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Compiling manual for MAC OS X
[proxmark3-svn] / armsrc / iso14443.c
index 7271b9d07b02a6a565e0eafef6d77b5c3da98bc0..c7f49f14059293dc46e5a8c845175b5c03d8e6a9 100644 (file)
-//-----------------------------------------------------------------------------\r
-// Routines to support ISO 14443. This includes both the reader software and\r
-// the `fake tag' modes. At the moment only the Type B modulation is\r
-// supported.\r
-// Jonathan Westhues, split Nov 2006\r
-//-----------------------------------------------------------------------------\r
-#include <proxmark3.h>\r
-#include "apps.h"\r
-#include "../common/iso14443_crc.c"\r
-\r
-\r
-//static void GetSamplesFor14443(BOOL weTx, int n);\r
-\r
-#define DMA_BUFFER_SIZE 256\r
-\r
-//=============================================================================\r
-// An ISO 14443 Type B tag. We listen for commands from the reader, using\r
-// a UART kind of thing that's implemented in software. When we get a\r
-// frame (i.e., a group of bytes between SOF and EOF), we check the CRC.\r
-// If it's good, then we can do something appropriate with it, and send\r
-// a response.\r
-//=============================================================================\r
-\r
-//-----------------------------------------------------------------------------\r
-// Code up a string of octets at layer 2 (including CRC, we don't generate\r
-// that here) so that they can be transmitted to the reader. Doesn't transmit\r
-// them yet, just leaves them ready to send in ToSend[].\r
-//-----------------------------------------------------------------------------\r
-static void CodeIso14443bAsTag(const BYTE *cmd, int len)\r
-{\r
-    int i;\r
-\r
-    ToSendReset();\r
-\r
-    // Transmit a burst of ones, as the initial thing that lets the\r
-    // reader get phase sync. This (TR1) must be > 80/fs, per spec,\r
-    // but tag that I've tried (a Paypass) exceeds that by a fair bit,\r
-    // so I will too.\r
-    for(i = 0; i < 20; i++) {\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    // Send SOF.\r
-    for(i = 0; i < 10; i++) {\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-    }\r
-    for(i = 0; i < 2; i++) {\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    for(i = 0; i < len; i++) {\r
-        int j;\r
-        BYTE b = cmd[i];\r
-\r
-        // Start bit\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-\r
-        // Data bits\r
-        for(j = 0; j < 8; j++) {\r
-            if(b & 1) {\r
-                ToSendStuffBit(1);\r
-                ToSendStuffBit(1);\r
-                ToSendStuffBit(1);\r
-                ToSendStuffBit(1);\r
-            } else {\r
-                ToSendStuffBit(0);\r
-                ToSendStuffBit(0);\r
-                ToSendStuffBit(0);\r
-                ToSendStuffBit(0);\r
-            }\r
-            b >>= 1;\r
-        }\r
-\r
-        // Stop bit\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    // Send SOF.\r
-    for(i = 0; i < 10; i++) {\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-        ToSendStuffBit(0);\r
-    }\r
-    for(i = 0; i < 10; i++) {\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    // Convert from last byte pos to length\r
-    ToSendMax++;\r
-\r
-    // Add a few more for slop\r
-    ToSendMax += 2;\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// The software UART that receives commands from the reader, and its state\r
-// variables.\r
-//-----------------------------------------------------------------------------\r
-static struct {\r
-    enum {\r
-        STATE_UNSYNCD,\r
-        STATE_GOT_FALLING_EDGE_OF_SOF,\r
-        STATE_AWAITING_START_BIT,\r
-        STATE_RECEIVING_DATA,\r
-        STATE_ERROR_WAIT\r
-    }       state;\r
-    WORD    shiftReg;\r
-    int     bitCnt;\r
-    int     byteCnt;\r
-    int     byteCntMax;\r
-    int     posCnt;\r
-    BYTE   *output;\r
-} Uart;\r
-\r
-static BOOL Handle14443UartBit(int bit)\r
-{\r
-    switch(Uart.state) {\r
-        case STATE_UNSYNCD:\r
-            if(!bit) {\r
-                // we went low, so this could be the beginning\r
-                // of an SOF\r
-                Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;\r
-                Uart.posCnt = 0;\r
-                Uart.bitCnt = 0;\r
-            }\r
-            break;\r
-\r
-        case STATE_GOT_FALLING_EDGE_OF_SOF:\r
-            Uart.posCnt++;\r
-            if(Uart.posCnt == 2) {\r
-                if(bit) {\r
-                    if(Uart.bitCnt >= 10) {\r
-                        // we've seen enough consecutive\r
-                        // zeros that it's a valid SOF\r
-                        Uart.posCnt = 0;\r
-                        Uart.byteCnt = 0;\r
-                        Uart.state = STATE_AWAITING_START_BIT;\r
-                    } else {\r
-                        // didn't stay down long enough\r
-                        // before going high, error\r
-                        Uart.state = STATE_ERROR_WAIT;\r
