]> cvs.zerfleddert.de Git - proxmark3-svn/commitdiff
fix issue #103: revert type change. Samples from FPGA are signed.
authorpwpiwi <pwpiwi@users.noreply.github.com>
Tue, 2 Jun 2015 05:22:23 +0000 (07:22 +0200)
committerpwpiwi <pwpiwi@users.noreply.github.com>
Tue, 2 Jun 2015 05:28:47 +0000 (07:28 +0200)
Renamed iso14443.c to iso14443b.c

armsrc/Makefile
armsrc/iso14443.c [deleted file]
armsrc/iso14443b.c [new file with mode: 0644]

index 899b03075af35d1d51a0d61f318d1028959ae09f..502ab958c8aa3f6b3ab2ea35f3823122bcf4294c 100644 (file)
@@ -17,7 +17,7 @@ APP_CFLAGS    = -DWITH_LF -DWITH_ISO15693 -DWITH_ISO14443a -DWITH_ISO14443b -DWITH_
 SRC_LF = lfops.c hitag2.c lfsampling.c
 SRC_ISO15693 = iso15693.c iso15693tools.c
 SRC_ISO14443a = epa.c iso14443a.c mifareutil.c mifarecmd.c mifaresniff.c
-SRC_ISO14443b = iso14443.c
+SRC_ISO14443b = iso14443b.c
 SRC_CRAPTO1 = crapto1.c crypto1.c des.c aes.c 
 SRC_CRC = iso14443crc.c crc.c crc16.c crc32.c 
 
diff --git a/armsrc/iso14443.c b/armsrc/iso14443.c
deleted file mode 100644 (file)
index c202e31..0000000
+++ /dev/null
@@ -1,1245 +0,0 @@
-//-----------------------------------------------------------------------------
-// Jonathan Westhues, split Nov 2006
-//
-// This code is licensed to you under the terms of the GNU GPL, version 2 or,
-// at your option, any later version. See the LICENSE.txt file for the text of
-// 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.
-//-----------------------------------------------------------------------------
-
-#include "proxmark3.h"
-#include "apps.h"
-#include "util.h"
-#include "string.h"
-
-#include "iso14443crc.h"
-
-//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
-
-//=============================================================================
-// An ISO 14443 Type B tag. We listen for commands from the reader, using
-// a UART kind of thing that's implemented in software. When we get a
-// frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
-// If it's good, then we can do something appropriate with it, and send
-// a response.
-//=============================================================================
-
-//-----------------------------------------------------------------------------
-// Code up a string of octets at layer 2 (including CRC, we don't generate
-// that here) so that they can be transmitted to the reader. Doesn't transmit
-// them yet, just leaves them ready to send in ToSend[].
-//-----------------------------------------------------------------------------
-static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
-{
-       int i;
-
-       ToSendReset();
-
-       // Transmit a burst of ones, as the initial thing that lets the
-       // reader get phase sync. This (TR1) must be > 80/fs, per spec,
-       // but tag that I've tried (a Paypass) exceeds that by a fair bit,
-       // so I will too.
-       for(i = 0; i < 20; i++) {
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-       }
-
-       // Send SOF.
-       for(i = 0; i < 10; i++) {
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-       }
-       for(i = 0; i < 2; i++) {
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-       }
-
-       for(i = 0; i < len; i++) {
-               int j;
-               uint8_t b = cmd[i];
-
-               // Start bit
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-
-               // Data bits
-               for(j = 0; j < 8; j++) {
-                       if(b & 1) {
-                               ToSendStuffBit(1);
-                               ToSendStuffBit(1);
-                               ToSendStuffBit(1);
-                               ToSendStuffBit(1);
-                       } else {
-                               ToSendStuffBit(0);
-                               ToSendStuffBit(0);
-                               ToSendStuffBit(0);
-                               ToSendStuffBit(0);
-                       }
-                       b >>= 1;
-               }
-
-               // Stop bit
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-       }
-
-       // Send SOF.
-       for(i = 0; i < 10; i++) {
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-               ToSendStuffBit(0);
-       }
-       for(i = 0; i < 10; i++) {
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-       }
-
-       // Convert from last byte pos to length
-       ToSendMax++;
-
-       // Add a few more for slop
-       ToSendMax += 2;
-}
-
-//-----------------------------------------------------------------------------
-// The software UART that receives commands from the reader, and its state
-// variables.
-//-----------------------------------------------------------------------------
-static struct {
-       enum {
-               STATE_UNSYNCD,
-               STATE_GOT_FALLING_EDGE_OF_SOF,
-               STATE_AWAITING_START_BIT,
-               STATE_RECEIVING_DATA,
-               STATE_ERROR_WAIT
-       }       state;
-       uint16_t    shiftReg;
-       int     bitCnt;
-       int     byteCnt;
-       int     byteCntMax;
-       int     posCnt;
-       uint8_t   *output;
-} Uart;
-
-/* Receive & handle a bit coming from the reader.
- *
- * LED handling:
- * LED A -> ON once we have received the SOF and are expecting the rest.
- * LED A -> OFF once we have received EOF or are in error state or unsynced
- *
- * Returns: true if we received a EOF
- *          false if we are still waiting for some more
- */
-static int Handle14443UartBit(int bit)
-{
-       switch(Uart.state) {
-               case STATE_UNSYNCD:
-                       LED_A_OFF();
-                       if(!bit) {
-                               // we went low, so this could be the beginning
-                               // of an SOF
-                               Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
-                               Uart.posCnt = 0;
-                               Uart.bitCnt = 0;
-                       }
-                       break;
-
-               case STATE_GOT_FALLING_EDGE_OF_SOF:
-                       Uart.posCnt++;
-                       if(Uart.posCnt == 2) {
-                               if(bit) {
-                                       if(Uart.bitCnt >= 10) {
-                                               // we've seen enough consecutive
-                                               // zeros that it's a valid SOF
-                                               Uart.posCnt = 0;
-                                               Uart.byteCnt = 0;
-                                               Uart.state = STATE_AWAITING_START_BIT;
-                                               LED_A_ON(); // Indicate we got a valid SOF
-                                       } else {
-                                               // didn't stay down long enough
-                                               // before going high, error
-                                               Uart.state = STATE_ERROR_WAIT;
-                                       }
-                               } else {
-                                       // do nothing, keep waiting
-                               }
-                               Uart.bitCnt++;
-                       }
-                       if(Uart.posCnt >= 4) Uart.posCnt = 0;
-                       if(Uart.bitCnt > 14) {
-                               // Give up if we see too many zeros without
-                               // a one, too.
