]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - armsrc/iso14443a.c
hf mf mifare:
[proxmark3-svn] / armsrc / iso14443a.c
index f5348e77552e5329266950e449a305b152421123..0431876eca41eb756342de78d8a3e58a75711f78 100644 (file)
 #include "iso14443a.h"
 #include "crapto1.h"
 #include "mifareutil.h"
-
+#include "BigBuf.h"
 static uint32_t iso14a_timeout;
-uint8_t *trace = (uint8_t *) BigBuf+TRACE_OFFSET;
 int rsamples = 0;
-int traceLen = 0;
-int tracing = TRUE;
 uint8_t trigger = 0;
 // the block number for the ISO14443-4 PCB
 static uint8_t iso14_pcb_blocknum = 0;
@@ -144,23 +141,40 @@ const uint8_t OddByteParity[256] = {
   1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
 };
 
+
 void iso14a_set_trigger(bool enable) {
        trigger = enable;
 }
 
-void iso14a_clear_trace() {
-       memset(trace, 0x44, TRACE_SIZE);
-       traceLen = 0;
-}
-
-void iso14a_set_tracing(bool enable) {
-       tracing = enable;
-}
 
 void iso14a_set_timeout(uint32_t timeout) {
        iso14a_timeout = timeout;
+       if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
+}
+
+
+void iso14a_set_ATS_timeout(uint8_t *ats) {
+
+       uint8_t tb1;
+       uint8_t fwi; 
+       uint32_t fwt;
+       
+       if (ats[0] > 1) {                                                       // there is a format byte T0
+               if ((ats[1] & 0x20) == 0x20) {                  // there is an interface byte TB(1)
+                       if ((ats[1] & 0x10) == 0x10) {          // there is an interface byte TA(1) preceding TB(1)
+                               tb1 = ats[3];
+                       } else {
+                               tb1 = ats[2];
+                       }
+                       fwi = (tb1 & 0xf0) >> 4;                        // frame waiting indicator (FWI)
+                       fwt = 256 * 16 * (1 << fwi);            // frame waiting time (FWT) in 1/fc
+                       
+                       iso14a_set_timeout(fwt/(8*16));
+               }
+       }
 }
 
+
 //-----------------------------------------------------------------------------
 // Generate the parity value for a byte sequence
 //
@@ -199,7 +213,6 @@ void AppendCrc14443a(uint8_t* data, int len)
        ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
 }
 
-
 //=============================================================================
 // ISO 14443 Type A - Miller decoder
 //=============================================================================
@@ -254,26 +267,27 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
 
        Uart.twoBits = (Uart.twoBits << 8) | bit;
        
-       if (Uart.state == STATE_UNSYNCD) {                                                                                              // not yet synced
+       if (Uart.state == STATE_UNSYNCD) {                                                                                      // not yet synced
        