-                    }\r
-                } else {\r
-                    // do nothing, keep waiting\r
-                }\r
-                Uart.bitCnt++;\r
-            }\r
-            if(Uart.posCnt >= 4) Uart.posCnt = 0;\r
-            if(Uart.bitCnt > 14) {\r
-                // Give up if we see too many zeros without\r
-                // a one, too.\r
-                Uart.state = STATE_ERROR_WAIT;\r
-            }\r
-            break;\r
-\r
-        case STATE_AWAITING_START_BIT:\r
-            Uart.posCnt++;\r
-            if(bit) {\r
-                if(Uart.posCnt > 25) {\r
-                    // stayed high for too long between\r
-                    // characters, error\r
-                    Uart.state = STATE_ERROR_WAIT;\r
-                }\r
-            } else {\r
-                // falling edge, this starts the data byte\r
-                Uart.posCnt = 0;\r
-                Uart.bitCnt = 0;\r
-                Uart.shiftReg = 0;\r
-                Uart.state = STATE_RECEIVING_DATA;\r
-            }\r
-            break;\r
-\r
-        case STATE_RECEIVING_DATA:\r
-            Uart.posCnt++;\r
-            if(Uart.posCnt == 2) {\r
-                // time to sample a bit\r
-                Uart.shiftReg >>= 1;\r
-                if(bit) {\r
-                    Uart.shiftReg |= 0x200;\r
-                }\r
-                Uart.bitCnt++;\r
-            }\r
-            if(Uart.posCnt >= 4) {\r
-                Uart.posCnt = 0;\r
-            }\r
-            if(Uart.bitCnt == 10) {\r
-                if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))\r
-                {\r
-                    // this is a data byte, with correct\r
-                    // start and stop bits\r
-                    Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;\r
-                    Uart.byteCnt++;\r
-\r
-                    if(Uart.byteCnt >= Uart.byteCntMax) {\r
-                        // Buffer overflowed, give up\r
-                        Uart.posCnt = 0;\r
-                        Uart.state = STATE_ERROR_WAIT;\r
-                    } else {\r
-                        // so get the next byte now\r
-                        Uart.posCnt = 0;\r
-                        Uart.state = STATE_AWAITING_START_BIT;\r
-                    }\r
-                } else if(Uart.shiftReg == 0x000) {\r
-                    // this is an EOF byte\r
-                    return TRUE;\r
-                } else {\r
-                    // this is an error\r
-                    Uart.posCnt = 0;\r
-                    Uart.state = STATE_ERROR_WAIT;\r
-                }\r
-            }\r
-            break;\r
-\r
-        case STATE_ERROR_WAIT:\r
-            // We're all screwed up, so wait a little while\r
-            // for whatever went wrong to finish, and then\r
-            // start over.\r
-            Uart.posCnt++;\r
-            if(Uart.posCnt > 10) {\r
-                Uart.state = STATE_UNSYNCD;\r
-            }\r
-            break;\r
-\r
-        default:\r
-            Uart.state = STATE_UNSYNCD;\r
-            break;\r
-    }\r
-\r
-    return FALSE;\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// Receive a command (from the reader to us, where we are the simulated tag),\r
-// and store it in the given buffer, up to the given maximum length. Keeps\r
-// spinning, waiting for a well-framed command, until either we get one\r
-// (returns TRUE) or someone presses the pushbutton on the board (FALSE).\r
-//\r
-// Assume that we're called with the SSC (to the FPGA) and ADC path set\r
-// correctly.\r
-//-----------------------------------------------------------------------------\r
-static BOOL GetIso14443CommandFromReader(BYTE *received, int *len, int maxLen)\r
-{\r
-    BYTE mask;\r
-    int i, bit;\r
-\r
-    // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen\r
-    // only, since we are receiving, not transmitting).\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);\r
-\r
-\r
-    // Now run a `software UART' on the stream of incoming samples.\r
-    Uart.output = received;\r
-    Uart.byteCntMax = maxLen;\r
-    Uart.state = STATE_UNSYNCD;\r
-\r
-    for(;;) {\r
-        WDT_HIT();\r
-\r
-        if(BUTTON_PRESS()) return FALSE;\r
-\r
-        if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-            SSC_TRANSMIT_HOLDING = 0x00;\r
-        }\r
-        if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-            BYTE b = (BYTE)SSC_RECEIVE_HOLDING;\r
-\r
-            mask = 0x80;\r
-            for(i = 0; i < 8; i++, mask >>= 1) {\r
-                bit = (b & mask);\r
-                if(Handle14443UartBit(bit)) {\r
-                    *len = Uart.byteCnt;\r
-                    return TRUE;\r
-                }\r
-            }\r
-        }\r
-    }\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// Main loop of simulated tag: receive commands from reader, decide what\r
-// response to send, and send it.\r
-//-----------------------------------------------------------------------------\r
