#defines for ADC channels so we can see what's what

[proxmark3-svn] / armsrc / iso14443.c

diff --git a/armsrc/iso14443.c b/armsrc/iso14443.c
index 3a4a9ac1f63af0029188f3785771a629c54c6d28..311254d9e55a7d93a69c50f6c7ff17e977a9657f 100644 (file)
--- a/armsrc/iso14443.c
+++ b/armsrc/iso14443.c
@@ -131,10 +131,20 @@ static struct {
     BYTE   *output;\r
 } Uart;\r
 \r
     BYTE   *output;\r
 } Uart;\r
 \r

+/* Receive & handle a bit coming from the reader.\r
+ *\r
+ * LED handling:\r
+ * LED A -> ON once we have received the SOF and are expecting the rest.\r
+ * LED A -> OFF once we have received EOF or are in error state or unsynced\r
+ *\r
+ * Returns: true if we received a EOF\r
+ *          false if we are still waiting for some more\r
+ */\r

 static BOOL Handle14443UartBit(int bit)\r
 {\r
     switch(Uart.state) {\r
         case STATE_UNSYNCD:\r
 static BOOL Handle14443UartBit(int bit)\r
 {\r
     switch(Uart.state) {\r
         case STATE_UNSYNCD:\r

+               LED_A_OFF();\r

             if(!bit) {\r
                 // we went low, so this could be the beginning\r
                 // of an SOF\r
             if(!bit) {\r
                 // we went low, so this could be the beginning\r
                 // of an SOF\r


@@ -154,6 +164,7 @@ static BOOL Handle14443UartBit(int bit)
                         Uart.posCnt = 0;\r
                         Uart.byteCnt = 0;\r
                         Uart.state = STATE_AWAITING_START_BIT;\r
                         Uart.posCnt = 0;\r
                         Uart.byteCnt = 0;\r
                         Uart.state = STATE_AWAITING_START_BIT;\r

+                        LED_A_ON(); // Indicate we got a valid SOF\r

                     } else {\r
                         // didn't stay down long enough\r
                         // before going high, error\r
                     } else {\r
                         // didn't stay down long enough\r
                         // before going high, error\r


@@ -186,6 +197,7 @@ static BOOL Handle14443UartBit(int bit)
                 Uart.bitCnt = 0;\r
                 Uart.shiftReg = 0;\r
                 Uart.state = STATE_RECEIVING_DATA;\r
                 Uart.bitCnt = 0;\r
                 Uart.shiftReg = 0;\r
                 Uart.state = STATE_RECEIVING_DATA;\r

+                LED_A_ON(); // Indicate we're receiving\r

             }\r
             break;\r
 \r
             }\r
             break;\r
 \r


@@ -221,6 +233,7 @@ static BOOL Handle14443UartBit(int bit)
                     }\r
                 } else if(Uart.shiftReg == 0x000) {\r
                     // this is an EOF byte\r
                     }\r
                 } else if(Uart.shiftReg == 0x000) {\r
                     // this is an EOF byte\r

+                       LED_A_OFF(); // Finished receiving\r

                     return TRUE;\r
                 } else {\r
                     // this is an error\r
                     return TRUE;\r
                 } else {\r
                     // this is an error\r


@@ -245,6 +258,8 @@ static BOOL Handle14443UartBit(int bit)
             break;\r
     }\r
 \r
             break;\r
     }\r
 \r

+    if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error\r
+\r

     return FALSE;\r
 }\r
 \r
     return FALSE;\r
 }\r
 \r


@@ -264,6 +279,8 @@ static BOOL GetIso14443CommandFromReader(BYTE *received, int *len, int maxLen)
 \r
     // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen\r
     // only, since we are receiving, not transmitting).\r
 \r
     // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen\r
     // only, since we are receiving, not transmitting).\r

+    // Signal field is off with the appropriate LED\r
+    LED_D_OFF();\r

     FpgaWriteConfWord(\r
        FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);\r
 \r
     FpgaWriteConfWord(\r
        FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);\r
 \r


