fixing iso14443b (issue #103):
authorpwpiwi <pwpiwi@users.noreply.github.com>
Sun, 21 Jun 2015 16:00:42 +0000 (18:00 +0200)
committerpwpiwi <pwpiwi@users.noreply.github.com>
Sun, 21 Jun 2015 16:04:24 +0000 (18:04 +0200)
- fix hf 14b snoop
- fix hf 14b sim

armsrc/iso14443b.c
fpga/fpga_hf.bit
fpga/hi_read_rx_xcorr.v

index 8d1a5cca433c499a226ec56c854fa4794cb79827..1ae1692b932270671298863365a1a033368a2171 100644 (file)
@@ -122,8 +122,7 @@ static struct {
                STATE_UNSYNCD,
                STATE_GOT_FALLING_EDGE_OF_SOF,
                STATE_AWAITING_START_BIT,
-               STATE_RECEIVING_DATA,
-               STATE_ERROR_WAIT
+               STATE_RECEIVING_DATA
        }       state;
        uint16_t    shiftReg;
        int     bitCnt;
@@ -145,7 +144,7 @@ static struct {
  * Returns: true if we received a EOF
  *          false if we are still waiting for some more
  */
-static int Handle14443bUartBit(int bit)
+static RAMFUNC int Handle14443bUartBit(uint8_t bit)
 {
        switch(Uart.state) {
                case STATE_UNSYNCD:
@@ -172,7 +171,7 @@ static int Handle14443bUartBit(int bit)
                                        } else {
                                                // didn't stay down long enough
                                                // before going high, error
-                                               Uart.state = STATE_ERROR_WAIT;
+                                               Uart.state = STATE_UNSYNCD;
                                        }
                                } else {
                                        // do nothing, keep waiting
@@ -183,7 +182,8 @@ static int Handle14443bUartBit(int bit)
                        if(Uart.bitCnt > 12) {
                                // Give up if we see too many zeros without
                                // a one, too.
-                               Uart.state = STATE_ERROR_WAIT;
+                               LED_A_OFF();
+                               Uart.state = STATE_UNSYNCD;
                        }
                        break;
 
@@ -193,7 +193,7 @@ static int Handle14443bUartBit(int bit)
                                if(Uart.posCnt > 50/2) {        // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
                                        // stayed high for too long between
                                        // characters, error
-                                       Uart.state = STATE_ERROR_WAIT;
+                                       Uart.state = STATE_UNSYNCD;
                                }
                        } else {
                                // falling edge, this starts the data byte
@@ -227,41 +227,30 @@ static int Handle14443bUartBit(int bit)
 
                                        if(Uart.byteCnt >= Uart.byteCntMax) {
                                                // Buffer overflowed, give up
-                                               Uart.posCnt = 0;
-                                               Uart.state = STATE_ERROR_WAIT;
+                                               LED_A_OFF();
+                                               Uart.state = STATE_UNSYNCD;
                                        } else {
                                                // so get the next byte now
                                                Uart.posCnt = 0;
                                                Uart.state = STATE_AWAITING_START_BIT;
                                        }
-                               } else if(Uart.shiftReg == 0x000) {
+                               } else if (Uart.shiftReg == 0x000) {
                                        // this is an EOF byte
                                        LED_A_OFF(); // Finished receiving
+                                       Uart.state = STATE_UNSYNCD;
                                        if (Uart.byteCnt != 0) {
                                                return TRUE;
                                        }
-                                       Uart.posCnt = 0;
-                                       Uart.state = STATE_ERROR_WAIT;
                                } else {
                                        // this is an error
-                                       Uart.posCnt = 0;
-                                       Uart.state = STATE_ERROR_WAIT;
+                                       LED_A_OFF();
+                                       Uart.state = STATE_UNSYNCD;
                                }
                        }
                        break;
 
-               case STATE_ERROR_WAIT:
-                       // We're all screwed up, so wait a little while
-                       // for whatever went wrong to finish, and then
-                       // start over.
-                       Uart.posCnt++;
-                       if(Uart.posCnt > 10) {
-                               Uart.state = STATE_UNSYNCD;
-                               LED_A_OFF();
-                       }
-                       break;
-
                default:
+                       LED_A_OFF();
                        Uart.state = STATE_UNSYNCD;
                        break;
        }
@@ -269,6 +258,23 @@ static int Handle14443bUartBit(int bit)
        return FALSE;
 }
 