-               if (Uart.highCnt < 7) {                                                                                                 // wait for a stable unmodulated signal
+               if (Uart.highCnt < 2) {                                                                                                 // wait for a stable unmodulated signal
                        if (Uart.twoBits == 0xffff) {
                                Uart.highCnt++;
                        } else {
                                Uart.highCnt = 0;
                        }
                } else {        
-                       Uart.syncBit = 0xFFFF; // not set
-                       // look for 00xx1111 (the start bit)
-                       if              ((Uart.twoBits & 0x6780) == 0x0780) Uart.syncBit = 7; 
-                       else if ((Uart.twoBits & 0x33C0) == 0x03C0) Uart.syncBit = 6;
-                       else if ((Uart.twoBits & 0x19E0) == 0x01E0) Uart.syncBit = 5;
-                       else if ((Uart.twoBits & 0x0CF0) == 0x00F0) Uart.syncBit = 4;
-                       else if ((Uart.twoBits & 0x0678) == 0x0078) Uart.syncBit = 3;
-                       else if ((Uart.twoBits & 0x033C) == 0x003C) Uart.syncBit = 2;
-                       else if ((Uart.twoBits & 0x019E) == 0x001E) Uart.syncBit = 1;
-                       else if ((Uart.twoBits & 0x00CF) == 0x000F) Uart.syncBit = 0;
-                       if (Uart.syncBit != 0xFFFF) {
+                       Uart.syncBit = 0xFFFF;                                                                                          // not set
+                                                                                                                                                               // we look for a ...1111111100x11111xxxxxx pattern (the start bit)
+                       if              ((Uart.twoBits & 0xDF00) == 0x1F00) Uart.syncBit = 8;           // mask is   11x11111 xxxxxxxx, 
+                                                                                                                                                               // check for 00x11111 xxxxxxxx
+                       else if ((Uart.twoBits & 0xEF80) == 0x8F80) Uart.syncBit = 7;           // both masks shifted right one bit, left padded with '1'
+                       else if ((Uart.twoBits & 0xF7C0) == 0xC7C0) Uart.syncBit = 6;           // ...
+                       else if ((Uart.twoBits & 0xFBE0) == 0xE3E0) Uart.syncBit = 5;
+                       else if ((Uart.twoBits & 0xFDF0) == 0xF1F0) Uart.syncBit = 4;
+                       else if ((Uart.twoBits & 0xFEF8) == 0xF8F8) Uart.syncBit = 3;
+                       else if ((Uart.twoBits & 0xFF7C) == 0xFC7C) Uart.syncBit = 2;
+                       else if ((Uart.twoBits & 0xFFBE) == 0xFE3E) Uart.syncBit = 1;
+                       if (Uart.syncBit != 0xFFFF) {                                                                           // found a sync bit
                                Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
                                Uart.startTime -= Uart.syncBit;
                                Uart.endTime = Uart.startTime;
@@ -286,11 +300,9 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
                if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {                  
                        if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) {          // Modulation in both halves - error
                                UartReset();
-                               Uart.highCnt = 6;
                        } else {                                                                                                                        // Modulation in first half = Sequence Z = logic "0"
                                if (Uart.state == STATE_MILLER_X) {                                                             // error - must not follow after X
                                        UartReset();
-                                       Uart.highCnt = 6;
                                } else {
                                        Uart.bitCount++;
                                        Uart.shiftReg = (Uart.shiftReg >> 1);                                           // add a 0 to the shiftreg
@@ -345,12 +357,13 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
                                        if (Uart.len) {
                                                return TRUE;                                                                                    // we are finished with decoding the raw data sequence
                                        } else {
-                                               UartReset();                                    // Nothing receiver - start over
+                                               UartReset();                                                                                    // Nothing received - start over
+                                               Uart.highCnt = 1;
                                        }
                                }
                                if (Uart.state == STATE_START_OF_COMMUNICATION) {                               // error - must not follow directly after SOC
                                        UartReset();
-                                       Uart.highCnt = 6;
+                                       Uart.highCnt = 1;
                                } else {                                                                                                                // a logic "0"
                                        Uart.bitCount++;
                                        Uart.shiftReg = (Uart.shiftReg >> 1);                                           // add a 0 to the shiftreg
@@ -537,32 +550,28 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
        // bit 1 - trigger from first reader 7-bit request
        
        LEDsoff();
-       // init trace buffer
-       iso14a_clear_trace();
-       iso14a_set_tracing(TRUE);
 
-       // 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.
-       // triggered == FALSE -- to wait first for card
-       bool triggered = !(param & 0x03); 
-       
+       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
+       // Allocate memory from BigBuf for some buffers
+       // free all previous allocations first
+       BigBuf_free();
+
        // The command (reader -> tag) that we're receiving.
-       // The length of a received command will in most cases be no more than 18 bytes.
-       // So 32 should be enough!
-       uint8_t *receivedCmd = ((uint8_t *)BigBuf) + RECV_CMD_OFFSET;
-       uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
+       uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
+       uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
        
