textual changes.

[proxmark3-svn] / armsrc / iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index a393ed58d3f9d68fedd2376fdc233125ad209bad..2aebb3060102b966c0ae4ed9523a5ef565b664f8 100644 (file)
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -10,31 +10,46 @@
 //-----------------------------------------------------------------------------
 #include "iso14443b.h"
 
 //-----------------------------------------------------------------------------
 #include "iso14443b.h"
 

-#define RECEIVE_SAMPLES_TIMEOUT 50000
-#define ISO14443B_DMA_BUFFER_SIZE 256
+#ifndef FWT_TIMEOUT_14B
+# define FWT_TIMEOUT_14B 60000
+#endif
+#ifndef ISO14443B_DMA_BUFFER_SIZE
+# define ISO14443B_DMA_BUFFER_SIZE 256
+#endif
+#ifndef RECEIVE_MASK
+# define RECEIVE_MASK  (ISO14443B_DMA_BUFFER_SIZE-1)
+#endif

 
 // Guard Time (per 14443-2)
 
 // Guard Time (per 14443-2)

-#define TR0 0  
+#ifndef TR0
+# define TR0 0
+#endif
+

 // Synchronization time (per 14443-2)
 // Synchronization time (per 14443-2)

-#define TR1 0
+#ifndef TR1
+# define TR1 0
+#endif

 // Frame Delay Time PICC to PCD  (per 14443-3 Amendment 1)
 // Frame Delay Time PICC to PCD  (per 14443-3 Amendment 1)

-#define TR2 0
+#ifndef TR2
+# define TR2 0
+#endif

 
 // 4sample
 #define SEND4STUFFBIT(x) ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);
 
 // 4sample
 #define SEND4STUFFBIT(x) ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);

+//#define SEND4STUFFBIT(x) ToSendStuffBit(x);

 
 static void switch_off(void);
 
 // the block number for the ISO14443-4 PCB  (used with APDUs)
 static uint8_t pcb_blocknum = 0;
 
 
 static void switch_off(void);
 
 // the block number for the ISO14443-4 PCB  (used with APDUs)
 static uint8_t pcb_blocknum = 0;
 

-static uint32_t iso14b_timeout = RECEIVE_SAMPLES_TIMEOUT;
+static uint32_t iso14b_timeout = FWT_TIMEOUT_14B;

 // param timeout is in ftw_ 
 void iso14b_set_timeout(uint32_t timeout) {
        // 9.4395us = 1etu.
        // clock is about 1.5 us
        iso14b_timeout = timeout;
 // param timeout is in ftw_ 
 void iso14b_set_timeout(uint32_t timeout) {
        // 9.4395us = 1etu.
        // clock is about 1.5 us
        iso14b_timeout = timeout;

-       if(MF_DBGLEVEL >= 2) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout);
+       if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout);

 }
 
 static void switch_off(void){  
 }
 
 static void switch_off(void){  


@@ -204,9 +219,6 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len) {
        *
        */
        
        *
        */
        

-       // ToSendStuffBit,  40 calls
-       // 1 ETU = 1startbit, 1stopbit, 8databits == 10bits.
-       // 1 ETU = 10 * 4 == 40 stuffbits ( ETU_TAG_BIT )

        int i,j;
        uint8_t b;
        
        int i,j;
        uint8_t b;
        


@@ -223,41 +235,50 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len) {
        // Send SOF.
        // 10-11 ETU * 4times samples ZEROS
        for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }
        // Send SOF.
        // 10-11 ETU * 4times samples ZEROS
        for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }

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

        
        // 2-3 ETU * 4times samples ONES
        for(i = 0; i < 3; i++)  { SEND4STUFFBIT(1); }
        
        // 2-3 ETU * 4times samples ONES
        for(i = 0; i < 3; i++)  { SEND4STUFFBIT(1); }

+       //for(i = 0; i < 3; i++)  { ToSendStuffBit(1); }

        
        // data
        for(i = 0; i < len; ++i) {
                
                // Start bit
                SEND4STUFFBIT(0);
        
        // data
        for(i = 0; i < len; ++i) {
                
                // Start bit
                SEND4STUFFBIT(0);