+
+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();
+}
+
+
 //-----------------------------------------------------------------------------
 // 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
@@ -278,44 +284,34 @@ static int Handle14443bUartBit(int bit)
 // Assume that we're called with the SSC (to the FPGA) and ADC path set
 // correctly.
 //-----------------------------------------------------------------------------
-static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen)
+static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len)
 {
-       uint8_t mask;
-       int i, bit;
-
        // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
        // only, since we are receiving, not transmitting).
        // Signal field is off with the appropriate LED
        LED_D_OFF();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
 
-
        // Now run a `software UART' on the stream of incoming samples.
-       Uart.output = received;
-       Uart.byteCntMax = maxLen;
-       Uart.state = STATE_UNSYNCD;
+       UartInit(received);
 
        for(;;) {
                WDT_HIT();
 
                if(BUTTON_PRESS()) return FALSE;
 
-               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(Handle14443bUartBit(bit)) {
+                       for(uint8_t mask = 0x80; mask != 0x00; mask >>= 1) {
+                               if(Handle14443bUartBit(b & mask)) {
                                        *len = Uart.byteCnt;
                                        return TRUE;
                                }
                        }
                }
        }
+       
+       return FALSE;
 }
 
 //-----------------------------------------------------------------------------
@@ -324,9 +320,12 @@ static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {
-       // the only command we understand is REQB, AFI=0, Select All, N=0:
+       // the only commands we understand is REQB, AFI=0, Select All, N=0:
        static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-       // ... and we respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
+       // ... and REQB, AFI=0, Normal Request, N=0:
+       static const uint8_t cmd2[] = { 0x05, 0x00, 0x00, 0x71, 0xFF };
+
+       // ... and we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
        // supports only 106kBit/s in both directions, max frame size = 32Bytes,
        // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
        static const uint8_t response1[] = {
@@ -334,25 +333,27 @@ void SimulateIso14443bTag(void)
                0x00, 0x21, 0x85, 0x5e, 0xd7
        };
 
-       uint8_t *resp;
-       int respLen;
+       clear_trace();
+       set_tracing(TRUE);
+
+       const uint8_t *resp;
+       uint8_t *respCode;
+       uint16_t respLen, respCodeLen;
 
        // allocate command receive buffer
        BigBuf_free();
        uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
-       int len;
-
-       int i;
 
-       int cmdsRecvd = 0;
+       uint16_t len;
+       uint16_t cmdsRecvd = 0;
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
 
        // prepare the (only one) tag answer:
        CodeIso14443bAsTag(response1, sizeof(response1));
-       uint8_t *resp1 = BigBuf_malloc(ToSendMax);
-       memcpy(resp1, ToSend, ToSendMax); 
-       uint16_t resp1Len = ToSendMax;
+       uint8_t *resp1Code = BigBuf_malloc(ToSendMax);
+       memcpy(resp1Code, ToSend, ToSendMax); 
+       uint16_t resp1CodeLen = ToSendMax;
 
        // We need to listen to the high-frequency, peak-detected path.
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
@@ -361,20 +362,28 @@ void SimulateIso14443bTag(void)
        cmdsRecvd = 0;
 
        for(;;) {
-               uint8_t b1, b2;
 
-               if(!GetIso14443bCommandFromReader(receivedCmd, &len, 100)) {
+               if(!GetIso14443bCommandFromReader(receivedCmd, &len)) {
                        Dbprintf("button pressed, received %d commands", cmdsRecvd);
                        break;
-                       }
+               }
 
-               // Good, look at the command now.
+               if (tracing) {
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       LogTrace(receivedCmd, len, 0, 0, parity, TRUE);
+               }
 
-               if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0) {
-                       resp = resp1; respLen = resp1Len;
+               // Good, look at the command now.
+               if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
+                       || (len == sizeof(cmd2) && memcmp(receivedCmd, cmd2, len) == 0) ) {
+                       resp = response1; 
+                       respLen = sizeof(response1);
+                       respCode = resp1Code; 
+                       respCodeLen = resp1CodeLen;
                } else {
                        Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
                        // And print whether the CRC fails, just for good measure
+                       uint8_t b1, b2;
                        ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
                        if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
                                // Not so good, try again.
@@ -392,7 +401,7 @@ void SimulateIso14443bTag(void)
                        break;
                }
 
-               if(respLen <= 0) continue;
+               if(respCodeLen <= 0) continue;
 
                // Modulate BPSK
                // Signal field is off with the appropriate LED
@@ -402,15 +411,15 @@ void SimulateIso14443bTag(void)
                FpgaSetupSsc();
 
                // Transmit the response.
-               i = 0;
+               uint16_t i = 0;
                for(;;) {
                        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                               uint8_t b = resp[i];
+                               uint8_t b = respCode[i];
 
                                AT91C_BASE_SSC->SSC_THR = b;
 