@@ -371,6 +388,8 @@ void SimulateIso14443Tag(void)
         if(respLen <= 0) continue;\r
 \r
         // Modulate BPSK\r
         if(respLen <= 0) continue;\r
 \r
         // Modulate BPSK\r

+        // Signal field is off with the appropriate LED\r
+        LED_D_OFF();\r

         FpgaWriteConfWord(\r
                FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);\r
         SSC_TRANSMIT_HOLDING = 0xff;\r
         FpgaWriteConfWord(\r
                FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);\r
         SSC_TRANSMIT_HOLDING = 0xff;\r


@@ -426,6 +445,17 @@ static struct {
     int     sumQ;\r
 } Demod;\r
 \r
     int     sumQ;\r
 } Demod;\r
 \r

+/*\r
+ * Handles reception of a bit from the tag\r
+ *\r
+ * LED handling:\r
+ * LED C -> ON once we have received the SOF and are expecting the rest.\r
+ * LED C -> OFF once we have received EOF or are unsynced\r
+ *\r
+ * Returns: true if we received a EOF\r
+ *          false if we are still waiting for some more\r
+ *
+ */\r

 static BOOL Handle14443SamplesDemod(int ci, int cq)\r
 {\r
     int v;\r
 static BOOL Handle14443SamplesDemod(int ci, int cq)\r
 {\r
     int v;\r


@@ -498,6 +528,7 @@ static BOOL Handle14443SamplesDemod(int ci, int cq)
                 if(Demod.posCount < 12) {\r
                     Demod.state = DEMOD_UNSYNCD;\r
                 } else {\r
                 if(Demod.posCount < 12) {\r
                     Demod.state = DEMOD_UNSYNCD;\r
                 } else {\r

+                       LED_C_ON(); // Got SOF\r

                     Demod.state = DEMOD_AWAITING_START_BIT;\r
                     Demod.posCount = 0;\r
                     Demod.len = 0;\r
                     Demod.state = DEMOD_AWAITING_START_BIT;\r
                     Demod.posCount = 0;\r
                     Demod.len = 0;\r


@@ -557,6 +588,7 @@ static BOOL Handle14443SamplesDemod(int ci, int cq)
                         Demod.state = DEMOD_AWAITING_START_BIT;\r
                     } else if(s == 0x000) {\r
                         // This is EOF\r
                         Demod.state = DEMOD_AWAITING_START_BIT;\r
                     } else if(s == 0x000) {\r
                         // This is EOF\r

+                       LED_C_OFF();\r

                         return TRUE;\r
                         Demod.state = DEMOD_UNSYNCD;\r
                     } else {\r
                         return TRUE;\r
                         Demod.state = DEMOD_UNSYNCD;\r
                     } else {\r


@@ -572,9 +604,16 @@ static BOOL Handle14443SamplesDemod(int ci, int cq)
             break;\r
     }\r
 \r
             break;\r
     }\r
 \r

+    if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized...\r

     return FALSE;\r
 }\r
 \r
     return FALSE;\r
 }\r
 \r

+/*\r
+ *  Demodulate the samples we received from the tag\r
+ *  weTx: set to 'TRUE' if we behave like a reader\r
+ *        set to 'FALSE' if we behave like a snooper\r
+ *  quiet: set to 'TRUE' to disable debug output
+ */\r

 static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)\r
 {\r
     int max = 0;\r
 static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)\r
 {\r
     int max = 0;\r


@@ -607,6 +646,8 @@ static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)
     lastRxCounter = DMA_BUFFER_SIZE;\r
     FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE);\r
 \r
     lastRxCounter = DMA_BUFFER_SIZE;\r
     FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE);\r
 \r

+    // Signal field is ON with the appropriate LED:\r
+       if (weTx) LED_D_ON(); else LED_D_OFF();\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
     // 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


@@ -616,7 +657,6 @@ static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)
         int behindBy = lastRxCounter - PDC_RX_COUNTER(SSC_BASE);\r
         if(behindBy > max) max = behindBy;\r
 \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
         while(((lastRxCounter-PDC_RX_COUNTER(SSC_BASE)) & (DMA_BUFFER_SIZE-1))\r
                     > 2)\r
         {\r