+               //ToSendStuffBit(0);

 
                // Data bits
                b = cmd[i];
                for(j = 0; j < 8; ++j) {
                        if(b & 1) { 
                                SEND4STUFFBIT(1); 
 
                // Data bits
                b = cmd[i];
                for(j = 0; j < 8; ++j) {
                        if(b & 1) { 
                                SEND4STUFFBIT(1); 

+                               //ToSendStuffBit(1);

                        } else {
                                SEND4STUFFBIT(0);
                        } else {
                                SEND4STUFFBIT(0);

+                               //ToSendStuffBit(0);

                        }
                        b >>= 1;
                }
 
                // Stop bit
                SEND4STUFFBIT(1);
                        }
                        b >>= 1;
                }
 
                // Stop bit
                SEND4STUFFBIT(1);

+               //ToSendStuffBit(1);

                
                // Extra Guard bit
                // For PICC it ranges 0-18us (1etu = 9us)
                SEND4STUFFBIT(1);
                
                // Extra Guard bit
                // For PICC it ranges 0-18us (1etu = 9us)
                SEND4STUFFBIT(1);

+               //ToSendStuffBit(1);

        }
 
        // Send EOF.
        // 10-11 ETU * 4 sample rate = ZEROS
        for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }
        }
 
        // Send EOF.
        // 10-11 ETU * 4 sample rate = ZEROS
        for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }

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

        
        // why this?
        for(i = 0; i < 40; i++) { SEND4STUFFBIT(1); }
        
        // why this?
        for(i = 0; i < 40; i++) { SEND4STUFFBIT(1); }

+       //for(i = 0; i < 40; i++) { ToSendStuffBit(1); }

        
        // Convert from last byte pos to length
        ++ToSendMax;
        
        // Convert from last byte pos to length
        ++ToSendMax;


@@ -403,13 +424,25 @@ static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) {
        // Signal field is off with the appropriate LED
        LED_D_OFF();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
        // Signal field is off with the appropriate LED
        LED_D_OFF();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);

-       
+               

        StartCountSspClk();
        
        StartCountSspClk();
        

+       volatile uint8_t b;
+
+       // clear receiving shift register and holding register
+       // What does this loop do? Is it TR1?
+       for(uint8_t c = 0; c < 10;) {
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       AT91C_BASE_SSC->SSC_THR = 0xFF;
+                       ++c;
+               }
+       }
+       

        // Now run a `software UART' on the stream of incoming samples.
        UartInit(received);
        // Now run a `software UART' on the stream of incoming samples.
        UartInit(received);

-       
-       uint8_t mask, b = 0;
+
+       b = 0;
+       uint8_t mask;

        while( !BUTTON_PRESS() ) {
                WDT_HIT();
 
        while( !BUTTON_PRESS() ) {
                WDT_HIT();
 


@@ -426,27 +459,70 @@ static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) {
        return FALSE;
 }
 
        return FALSE;
 }
 

+void ClearFpgaShiftingRegisters(void){

 
 

-static void TransmitFor14443b_AsTag( uint8_t *response, uint16_t len) {
+       volatile uint8_t b;

 
 

-               // Signal field is off with the appropriate LED
-               LED_D_OFF();
-               
-               // Modulate BPSK
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
+       // clear receiving shift register and holding register
+       while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+
+       b = AT91C_BASE_SSC->SSC_RHR; (void) b;
+
+       while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+
+       b = AT91C_BASE_SSC->SSC_RHR; (void) b;
+       

                
                

-               // 8 ETU / 8bits. 8/4= 2 etus.
-               AT91C_BASE_SSC->SSC_THR = 0XFF;
+       // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
+       for (uint8_t j = 0; j < 5; j++) {       // allow timeout - better late than never
+               while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+               if (AT91C_BASE_SSC->SSC_RHR) break;
+       }
+       
+       // Clear TXRDY:
+       //AT91C_BASE_SSC->SSC_THR = 0xFF;
+}

 
 