                                i++;
-                               if(i > respLen) {
+                               if(i > respCodeLen) {
                                        break;
                                }
                        }
@@ -419,6 +428,13 @@ void SimulateIso14443bTag(void)
                                (void)b;
                        }
                }
+               
+               // trace the response:
+               if (tracing) {
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       LogTrace(resp, respLen, 0, 0, parity, FALSE);
+               }
+                       
        }
 }
 
@@ -436,8 +452,7 @@ static struct {
                DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
                DEMOD_GOT_FALLING_EDGE_OF_SOF,
                DEMOD_AWAITING_START_BIT,
-               DEMOD_RECEIVING_DATA,
-               DEMOD_ERROR_WAIT
+               DEMOD_RECEIVING_DATA
        }       state;
        int     bitCount;
        int     posCount;
@@ -684,22 +699,6 @@ static void DemodInit(uint8_t *data)
 }
 
 
-static void UartReset()
-{
-       Uart.byteCntMax = MAX_FRAME_SIZE;
-       Uart.state = STATE_UNSYNCD;
-       Uart.byteCnt = 0;
-       Uart.bitCnt = 0;
-}
-
-
-static void UartInit(uint8_t *data)
-{
-       Uart.output = data;
-       UartReset();
-}
-
-
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer
  *  quiet: set to 'TRUE' to disable debug output
@@ -1163,11 +1162,11 @@ void RAMFUNC SnoopIso14443b(void)
                                /* false-triggered by the commands from the reader. */
                                DemodReset();
                        }
-                       ReaderIsActive = (Uart.state != STATE_UNSYNCD);
+                       ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                }
 
                if(!ReaderIsActive) {                                           // no need to try decoding tag data if the reader is sending - and we cannot afford the time
-                       if(Handle14443bSamplesDemod(ci & 0xFE, cq & 0xFE)) {
+                       if(Handle14443bSamplesDemod(ci | 0x01, cq | 0x01)) {
 
                                //Use samples as a time measurement
                                if(tracing)
index 49bec2242cb7720524289f3eba1397bbc2a22867..a4d72e373bb59cfa56cc3869b1ccb3c18908250a 100644 (file)
Binary files a/fpga/fpga_hf.bit and b/fpga/fpga_hf.bit differ
index 4a5de5536c64cffc2233db2d77ab9bc433672d10..f816199e94d8d6c0f4f87dcd60cecb9742f80d1a 100644 (file)
@@ -28,22 +28,12 @@ assign pwr_oe1 = 1'b0;
 assign pwr_oe3 = 1'b0;
 assign pwr_oe4 = 1'b0;
 
-(* clock_signal = "yes" *) reg fc_div_2;
+wire adc_clk = ck_1356megb;
+
+reg fc_div_2;
 always @(negedge ck_1356megb)
     fc_div_2 <= fc_div_2 + 1;
 
-(* clock_signal = "yes" *) reg adc_clk;
-always @(xcorr_is_848, ck_1356megb, fc_div_2)
-if (xcorr_is_848)
-       // The subcarrier frequency is fc/16; we will sample at fc, so that 
-       // means the subcarrier is 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 ...
-       adc_clk <= ck_1356megb;
-else
-    // The subcarrier frequency is fc/32; we will sample at fc/2, and
-    // the subcarrier will look identical.
-    adc_clk <= fc_div_2;
-
-       
 // When we're a reader, we just need to do the BPSK demod; but when we're an
 // eavesdropper, we also need to pick out the commands sent by the reader,
 // using AM. Do this the same way that we do it for the simulated tag.
@@ -85,12 +75,16 @@ reg ssp_clk;
 reg ssp_frame;
 
 
+always @(negedge adc_clk)
+begin
+       if (xcorr_is_848 | fc_div_2)
+               corr_i_cnt <= corr_i_cnt + 1;
+end            
+               
 
 // ADC data appears on the rising edge, so sample it on the falling edge
 always @(negedge adc_clk)
 begin
-    corr_i_cnt <= corr_i_cnt + 1;
-
     // These are the correlators: we correlate against in-phase and quadrature
     // versions of our reference signal, and keep the (signed) result to
     // send out later over the SSP.
@@ -98,7 +92,7 @@ begin
     begin
         if(snoop)
         begin
-                       // 7 most significant bits of tag signal (signed), 1 bit reader signal:
+                       // Send only 7 most significant bits of tag signal (signed), LSB is reader signal:
             corr_i_out <= {corr_i_accum[13:7], after_hysteresis_prev_prev};
             corr_q_out <= {corr_q_accum[13:7], after_hysteresis_prev};
                        after_hysteresis_prev_prev <= after_hysteresis;
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