@@ -642,7 +682,6 @@ static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet)
                 gotFrame = 1;\r
             }\r
         }\r
                 gotFrame = 1;\r
             }\r
         }\r

-        LED_D_OFF();\r

 \r
         if(samples > 2000) {\r
             break;\r
 \r
         if(samples > 2000) {\r
             break;\r


@@ -697,7 +736,11 @@ static void TransmitFor14443(void)
         SSC_TRANSMIT_HOLDING = 0xff;\r
     }\r
 \r
         SSC_TRANSMIT_HOLDING = 0xff;\r
     }\r
 \r

-    FpgaWriteConfWord(\r
+    // Signal field is ON with the appropriate Red LED\r
+       LED_D_ON();\r
+       // Signal we are transmitting with the Green LED\r
+       LED_B_ON();\r
+       FpgaWriteConfWord(\r

        FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);\r
 \r
     for(c = 0; c < 10;) {\r
        FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);\r
 \r
     for(c = 0; c < 10;) {\r


@@ -727,6 +770,7 @@ static void TransmitFor14443(void)
         }\r
         WDT_HIT();\r
     }\r
         }\r
         WDT_HIT();\r
     }\r

+    LED_B_OFF(); // Finished sending\r

 }\r
 \r
 //-----------------------------------------------------------------------------\r
 }\r
 \r
 //-----------------------------------------------------------------------------\r


@@ -797,28 +841,30 @@ void AcquireRawAdcSamplesIso14443(DWORD parameter)
 \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
 \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
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r

+    LED_D_OFF();\r

     SpinDelay(200);\r
 \r
     SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
     FpgaSetupSsc();\r
 \r
     // Now give it time to spin up.\r
     SpinDelay(200);\r
 \r
     SetAdcMuxFor(GPIO_MUXSEL_HIPKD);\r
     FpgaSetupSsc();\r
 \r
     // Now give it time to spin up.\r

+    // Signal field is on with the appropriate LED\r
+    LED_D_ON();\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
     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
+//    LED_A_ON();\r

     GetSamplesFor14443Demod(TRUE, 2000, FALSE);\r
     GetSamplesFor14443Demod(TRUE, 2000, FALSE);\r

-    LED_A_OFF();\r
+//    LED_A_OFF();\r

 }\r
 
 //-----------------------------------------------------------------------------\r
 // Read a SRI512 ISO 14443 tag.\r
 }\r
 
 //-----------------------------------------------------------------------------\r
 // Read a SRI512 ISO 14443 tag.\r

-// 
+//

 // 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.
 // 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.


@@ -839,6 +885,8 @@ void ReadSRI512Iso14443(DWORD parameter)
     FpgaSetupSsc();\r
 \r
     // Now give it time to spin up.\r
     FpgaSetupSsc();\r
 \r
     // Now give it time to spin up.\r

+    // Signal field is on with the appropriate LED\r
+    LED_D_ON();\r

     FpgaWriteConfWord(\r
        FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);\r
     SpinDelay(200);\r
     FpgaWriteConfWord(\r
        FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);\r
     SpinDelay(200);\r


@@ -847,9 +895,9 @@ void ReadSRI512Iso14443(DWORD parameter)
     BYTE cmd1[] = { 0x06, 0x00, 0x97, 0x5b};\r
     CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
     TransmitFor14443();\r
     BYTE cmd1[] = { 0x06, 0x00, 0x97, 0x5b};\r
     CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
     TransmitFor14443();\r

-    LED_A_ON();\r
+//    LED_A_ON();\r

     GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
     GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r

-    LED_A_OFF();\r
+//    LED_A_OFF();\r

 
     if (Demod.len == 0) {
        DbpString("No response from tag");
 
     if (Demod.len == 0) {
        DbpString("No response from tag");


@@ -865,9 +913,9 @@ void ReadSRI512Iso14443(DWORD parameter)
     ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);\r
     CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
     TransmitFor14443();\r
     ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);\r
     CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
     TransmitFor14443();\r

-    LED_A_ON();\r
+//    LED_A_ON();\r

     GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
     GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r