-void SimulateIso14443Tag(void)\r
-{\r
-    static const BYTE cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };\r
-    static const BYTE response1[] = {\r
-        0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,\r
-        0x00, 0x21, 0x85, 0x5e, 0xd7\r
-    };\r
-\r
-    BYTE *resp;\r
-    int respLen;\r
-\r
-    BYTE *resp1 = (((BYTE *)BigBuf) + 800);\r
-    int resp1Len;\r
-\r
-    BYTE *receivedCmd = (BYTE *)BigBuf;\r
-    int len;\r
-\r
-    int i;\r
-\r
-    int cmdsRecvd = 0;\r
-\r
-    memset(receivedCmd, 0x44, 400);\r
-\r
-    CodeIso14443bAsTag(response1, sizeof(response1));\r
-    memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;\r
-\r
-    // We need to listen to the high-frequency, peak-detected path.\r
-    SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
-    FpgaSetupSsc();\r
-\r
-    cmdsRecvd = 0;\r
-\r
-    for(;;) {\r
-        BYTE b1, b2;\r
-\r
-        if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {\r
-            DbpIntegers(cmdsRecvd, 0, 0);\r
-            DbpString("button press");\r
-            break;\r
-        }\r
-\r
-        // Good, look at the command now.\r
-\r
-        if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {\r
-            resp = resp1; respLen = resp1Len;\r
-        } else {\r
-            DbpString("new cmd from reader:");\r
-            DbpIntegers(len, 0x1234, cmdsRecvd);\r
-            // And print whether the CRC fails, just for good measure\r
-            ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);\r
-            if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {\r
-                // Not so good, try again.\r
-                DbpString("+++CRC fail");\r
-            } else {\r
-                DbpString("CRC passes");\r
-            }\r
-            break;\r
-        }\r
-\r
-        memset(receivedCmd, 0x44, 32);\r
-\r
-        cmdsRecvd++;\r
-\r
-        if(cmdsRecvd > 0x30) {\r
-            DbpString("many commands later...");\r
-            break;\r
-        }\r
-\r
-        if(respLen <= 0) continue;\r
-\r
-        // Modulate BPSK\r
-        FpgaWriteConfWord(\r
-               FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);\r
-        SSC_TRANSMIT_HOLDING = 0xff;\r
-        FpgaSetupSsc();\r
-\r
-        // Transmit the response.\r
-        i = 0;\r
-        for(;;) {\r
-            if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-                BYTE b = resp[i];\r
-\r
-                SSC_TRANSMIT_HOLDING = b;\r
-\r
-                i++;\r
-                if(i > respLen) {\r
-                    break;\r
-                }\r
-            }\r
-            if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-                volatile BYTE b = (BYTE)SSC_RECEIVE_HOLDING;\r
-                (void)b;\r
-            }\r
-        }\r
-    }\r
-}\r
-\r
-//=============================================================================\r
-// An ISO 14443 Type B reader. We take layer two commands, code them\r
-// appropriately, and then send them to the tag. We then listen for the\r
-// tag's response, which we leave in the buffer to be demodulated on the\r
-// PC side.\r
-//=============================================================================\r
-\r
-static struct {\r
-    enum {\r
-        DEMOD_UNSYNCD,\r
-        DEMOD_PHASE_REF_TRAINING,\r
-        DEMOD_AWAITING_FALLING_EDGE_OF_SOF,\r
-        DEMOD_GOT_FALLING_EDGE_OF_SOF,\r
-        DEMOD_AWAITING_START_BIT,\r
-        DEMOD_RECEIVING_DATA,\r
-        DEMOD_ERROR_WAIT\r
-    }       state;\r
-    int     bitCount;\r
-    int     posCount;\r
-    int     thisBit;\r
-    int     metric;\r
-    int     metricN;\r
-    WORD    shiftReg;\r
-    BYTE   *output;\r
-    int     len;\r
-    int     sumI;\r
-    int     sumQ;\r
-} Demod;\r
-\r
-static BOOL Handle14443SamplesDemod(int ci, int cq)\r
-{\r
-    int v;\r
-\r
-    // The soft decision on the bit uses an estimate of just the\r
-    // quadrant of the reference angle, not the exact angle.\r
-#define MAKE_SOFT_DECISION() { \\r
-        if(Demod.sumI > 0) { \\r
-            v = ci; \\r
-        } else { \\r
-            v = -ci; \\r
-        } \\r
-        if(Demod.sumQ > 0) { \\r
-            v += cq; \\r
-        } else { \\r
-            v -= cq; \\r
-        } \\r
-    }\r
-\r
-    switch(Demod.state) {\r
-        case DEMOD_UNSYNCD:\r
-            v = ci;\r
-            if(v < 0) v = -v;\r
-            if(cq > 0) {\r
-                v += cq;\r
-            } else {\r
-                v -= cq;\r
-            }\r
-            if(v > 40) {\r
-                Demod.posCount = 0;\r
-                Demod.state = DEMOD_PHASE_REF_TRAINING;\r
-                Demod.sumI = 0;\r
-                Demod.sumQ = 0;\r
-            }\r
-            break;\r
-\r
-        case DEMOD_PHASE_REF_TRAINING:\r
-            if(Demod.posCount < 8) {\r
-                Demod.sumI += ci;\r
-                Demod.sumQ += cq;\r
-            } else if(Demod.posCount > 100) {\r
-                // error, waited too long\r