        // The response (tag -> reader) that we're receiving.
-       uint8_t *receivedResponse = ((uint8_t *)BigBuf) + RECV_RESP_OFFSET;
-       uint8_t *receivedResponsePar = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
-       
-       // As we receive stuff, we copy it from receivedCmd or receivedResponse
-       // into trace, along with its length and other annotations.
-       //uint8_t *trace = (uint8_t *)BigBuf;
+       uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
+       uint8_t *receivedResponsePar = BigBuf_malloc(MAX_PARITY_SIZE);
        
        // The DMA buffer, used to stream samples from the FPGA
-       uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+       uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
+
+       // init trace buffer
+       clear_trace();
+       set_tracing(TRUE);
+
        uint8_t *data = dmaBuf;
        uint8_t previous_data = 0;
        int maxDataLen = 0;
@@ -570,8 +579,6 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
        bool TagIsActive = FALSE;
        bool ReaderIsActive = FALSE;
        
-       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
        // Set up the demodulator for tag -> reader responses.
        DemodInit(receivedResponse, receivedResponsePar);
        
@@ -581,6 +588,12 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
        // Setup and start DMA.
        FpgaSetupSscDma((uint8_t *)dmaBuf, 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.
+       // triggered == FALSE -- to wait first for card
+       bool triggered = !(param & 0x03); 
+       
        // And now we loop, receiving samples.
        for(uint32_t rsamples = 0; TRUE; ) {
 
@@ -602,7 +615,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
                // test for length of buffer
                if(dataLen > maxDataLen) {
                        maxDataLen = dataLen;
-                       if(dataLen > 400) {
+                       if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
                                Dbprintf("blew circular buffer! dataLen=%d", dataLen);
                                break;
                        }
@@ -685,7 +698,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 
        FpgaDisableSscDma();
        Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
-       Dbprintf("traceLen=%d, Uart.output[0]=%08x", traceLen, (uint32_t)Uart.output[0]);
+       Dbprintf("traceLen=%d, Uart.output[0]=%08x", BigBuf_get_traceLen(), (uint32_t)Uart.output[0]);
        LEDsoff();
 }
 
@@ -831,7 +844,7 @@ int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par);
 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
                                 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity);
 
-static uint8_t* free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
+static uint8_t* free_buffer_pointer;
 
 typedef struct {
   uint8_t* response;
@@ -841,10 +854,6 @@ typedef struct {
   uint32_t ProxToAirDuration;
 } tag_response_info_t;
 
-void reset_free_buffer() {
-  free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
-}
-
 bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
        // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
        // This will need the following byte array for a modulation sequence
@@ -856,7 +865,8 @@ bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffe
        // ----------- +
        //    166 bytes, since every bit that needs to be send costs us a byte
        //
-  
   // Prepare the tag modulation bits from the message
   CodeIso14443aAsTag(response_info->response,response_info->response_n);
   
@@ -877,15 +887,22 @@ bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffe
   return true;
 }
 
+
+// "precompile" responses. There are 7 predefined responses with a total of 28 bytes data to transmit.
+// Coded responses need one byte per bit to transfer (data, parity, start, stop, correction) 
+// 28 * 8 data bits, 28 * 1 parity bits, 7 start bits, 7 stop bits, 7 correction bits
+// -> need 273 bytes buffer
+#define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 273
+
 bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
   // Retrieve and store the current buffer index
   response_info->modulation = free_buffer_pointer;
   
   // Determine the maximum size we can use from our buffer
-  size_t max_buffer_size = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + FREE_BUFFER_SIZE) - free_buffer_pointer;
+  size_t max_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE;
   