-                               Uart.state = STATE_ERROR_WAIT;
-                       }
-                       break;
-
-               case STATE_AWAITING_START_BIT:
-                       Uart.posCnt++;
-                       if(bit) {
-                               if(Uart.posCnt > 25) {
-                                       // stayed high for too long between
-                                       // characters, error
-                                       Uart.state = STATE_ERROR_WAIT;
-                               }
-                       } else {
-                               // falling edge, this starts the data byte
-                               Uart.posCnt = 0;
-                               Uart.bitCnt = 0;
-                               Uart.shiftReg = 0;
-                               Uart.state = STATE_RECEIVING_DATA;
-                               LED_A_ON(); // Indicate we're receiving
-                       }
-                       break;
-
-               case STATE_RECEIVING_DATA:
-                       Uart.posCnt++;
-                       if(Uart.posCnt == 2) {
-                               // time to sample a bit
-                               Uart.shiftReg >>= 1;
-                               if(bit) {
-                                       Uart.shiftReg |= 0x200;
-                               }
-                               Uart.bitCnt++;
-                       }
-                       if(Uart.posCnt >= 4) {
-                               Uart.posCnt = 0;
-                       }
-                       if(Uart.bitCnt == 10) {
-                               if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
-                               {
-                                       // this is a data byte, with correct
-                                       // start and stop bits
-                                       Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
-                                       Uart.byteCnt++;
-
-                                       if(Uart.byteCnt >= Uart.byteCntMax) {
-                                               // Buffer overflowed, give up
-                                               Uart.posCnt = 0;
-                                               Uart.state = STATE_ERROR_WAIT;
-                                       } else {
-                                               // so get the next byte now
-                                               Uart.posCnt = 0;
-                                               Uart.state = STATE_AWAITING_START_BIT;
-                                       }
-                               } else if(Uart.shiftReg == 0x000) {
-                                       // this is an EOF byte
-                                       LED_A_OFF(); // Finished receiving
-                                       return TRUE;
-                               } else {
-                                       // this is an error
-                                       Uart.posCnt = 0;
-                                       Uart.state = STATE_ERROR_WAIT;
-                               }
-                       }
-                       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;
-                       }
-                       break;
-
-               default:
-                       Uart.state = STATE_UNSYNCD;
-                       break;
-       }
-
-       // This row make the error blew circular buffer in hf 14b snoop
-       //if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
-
-       return FALSE;
-}
-
-//-----------------------------------------------------------------------------
-// Receive a command (from the reader to us, where we are the simulated tag),
-// and store it in the given buffer, up to the given maximum length. Keeps
-// spinning, waiting for a well-framed command, until either we get one
-// (returns TRUE) or someone presses the pushbutton on the board (FALSE).
-//
-// 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)
-{
-       uint8_t mask;
-       int i, bit;
-
-       // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
-       // only, since we are receiving, not transmitting).
-       // Signal field is off with the appropriate LED
-       LED_D_OFF();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
-
-
-       // Now run a `software UART' on the stream of incoming samples.
-       Uart.output = received;
-       Uart.byteCntMax = maxLen;
-       Uart.state = STATE_UNSYNCD;
-
-       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;
-
-                       mask = 0x80;
-                       for(i = 0; i < 8; i++, mask >>= 1) {
-                               bit = (b & mask);
-                               if(Handle14443UartBit(bit)) {
-                                       *len = Uart.byteCnt;
-                                       return TRUE;
-                               }
-                       }
-               }
-       }
-}
-
-//-----------------------------------------------------------------------------
-// Main loop of simulated tag: receive commands from reader, decide what
-// response to send, and send it.
-//-----------------------------------------------------------------------------
-void SimulateIso14443Tag(void)
-{
-       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-       static const uint8_t response1[] = {
-               0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
-               0x00, 0x21, 0x85, 0x5e, 0xd7
-       };
-
-       uint8_t *resp;
-       int respLen;
-
-       uint8_t *resp1 = BigBuf_get_addr() + 800;
-       int resp1Len;
-
-       uint8_t *receivedCmd = BigBuf_get_addr();
-       int len;
-
-       int i;
-
-       int cmdsRecvd = 0;
-
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-       memset(receivedCmd, 0x44, 400);
-
-       CodeIso14443bAsTag(response1, sizeof(response1));
-       memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
-
-       // We need to listen to the high-frequency, peak-detected path.
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-       FpgaSetupSsc();
-
-       cmdsRecvd = 0;
-
-       for(;;) {
-               uint8_t b1, b2;
-
-               if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {
-               Dbprintf("button pressed, received %d commands", cmdsRecvd);
-               break;
-               }
-
-               // Good, look at the command now.
-
-               if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {
-                       resp = resp1; respLen = resp1Len;
-               } else {
-                       Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
-                       // And print whether the CRC fails, just for good measure
-                       ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
-                       if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
-                               // Not so good, try again.
-                               DbpString("+++CRC fail");
-                       } else {
-                               DbpString("CRC passes");
-                       }
-                       break;
-               }
-
-               memset(receivedCmd, 0x44, 32);
-
-               cmdsRecvd++;
-
-               if(cmdsRecvd > 0x30) {
-                       DbpString("many commands later...");
-                       break;
-               }
-
-               if(respLen <= 0) continue;
-
-               // Modulate BPSK
-               // Signal field is off with the appropriate LED
-               LED_D_OFF();
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
-               AT91C_BASE_SSC->SSC_THR = 0xff;
-               FpgaSetupSsc();
-
-               // Transmit the response.
-               i = 0;
-               for(;;) {
-                       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;
-                               }
-                       }
-                       if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                               volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                               (void)b;
-                       }
-               }
-       }
-}
-
-//=============================================================================
-// An ISO 14443 Type B reader. We take layer two commands, code them
-// appropriately, and then send them to the tag. We then listen for the
-// tag's response, which we leave in the buffer to be demodulated on the
-// PC side.