-                Demod.state = DEMOD_UNSYNCD;\r
-            } else {\r
-                MAKE_SOFT_DECISION();\r
-                if(v < 0) {\r
-                    Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;\r
-                    Demod.posCount = 0;\r
-                }\r
-            }\r
-            Demod.posCount++;\r
-            break;\r
-\r
-        case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:\r
-            MAKE_SOFT_DECISION();\r
-            if(v < 0) {\r
-                Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;\r
-                Demod.posCount = 0;\r
-            } else {\r
-                if(Demod.posCount > 100) {\r
-                    Demod.state = DEMOD_UNSYNCD;\r
-                }\r
-            }\r
-            Demod.posCount++;\r
-            break;\r
-\r
-        case DEMOD_GOT_FALLING_EDGE_OF_SOF:\r
-            MAKE_SOFT_DECISION();\r
-            if(v > 0) {\r
-                if(Demod.posCount < 12) {\r
-                    Demod.state = DEMOD_UNSYNCD;\r
-                } else {\r
-                    Demod.state = DEMOD_AWAITING_START_BIT;\r
-                    Demod.posCount = 0;\r
-                    Demod.len = 0;\r
-                    Demod.metricN = 0;\r
-                    Demod.metric = 0;\r
-                }\r
-            } else {\r
-                if(Demod.posCount > 100) {\r
-                    Demod.state = DEMOD_UNSYNCD;\r
-                }\r
-            }\r
-            Demod.posCount++;\r
-            break;\r
-\r
-        case DEMOD_AWAITING_START_BIT:\r
-            MAKE_SOFT_DECISION();\r
-            if(v > 0) {\r
-                if(Demod.posCount > 10) {\r
-                    Demod.state = DEMOD_UNSYNCD;\r
-                }\r
-            } else {\r
-                Demod.bitCount = 0;\r
-                Demod.posCount = 1;\r
-                Demod.thisBit = v;\r
-                Demod.shiftReg = 0;\r
-                Demod.state = DEMOD_RECEIVING_DATA;\r
-            }\r
-            break;\r
-\r
-        case DEMOD_RECEIVING_DATA:\r
-            MAKE_SOFT_DECISION();\r
-            if(Demod.posCount == 0) {\r
-                Demod.thisBit = v;\r
-                Demod.posCount = 1;\r
-            } else {\r
-                Demod.thisBit += v;\r
-\r
-                if(Demod.thisBit > 0) {\r
-                    Demod.metric += Demod.thisBit;\r
-                } else {\r
-                    Demod.metric -= Demod.thisBit;\r
-                }\r
-                (Demod.metricN)++;\r
-\r
-                Demod.shiftReg >>= 1;\r
-                if(Demod.thisBit > 0) {\r
-                    Demod.shiftReg |= 0x200;\r
-                }\r
-\r
-                Demod.bitCount++;\r
-                if(Demod.bitCount == 10) {\r
-                    WORD s = Demod.shiftReg;\r
-                    if((s & 0x200) && !(s & 0x001)) {\r
-                        BYTE b = (s >> 1);\r
-                        Demod.output[Demod.len] = b;\r
-                        Demod.len++;\r
-                        Demod.state = DEMOD_AWAITING_START_BIT;\r
-                    } else if(s == 0x000) {\r
-                        // This is EOF\r
-                        return TRUE;\r
-                        Demod.state = DEMOD_UNSYNCD;\r
-                    } else {\r
-                        Demod.state = DEMOD_UNSYNCD;\r
-                    }\r
-                }\r
-                Demod.posCount = 0;\r
-            }\r
-            break;\r
-\r
-        default:\r
-            Demod.state = DEMOD_UNSYNCD;\r
-            break;\r
-    }\r
-\r
-    return FALSE;\r
-}\r
-\r
-static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)\r
-{\r
-    int max = 0;\r
-    BOOL gotFrame = FALSE;\r
-\r
-//#   define DMA_BUFFER_SIZE 8\r
-    SBYTE *dmaBuf;\r
-\r
-    int lastRxCounter;\r
-    SBYTE *upTo;\r
-\r
-    int ci, cq;\r
-\r
-    int samples = 0;\r
-\r
-    // Clear out the state of the "UART" that receives from the tag.\r
-    memset(BigBuf, 0x44, 400);\r
-    Demod.output = (BYTE *)BigBuf;\r
-    Demod.len = 0;\r
-    Demod.state = DEMOD_UNSYNCD;\r
-\r
-    // And the UART that receives from the reader\r
-    Uart.output = (((BYTE *)BigBuf) + 1024);\r
-    Uart.byteCntMax = 100;\r
-    Uart.state = STATE_UNSYNCD;\r
-\r
-    // Setup for the DMA.\r
-    dmaBuf = (SBYTE *)(BigBuf + 32);\r
-    upTo = dmaBuf;\r
-    lastRxCounter = DMA_BUFFER_SIZE;\r
-    FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE);\r
-\r
-    // And put the FPGA in the appropriate mode\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |\r
-       (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));\r
-\r
-    for(;;) {\r
-        int behindBy = lastRxCounter - PDC_RX_COUNTER(SSC_BASE);\r
-        if(behindBy > max) max = behindBy;\r
-\r
-        LED_D_ON();\r
-        while(((lastRxCounter-PDC_RX_COUNTER(SSC_BASE)) & (DMA_BUFFER_SIZE-1))\r
-                    > 2)\r
-        {\r
-            ci = upTo[0];\r
-            cq = upTo[1];\r
-            upTo += 2;\r
-            if(upTo - dmaBuf > DMA_BUFFER_SIZE) {\r