-    LED_A_OFF();\r
+//    LED_A_OFF();\r

     if (Demod.len != 3) {
        DbpString("Expected 3 bytes from tag, got:");
        DbpIntegers(Demod.len,0x0,0x0);
     if (Demod.len != 3) {
        DbpString("Expected 3 bytes from tag, got:");
        DbpIntegers(Demod.len,0x0,0x0);


@@ -886,7 +934,30 @@ void ReadSRI512Iso14443(DWORD parameter)
        return;
     }
     // Tag is now selected,
        return;
     }
     // Tag is now selected,

-    // loop to read all 16 blocks, address from 0 to 15
+    // 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);
+       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);
+       // 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;
     DbpString("Tag memory dump, block 0 to 15");
     cmd1[0] = 0x08;
     i = 0x00;


@@ -899,9 +970,9 @@ void ReadSRI512Iso14443(DWORD parameter)
            ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);\r
            CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
            TransmitFor14443();\r
            ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);\r
            CodeIso14443bAsReader(cmd1, sizeof(cmd1));\r
            TransmitFor14443();\r

-           LED_A_ON();\r
+//         LED_A_ON();\r

            GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r
            GetSamplesFor14443Demod(TRUE, 2000,TRUE);\r

-           LED_A_OFF();
+//         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;
            if (Demod.len != 6) { // Check if we got an answer from the tag
                DbpString("Expected 6 bytes from tag, got less...");
                return;


@@ -909,13 +980,13 @@ void ReadSRI512Iso14443(DWORD parameter)
            // 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
            // 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, 0x0: ");
+               DbpString("CRC Error reading block! - Below: expected, got");

                DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5],0);
                // Do not return;, let's go on... (we should retry, maybe ?)
            }
            // Now print out the memory location:
            DbpString("Address , Contents, CRC");
                DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5],0);
                // 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[0]<<24) + (Demod.output[1]<<16) + (Demod.output[2]<<8) + Demod.output[3], (Demod.output[4]<<8)+Demod.output[5]);
+           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) {
                break;
            }
            if (i == 0xff) {
                break;
            }


@@ -934,6 +1005,13 @@ void ReadSRI512Iso14443(DWORD parameter)
 // triggering so that we start recording at the point that the tag is moved\r
 // near the reader.\r
 //-----------------------------------------------------------------------------\r
 // triggering so that we start recording at the point that the tag is moved\r
 // near the reader.\r
 //-----------------------------------------------------------------------------\r

+/*\r
+ * Memory usage for this function, (within BigBuf)\r
+ * 0-1023 : Demodulated samples receive (1024 bytes)\r
+ * 1024-1535 : Last Received command, 512 bytes (reader->tag)\r
+ * 1536-2047 : Last Received command, 512 bytes(tag->reader)\r
+ * 2048-2304 : DMA Buffer, 256 bytes (samples)
+ */\r

 void SnoopIso14443(void)\r
 {\r
     // We won't start recording the frames that we acquire until we trigger;\r
 void SnoopIso14443(void)\r
 {\r
     // We won't start recording the frames that we acquire until we trigger;\r


@@ -942,9 +1020,9 @@ void SnoopIso14443(void)
     BOOL triggered = FALSE;\r
 \r
     // The command (reader -> tag) that we're working on receiving.\r
     BOOL triggered = FALSE;\r
 \r
     // The command (reader -> tag) that we're working on receiving.\r

-    BYTE *receivedCmd = (((BYTE *)BigBuf) + 1024);\r
+    BYTE *receivedCmd = (BYTE *)(BigBuf) + 1024;\r

     // The response (tag -> reader) that we're working on receiving.\r
     // The response (tag -> reader) that we're working on receiving.\r

-    BYTE *receivedResponse = (((BYTE *)BigBuf) + 1536);\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
 \r
     // As we receive stuff, we copy it from receivedCmd or receivedResponse\r
     // into trace, along with its length and other annotations.\r