-//=============================================================================
-
-static struct {
-       enum {
-               DEMOD_UNSYNCD,
-               DEMOD_PHASE_REF_TRAINING,
-               DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
-               DEMOD_GOT_FALLING_EDGE_OF_SOF,
-               DEMOD_AWAITING_START_BIT,
-               DEMOD_RECEIVING_DATA,
-               DEMOD_ERROR_WAIT
-       }       state;
-       int     bitCount;
-       int     posCount;
-       int     thisBit;
-       int     metric;
-       int     metricN;
-       uint16_t    shiftReg;
-       uint8_t   *output;
-       int     len;
-       int     sumI;
-       int     sumQ;
-} Demod;
-
-/*
- * Handles reception of a bit from the tag
- *
- * 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
- *
- * Returns: true if we received a EOF
- *          false if we are still waiting for some more
- *
- */
-static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
-{
-       int v;
-
-       // 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() { \
-               if(Demod.sumI > 0) { \
-                       v = ci; \
-               } else { \
-                       v = -ci; \
-               } \
-               if(Demod.sumQ > 0) { \
-                       v += cq; \
-               } else { \
-                       v -= cq; \
-               } \
-       }
-
-       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;
-                               Demod.state = DEMOD_PHASE_REF_TRAINING;
-                               Demod.sumI = 0;
-                               Demod.sumQ = 0;
-                       }
-                       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;
-                               }
-                       }
-                       Demod.posCount++;
-                       break;
-
-               case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
-                       MAKE_SOFT_DECISION();
-                       if(v < 0) {
-                               Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
-                               Demod.posCount = 0;
-                       } else {
-                               if(Demod.posCount > 100) {
-                                       Demod.state = DEMOD_UNSYNCD;
-                               }
-                       }
-                       Demod.posCount++;
-                       break;
-
-               case DEMOD_GOT_FALLING_EDGE_OF_SOF:
-                       MAKE_SOFT_DECISION();
-                       if(v > 0) {
-                               if(Demod.posCount < 12) {
-                                       Demod.state = DEMOD_UNSYNCD;
-                               } else {
-                                       LED_C_ON(); // Got SOF
-                                       Demod.state = DEMOD_AWAITING_START_BIT;
-                                       Demod.posCount = 0;
-                                       Demod.len = 0;
-                                       Demod.metricN = 0;
-                                       Demod.metric = 0;
-                               }
-                       } else {
-                               if(Demod.posCount > 100) {
-                                       Demod.state = DEMOD_UNSYNCD;
-                               }
-                       }
-                       Demod.posCount++;
-                       break;
-
-               case DEMOD_AWAITING_START_BIT:
-                       MAKE_SOFT_DECISION();
-                       if(v > 0) {
-                               if(Demod.posCount > 10) {
-                                       Demod.state = DEMOD_UNSYNCD;
-                               }
-                       } else {
-                               Demod.bitCount = 0;
-                               Demod.posCount = 1;
-                               Demod.thisBit = v;
-                               Demod.shiftReg = 0;
-                               Demod.state = DEMOD_RECEIVING_DATA;
-                       }
-                       break;
-
-               case DEMOD_RECEIVING_DATA:
-                       MAKE_SOFT_DECISION();
-                       if(Demod.posCount == 0) {
-                               Demod.thisBit = v;
-                               Demod.posCount = 1;
-                       } else {
-                               Demod.thisBit += v;
-
-                               if(Demod.thisBit > 0) {
-                                       Demod.metric += Demod.thisBit;
-                               } else {
-                                       Demod.metric -= Demod.thisBit;
-                               }
-                               (Demod.metricN)++;
-
-                               Demod.shiftReg >>= 1;
-                               if(Demod.thisBit > 0) {
-                                       Demod.shiftReg |= 0x200;
-                               }
-
-                               Demod.bitCount++;
-                               if(Demod.bitCount == 10) {
-                                       uint16_t s = Demod.shiftReg;
-                                       if((s & 0x200) && !(s & 0x001)) {
-                                               uint8_t b = (s >> 1);
-                                               Demod.output[Demod.len] = b;
-                                               Demod.len++;
-                                               Demod.state = DEMOD_AWAITING_START_BIT;
-                                       } else if(s == 0x000) {
-                                               // This is EOF
-                                               LED_C_OFF();
-                                               Demod.state = DEMOD_UNSYNCD;
-                                               return TRUE;
-                                       } else {
-                                               Demod.state = DEMOD_UNSYNCD;
-                                       }
-                               }
-                               Demod.posCount = 0;
-                       }
-                       break;
-
-               default:
-                       Demod.state = DEMOD_UNSYNCD;
-                       break;
-       }
-
-       if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized...
-       return FALSE;
-}
-static void DemodReset()
-{
-       // Clear out the state of the "UART" that receives from the tag.
-       Demod.len = 0;
-       Demod.state = DEMOD_UNSYNCD;
-       memset(Demod.output, 0x00, MAX_FRAME_SIZE);
-}
-static void DemodInit(uint8_t *data)
-{
-       Demod.output = data;
-       DemodReset();
-}
-
-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
- *  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
- */
-static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
-{
-       int max = 0;
-       int gotFrame = FALSE;
-       int lastRxCounter, ci, cq, samples = 0;
-
-       // Allocate memory from BigBuf for some buffers
-       // free all previous allocations first
-       BigBuf_free();
-       
-       // The response (tag -> reader) that we're receiving.
-       uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
-       
-       // The DMA buffer, used to stream samples from the FPGA
-       uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
-
-       // Set up the demodulator for tag -> reader responses.
-       DemodInit(receivedResponse);
-
-       // Setup and start DMA.
-       FpgaSetupSscDma(dmaBuf, DMA_BUFFER_SIZE);
-
-       uint8_t *upTo= dmaBuf;
-       lastRxCounter = DMA_BUFFER_SIZE;
-
-       // 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));
-
-       for(;;) {
-               int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
-               if(behindBy > max) max = behindBy;
-
-               while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (DMA_BUFFER_SIZE-1))
-                                       > 2)
-               {
-                       ci = upTo[0];
-                       cq = upTo[1];
-                       upTo += 2;
-                       if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
-                               upTo = dmaBuf;
-                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
-                               AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
-                       }
-                       lastRxCounter -= 2;
-                       if(lastRxCounter <= 0) {
-                               lastRxCounter += DMA_BUFFER_SIZE;
-                       }
-
-                       samples += 2;
-
-                       if(Handle14443SamplesDemod(ci, cq)) {
-                               gotFrame = 1;
-                       }
-               }
-
-               if(samples > n) {
-                       break;
-               }
-       }
-       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
-       if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
-       //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);
-       }
-}
-
-//-----------------------------------------------------------------------------
-// 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[].
-//-----------------------------------------------------------------------------
-static void TransmitFor14443(void)
-{
-       int c;
-
-       FpgaSetupSsc();
-
-       while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-               AT91C_BASE_SSC->SSC_THR = 0xff;
-       }
-
-       // Signal field is ON with the appropriate Red LED
-       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);
-
-       for(c = 0; c < 10;) {
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = 0xff;
-                       c++;
-               }
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
-                       (void)r;
-               }
-               WDT_HIT();
-       }
-
-       c = 0;
-       for(;;) {
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = ToSend[c];
-                       c++;
-                       if(c >= ToSendMax) {
-                               break;
-                       }
-               }
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
-                       (void)r;
-               }
-               WDT_HIT();
-       }
-       LED_B_OFF(); // Finished sending
-}
-
-//-----------------------------------------------------------------------------
-// Code a layer 2 command (string of octets, including CRC) into ToSend[],
-// so that it is ready to transmit to the tag using TransmitFor14443().