-                upTo -= DMA_BUFFER_SIZE;\r
-                PDC_RX_NEXT_POINTER(SSC_BASE) = (DWORD)upTo;\r
-                PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE;\r
-            }\r
-            lastRxCounter -= 2;\r
-            if(lastRxCounter <= 0) {\r
-                lastRxCounter += DMA_BUFFER_SIZE;\r
-            }\r
-\r
-            samples += 2;\r
-\r
-            Handle14443UartBit(1);\r
-            Handle14443UartBit(1);\r
-\r
-            if(Handle14443SamplesDemod(ci, cq)) {\r
-                gotFrame = 1;\r
-            }\r
-        }\r
-        LED_D_OFF();\r
-\r
-        if(samples > 2000) {\r
-            break;\r
-        }\r
-    }\r
-    PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE;\r
-    if (!quiet) DbpIntegers(max, gotFrame, Demod.len);\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// Read the tag's response. We just receive a stream of slightly-processed\r
-// samples from the FPGA, which we will later do some signal processing on,\r
-// to get the bits.\r
-//-----------------------------------------------------------------------------\r
-/*static void GetSamplesFor14443(BOOL weTx, int n)\r
-{\r
-    BYTE *dest = (BYTE *)BigBuf;\r
-    int c;\r
-\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |\r
-       (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));\r
-\r
-    c = 0;\r
-    for(;;) {\r
-        if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-            SSC_TRANSMIT_HOLDING = 0x43;\r
-        }\r
-        if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-            SBYTE b;\r
-            b = (SBYTE)SSC_RECEIVE_HOLDING;\r
-\r
-            dest[c++] = (BYTE)b;\r
-\r
-            if(c >= n) {\r
-                break;\r
-            }\r
-        }\r
-    }\r
-}*/\r
-\r
-//-----------------------------------------------------------------------------\r
-// Transmit the command (to the tag) that was placed in ToSend[].\r
-//-----------------------------------------------------------------------------\r
-static void TransmitFor14443(void)\r
-{\r
-    int c;\r
-\r
-    FpgaSetupSsc();\r
-\r
-    while(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-        SSC_TRANSMIT_HOLDING = 0xff;\r
-    }\r
-\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);\r
-\r
-    for(c = 0; c < 10;) {\r
-        if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-            SSC_TRANSMIT_HOLDING = 0xff;\r
-            c++;\r
-        }\r
-        if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-            volatile DWORD r = SSC_RECEIVE_HOLDING;\r
-            (void)r;\r
-        }\r
-        WDT_HIT();\r
-    }\r
-\r
-    c = 0;\r
-    for(;;) {\r
-        if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-            SSC_TRANSMIT_HOLDING = ToSend[c];\r
-            c++;\r
-            if(c >= ToSendMax) {\r
-                break;\r
-            }\r
-        }\r
-        if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-            volatile DWORD r = SSC_RECEIVE_HOLDING;\r
-            (void)r;\r
-        }\r
-        WDT_HIT();\r
-    }\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// Code a layer 2 command (string of octets, including CRC) into ToSend[],\r
-// so that it is ready to transmit to the tag using TransmitFor14443().\r
-//-----------------------------------------------------------------------------\r
-void CodeIso14443bAsReader(const BYTE *cmd, int len)\r
-{\r
-    int i, j;\r
-    BYTE b;\r
-\r
-    ToSendReset();\r
-\r
-    // Establish initial reference level\r
-    for(i = 0; i < 40; i++) {\r
-        ToSendStuffBit(1);\r
-    }\r
-    // Send SOF\r
-    for(i = 0; i < 10; i++) {\r
-        ToSendStuffBit(0);\r
-    }\r
-\r
-    for(i = 0; i < len; i++) {\r
-        // Stop bits/EGT\r
-        ToSendStuffBit(1);\r
-        ToSendStuffBit(1);\r
-        // Start bit\r
-        ToSendStuffBit(0);\r
-        // Data bits\r
-        b = cmd[i];\r
-        for(j = 0; j < 8; j++) {\r
-            if(b & 1) {\r
-                ToSendStuffBit(1);\r
-            } else {\r
-                ToSendStuffBit(0);\r
-            }\r
-            b >>= 1;\r
-        }\r
-    }\r
-    // Send EOF\r
-    ToSendStuffBit(1);\r
-    for(i = 0; i < 10; i++) {\r
-        ToSendStuffBit(0);\r
-    }\r
-    for(i = 0; i < 8; i++) {\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    // And then a little more, to make sure that the last character makes\r
-    // it out before we switch to rx mode.\r
-    for(i = 0; i < 24; i++) {\r
-        ToSendStuffBit(1);\r
-    }\r
-\r
-    // Convert from last character reference to length\r
-    ToSendMax++;\r
-}\r
-\r
-//-----------------------------------------------------------------------------\r
-// Read an ISO 14443 tag. We send it some set of commands, and record the\r
+//-----------------------------------------------------------------------------
+// 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
+*/
+//=============================================================================