-               FpgaSetupSsc();
+void WaitForFpgaDelayQueueIsEmpty( uint16_t delay ){
+       // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
+       uint8_t fpga_queued_bits = delay >> 3;  // twich /8 ??   >>3, 
+       for (uint8_t i = 0; i <= fpga_queued_bits/8 + 1; ) {
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       AT91C_BASE_SSC->SSC_THR = 0xFF;
+                       i++;
+               }
+       }
+}

 
 

-               // Transmit the response.
-               for(uint16_t i = 0; i < len;) {
-                       if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
-                               AT91C_BASE_SSC->SSC_THR = response[i];
-                               ++i;
-                       }
+static void TransmitFor14443b_AsTag( uint8_t *response, uint16_t len) {
+
+       volatile uint32_t b;
+       
+       // Signal field is off with the appropriate LED
+       LED_D_OFF();
+       //uint16_t fpgasendQueueDelay = 0;
+       
+       // Modulate BPSK
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
+       SpinDelay(40);
+       
+       ClearFpgaShiftingRegisters();
+       
+       FpgaSetupSsc();
+
+       // Transmit the response.
+       for(uint16_t i = 0; i < len;) {
+               if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+                       AT91C_BASE_SSC->SSC_THR = response[++i];

                }
                }

+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                       b = AT91C_BASE_SSC->SSC_RHR;
+                       (void)b;
+               }                       
+       }
+       
+       //WaitForFpgaDelayQueueIsEmpty(fpgasendQueueDelay);
+       AT91C_BASE_SSC->SSC_THR = 0xFF;         

 }      
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 }      
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what


@@ -496,8 +572,9 @@ void SimulateIso14443bTag(uint32_t pupi) {
 
        // ...PUPI/UID supplied from user. Adjust ATQB response accordingly
        if ( pupi > 0 ) {
 
        // ...PUPI/UID supplied from user. Adjust ATQB response accordingly
        if ( pupi > 0 ) {

+               uint8_t len = sizeof(respATQB);

                num_to_bytes(pupi, 4, respATQB+1);
                num_to_bytes(pupi, 4, respATQB+1);

-               ComputeCrc14443(CRC_14443_B, respATQB, 12, respATQB+13, respATQB+14);
+               ComputeCrc14443(CRC_14443_B, respATQB, 12, &respATQB[len-2], &respATQB[len-1]);

        }
 
        // prepare "ATQB" tag answer (encoded):
        }
 
        // prepare "ATQB" tag answer (encoded):


@@ -537,13 +614,10 @@ void SimulateIso14443bTag(uint32_t pupi) {
                // REQ or WUP request in ANY state 
                // WUP in HALTED state
                if (len == 5 ) {
                // REQ or WUP request in ANY state 
                // WUP in HALTED state
                if (len == 5 ) {

-                               if ( (receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8)== 0x8 && cardSTATE != SIM_HALTED) ||
-                    (receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8)== 0) ){
-                                       
-                               TransmitFor14443b_AsTag( encodedATQB, encodedATQBLen );
-                               LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, FALSE);
+                               if ( (receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8)== 0x8 && cardSTATE == SIM_HALTED) ||
+                     receivedCmd[0] == ISO14443B_REQB ){
+                               LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);                                             

                                cardSTATE = SIM_SELECTING;
                                cardSTATE = SIM_SELECTING;

-                               continue;

                        }
                }
                
                        }
                }
                


@@ -557,17 +631,17 @@ void SimulateIso14443bTag(uint32_t pupi) {
                    send halt response ( waiting for wupb )
                */
                
                    send halt response ( waiting for wupb )
                */
                

-               switch(cardSTATE){
+               switch (cardSTATE) {

                        case SIM_NOFIELD:
                        case SIM_HALTED:
                        case SIM_NOFIELD:
                        case SIM_HALTED:

-                       case SIM_IDLE:{
+                       case SIM_IDLE: {

                                LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);   
                                break;
                        }
                        case SIM_SELECTING: {
                                TransmitFor14443b_AsTag( encodedATQB, encodedATQBLen );
                                LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, FALSE);
                                LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);   
                                break;
                        }
                        case SIM_SELECTING: {
                                TransmitFor14443b_AsTag( encodedATQB, encodedATQBLen );
                                LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, FALSE);

-                               cardSTATE = SIM_IDLE;
+                               cardSTATE = SIM_WORK;