-//-----------------------------------------------------------------------------
-static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
-{
-       int i, j;
-       uint8_t b;
-
-       ToSendReset();
-
-       // Establish initial reference level
-       for(i = 0; i < 40; i++) {
-               ToSendStuffBit(1);
-       }
-       // Send SOF
-       for(i = 0; i < 10; i++) {
-               ToSendStuffBit(0);
-       }
-
-       for(i = 0; i < len; i++) {
-               // Stop bits/EGT
-               ToSendStuffBit(1);
-               ToSendStuffBit(1);
-               // Start bit
-               ToSendStuffBit(0);
-               // Data bits
-               b = cmd[i];
-               for(j = 0; j < 8; j++) {
-                       if(b & 1) {
-                               ToSendStuffBit(1);
-                       } else {
-                               ToSendStuffBit(0);
-                       }
-                       b >>= 1;
-               }
-       }
-       // Send EOF
-       ToSendStuffBit(1);
-       for(i = 0; i < 10; i++) {
-               ToSendStuffBit(0);
-       }
-       for(i = 0; i < 8; i++) {
-               ToSendStuffBit(1);
-       }
-
-       // And then a little more, to make sure that the last character makes
-       // it out before we switch to rx mode.
-       for(i = 0; i < 24; i++) {
-               ToSendStuffBit(1);
-       }
-
-       // Convert from last character reference to length
-       ToSendMax++;
-}
-
-//-----------------------------------------------------------------------------
-// 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);
-       TransmitFor14443();
-       if (tracing) {
-               uint8_t parity[MAX_PARITY_SIZE];
-               GetParity(cmd, len, parity);
-               LogTrace(cmd,len, 0, 0, parity, TRUE);
-       }
-}
-
-//-----------------------------------------------------------------------------
-// Read a SRI512 ISO 14443 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
-// we have a single tag in the field.
-//
-// I tried to be systematic and check every answer of the tag, every CRC, etc...
-//-----------------------------------------------------------------------------
-void ReadSTMemoryIso14443(uint32_t dwLast)
-{
-       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();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-       SpinDelay(200);
-
-       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);
-
-       // First command: wake up the tag using the INITIATE command
-       uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
-
-       CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-//    LED_A_ON();
-       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
-
-       if (Demod.len == 0) {
-       DbpString("No response from tag");
-       return;
-       } else {
-       Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
-               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));
-
-//    LED_A_ON();
-       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
-       if (Demod.len != 3) {
-       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]) {
-       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]) {
-       Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", 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
-
-//    LED_A_ON();
-       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
-       if (Demod.len != 10) {
-       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]);
-                  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]);
-       // 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]);
-
-       // Now loop to read all 16 blocks, address from 0 to last block
-       Dbprintf("Tag memory dump, block 0 to %d",dwLast);
-       cmd1[0] = 0x08;
-       i = 0x00;
-       dwLast++;
-       for (;;) {
-                  if (i == dwLast) {
-                       DbpString("System area block (0xff):");
-                       i = 0xff;
-               }
-               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();
-               if (Demod.len != 6) { // Check if we got an answer from the tag
-               DbpString("Expected 6 bytes from tag, got less...");
-               return;
-               }
-               // The check the CRC of the answer (use cmd1 as temporary variable):
-               ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
-                       if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
-               Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
-                       (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
-               // Do not return;, let's go on... (we should retry, maybe ?)
-               }
-               // Now print out the memory location:
-               Dbprintf("Address=%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]);
-               if (i == 0xff) {
-               break;
-               }
-               i++;
-       }
-}
-
-
-//=============================================================================
-// Finally, the `sniffer' combines elements from both the reader and
-// simulated tag, to show both sides of the conversation.
-//=============================================================================
-
-//-----------------------------------------------------------------------------
-// Record the sequence of commands sent by the reader to the tag, with
-// triggering so that we start recording at the point that the tag is moved
-// near the reader.
-//-----------------------------------------------------------------------------
-/*
- * Memory usage for this function, (within BigBuf)
- * 0-4095 : Demodulated samples receive (4096 bytes) - DEMOD_TRACE_SIZE
- * 4096-6143 : Last Received command, 2048 bytes (reader->tag) - READER_TAG_BUFFER_SIZE
- * 6144-8191 : Last Received command, 2048 bytes(tag->reader) - TAG_READER_BUFFER_SIZE
- * 8192-9215 : DMA Buffer, 1024 bytes (samples) - DEMOD_DMA_BUFFER_SIZE
- */
-void RAMFUNC SnoopIso14443(void)
-{
-       // We won't start recording the frames that we acquire until we trigger;
-       // a good trigger condition to get started is probably when we see a
-       // response from the tag.
-       int triggered = TRUE;
-
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-       BigBuf_free();
-
-       clear_trace();
-       set_tracing(TRUE);
-
-       // The DMA buffer, used to stream samples from the FPGA
-       uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
-       int lastRxCounter;
-       uint8_t *upTo;
-       int ci, cq;
-       int maxBehindBy = 0;
-
-       // Count of samples received so far, so that we can include timing
-       // information in the trace buffer.
-       int samples = 0;
-
-       DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
-       UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
-
-       // Print some debug information about the buffer sizes
-       Dbprintf("Snooping buffers initialized:");
-       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);
-
-       // Signal field is off with the appropriate LED
-       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 |
-               FPGA_HF_READER_RX_XCORR_SNOOP);
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
-       // Setup for the DMA.
-       FpgaSetupSsc();
-       upTo = dmaBuf;
-       lastRxCounter = DMA_BUFFER_SIZE;
-       FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
-       uint8_t parity[MAX_PARITY_SIZE];
-       LED_A_ON();
-               
-       // And now we loop, receiving samples.
-       for(;;) {
-               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
-                                                               (DMA_BUFFER_SIZE-1);
-               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(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
-                       upTo = dmaBuf;
-                       lastRxCounter += DMA_BUFFER_SIZE;
-                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
-                       AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
-               }
-
-               samples += 2;
-
-               if(Handle14443UartBit(ci & 1)) {
-                       if(triggered && tracing) {
-                               GetParity(Uart.output, Uart.byteCnt, parity);
-                               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();
-               }
-               if(Handle14443UartBit(cq & 1)) {
-                       if(triggered && tracing) {
-                               GetParity(Uart.output, Uart.byteCnt, parity);
-                               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();
-               }
-
-               if(Handle14443SamplesDemod(ci, cq)) {
-
-                       //Use samples as a time measurement
-                       if(tracing)
-                       {
-                               uint8_t parity[MAX_PARITY_SIZE];
-                               GetParity(Demod.output, Demod.len, parity);
-                               LogTrace(Demod.output,Demod.len,samples, samples,parity,FALSE);
-                       }
-                       triggered = TRUE;
-                       LED_A_OFF();
-                       LED_B_ON();
-
-                       // And ready to receive another response.