+// 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 command (reader -> tag) that we're receiving.
+       uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
+       
+       // The response (tag -> reader) that we're receiving.
+       uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
+       
+       // The DMA buffer, used to stream samples from the FPGA
+       uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
+
+       // Set up the demodulator for tag -> reader responses.
+       DemodInit(receivedResponse);
+       // Set up the demodulator for the reader -> tag commands
+       UartInit(receivedCmd);
+
+       // 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 -= DMA_BUFFER_SIZE;
+                               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;
+
+                       Handle14443UartBit(1);
+                       Handle14443UartBit(1);
+
+                       if(Handle14443SamplesDemod(ci, cq)) {
+                               gotFrame = 1;
+                       }
+               }
+
+               if(samples > 2000) {
+                       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)\r
-//-----------------------------------------------------------------------------\r
-void AcquireRawAdcSamplesIso14443(DWORD parameter)\r
-{\r
-    BYTE cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };\r
-\r
-    // Make sure that we start from off, since the tags are stateful;\r
-    // confusing things will happen if we don't reset them between reads.\r
-    LED_D_OFF();\r
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-    SpinDelay(200);\r
-\r
-    SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
-    FpgaSetupSsc();\r
-\r
-    // Now give it time to spin up.\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);\r
-    SpinDelay(200);\r
-\r
-    CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
-    TransmitFor14443();\r
-    LED_A_ON();\r
-    GetSamplesFor14443Demod(TRUE, 2000, FALSE);\r
-    LED_A_OFF();\r
-}\r
-
-//-----------------------------------------------------------------------------\r
-// Read a SRI512 ISO 14443 tag.\r
-// 
+// 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...\r
-//-----------------------------------------------------------------------------\r
-void ReadSRI512Iso14443(DWORD parameter)\r
-{\r
-    BYTE i = 0x00;
-\r
-    // Make sure that we start from off, since the tags are stateful;\r
-    // confusing things will happen if we don't reset them between reads.\r
-    LED_D_OFF();\r
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-    SpinDelay(200);\r
-\r
-    SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
-    FpgaSetupSsc();\r
-\r
-    // Now give it time to spin up.\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);\r
-    SpinDelay(200);\r
-
-    // First command: wake up the tag using the INITIATE command\r
-    BYTE cmd1[] = { 0x06, 0x00, 0x97, 0x5b};\r
-    CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
-    TransmitFor14443();\r
-    LED_A_ON();\r
-    GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
-    LED_A_OFF();\r
-
-    if (Demod.len == 0) {
+// 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, 2000,TRUE);
+//    LED_A_OFF();
+
+       if (Demod.len == 0) {
        DbpString("No response from tag");
        return;
-    } else {
-       DbpString("Randomly generated UID from tag (+ 2 byte CRC):");
-       DbpIntegers(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]);\r
-    CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
-    TransmitFor14443();\r
-    LED_A_ON();\r
-    GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
-    LED_A_OFF();\r
-    if (Demod.len != 3) {
-       DbpString("Expected 3 bytes from tag, got:");
-       DbpIntegers(Demod.len,0x0,0x0);
+       } 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, 2000,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]);\r
-    if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {\r
+       }
+       // 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]) {
-       DbpString("Bad response to SELECT from Tag, aborting:");
-       DbpIntegers(cmd1[1],Demod.output[0],0x0);
+       }
+       // 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]);
-    CodeIso14443bAsReader(cmd1, 3); // Only first three bytes for this one\r
-    TransmitFor14443();\r
-    LED_A_ON();\r
-    GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
-    LED_A_OFF();\r
-    if (Demod.len != 10) {
-       DbpString("Expected 10 bytes from tag, got:");
-       DbpIntegers(Demod.len,0x0,0x0);
+       }
+       // 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, 2000,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]);\r
-           if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {\r
-       DbpString("CRC Error reading block! - Below: expected, got");
-       DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9],0);
+       }
+       // 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 ?)
