void RAMFUNC SnoopIso14443b(void)

 {
        // We won't start recording the frames that we acquire until we trigger;
        // a good trigger condition to get started is probably when we see a
 {
        // 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


@@ -1071,7 +1179,7 @@ void RAMFUNC SnoopIso14443(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;


@@ -1089,120 +1197,107 @@ void RAMFUNC SnoopIso14443(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 with the appropriate LED
-       LED_D_OFF();
+       // Signal field is off, no reader signal, no tag signal
+       LEDsoff();

 
        // And put the FPGA in the appropriate mode
 
        // And put the FPGA in the appropriate mode

-       FpgaWriteConfWord(
-               FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
-               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];
        uint8_t parity[MAX_PARITY_SIZE];

-       LED_A_ON();
-               
+

        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;
        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;

-                       if(behindBy > (9*DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
-                               Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
-                               break;
-                       }

                }
                }

+

                if(behindBy < 2) continue;
 
                ci = upTo[0];
                cq = upTo[1];
                upTo += 2;
                lastRxCounter -= 2;
                if(behindBy < 2) continue;
 
                ci = upTo[0];
                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();
+                       if(behindBy > (9*ISO14443B_DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
+                               Dbprintf("blew circular buffer! behindBy=%d", behindBy);
+                               break;
+                       }
+                       if(!tracing) {
+                               DbpString("Reached trace limit");
+                               break;
+                       }
+                       if(BUTTON_PRESS()) {
+                               DbpString("cancelled");
+                               break;
+                       }

                }
 
                samples += 2;
 
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending
                }
 
                samples += 2;
 
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending

-                       if(Handle14443UartBit(ci & 0x01)) {
+                       if(Handle14443bUartBit(ci & 0x01)) {

                        if(triggered && tracing) {
                        if(triggered && tracing) {

-                               GetParity(Uart.output, Uart.byteCnt, parity);
-                               LogTrace(Uart.output,Uart.byteCnt,samples, samples,parity,TRUE);
+                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);

                        }
                        }

-                       if(Uart.byteCnt==0) Dbprintf("[1] Error, Uart.byteCnt==0, Uart.bitCnt=%d", Uart.bitCnt);
-

                        /* And ready to receive another command. */
                        UartReset();
                        /* And also reset the demod code, which might have been */
                        /* false-triggered by the commands from the reader. */
                        DemodReset();
                }
                        /* And ready to receive another command. */
                        UartReset();
                        /* And also reset the demod code, which might have been */
                        /* false-triggered by the commands from the reader. */
                        DemodReset();
                }

-                       if(Handle14443UartBit(cq & 0x01)) {
+                       if(Handle14443bUartBit(cq & 0x01)) {

                        if(triggered && tracing) {
                        if(triggered && tracing) {

-                               GetParity(Uart.output, Uart.byteCnt, parity);
-                               LogTrace(Uart.output,Uart.byteCnt,samples, samples, parity, TRUE);
+                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);

                        }
                        }

-                       if(Uart.byteCnt==0) Dbprintf("[2] Error, Uart.byteCnt==0, Uart.bitCnt=%d", Uart.bitCnt);
-

                        /* And ready to receive another command. */
                        UartReset();
                        /* And also reset the demod code, which might have been */
                        /* false-triggered by the commands from the reader. */
                        DemodReset();
                }
                        /* And ready to receive another command. */
                        UartReset();
                        /* And also reset the demod code, which might have been */
                        /* 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(Handle14443SamplesDemod(ci & 0xFE, cq & 0xFE)) {
+                       // is this | 0x01 the error?   & 0xfe  in https://github.com/Proxmark/proxmark3/issues/103
+                       if(Handle14443bSamplesDemod(ci | 0x01, cq | 0x01)) {

 
                        //Use samples as a time measurement
                        if(tracing)
                        {
 
                        //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);
+                               //uint8_t parity[MAX_PARITY_SIZE];
+                               LogTrace(Demod.output, Demod.len, samples, samples, parity, FALSE);

                        }
                        triggered = TRUE;
                        }
                        triggered = TRUE;

-                       LED_A_OFF();
-                       LED_B_ON();

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

-                       TagIsActive = (Demod.state != DEMOD_UNSYNCD);
+                       TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);

                }
 
                }
 

-               WDT_HIT();
-
-               if(!tracing) {
-                       DbpString("Reached trace limit");
-                       break;
-               }
-
-               if(BUTTON_PRESS()) {
-                       DbpString("cancelled");
-                       break;
-               }

        }
        }

+

        FpgaDisableSscDma();
        FpgaDisableSscDma();

-       LED_A_OFF();
-       LED_B_OFF();
-       LED_C_OFF();
+       LEDsoff();

        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
        DbpString("Snoop statistics:");
        Dbprintf("  Max behind by: %i", maxBehindBy);
        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
        DbpString("Snoop statistics:");
        Dbprintf("  Max behind by: %i", maxBehindBy);


@@ -1225,48 +1320,26 @@ void RAMFUNC SnoopIso14443(void)
  * none
  *
  */
  * none
  *
  */

-void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield_trace, uint8_t data[])
+void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, uint8_t data[])

 {
 {

-       uint8_t powerfield = powerfield_trace & 1;
-       uint8_t trace = powerfield_trace & 2;
-       if (trace){
-               clear_trace();
+       iso14443b_setup();
+       
+       if ( datalen == 0 && recv == 0 && powerfield == 0){
+               
+       } else {                

                set_tracing(TRUE);
                set_tracing(TRUE);

-       }
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-       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))
-       {
-               SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-               FpgaSetupSsc();
-
-               // 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);
-               SpinDelay(200);
+               CodeAndTransmit14443bAsReader(data, datalen);

        }
 
        }
 

-       CodeAndTransmit14443bAsReader(data, datalen);
-
-       if(recv)
-       {
-               GetSamplesFor14443Demod(TRUE, 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, FALSE);
+               uint16_t iLen = MIN(Demod.len, USB_CMD_DATA_SIZE);
+               cmd_send(CMD_ACK, iLen, 0, 0, Demod.output, iLen);

        }
        }

-       if(!powerfield)
-       {
+       
+       if(!powerfield) {

                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

+               FpgaDisableSscDma();

                LED_D_OFF();
        }
 }
                LED_D_OFF();
        }
 }