-                       DemodReset();
-               }
-               WDT_HIT();
-
-               if(!tracing) {
-                       DbpString("Reached trace limit");
-                       break;
-               }
-
-               if(BUTTON_PRESS()) {
-                       DbpString("cancelled");
-                       break;
-               }
-       }
-       FpgaDisableSscDma();
-       LED_A_OFF();
-       LED_B_OFF();
-       LED_C_OFF();
-       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
-       DbpString("Snoop statistics:");
-       Dbprintf("  Max behind by: %i", maxBehindBy);
-       Dbprintf("  Uart State: %x", Uart.state);
-       Dbprintf("  Uart ByteCnt: %i", Uart.byteCnt);
-       Dbprintf("  Uart ByteCntMax: %i", Uart.byteCntMax);
-       Dbprintf("  Trace length: %i", BigBuf_get_traceLen());
-}
-
-/*
- * Send raw command to tag ISO14443B
- * @Input
- * datalen     len of buffer data
- * recv        bool when true wait for data from tag and send to client
- * powerfield  bool leave the field on when true
- * data        buffer with byte to send
- *
- * @Output
- * none
- *
- */
-
-void SendRawCommand14443B(uint32_t datalen, uint32_t recv,uint8_t powerfield, uint8_t data[])
-{
-       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);
-
-       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(!powerfield)
-       {
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-               LED_D_OFF();
-       }
-}
-
diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
new file mode 100644 (file)
index 0000000..8add8f9
--- /dev/null
@@ -0,0 +1,1259 @@
+//-----------------------------------------------------------------------------
+// Jonathan Westhues, split Nov 2006
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// 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.
+//-----------------------------------------------------------------------------
+
+#include "proxmark3.h"
+#include "apps.h"
+#include "util.h"
+#include "string.h"
+
+#include "iso14443crc.h"
+
+//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
+
+//=============================================================================
+// An ISO 14443 Type B tag. We listen for commands from the reader, using
+// a UART kind of thing that's implemented in software. When we get a
+// frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
+// If it's good, then we can do something appropriate with it, and send
+// a response.
+//=============================================================================
+
+//-----------------------------------------------------------------------------
+// Code up a string of octets at layer 2 (including CRC, we don't generate
+// that here) so that they can be transmitted to the reader. Doesn't transmit
+// them yet, just leaves them ready to send in ToSend[].
+//-----------------------------------------------------------------------------
+static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
+{
+       int i;
+
+       ToSendReset();
+
+       // Transmit a burst of ones, as the initial thing that lets the
+       // reader get phase sync. This (TR1) must be > 80/fs, per spec,
+       // but tag that I've tried (a Paypass) exceeds that by a fair bit,
+       // so I will too.
+       for(i = 0; i < 20; i++) {
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+       }
+
+       // Send SOF.
+       for(i = 0; i < 10; i++) {
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+       }
+       for(i = 0; i < 2; i++) {
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+       }
+
+       for(i = 0; i < len; i++) {
+               int j;
+               uint8_t b = cmd[i];
+
+               // Start bit
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+
+               // Data bits
+               for(j = 0; j < 8; j++) {
+                       if(b & 1) {
+                               ToSendStuffBit(1);
+                               ToSendStuffBit(1);
+                               ToSendStuffBit(1);
+                               ToSendStuffBit(1);
+                       } else {
+                               ToSendStuffBit(0);
+                               ToSendStuffBit(0);
+                               ToSendStuffBit(0);
+                               ToSendStuffBit(0);
+                       }
+                       b >>= 1;
+               }
+
+               // Stop bit
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+       }
+
+       // Send SOF.
+       for(i = 0; i < 10; i++) {
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+               ToSendStuffBit(0);
+       }
+       for(i = 0; i < 10; i++) {
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+       }
+
+       // Convert from last byte pos to length
+       ToSendMax++;
+
+       // Add a few more for slop
+       ToSendMax += 2;
+}
+
+//-----------------------------------------------------------------------------
+// The software UART that receives commands from the reader, and its state
+// variables.
+//-----------------------------------------------------------------------------
+static struct {
+       enum {
+               STATE_UNSYNCD,
+               STATE_GOT_FALLING_EDGE_OF_SOF,
+               STATE_AWAITING_START_BIT,
+               STATE_RECEIVING_DATA,
+               STATE_ERROR_WAIT
+       }       state;
+       uint16_t    shiftReg;
+       int     bitCnt;
+       int     byteCnt;
+       int     byteCntMax;
+       int     posCnt;
+       uint8_t   *output;
+} Uart;
+
+/* Receive & handle a bit coming from the reader.
+ *
+ * LED handling:
+ * LED A -> ON once we have received the SOF and are expecting the rest.
+ * LED A -> OFF once we have received EOF or are in error state or unsynced
+ *
+ * Returns: true if we received a EOF
+ *          false if we are still waiting for some more
+ */
+static int Handle14443UartBit(int bit)
+{
+       switch(Uart.state) {
+               case STATE_UNSYNCD:
+                       LED_A_OFF();
+                       if(!bit) {
+                               // we went low, so this could be the beginning
+                               // of an SOF
+                               Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
+                               Uart.posCnt = 0;
+                               Uart.bitCnt = 0;
+                       }
+                       break;
+
+               case STATE_GOT_FALLING_EDGE_OF_SOF:
+                       Uart.posCnt++;
+                       if(Uart.posCnt == 2) {
+                               if(bit) {
+                                       if(Uart.bitCnt >= 10) {
+                                               // we've seen enough consecutive
+                                               // zeros that it's a valid SOF
+                                               Uart.posCnt = 0;
+                                               Uart.byteCnt = 0;
+                                               Uart.state = STATE_AWAITING_START_BIT;
+                                               LED_A_ON(); // Indicate we got a valid SOF
+                                       } else {
+                                               // didn't stay down long enough
+                                               // before going high, error
+                                               Uart.state = STATE_ERROR_WAIT;
+                                       }
+                               } else {
+                                       // do nothing, keep waiting
+                               }
+                               Uart.bitCnt++;
+                       }
+                       if(Uart.posCnt >= 4) Uart.posCnt = 0;
+                       if(Uart.bitCnt > 14) {
+                               // Give up if we see too many zeros without
+                               // a one, too.