-    }
-    DbpString("Tag UID (64 bits):");
-    DbpIntegers((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], 0);
-
-    // Now loop to read all 16 blocks, address from 0 to 15
-    DbpString("Tag memory dump, block 0 to 15");
-    cmd1[0] = 0x08;
-    i = 0x00;
-    for (;;) {
-           if (i == 0x10) {
-                   DbpString("System area block (0xff):");
-                   i = 0xff;
-           }
-           cmd1[1] = i;
-           ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);\r
-           CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
-           TransmitFor14443();\r
-           LED_A_ON();\r
-           GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
-           LED_A_OFF();
-           if (Demod.len != 6) { // Check if we got an answer from the tag
+       }
+       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, 2000,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]);\r
-            if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {\r
-               DbpString("CRC Error reading block! - Below: expected, got");
-               DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5],0);
+               }
+               // 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:
-           DbpString("Address , Contents, CRC");
-           DbpIntegers(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) {
+               }
+               // 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++;
-    }
-}\r
-
-\r
-//=============================================================================\r
-// Finally, the `sniffer' combines elements from both the reader and\r
-// simulated tag, to show both sides of the conversation.\r
-//=============================================================================\r
-\r
-//-----------------------------------------------------------------------------\r
-// Record the sequence of commands sent by the reader to the tag, with\r
-// triggering so that we start recording at the point that the tag is moved\r
-// near the reader.\r
-//-----------------------------------------------------------------------------\r
-void SnoopIso14443(void)\r
-{\r
-    // We won't start recording the frames that we acquire until we trigger;\r
-    // a good trigger condition to get started is probably when we see a\r
-    // response from the tag.\r
-    BOOL triggered = FALSE;\r
-\r
-    // The command (reader -> tag) that we're working on receiving.\r
-    BYTE *receivedCmd = (((BYTE *)BigBuf) + 1024);\r
-    // The response (tag -> reader) that we're working on receiving.\r
-    BYTE *receivedResponse = (((BYTE *)BigBuf) + 1536);\r
-\r
-    // As we receive stuff, we copy it from receivedCmd or receivedResponse\r
-    // into trace, along with its length and other annotations.\r
-    BYTE *trace = (BYTE *)BigBuf;\r
-    int traceLen = 0;\r
-\r
-    // The DMA buffer, used to stream samples from the FPGA.\r
-//#   define DMA_BUFFER_SIZE 256\r
-    SBYTE *dmaBuf = ((SBYTE *)BigBuf) + 2048;\r
-    int lastRxCounter;\r
-    SBYTE *upTo;\r
-    int ci, cq;\r
-    int maxBehindBy = 0;\r
-\r
-    // Count of samples received so far, so that we can include timing\r
-    // information in the trace buffer.\r
-    int samples = 0;\r
-\r
-    memset(trace, 0x44, 1000);\r
-\r
-    // Set up the demodulator for tag -> reader responses.\r
-    Demod.output = receivedResponse;\r
-    Demod.len = 0;\r
-    Demod.state = DEMOD_UNSYNCD;\r
-\r
-    // And the reader -> tag commands\r
-    memset(&Uart, 0, sizeof(Uart));\r
-    Uart.output = receivedCmd;\r
-    Uart.byteCntMax = 100;\r
-    Uart.state = STATE_UNSYNCD;\r
-\r
-    // And put the FPGA in the appropriate mode\r
-    FpgaWriteConfWord(\r
-       FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |\r
-       FPGA_HF_READER_RX_XCORR_SNOOP);\r
-    SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
-\r
-    // Setup for the DMA.\r
-    FpgaSetupSsc();\r
-    upTo = dmaBuf;\r
-    lastRxCounter = DMA_BUFFER_SIZE;\r
-    FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE);\r
-\r
-    LED_A_ON();\r
-\r
-    // And now we loop, receiving samples.\r
-    for(;;) {\r
-        int behindBy = (lastRxCounter - PDC_RX_COUNTER(SSC_BASE)) &\r
-                                (DMA_BUFFER_SIZE-1);\r
-        if(behindBy > maxBehindBy) {\r
-            maxBehindBy = behindBy;\r
-            if(behindBy > 100) {\r
-                DbpString("blew circular buffer!");\r