@@ -952,8 +1030,7 @@ void SnoopIso14443(void)
     int traceLen = 0;\r
 \r
     // The DMA buffer, used to stream samples from the FPGA.\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
+    SBYTE *dmaBuf = (SBYTE *)(BigBuf) + 2048;\r

     int lastRxCounter;\r
     SBYTE *upTo;\r
     int ci, cq;\r
     int lastRxCounter;\r
     SBYTE *upTo;\r
     int ci, cq;\r


@@ -963,7 +1040,8 @@ void SnoopIso14443(void)
     // information in the trace buffer.\r
     int samples = 0;\r
 \r
     // information in the trace buffer.\r
     int samples = 0;\r
 \r

-    memset(trace, 0x44, 1000);\r
+    // Initialize the trace buffer\r
+    memset(trace, 0x44, 1024);\r

 \r
     // Set up the demodulator for tag -> reader responses.\r
     Demod.output = receivedResponse;\r
 \r
     // Set up the demodulator for tag -> reader responses.\r
     Demod.output = receivedResponse;\r


@@ -977,6 +1055,8 @@ void SnoopIso14443(void)
     Uart.state = STATE_UNSYNCD;\r
 \r
     // And put the FPGA in the appropriate mode\r
     Uart.state = STATE_UNSYNCD;\r
 \r
     // And put the FPGA in the appropriate mode\r

+    // Signal field is off with the appropriate LED\r
+    LED_D_OFF();\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
     FpgaWriteConfWord(\r
        FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |\r
        FPGA_HF_READER_RX_XCORR_SNOOP);\r


@@ -987,17 +1067,15 @@ void SnoopIso14443(void)
     upTo = dmaBuf;\r
     lastRxCounter = DMA_BUFFER_SIZE;\r
     FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE);\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
     // And now we loop, receiving samples.\r
     for(;;) {\r

-        int behindBy = (lastRxCounter - PDC_RX_COUNTER(SSC_BASE)) &\r
+       int behindBy = (lastRxCounter - PDC_RX_COUNTER(SSC_BASE)) &\r

                                 (DMA_BUFFER_SIZE-1);\r
         if(behindBy > maxBehindBy) {\r
             maxBehindBy = behindBy;\r
                                 (DMA_BUFFER_SIZE-1);\r
         if(behindBy > maxBehindBy) {\r
             maxBehindBy = behindBy;\r

-            if(behindBy > 100) {\r
+            if(behindBy > (DMA_BUFFER_SIZE-2)) { // TODO: understand whether we can increase/decrease as we want or not?\r

                 DbpString("blew circular buffer!");\r
                 DbpString("blew circular buffer!");\r

+                DbpIntegers(behindBy,0,0);\r

                 goto done;\r
             }\r
         }\r
                 goto done;\r
             }\r
         }\r


@@ -1010,7 +1088,7 @@ void SnoopIso14443(void)
         if(upTo - dmaBuf > DMA_BUFFER_SIZE) {\r
             upTo -= DMA_BUFFER_SIZE;\r
             lastRxCounter += DMA_BUFFER_SIZE;\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_POINTER(SSC_BASE) = (DWORD) upTo;\r

             PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE;\r
         }\r
 \r
             PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE;\r
         }\r
 \r


@@ -1070,14 +1148,13 @@ void SnoopIso14443(void)
             if(traceLen > 1000) break;\r
 \r
             triggered = TRUE;\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
             // And ready to receive another response.\r
             memset(&Demod, 0, sizeof(Demod));\r
             Demod.output = receivedResponse;\r
             Demod.state = DEMOD_UNSYNCD;\r
         }\r

+               WDT_HIT();\r

 \r
         if(BUTTON_PRESS()) {\r
             DbpString("cancelled");\r
 \r
         if(BUTTON_PRESS()) {\r
             DbpString("cancelled");\r


@@ -1091,7 +1168,6 @@ void SnoopIso14443(void)
     DbpIntegers(Uart.byteCntMax, traceLen, 0x23);\r
 \r
 done:\r
     DbpIntegers(Uart.byteCntMax, traceLen, 0x23);\r
 \r
 done:\r

+       LED_D_OFF();\r

     PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE;\r
     PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE;\r

-    LED_A_OFF();\r
-    LED_B_OFF();\r

 }\r
 }\r