+                               Uart.state = STATE_ERROR_WAIT;
+                       }
+                       break;
+
+               case STATE_AWAITING_START_BIT:
+                       Uart.posCnt++;
+                       if(bit) {
+                               if(Uart.posCnt > 25) {
+                                       // stayed high for too long between
+                                       // characters, error
+                                       Uart.state = STATE_ERROR_WAIT;
+                               }
+                       } else {
+                               // falling edge, this starts the data byte
+                               Uart.posCnt = 0;
+                               Uart.bitCnt = 0;
+                               Uart.shiftReg = 0;
+                               Uart.state = STATE_RECEIVING_DATA;
+                               LED_A_ON(); // Indicate we're receiving
+                       }
+                       break;
+
+               case STATE_RECEIVING_DATA:
+                       Uart.posCnt++;
+                       if(Uart.posCnt == 2) {
+                               // time to sample a bit
+                               Uart.shiftReg >>= 1;
+                               if(bit) {
+                                       Uart.shiftReg |= 0x200;
+                               }
+                               Uart.bitCnt++;
+                       }
+                       if(Uart.posCnt >= 4) {
+                               Uart.posCnt = 0;
+                       }
+                       if(Uart.bitCnt == 10) {
+                               if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
+                               {
+                                       // this is a data byte, with correct
+                                       // start and stop bits
+                                       Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
+                                       Uart.byteCnt++;
+
+                                       if(Uart.byteCnt >= Uart.byteCntMax) {
+                                               // Buffer overflowed, give up
+                                               Uart.posCnt = 0;
+                                               Uart.state = STATE_ERROR_WAIT;
+                                       } else {
+                                               // so get the next byte now
+                                               Uart.posCnt = 0;
+                                               Uart.state = STATE_AWAITING_START_BIT;
+                                       }
+                               } else if(Uart.shiftReg == 0x000) {
+                                       // this is an EOF byte
+                                       LED_A_OFF(); // Finished receiving
+                                       return TRUE;
+                               } else {
+                                       // this is an error
+                                       Uart.posCnt = 0;
+                                       Uart.state = STATE_ERROR_WAIT;
+                               }
+                       }
+                       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;
+                       }
+                       break;
+
+               default:
+                       Uart.state = STATE_UNSYNCD;
+                       break;
+       }
+
+       // This row make the error blew circular buffer in hf 14b snoop
+       //if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
+
+       return FALSE;
+}
+
+//-----------------------------------------------------------------------------
+// Receive a command (from the reader to us, where we are the simulated tag),
+// and store it in the given buffer, up to the given maximum length. Keeps
+// spinning, waiting for a well-framed command, until either we get one
+// (returns TRUE) or someone presses the pushbutton on the board (FALSE).
+//
+// 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)
+{
+       uint8_t mask;
+       int i, bit;
+
+       // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
+       // only, since we are receiving, not transmitting).
+       // Signal field is off with the appropriate LED
+       LED_D_OFF();
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
+
+
+       // Now run a `software UART' on the stream of incoming samples.
+       Uart.output = received;
+       Uart.byteCntMax = maxLen;
+       Uart.state = STATE_UNSYNCD;
+
+       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;
+
+                       mask = 0x80;
+                       for(i = 0; i < 8; i++, mask >>= 1) {
+                               bit = (b & mask);
+                               if(Handle14443UartBit(bit)) {
+                                       *len = Uart.byteCnt;
+                                       return TRUE;
+                               }
+                       }
+               }
+       }
+}
+
+//-----------------------------------------------------------------------------
+// Main loop of simulated tag: receive commands from reader, decide what
+// response to send, and send it.
+//-----------------------------------------------------------------------------
+void SimulateIso14443Tag(void)
+{
+       static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
+       static const uint8_t response1[] = {
+               0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
+               0x00, 0x21, 0x85, 0x5e, 0xd7
+       };
+
+       uint8_t *resp;
+       int respLen;
+
+       uint8_t *resp1 = BigBuf_get_addr() + 800;
+       int resp1Len;
+
+       uint8_t *receivedCmd = BigBuf_get_addr();
+       int len;
+
+       int i;
+
+       int cmdsRecvd = 0;
+
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+       memset(receivedCmd, 0x44, 400);
+
+       CodeIso14443bAsTag(response1, sizeof(response1));
+       memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
+
+       // We need to listen to the high-frequency, peak-detected path.
+       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+       FpgaSetupSsc();
+
+       cmdsRecvd = 0;
+
+       for(;;) {
+               uint8_t b1, b2;
+
+               if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {
+               Dbprintf("button pressed, received %d commands", cmdsRecvd);
+               break;
+               }
+
+               // Good, look at the command now.
+
+               if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {
+                       resp = resp1; respLen = resp1Len;
+               } else {
+                       Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
+                       // And print whether the CRC fails, just for good measure
+                       ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
+                       if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
+                               // Not so good, try again.
+                               DbpString("+++CRC fail");
+                       } else {
+                               DbpString("CRC passes");
+                       }
+                       break;
+               }
+
+               memset(receivedCmd, 0x44, 32);
+
+               cmdsRecvd++;
+
+               if(cmdsRecvd > 0x30) {
+                       DbpString("many commands later...");
+                       break;
+               }
+
+               if(respLen <= 0) continue;
+
+               // Modulate BPSK
+               // Signal field is off with the appropriate LED
+               LED_D_OFF();
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
+               AT91C_BASE_SSC->SSC_THR = 0xff;
+               FpgaSetupSsc();
+
+               // Transmit the response.
+               i = 0;
+               for(;;) {
+                       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;
+                               }
+                       }
+                       if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                               volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+                               (void)b;
+                       }
+               }
+       }
+}
+
+//=============================================================================
+// An ISO 14443 Type B reader. We take layer two commands, code them
+// appropriately, and then send them to the tag. We then listen for the
+// tag's response, which we leave in the buffer to be demodulated on the
+// PC side.
+//=============================================================================
+
+static struct {
+       enum {
+               DEMOD_UNSYNCD,
+               DEMOD_PHASE_REF_TRAINING,
+               DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
+               DEMOD_GOT_FALLING_EDGE_OF_SOF,
+               DEMOD_AWAITING_START_BIT,
+               DEMOD_RECEIVING_DATA,
+               DEMOD_ERROR_WAIT
+       }       state;
+       int     bitCount;
+       int     posCount;
+       int     thisBit;
+       int     metric;
+       int     metricN;
+       uint16_t    shiftReg;
+       uint8_t   *output;
+       int     len;
+       int     sumI;
+       int     sumQ;
+} Demod;
+
+/*
+ * Handles reception of a bit from the tag
+ *
+ * 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
+ *
+ * Returns: true if we received a EOF
+ *          false if we are still waiting for some more
+ *
+ */
+static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
+{
+       int v;
+
+       // 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() { \
+               if(Demod.sumI > 0) { \
+                       v = ci; \
+               } else { \
+                       v = -ci; \
+               } \
+               if(Demod.sumQ > 0) { \
+                       v += cq; \
+               } else { \
+                       v -= cq; \
+               } \
+       }
+
+       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;
+                               Demod.state = DEMOD_PHASE_REF_TRAINING;
+                               Demod.sumI = 0;
+                               Demod.sumQ = 0;
+                       }
+                       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;