                                break;
                        }
                        case SIM_HALTING: {
                                break;
                        }
                        case SIM_HALTING: {


@@ -576,13 +650,13 @@ void SimulateIso14443bTag(uint32_t pupi) {
                                cardSTATE = SIM_HALTED;
                                break;
                        }
                                cardSTATE = SIM_HALTED;
                                break;
                        }

-                       case SIM_ACKNOWLEDGE:{
+                       case SIM_ACKNOWLEDGE: {

                                TransmitFor14443b_AsTag( encodedOK, encodedOKLen );
                                LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE);
                                cardSTATE = SIM_IDLE;                   
                                break;
                        }
                                TransmitFor14443b_AsTag( encodedOK, encodedOKLen );
                                LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE);
                                cardSTATE = SIM_IDLE;                   
                                break;
                        }

-                       case SIM_WORK:{
+                       case SIM_WORK: {

                                if ( len == 7 && receivedCmd[0] == ISO14443B_HALT ) {
                                        cardSTATE = SIM_HALTED;
                                } else if ( len == 11 && receivedCmd[0] == ISO14443B_ATTRIB ) {
                                if ( len == 7 && receivedCmd[0] == ISO14443B_HALT ) {
                                        cardSTATE = SIM_HALTED;
                                } else if ( len == 11 && receivedCmd[0] == ISO14443B_ATTRIB ) {


@@ -611,6 +685,7 @@ void SimulateIso14443bTag(uint32_t pupi) {
                }
                        
                ++cmdsReceived;
                }
                        
                ++cmdsReceived;

+               // iceman, could add a switch to turn this on/off (if off, no logging?)

                if(cmdsReceived > 1000) {
                        DbpString("14B Simulate, 1000 commands later...");
                        break;
                if(cmdsReceived > 1000) {
                        DbpString("14B Simulate, 1000 commands later...");
                        break;


@@ -641,12 +716,13 @@ void SimulateIso14443bTag(uint32_t pupi) {
  *          false if we are still waiting for some more
  *
  */
  *          false if we are still waiting for some more
  *
  */

+ // iceman, this threshold value,  what makes 8 a good amplituted for this IQ values? 

 #ifndef SUBCARRIER_DETECT_THRESHOLD
 #ifndef SUBCARRIER_DETECT_THRESHOLD

-# define SUBCARRIER_DETECT_THRESHOLD   8
+# define SUBCARRIER_DETECT_THRESHOLD   6

 #endif
 
 static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
 #endif
 
 static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {

-       int v=0;// , myI, myQ = 0;
+       int v = 0, myI = 0, myQ = 0;

 // 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() { \
 // 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() { \


@@ -664,7 +740,7 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
 
 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by 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)))
 
 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))

-#define CHECK_FOR_SUBCARRIER() { \
+#define CHECK_FOR_SUBCARRIER_old() { \

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


@@ -697,10 +773,10 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
        }
 
 //note: couldn't we just use MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2) from common.h - marshmellow
        }
 
 //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_un() { \
+#define CHECK_FOR_SUBCARRIER() { \

                myI = ABS(ci); \
                myQ = ABS(cq); \
                myI = ABS(ci); \
                myQ = ABS(cq); \

-               v = MAX(myI,myQ) + (MIN(myI,myQ) >> 1); \
+               v = MAX(myI, myQ) + (MIN(myI, myQ) >> 1); \

        }
 
        switch(Demod.state) {
        }
 
        switch(Demod.state) {


@@ -746,7 +822,7 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
                                Demod.posCount = 0;     // start of SOF sequence
                        } else {
                                // maximum length of TR1 = 200 1/fs
                                Demod.posCount = 0;     // start of SOF sequence
                        } else {
                                // maximum length of TR1 = 200 1/fs

-                               if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
+                               if(Demod.posCount > 26*2) Demod.state = DEMOD_UNSYNCD;

                        }
                        ++Demod.posCount;
                        break;
                        }
                        ++Demod.posCount;
                        break;


@@ -758,7 +834,7 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
                        
                        if(v > 0) {
                                // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
                        
                        if(v > 0) {
                                // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges

-                               if(Demod.posCount < 9*2) { 
+                               if(Demod.posCount < 8*2) { 

                                        Demod.state = DEMOD_UNSYNCD;
                                } else {
                                        LED_C_ON(); // Got SOF
                                        Demod.state = DEMOD_UNSYNCD;
                                } else {
                                        LED_C_ON(); // Got SOF


@@ -769,7 +845,7 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
                                }
                        } else {
                                // low phase of SOF too long (> 12 etu)
                                }
                        } else {
                                // low phase of SOF too long (> 12 etu)

-                               if (Demod.posCount > 12*2) { 
+                               if (Demod.posCount > 14*2) { 

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


@@ -782,7 +858,7 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
                        MAKE_SOFT_DECISION();
                        
                        if (v > 0) {
                        MAKE_SOFT_DECISION();
                        
                        if (v > 0) {

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


@@ -809,11 +885,12 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
                                Demod.shiftReg >>= 1;
 
                                // logic '1'
                                Demod.shiftReg >>= 1;
 
                                // logic '1'

-                               if(Demod.thisBit > 0)  Demod.shiftReg |= 0x200;
+                               if (Demod.thisBit > 0)  Demod.shiftReg |= 0x200;

 
                                ++Demod.bitCount;
                                
 
                                ++Demod.bitCount;
                                

-                               if(Demod.bitCount == 10) {
+                               // 1 start 8 data 1 stop = 10
+                               if (Demod.bitCount == 10) {

                                        
                                        uint16_t s = Demod.shiftReg;
                                        
                                        
                                        uint16_t s = Demod.shiftReg;
                                        


@@ -850,9 +927,9 @@ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
  *  quiet: set to 'TRUE' to disable debug output
  */
 static void GetTagSamplesFor14443bDemod() {
  *  quiet: set to 'TRUE' to disable debug output
  */
 static void GetTagSamplesFor14443bDemod() {

-       bool gotFrame = FALSE;
+       bool gotFrame = FALSE, finished = FALSE;

        int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
        int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;

-       int max = 0, ci = 0, cq = 0, samples = 0;
+       int ci = 0, cq = 0, samples = 0;

        uint32_t time_0 = 0, time_stop = 0;
 
        BigBuf_free();
        uint32_t time_0 = 0, time_stop = 0;
 
        BigBuf_free();


@@ -869,60 +946,59 @@ static void GetTagSamplesFor14443bDemod() {
                if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); 
                return;
        }
                if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); 
                return;
        }

-       
-       time_0 = GetCountSspClk();
-       
+

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

+
+       // get current clock
+       time_0 = GetCountSspClk();

        
        

-       while( !BUTTON_PRESS() ) {
-               WDT_HIT();
+       // rx counter - dma counter? (how much?) & (mod) mask > 2. (since 2bytes at the time is read)
+       while ( !finished ) {

 
 

-               int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
-               if(behindBy > max) max = behindBy;
+               LED_A_INV();
+               WDT_HIT();

 
 

-               // rx counter - dma counter? (how much?) & (mod) dma buff / 2.  (since 2bytes at the time is read)
-               while(((lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {
+               // LSB is a fpga signal bit.
+               ci = upTo[0] >> 1;
+               cq = upTo[1] >> 1;
+               upTo += 2;
+               samples += 2;

 
 

-                       ci = upTo[0];
-                       cq = upTo[1];
-                       upTo += 2;
-                       samples += 2;
-                       
-                       // restart DMA buffer to receive again.
-                       if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
-                               upTo = dmaBuf;
-                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
-                               AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
-                       }
-                       
-                       lastRxCounter -= 2;
-                       if(lastRxCounter <= 0)
-                               lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
+               lastRxCounter -= 2;

 
 

-                       // is this | 0x01 the error?   & 0xfe  in https://github.com/Proxmark/proxmark3/issues/103
-                       //gotFrame =  Handle14443bTagSamplesDemod(ci & 0xfe, cq & 0xfe);
-                       gotFrame =  Handle14443bTagSamplesDemod(ci, cq);
-                       if ( gotFrame ) break;
-                       LED_A_INV();
+               // restart DMA buffer to receive again.
+               if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
+                       upTo = dmaBuf;
+                       lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
+                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
+                       AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;