-                goto done;\r
-            }\r
-        }\r
-        if(behindBy < 2) continue;\r
-\r
-        ci = upTo[0];\r
-        cq = upTo[1];\r
-        upTo += 2;\r
-        lastRxCounter -= 2;\r
-        if(upTo - dmaBuf > DMA_BUFFER_SIZE) {\r
-            upTo -= DMA_BUFFER_SIZE;\r
-            lastRxCounter += DMA_BUFFER_SIZE;\r
-            PDC_RX_NEXT_POINTER(SSC_BASE) = (DWORD)upTo;\r
-            PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE;\r
-        }\r
-\r
-        samples += 2;\r
-\r
-#define HANDLE_BIT_IF_BODY \\r
-            if(triggered) { \\r
-                trace[traceLen++] = ((samples >>  0) & 0xff); \\r
-                trace[traceLen++] = ((samples >>  8) & 0xff); \\r
-                trace[traceLen++] = ((samples >> 16) & 0xff); \\r
-                trace[traceLen++] = ((samples >> 24) & 0xff); \\r
-                trace[traceLen++] = 0; \\r
-                trace[traceLen++] = 0; \\r
-                trace[traceLen++] = 0; \\r
-                trace[traceLen++] = 0; \\r
-                trace[traceLen++] = Uart.byteCnt; \\r
-                memcpy(trace+traceLen, receivedCmd, Uart.byteCnt); \\r
-                traceLen += Uart.byteCnt; \\r
-                if(traceLen > 1000) break; \\r
-            } \\r
-            /* And ready to receive another command. */ \\r
-            memset(&Uart, 0, sizeof(Uart)); \\r
-            Uart.output = receivedCmd; \\r
-            Uart.byteCntMax = 100; \\r
-            Uart.state = STATE_UNSYNCD; \\r
-            /* And also reset the demod code, which might have been */ \\r
-            /* false-triggered by the commands from the reader. */ \\r
-            memset(&Demod, 0, sizeof(Demod)); \\r
-            Demod.output = receivedResponse; \\r
-            Demod.state = DEMOD_UNSYNCD; \\r
-\r
-        if(Handle14443UartBit(ci & 1)) {\r
-            HANDLE_BIT_IF_BODY\r
-        }\r
-        if(Handle14443UartBit(cq & 1)) {\r
-            HANDLE_BIT_IF_BODY\r
-        }\r
-\r
-        if(Handle14443SamplesDemod(ci, cq)) {\r
-            // timestamp, as a count of samples\r
-            trace[traceLen++] = ((samples >>  0) & 0xff);\r
-            trace[traceLen++] = ((samples >>  8) & 0xff);\r
-            trace[traceLen++] = ((samples >> 16) & 0xff);\r
-            trace[traceLen++] = 0x80 | ((samples >> 24) & 0xff);\r
-            // correlation metric (~signal strength estimate)\r
-            if(Demod.metricN != 0) {\r
-                Demod.metric /= Demod.metricN;\r
-            }\r
-            trace[traceLen++] = ((Demod.metric >>  0) & 0xff);\r
-            trace[traceLen++] = ((Demod.metric >>  8) & 0xff);\r
-            trace[traceLen++] = ((Demod.metric >> 16) & 0xff);\r
-            trace[traceLen++] = ((Demod.metric >> 24) & 0xff);\r
-            // length\r
-            trace[traceLen++] = Demod.len;\r
-            memcpy(trace+traceLen, receivedResponse, Demod.len);\r
-            traceLen += Demod.len;\r
-            if(traceLen > 1000) break;\r
-\r
-            triggered = TRUE;\r
-            LED_A_OFF();\r
-            LED_B_ON();\r
-\r
-            // And ready to receive another response.\r
-            memset(&Demod, 0, sizeof(Demod));\r
-            Demod.output = receivedResponse;\r
-            Demod.state = DEMOD_UNSYNCD;\r
-        }\r
-\r
-        if(BUTTON_PRESS()) {\r
-            DbpString("cancelled");\r
-            goto done;\r
-        }\r
-    }\r
-\r
-    DbpString("in done pt");\r
-\r
-    DbpIntegers(maxBehindBy, Uart.state, Uart.byteCnt);\r
-    DbpIntegers(Uart.byteCntMax, traceLen, 0x23);\r
-\r
-done:\r
-    PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE;\r
-    LED_A_OFF();\r
-    LED_B_OFF();\r
-}\r
+               }
+               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 -= DMA_BUFFER_SIZE;
+                       lastRxCounter += DMA_BUFFER_SIZE;
+                       AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
+                       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)
+       {
+               uint16_t iLen = MIN(Demod.len,USB_CMD_DATA_SIZE);
+               GetSamplesFor14443Demod(TRUE, 2000, TRUE);
+               cmd_send(CMD_ACK,iLen,0,0,Demod.output,iLen);
+       }
+       if(!powerfield)
+       {
+               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+               LED_D_OFF();
+       }
+}
+
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