   // Forward the prepare tag modulation function to the inner function
-  if (prepare_tag_modulation(response_info,max_buffer_size)) {
+  if (prepare_tag_modulation(response_info, max_buffer_size)) {
     // Update the free buffer offset
     free_buffer_pointer += ToSendMax;
     return true;
@@ -900,10 +917,6 @@ bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
 //-----------------------------------------------------------------------------
 void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 {
-       // Enable and clear the trace
-       iso14a_clear_trace();
-       iso14a_set_tracing(TRUE);
-
        uint8_t sak;
 
        // The first response contains the ATQA (note: bytes are transmitted in reverse order).
@@ -947,10 +960,11 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
        }
        
        // The second response contains the (mandatory) first 24 bits of the UID
-       uint8_t response2[5];
+       uint8_t response2[5] = {0x00};
 
        // Check if the uid uses the (optional) part
-       uint8_t response2a[5];
+       uint8_t response2a[5] = {0x00};
+       
        if (uid_2nd) {
                response2[0] = 0x88;
                num_to_bytes(uid_1st,3,response2+1);
@@ -971,12 +985,12 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
        response2[4] = response2[0] ^ response2[1] ^ response2[2] ^ response2[3];
 
        // Prepare the mandatory SAK (for 4 and 7 byte UID)
-       uint8_t response3[3];
+       uint8_t response3[3]  = {0x00};
        response3[0] = sak;
        ComputeCrc14443(CRC_14443_A, response3, 1, &response3[1], &response3[2]);
 
        // Prepare the optional second SAK (for 7 byte UID), drop the cascade bit
-       uint8_t response3a[3];
+       uint8_t response3a[3]  = {0x00};
        response3a[0] = sak & 0xFB;
        ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
 
@@ -1012,9 +1026,20 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
                .modulation_n = 0
        };
   
-       // Reset the offset pointer of the free buffer
-       reset_free_buffer();
-  
+       // We need to listen to the high-frequency, peak-detected path.
+       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+       BigBuf_free_keep_EM();
+
+       // allocate buffers:
+       uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
+       uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
+       free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
+
+       // clear trace
+       clear_trace();
+       set_tracing(TRUE);
+
        // Prepare the responses of the anticollision phase
        // there will be not enough time to do this at the moment the reader sends it REQA
        for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
@@ -1032,20 +1057,12 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
        int happened2 = 0;
        int cmdsRecvd = 0;
 
-       // We need to listen to the high-frequency, peak-detected path.
-       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-       // buffers used on software Uart:
-       uint8_t *receivedCmd = ((uint8_t *)BigBuf) + RECV_CMD_OFFSET;
-       uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
-
        cmdsRecvd = 0;
        tag_response_info_t* p_response;
 
        LED_A_ON();
        for(;;) {
                // Clean receive command buffer
-               
                if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
                        DbpString("Button press");
                        break;
@@ -1199,6 +1216,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 
        Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
        LED_A_OFF();
+       BigBuf_free_keep_EM();
 }
 
 
@@ -1363,6 +1381,7 @@ void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *p
   CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
 }
 
+
 //-----------------------------------------------------------------------------
 // Wait for commands from reader
 // Stop when button is pressed (return 1) or field was gone (return 2)
@@ -1385,9 +1404,9 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
        // Set ADC to read field strength
        AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
        AT91C_BASE_ADC->ADC_MR =
-                               ADC_MODE_PRESCALE(32) |
-                               ADC_MODE_STARTUP_TIME(16) |
-                               ADC_MODE_SAMPLE_HOLD_TIME(8);
+                               ADC_MODE_PRESCALE(63) |
+                               ADC_MODE_STARTUP_TIME(1) |
+                               ADC_MODE_SAMPLE_HOLD_TIME(15);
        AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
        // start ADC
        AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
@@ -1397,7 +1416,7 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
 
        // Clear RXRDY:
     uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-
+       
        for(;;) {
                WDT_HIT();
 