                }
 
                }
 

+               // https://github.com/Proxmark/proxmark3/issues/103
+               //gotFrame =  Handle14443bTagSamplesDemod(ci & 0xfe, cq & 0xfe);
+               gotFrame =  Handle14443bTagSamplesDemod(ci, cq);

                time_stop = GetCountSspClk() - time_0;
                time_stop = GetCountSspClk() - time_0;

-       
-               if(time_stop > iso14b_timeout || gotFrame)      break;
+
+               finished = (time_stop > iso14b_timeout || gotFrame);

        }
        
        FpgaDisableSscDma();
        }
        
        FpgaDisableSscDma();

-
+       
+       if ( upTo ) upTo = NULL;
+       

        if (MF_DBGLEVEL >= 3) {
        if (MF_DBGLEVEL >= 3) {

-               Dbprintf("max behindby = %d, samples = %d, gotFrame = %s, Demod.state = %d, Demod.len = %u",
-                       max,
-                       samples, 
-                       (gotFrame) ? "true" : "false", 
+               Dbprintf("Demod.state = %d, Demod.len = %u,  PDC_RCR = %u",     

                        Demod.state,
                        Demod.state,

-                       Demod.len
+                       Demod.len,
+                       AT91C_BASE_PDC_SSC->PDC_RCR

                );
        }
                );
        }

+       
+       // print the last batch of IQ values from FPGA
+       if (MF_DBGLEVEL == 4)
+               Dbhexdump(ISO14443B_DMA_BUFFER_SIZE, (uint8_t *)dmaBuf, FALSE); 
+       

        if ( Demod.len > 0 )
                LogTrace(Demod.output, Demod.len, Demod.startTime, Demod.endTime, NULL, FALSE);
 }
        if ( Demod.len > 0 )
                LogTrace(Demod.output, Demod.len, Demod.startTime, Demod.endTime, NULL, FALSE);
 }


@@ -933,29 +1009,47 @@ static void GetTagSamplesFor14443bDemod() {
 //-----------------------------------------------------------------------------
 static void TransmitFor14443b_AsReader(void) {
 
 //-----------------------------------------------------------------------------
 static void TransmitFor14443b_AsReader(void) {
 

-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
-       SpinDelay(20);
-       
-       int c;  

        // we could been in following mode:
        // FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ
        // if its second call or more
        // we could been in following mode:
        // FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ
        // if its second call or more

+       
+       // while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+               // AT91C_BASE_SSC->SSC_THR = 0XFF;
+       // }
+       
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
+       SpinDelay(40);

 
 

+       int c;  
+       volatile uint32_t b;
+                                                                                

        // What does this loop do? Is it TR1?
        // What does this loop do? Is it TR1?

-       for(c = 0; c < 10;) {
+       // 0xFF = 8 bits of 1.    1 bit == 1Etu,..  
+       // loop 10 * 8 = 80 ETU of delay, with a non modulated signal.  why?
+       // 80*9 = 720us.
+       for(c = 0; c < 50;) {

                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = 0xFF;
                        ++c;
                }
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = 0xFF;
                        ++c;
                }

+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                       b = AT91C_BASE_SSC->SSC_RHR;
+                       (void)b;
+               }

        }
        }

-       
+

        // Send frame loop
        for(c = 0; c < ToSendMax;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
        // Send frame loop
        for(c = 0; c < ToSendMax;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {

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

                }
                }

+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                       b = AT91C_BASE_SSC->SSC_RHR;
+                       (void)b;
+               }                                       

        }
        }

+       //WaitForFpgaDelayQueueIsEmpty(delay);
+       // We should wait here for the FPGA to send all bits.

        WDT_HIT();
 }
 
        WDT_HIT();
 }
 


@@ -975,6 +1069,9 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
        *
        *       1 ETU == 1 BIT!
        *   TR0 - 8 ETUS minimum.
        *
        *       1 ETU == 1 BIT!
        *   TR0 - 8 ETUS minimum.