+                               }
+                       }
+                       Demod.posCount++;
+                       break;
+
+               case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
+                       MAKE_SOFT_DECISION();
+                       if(v < 0) {
+                               Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
+                               Demod.posCount = 0;
+                       } else {
+                               if(Demod.posCount > 100) {
+                                       Demod.state = DEMOD_UNSYNCD;
+                               }
+                       }
+                       Demod.posCount++;
+                       break;
+
+               case DEMOD_GOT_FALLING_EDGE_OF_SOF:
+                       MAKE_SOFT_DECISION();
+                       if(v > 0) {
+                               if(Demod.posCount < 12) {
+                                       Demod.state = DEMOD_UNSYNCD;
+                               } else {
+                                       LED_C_ON(); // Got SOF
+                                       Demod.state = DEMOD_AWAITING_START_BIT;
+                                       Demod.posCount = 0;
+                                       Demod.len = 0;
+                                       Demod.metricN = 0;
+                                       Demod.metric = 0;
+                               }
+                       } else {
+                               if(Demod.posCount > 100) {
+                                       Demod.state = DEMOD_UNSYNCD;
+                               }
+                       }
+                       Demod.posCount++;
+                       break;
+
+               case DEMOD_AWAITING_START_BIT:
+                       MAKE_SOFT_DECISION();
+                       if(v > 0) {
+                               if(Demod.posCount > 10) {
+                                       Demod.state = DEMOD_UNSYNCD;
+                               }
+                       } else {
+                               Demod.bitCount = 0;
+                               Demod.posCount = 1;
+                               Demod.thisBit = v;
+                               Demod.shiftReg = 0;
+                               Demod.state = DEMOD_RECEIVING_DATA;
+                       }
+                       break;
+
+               case DEMOD_RECEIVING_DATA:
+                       MAKE_SOFT_DECISION();
+                       if(Demod.posCount == 0) {
+                               Demod.thisBit = v;
+                               Demod.posCount = 1;
+                       } else {
+                               Demod.thisBit += v;
+
+                               if(Demod.thisBit > 0) {
+                                       Demod.metric += Demod.thisBit;
+                               } else {
+                                       Demod.metric -= Demod.thisBit;
+                               }
+                               (Demod.metricN)++;
+
+                               Demod.shiftReg >>= 1;
+                               if(Demod.thisBit > 0) {
+                                       Demod.shiftReg |= 0x200;
+                               }
+
+                               Demod.bitCount++;
+                               if(Demod.bitCount == 10) {
+                                       uint16_t s = Demod.shiftReg;
+                                       if((s & 0x200) && !(s & 0x001)) {
+                                               uint8_t b = (s >> 1);
+                                               Demod.output[Demod.len] = b;
+                                               Demod.len++;
+                                               Demod.state = DEMOD_AWAITING_START_BIT;
+                                       } else if(s == 0x000) {
+                                               // This is EOF
+                                               LED_C_OFF();
+                                               Demod.state = DEMOD_UNSYNCD;
+                                               return TRUE;
+                                       } else {
+                                               Demod.state = DEMOD_UNSYNCD;
+                                       }
+                               }
+                               Demod.posCount = 0;
+                       }
+                       break;
+
+               default:
+                       Demod.state = DEMOD_UNSYNCD;
+                       break;
+       }
+
+       if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized...
+       return FALSE;
+}
+
+
+static void DemodReset()
+{
+       // Clear out the state of the "UART" that receives from the tag.
+       Demod.len = 0;
+       Demod.state = DEMOD_UNSYNCD;
+       memset(Demod.output, 0x00, MAX_FRAME_SIZE);
+}
+
+
+static void DemodInit(uint8_t *data)
+{
+       Demod.output = data;
+       DemodReset();
+}
+
+
+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
+ *  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
+ */
+static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
+{
+       int max = 0;
+       int gotFrame = FALSE;
+       int lastRxCounter, ci, cq, samples = 0;
+
+       // Allocate memory from BigBuf for some buffers
+       // free all previous allocations first
+       BigBuf_free();
+       
+       // The response (tag -> reader) that we're receiving.
+       uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
+       
+       // The 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);
+
+       // Setup and start DMA.
+       FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
+
+       int8_t *upTo = dmaBuf;
+       lastRxCounter = DMA_BUFFER_SIZE;
+
+       // 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));
+
+       for(;;) {
+               int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
+               if(behindBy > max) max = behindBy;
+
+               while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (DMA_BUFFER_SIZE-1))
+                                       > 2)
+               {
+                       ci = upTo[0];
+                       cq = upTo[1];
+                       upTo += 2;
+                       if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
+                               upTo = dmaBuf;
+                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
+                               AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
+                       }
+                       lastRxCounter -= 2;
+                       if(lastRxCounter <= 0) {
+                               lastRxCounter += DMA_BUFFER_SIZE;
+                       }
+
+                       samples += 2;
+
+                       if(Handle14443SamplesDemod(ci, cq)) {
+                               gotFrame = 1;
+                       }
+               }
+
+               if(samples > n) {
+                       break;
+               }
+       }
+       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
+       if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
+       //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);
+       }
+}
+
+
+//-----------------------------------------------------------------------------
+// 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[].
+//-----------------------------------------------------------------------------
+static void TransmitFor14443(void)
+{
+       int c;
+
+       FpgaSetupSsc();
+
+       while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+               AT91C_BASE_SSC->SSC_THR = 0xff;
+       }
+
+       // Signal field is ON with the appropriate Red LED
+       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);
+
+       for(c = 0; c < 10;) {
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       AT91C_BASE_SSC->SSC_THR = 0xff;
+                       c++;
+               }
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                       volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
+                       (void)r;
+               }
+               WDT_HIT();
+       }
+
+       c = 0;
+       for(;;) {
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       AT91C_BASE_SSC->SSC_THR = ToSend[c];
+                       c++;
+                       if(c >= ToSendMax) {
+                               break;
+                       }
+               }
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+                       volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
+                       (void)r;
+               }
+               WDT_HIT();
+       }
+       LED_B_OFF(); // Finished sending
+}
+
+
+//-----------------------------------------------------------------------------
+// Code a layer 2 command (string of octets, including CRC) into ToSend[],
+// so that it is ready to transmit to the tag using TransmitFor14443().
+//-----------------------------------------------------------------------------
+static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
+{
+       int i, j;
+       uint8_t b;
+
+       ToSendReset();
+
+       // Establish initial reference level
+       for(i = 0; i < 40; i++) {
+               ToSendStuffBit(1);
+       }
+       // Send SOF
+       for(i = 0; i < 10; i++) {
+               ToSendStuffBit(0);
+       }
+
+       for(i = 0; i < len; i++) {
+               // Stop bits/EGT
+               ToSendStuffBit(1);
+               ToSendStuffBit(1);
+               // Start bit
+               ToSendStuffBit(0);
+               // Data bits
+               b = cmd[i];
+               for(j = 0; j < 8; j++) {
+                       if(b & 1) {
+                               ToSendStuffBit(1);
+                       } else {
+                               ToSendStuffBit(0);
+                       }
+                       b >>= 1;
+               }
+       }
+       // Send EOF
+       ToSendStuffBit(1);
+       for(i = 0; i < 10; i++) {
+               ToSendStuffBit(0);
+       }
+       for(i = 0; i < 8; i++) {
+               ToSendStuffBit(1);
+       }
+
+       // And then a little more, to make sure that the last character makes
+       // it out before we switch to rx mode.