@@ -1409,7 +1428,7 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
                        analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
                        AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
                        if (analogCnt >= 32) {
-                               if ((33000 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
+                               if ((MAX_ADC_HF_VOLTAGE * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
                                        vtime = GetTickCount();
                                        if (!timer) timer = vtime;
                                        // 50ms no field --> card to idle state
@@ -1472,7 +1491,7 @@ static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNe
        AT91C_BASE_SSC->SSC_THR = SEC_F;
 
        // send cycle
-       for(; i <= respLen; ) {
+       for(; i < respLen; ) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = resp[i++];
                        FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
@@ -1484,14 +1503,15 @@ static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNe
        }
 
        // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
-       for (i = 0; i < 2 ; ) {
+       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 = SEC_F;
                        FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                        i++;
                }
        }
-       
+
        LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
 
        return 0;
@@ -1593,7 +1613,7 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receive
 
        // clear RXRDY:
     uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-       
+
        c = 0;
        for(;;) {
                WDT_HIT();
@@ -1603,7 +1623,7 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receive
                        if(ManchesterDecoding(b, offset, 0)) {
                                NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
                                return TRUE;
-                       } else if (c++ > iso14a_timeout) {
+                       } else if (c++ > iso14a_timeout && Demod.state == DEMOD_UNSYNCD) {
                                return FALSE; 
                        }
                }
@@ -1672,8 +1692,8 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
        uint8_t sel_all[]    = { 0x93,0x20 };
        uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
        uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
-       uint8_t *resp = ((uint8_t *)BigBuf) + RECV_RESP_OFFSET;
-       uint8_t *resp_par = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
+       uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
+       uint8_t resp_par[MAX_PARITY_SIZE];
        byte_t uid_resp[4];
        size_t uid_resp_len;
 
@@ -1801,6 +1821,10 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 
        // reset the PCB block number
        iso14_pcb_blocknum = 0;
+
+       // set default timeout based on ATS
+       iso14a_set_ATS_timeout(resp);
+
        return 1;       
 }
 
@@ -1865,17 +1889,18 @@ void ReaderIso14443a(UsbCommand *c)
 {
        iso14a_command_t param = c->arg[0];
        uint8_t *cmd = c->d.asBytes;
-       size_t len = c->arg[1];
-       size_t lenbits = c->arg[2];
+       size_t len = c->arg[1] & 0xffff;
+       size_t lenbits = c->arg[1] >> 16;
+       uint32_t timeout = c->arg[2];
        uint32_t arg0 = 0;
        byte_t buf[USB_CMD_DATA_SIZE];
        uint8_t par[MAX_PARITY_SIZE];
   
        if(param & ISO14A_CONNECT) {
-               iso14a_clear_trace();
+               clear_trace();
        }
 
-       iso14a_set_tracing(TRUE);
+       set_tracing(TRUE);
 
        if(param & ISO14A_REQUEST_TRIGGER) {
                iso14a_set_trigger(TRUE);
@@ -1891,7 +1916,7 @@ void ReaderIso14443a(UsbCommand *c)
        }
 
        if(param & ISO14A_SET_TIMEOUT) {
-               iso14a_set_timeout(c->arg[2]);
+               iso14a_set_timeout(timeout);
        }
 
        if(param & ISO14A_APDU) {
@@ -1945,7 +1970,7 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
                nttmp1 = prng_successor(nttmp1, 1);
                if (nttmp1 == nt2) return i;
                nttmp2 = prng_successor(nttmp2, 1);
-                       if (nttmp2 == nt1) return -i;
+               if (nttmp2 == nt1) return -i;
                }
        
        return(-99999); // either nt1 or nt2 are invalid nonces
@@ -1965,11 +1990,18 @@ void ReaderMifare(bool first_try)
        uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
        static uint8_t mf_nr_ar3;
 
-       uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + RECV_RESP_OFFSET);
-       uint8_t* receivedAnswerPar = (((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET);
+       uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
+       uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
 