+       *
+       *   QUESTION:  how long is a 1 or 0 in pulses in the xcorr_848 mode?
+       *              1 "stuffbit" = 1ETU (9us)

        */
        int i;
        uint8_t b;
        */
        int i;
        uint8_t b;


@@ -1021,7 +1118,8 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
        // Transition time. TR0 - guard time
        // 8ETUS minum?
        // Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF.        
        // Transition time. TR0 - guard time
        // 8ETUS minum?
        // Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF.        

-       for(i = 0; i < 40 ; ++i) ToSendStuffBit(1);
+       // I'm guessing this is for the FPGA to be able to send all bits before we switch to listening mode
+       for(i = 0; i < 32 ; ++i) ToSendStuffBit(1);

        
        // TR1 - Synchronization time
        // Convert from last character reference to length
        
        // TR1 - Synchronization time
        // Convert from last character reference to length


@@ -1189,12 +1287,13 @@ uint8_t iso14443b_select_card(iso14b_card_select_t *card )
                return 3;
        
        // CID
                return 3;
        
        // CID

-       if (card) card->cid = Demod.output[0];
-       
-       uint8_t fwt = card->atqb[6]>>4;
-       if ( fwt < 16 ){
-               uint32_t fwt_time = (302 << fwt);
-               iso14b_set_timeout( fwt_time);
+       if (card) { 
+               card->cid = Demod.output[0];
+               uint8_t fwt = card->atqb[6] >> 4;
+               if ( fwt < 16 ){
+                       uint32_t fwt_time = (302 << fwt);
+                       iso14b_set_timeout( fwt_time);
+               }

        }
        // reset PCB block number
        pcb_blocknum = 0;
        }
        // reset PCB block number
        pcb_blocknum = 0;


@@ -1420,16 +1519,13 @@ static void iso1444b_setup_snoop(void){
 void RAMFUNC SnoopIso14443b(void) {
 
        uint32_t time_0 = 0, time_start = 0, time_stop = 0;
 void RAMFUNC SnoopIso14443b(void) {
 
        uint32_t time_0 = 0, time_start = 0, time_stop = 0;

-       
+       int ci = 0, cq = 0;
+       int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
+

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

-       int triggered = TRUE;                   // TODO: set and evaluate trigger condition     
-       int ci, cq;
-       int maxBehindBy = 0;
-       //int behindBy  = 0;
-       int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
-       
+       bool triggered = TRUE;                  // TODO: set and evaluate trigger condition             

        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;
 
        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;
 


@@ -1452,40 +1548,25 @@ void RAMFUNC SnoopIso14443b(void) {
        for(;;) {
 
                WDT_HIT();
        for(;;) {
 
                WDT_HIT();

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

 
 

-               if ( behindBy > maxBehindBy )
-                       maxBehindBy = behindBy;
-               
-               if ( behindBy < 2 ) continue;
-               

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

-               upTo += 2;
-               
+               upTo += 2;              

                lastRxCounter -= 2;
                
                if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
                        upTo = dmaBuf;
                lastRxCounter -= 2;
                
                if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
                        upTo = dmaBuf;

-                       lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
+                       lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;

                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
                        AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
                        AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;

-                       WDT_HIT();
-                       
-                       // TODO: understand whether we can increase/decrease as we want or not?
-                       if ( behindBy > ( 9 * ISO14443B_DMA_BUFFER_SIZE/10) ) { 
-                               Dbprintf("blew circular buffer! behindBy=%d", behindBy);
-                               break;
-                       }
-                       
-                       if(!tracing) {
-                               DbpString("Trace full");
+               
+                       if (!tracing) {
+                               if (MF_DBGLEVEL >= 2) DbpString("Trace full");

                                break;
                        }
                                
                                break;
                        }
                                

-                       if(BUTTON_PRESS()) {
-                               DbpString("cancelled");
+                       if (BUTTON_PRESS()) {
+                               if (MF_DBGLEVEL >= 2) DbpString("cancelled");

                                break;
                        }
                }
                                break;
                        }
                }


@@ -1497,7 +1578,7 @@ void RAMFUNC SnoopIso14443b(void) {
                        // no need to try decoding reader data if the tag is sending
                        if (Handle14443bReaderUartBit(ci & 0x01)) {
 