+       for(i = 0; i < 24; i++) {
+               ToSendStuffBit(1);
+       }
+
+       // Convert from last character reference to length
+       ToSendMax++;
+}
+
+
+//-----------------------------------------------------------------------------
+// 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);
+       TransmitFor14443();
+       if (tracing) {
+               uint8_t parity[MAX_PARITY_SIZE];
+               GetParity(cmd, len, parity);
+               LogTrace(cmd,len, 0, 0, parity, TRUE);
+       }
+}
+
+
+//-----------------------------------------------------------------------------
+// Read a SRI512 ISO 14443 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
+// we have a single tag in the field.
+//
+// I tried to be systematic and check every answer of the tag, every CRC, etc...
+//-----------------------------------------------------------------------------
+void ReadSTMemoryIso14443(uint32_t dwLast)
+{
+       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();
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+       SpinDelay(200);
+
+       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);
+
+       // First command: wake up the tag using the INITIATE command
+       uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
+
+       CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
+//    LED_A_ON();
+       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
+//    LED_A_OFF();
+
+       if (Demod.len == 0) {
+       DbpString("No response from tag");
+       return;
+       } else {
+       Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
+               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));
+
+//    LED_A_ON();
+       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
+//    LED_A_OFF();
+       if (Demod.len != 3) {
+       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]) {
+       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]) {
+       Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", 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
+
+//    LED_A_ON();
+       GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
+//    LED_A_OFF();
+       if (Demod.len != 10) {
+       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]);
+                  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]);
+       // 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]);
+
+       // Now loop to read all 16 blocks, address from 0 to last block
+       Dbprintf("Tag memory dump, block 0 to %d",dwLast);
+       cmd1[0] = 0x08;
+       i = 0x00;
+       dwLast++;
+       for (;;) {
+                  if (i == dwLast) {
+                       DbpString("System area block (0xff):");
+                       i = 0xff;
+               }
+               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();
+               if (Demod.len != 6) { // Check if we got an answer from the tag
+               DbpString("Expected 6 bytes from tag, got less...");
+               return;
+               }
+               // The check the CRC of the answer (use cmd1 as temporary variable):
+               ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
+                       if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
+               Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
+                       (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
+               // Do not return;, let's go on... (we should retry, maybe ?)
+               }
+               // Now print out the memory location:
+               Dbprintf("Address=%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]);
+               if (i == 0xff) {
+               break;
+               }
+               i++;
+       }
+}
+
+
+//=============================================================================
+// Finally, the `sniffer' combines elements from both the reader and
+// simulated tag, to show both sides of the conversation.
+//=============================================================================
+
+//-----------------------------------------------------------------------------
+// Record the sequence of commands sent by the reader to the tag, with
+// triggering so that we start recording at the point that the tag is moved
+// near the reader.
+//-----------------------------------------------------------------------------
+/*
+ * Memory usage for this function, (within BigBuf)
+ * 0-4095 : Demodulated samples receive (4096 bytes) - DEMOD_TRACE_SIZE
+ * 4096-6143 : Last Received command, 2048 bytes (reader->tag) - READER_TAG_BUFFER_SIZE
+ * 6144-8191 : Last Received command, 2048 bytes(tag->reader) - TAG_READER_BUFFER_SIZE
+ * 8192-9215 : DMA Buffer, 1024 bytes (samples) - DEMOD_DMA_BUFFER_SIZE
+ */
+void RAMFUNC SnoopIso14443(void)
+{
+       // We won't start recording the frames that we acquire until we trigger;
+       // a good trigger condition to get started is probably when we see a
+       // response from the tag.
+       int triggered = TRUE;
+
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+       BigBuf_free();
+
+       clear_trace();
+       set_tracing(TRUE);
+
+       // The DMA buffer, used to stream samples from the FPGA
+       int8_t *dmaBuf = (int8_t*) BigBuf_malloc(DMA_BUFFER_SIZE);
+       int lastRxCounter;
+       int8_t *upTo;
+       int ci, cq;
+       int maxBehindBy = 0;
+
+       // Count of samples received so far, so that we can include timing
+       // information in the trace buffer.
+       int samples = 0;
+
+       DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
+       UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
+
+       // Print some debug information about the buffer sizes
+       Dbprintf("Snooping buffers initialized:");
+       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);
+
+       // Signal field is off with the appropriate LED
+       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 |
+               FPGA_HF_READER_RX_XCORR_SNOOP);
+       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+
+       // Setup for the DMA.
+       FpgaSetupSsc();
+       upTo = dmaBuf;
+       lastRxCounter = DMA_BUFFER_SIZE;
+       FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
+       uint8_t parity[MAX_PARITY_SIZE];
+       LED_A_ON();
+               
+       // And now we loop, receiving samples.
+       for(;;) {
+               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
+                                                               (DMA_BUFFER_SIZE-1);
+               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(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
+                       upTo = dmaBuf;
+                       lastRxCounter += DMA_BUFFER_SIZE;
+                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
+                       AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
+               }
+
+               samples += 2;
+
+               if(Handle14443UartBit(ci & 1)) {
+                       if(triggered && tracing) {
+                               GetParity(Uart.output, Uart.byteCnt, parity);
+                               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();
+               }
+               if(Handle14443UartBit(cq & 1)) {
+                       if(triggered && tracing) {
+                               GetParity(Uart.output, Uart.byteCnt, parity);
+                               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();
+               }
+
+               if(Handle14443SamplesDemod(ci, cq)) {
+
+                       //Use samples as a time measurement
+                       if(tracing)
+                       {
+                               uint8_t parity[MAX_PARITY_SIZE];
+                               GetParity(Demod.output, Demod.len, parity);
+                               LogTrace(Demod.output, Demod.len,samples, samples, parity, FALSE);
+                       }
+                       triggered = TRUE;
+                       LED_A_OFF();
+                       LED_B_ON();
+
+                       // And ready to receive another response.
+                       DemodReset();
+               }
+               WDT_HIT();
+
+               if(!tracing) {
+                       DbpString("Reached trace limit");
+                       break;
+               }
+
+               if(BUTTON_PRESS()) {
+                       DbpString("cancelled");
+                       break;
+               }
+       }
+       FpgaDisableSscDma();
+       LED_A_OFF();
+       LED_B_OFF();
+       LED_C_OFF();
+       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
+       DbpString("Snoop statistics:");
+       Dbprintf("  Max behind by: %i", maxBehindBy);
+       Dbprintf("  Uart State: %x", Uart.state);
+       Dbprintf("  Uart ByteCnt: %i", Uart.byteCnt);
+       Dbprintf("  Uart ByteCntMax: %i", Uart.byteCntMax);
+       Dbprintf("  Trace length: %i", BigBuf_get_traceLen());
+}
+
+
+/*
+ * Send raw command to tag ISO14443B
+ * @Input
+ * datalen     len of buffer data
+ * recv        bool when true wait for data from tag and send to client
+ * powerfield  bool leave the field on when true
+ * data        buffer with byte to send
+ *
+ * @Output
+ * none
+ *
+ */
+void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, uint8_t data[])
+{
+       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);
+
+       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(!powerfield)
+       {
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+               LED_D_OFF();
+       }
+}
+
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