-       iso14a_clear_trace();
-       iso14a_set_tracing(TRUE);
+       if (first_try) { 
+               iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+       }
+       
+       // free eventually allocated BigBuf memory. We want all for tracing.
+       BigBuf_free();
+       
+       clear_trace();
+       set_tracing(TRUE);
 
        byte_t nt_diff = 0;
        uint8_t par[1] = {0};   // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
@@ -1984,6 +2016,7 @@ void ReaderMifare(bool first_try)
        byte_t par_list[8] = {0x00};
        byte_t ks_list[8] = {0x00};
 
+       #define PRNG_SEQUENCE_LENGTH  (1 << 16);
        static uint32_t sync_time;
        static uint32_t sync_cycles;
        int catch_up_cycles = 0;
@@ -1993,9 +2026,8 @@ void ReaderMifare(bool first_try)
 
        if (first_try) { 
                mf_nr_ar3 = 0;
-               iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
                sync_time = GetCountSspClk() & 0xfffffff8;
-               sync_cycles = 65536;                                                                    // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+               sync_cycles = PRNG_SEQUENCE_LENGTH;                                                     // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).
                nt_attacked = 0;
                nt = 0;
                par[0] = 0;
@@ -2011,33 +2043,44 @@ void ReaderMifare(bool first_try)
        LED_B_OFF();
        LED_C_OFF();
        
-  
+
+       #define MAX_UNEXPECTED_RANDOM   4               // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
+       #define MAX_SYNC_TRIES                  16
+       uint16_t unexpected_random = 0;
+       uint16_t sync_tries = 0;
+       int16_t debug_info_nr = -1;
+       uint32_t debug_info[MAX_SYNC_TRIES];
+       
        for(uint16_t i = 0; TRUE; i++) {
                
+               LED_C_ON();
                WDT_HIT();
 
                // Test if the action was cancelled
                if(BUTTON_PRESS()) {
+                       isOK = -1;
                        break;
                }
                
-               LED_C_ON();
-
                if(!iso14443a_select_card(uid, NULL, &cuid)) {
                        if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
                        continue;
                }
 
-               sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
-               catch_up_cycles = 0;
+               if (debug_info_nr == -1) {
+                       sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
+                       catch_up_cycles = 0;
 
-               // if we missed the sync time already, advance to the next nonce repeat
-               while(GetCountSspClk() > sync_time) {
-                       sync_time = (sync_time & 0xfffffff8) + sync_cycles;
-               }
+                       // if we missed the sync time already, advance to the next nonce repeat
+                       while(GetCountSspClk() > sync_time) {
+                               sync_time = (sync_time & 0xfffffff8) + sync_cycles;
+                       }
 
-               // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
-               ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+                       // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
+                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+               } else {
+                       ReaderTransmit(mf_auth, sizeof(mf_auth), NULL);
+               }                       
 
                // Receive the (4 Byte) "random" nonce
                if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
@@ -2055,13 +2098,32 @@ void ReaderMifare(bool first_try)
                        int nt_distance = dist_nt(previous_nt, nt);
                        if (nt_distance == 0) {
                                nt_attacked = nt;
-                       }
-                       else {
-                               if (nt_distance == -99999) { // invalid nonce received, try again
-                                       continue;
+                       } else {
+                               if (nt_distance == -99999) { // invalid nonce received
+                                       unexpected_random++;
+                                       if (!nt_attacked && unexpected_random > MAX_UNEXPECTED_RANDOM) {
+                                               isOK = -3;              // Card has an unpredictable PRNG. Give up      
+                                               break;
+                                       } else {
+                                               continue;               // continue trying...
+                                       }
+                               }
+                               if (++sync_tries > MAX_SYNC_TRIES) {
+                                       if (sync_tries > 2 * MAX_SYNC_TRIES) {
+                                               isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly
+                                               break;
+                                       } else {                                // continue for a while, just to collect some debug info
+                                               debug_info[++debug_info_nr] = nt_distance;
+                                               continue;
+                                       }
                                }
                                sync_cycles = (sync_cycles - nt_distance);
-                               if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+                               if (sync_cycles <= 0) {
+                                       sync_cycles += PRNG_SEQUENCE_LENGTH;
+                               }
+                               if (MF_DBGLEVEL >= 3) {
+                                       Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+                               }
                                continue;
                        }
                }
@@ -2120,6 +2182,10 @@ void ReaderMifare(bool first_try)
                        if (nt_diff == 0 && first_try)
                        {
                                par[0]++;
+                               if (par[0] == 0x00) {           // tried all 256 possible parities without success. Card doesn't send NACK.
+                                       isOK = -2;
+                                       break;
+                               }
                        } else {
                                par[0] = ((par[0] & 0x1F) + 1) | par_low;
                        }
@@ -2128,6 +2194,14 @@ void ReaderMifare(bool first_try)
 