                        // no need to try decoding reader data if the tag is sending
                        if (Handle14443bReaderUartBit(ci & 0x01)) {
 

-                               time_stop = (GetCountSspClk()-time_0);
+                               time_stop = GetCountSspClk() - time_0;

                                
                                if (triggered)
                                        LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
                                
                                if (triggered)
                                        LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);


@@ -1508,12 +1589,12 @@ void RAMFUNC SnoopIso14443b(void) {
                                /* false-triggered by the commands from the reader. */
                                DemodReset();
                        } else {
                                /* false-triggered by the commands from the reader. */
                                DemodReset();
                        } else {

-                               time_start = (GetCountSspClk()-time_0);
+                               time_start = GetCountSspClk() - time_0;

                        }
                        
                        if (Handle14443bReaderUartBit(cq & 0x01)) {
                                
                        }
                        
                        if (Handle14443bReaderUartBit(cq & 0x01)) {
                                

-                               time_stop = (GetCountSspClk()-time_0);
+                               time_stop = GetCountSspClk() - time_0;

                                
                                if (triggered)
                                        LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
                                
                                if (triggered)
                                        LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);


@@ -1524,18 +1605,19 @@ void RAMFUNC SnoopIso14443b(void) {
                                        /* false-triggered by the commands from the reader. */
                                        DemodReset();
                        } else {
                                        /* false-triggered by the commands from the reader. */
                                        DemodReset();
                        } else {

-                               time_start = (GetCountSspClk()-time_0);
+                               time_start = GetCountSspClk() - time_0;

                        }
                        ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                        LED_A_OFF();
                }
                
                        }
                        ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                        LED_A_OFF();
                }
                

-               if(!ReaderIsActive) {
+               if (!ReaderIsActive) {

                        // no need to try decoding tag data if the reader is sending - and we cannot afford the time
                        // is this | 0x01 the error?   & 0xfe  in https://github.com/Proxmark/proxmark3/issues/103
                        // no need to try decoding tag data if the reader is sending - and we cannot afford the time
                        // is this | 0x01 the error?   & 0xfe  in https://github.com/Proxmark/proxmark3/issues/103

-                       if(Handle14443bTagSamplesDemod(ci & 0xFE, cq & 0xFE)) {
+                       // LSB is a fpga signal bit.
+                       if (Handle14443bTagSamplesDemod(ci >> 1, cq >> 1)) {

                                
                                

-                               time_stop = (GetCountSspClk()-time_0);
+                               time_stop = GetCountSspClk() - time_0;

                                
                                LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, FALSE);
 
                                
                                LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, FALSE);
 


@@ -1544,7 +1626,7 @@ void RAMFUNC SnoopIso14443b(void) {
                                // And ready to receive another response.
                                DemodReset();
                        } else {
                                // And ready to receive another response.
                                DemodReset();
                        } else {

-                               time_start = (GetCountSspClk()-time_0);
+                               time_start = GetCountSspClk() - time_0;

                        }
                        TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);
                }
                        }
                        TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);
                }


@@ -1553,13 +1635,12 @@ void RAMFUNC SnoopIso14443b(void) {
        switch_off(); // Snoop
        
        DbpString("Snoop statistics:");
        switch_off(); // Snoop
        
        DbpString("Snoop statistics:");

-       Dbprintf("  Max behind by: %i", maxBehindBy);

        Dbprintf("  Uart State: %x  ByteCount: %i  ByteCountMax: %i", Uart.state,  Uart.byteCnt,  Uart.byteCntMax);
        Dbprintf("  Trace length: %i", BigBuf_get_traceLen());
 
        // free mem refs.
        Dbprintf("  Uart State: %x  ByteCount: %i  ByteCountMax: %i", Uart.state,  Uart.byteCnt,  Uart.byteCntMax);
        Dbprintf("  Trace length: %i", BigBuf_get_traceLen());
 
        // free mem refs.

-       if ( dmaBuf ) dmaBuf = NULL;
-       if ( upTo )   upTo = NULL;
+       if ( upTo ) upTo = NULL;
+       

        // Uart.byteCntMax  should be set with ATQB value..
 }
 
        // Uart.byteCntMax  should be set with ATQB value..
 }