 
        mf_nr_ar[3] &= 0x1F;
+
+       if (isOK == -4) {
+               if (MF_DBGLEVEL >= 3) {
+                       for(uint16_t i = 0; i < MAX_SYNC_TRIES; i++) {
+                               Dbprintf("collected debug info[%d] = %d\n", i, debug_info[i]);
+                       }
+               }
+       }
        
        byte_t buf[28];
        memcpy(buf + 0,  uid, 4);
@@ -2136,13 +2210,13 @@ void ReaderMifare(bool first_try)
        memcpy(buf + 16, ks_list, 8);
        memcpy(buf + 24, mf_nr_ar, 4);
                
-       cmd_send(CMD_ACK,isOK,0,0,buf,28);
+       cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
 
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
 
-       iso14a_set_tracing(FALSE);
+       set_tracing(FALSE);
 }
 
 /**
@@ -2177,10 +2251,10 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        struct Crypto1State *pcs;
        pcs = &mpcs;
        uint32_t numReads = 0;//Counts numer of times reader read a block
-       uint8_t* receivedCmd = get_bigbufptr_recvcmdbuf();
-       uint8_t* receivedCmd_par = receivedCmd + MAX_FRAME_SIZE;
-       uint8_t* response = get_bigbufptr_recvrespbuf();
-       uint8_t* response_par = response + MAX_FRAME_SIZE;
+       uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
+       uint8_t receivedCmd_par[MAX_MIFARE_PARITY_SIZE];
+       uint8_t response[MAX_MIFARE_FRAME_SIZE];
+       uint8_t response_par[MAX_MIFARE_PARITY_SIZE];
        
        uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
        uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
@@ -2197,10 +2271,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
        uint8_t ar_nr_collected = 0;
 
-       // clear trace
-    iso14a_clear_trace();
-       iso14a_set_tracing(TRUE);
-
        // Authenticate response - nonce
        uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
        
@@ -2238,13 +2308,10 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        if (_7BUID) {
                rATQA[0] = 0x44;
                rUIDBCC1[0] = 0x88;
+               rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
                rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
        }
 
-       // We need to listen to the high-frequency, peak-detected path.
-       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-
        if (MF_DBGLEVEL >= 1)   {
                if (!_7BUID) {
                        Dbprintf("4B UID: %02x%02x%02x%02x", 
@@ -2256,15 +2323,24 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                }
        }
 
+       // We need to listen to the high-frequency, peak-detected path.
+       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+       // free eventually allocated BigBuf memory but keep Emulator Memory
+       BigBuf_free_keep_EM();
+
+       // clear trace
+       clear_trace();
+       set_tracing(TRUE);
+
+
        bool finished = FALSE;
        while (!BUTTON_PRESS() && !finished) {
                WDT_HIT();
 
                // find reader field
-               // Vref = 3300mV, and an 10:1 voltage divider on the input
-               // can measure voltages up to 33000 mV
                if (cardSTATE == MFEMUL_NOFIELD) {
-                       vHf = (33000 * AvgAdc(ADC_CHAN_HF)) >> 10;
+                       vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
                        if (vHf > MF_MINFIELDV) {
                                cardSTATE_TO_IDLE();
                                LED_A_ON();
@@ -2339,6 +2415,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
                                        break;
                                }
+
                                uint32_t ar = bytes_to_num(receivedCmd, 4);
                                uint32_t nr = bytes_to_num(&receivedCmd[4], 4);
 
@@ -2445,6 +2522,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                                ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0); 
                                                num_to_bytes(ans, 4, rAUTH_AT);
                                        }
+
                                        EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
                                        //Dbprintf("Sending rAUTH %02x%02x%02x%02x", rAUTH_AT[0],rAUTH_AT[1],rAUTH_AT[2],rAUTH_AT[3]);
                                        cardSTATE = MFEMUL_AUTH1;
@@ -2477,13 +2555,13 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                                || receivedCmd[0] == 0xB0) { // transfer
                                        if (receivedCmd[1] >= 16 * 4) {
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-                                               if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
+                                               if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
                                                break;
                                        }
 
                                        if (receivedCmd[1] / 4 != cardAUTHSC) {
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-                                               if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
+                                               if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
                                                break;
                                        }
                                }
@@ -2625,7 +2703,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                if(ar_nr_collected > 1) {
                        Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
                        Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
-                                        ar_nr_responses[0], // UID
+                                       ar_nr_responses[0], // UID
                                        ar_nr_responses[1], //NT
                                        ar_nr_responses[2], //AR1
                                        ar_nr_responses[3], //NR1
@@ -2644,7 +2722,8 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                        }
                }
        }
-       if (MF_DBGLEVEL >= 1)   Dbprintf("Emulator stopped. Tracing: %d  trace length: %d ",    tracing, traceLen);
+       if (MF_DBGLEVEL >= 1)   Dbprintf("Emulator stopped. Tracing: %d  trace length: %d ",    tracing, BigBuf_get_traceLen());
+       
 }
 
 
@@ -2661,24 +2740,24 @@ void RAMFUNC SniffMifare(uint8_t param) {
        // C(red) A(yellow) B(green)
        LEDsoff();
        // init trace buffer
-       iso14a_clear_trace();
-       iso14a_set_tracing(TRUE);
+       clear_trace();
+       set_tracing(TRUE);
 
        // The command (reader -> tag) that we're receiving.
        // The length of a received command will in most cases be no more than 18 bytes.
        // So 32 should be enough!
-       uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
-       uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
+       uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
+       uint8_t receivedCmdPar[MAX_MIFARE_PARITY_SIZE];
        // The response (tag -> reader) that we're receiving.
-       uint8_t *receivedResponse = (((uint8_t *)BigBuf) + RECV_RESP_OFFSET);
-       uint8_t *receivedResponsePar = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
+       uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
+       uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
 
-       // As we receive stuff, we copy it from receivedCmd or receivedResponse
-       // into trace, along with its length and other annotations.
-       //uint8_t *trace = (uint8_t *)BigBuf;
-       
-       // The DMA buffer, used to stream samples from the FPGA
-       uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
+       // free eventually allocated BigBuf memory
+       BigBuf_free();
+       // allocate the DMA buffer, used to stream samples from the FPGA
+       uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
        uint8_t *data = dmaBuf;
        uint8_t previous_data = 0;
        int maxDataLen = 0;
@@ -2686,8 +2765,6 @@ void RAMFUNC SniffMifare(uint8_t param) {
        bool ReaderIsActive = FALSE;
        bool TagIsActive = FALSE;
 
-       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
        // Set up the demodulator for tag -> reader responses.
        DemodInit(receivedResponse, receivedResponsePar);
 
@@ -2737,7 +2814,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
                // test for length of buffer
                if(dataLen > maxDataLen) {                                      // we are more behind than ever...
                        maxDataLen = dataLen;                                   
-                       if(dataLen > 400) {
+                       if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
                                Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
                                break;
                        }
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