Fix 15 snoop (#752)
authorpwpiwi <pwpiwi@users.noreply.github.com>
Sat, 12 Jan 2019 12:28:26 +0000 (13:28 +0100)
committerGitHub <noreply@github.com>
Sat, 12 Jan 2019 12:28:26 +0000 (13:28 +0100)
* fixing hf 15: implement hf 15 snoop
* rename hf 15 record to hf 15 snoop
* speedup sampling / decoding:
*   new FPGA mode FPGA_HF_READER_RX_XCORR_AMPLITUDE implements amplitude(ci, cq) on FPGA
*   inlining the decoders in iso15693.c
*   inlining memcpy/memset in LogTrace()
*   giving up the moving correlator for SOF in Handle15693SamplesFromTag
* decode more of EOF in Handle15693SamplesFromTag()
* some refactoring

17 files changed:
CHANGELOG.md
armsrc/BigBuf.c
armsrc/appmain.c
armsrc/apps.h
armsrc/fpgaloader.h
armsrc/iclass.c
armsrc/iso14443a.c
armsrc/iso14443b.c
armsrc/iso15693.c
armsrc/iso15693.h [new file with mode: 0644]
client/cmdhf.c
client/cmdhf15.c
common/iso15693tools.h
fpga/fpga_hf.bit
fpga/fpga_hf.v
fpga/hi_read_rx_xcorr.v
include/usb_cmd.h

index 19db519529cc57bfae2fb04059ae638984c50c65..f2c285b4bfe8da98afbf3c677e96a8b98a9053d4 100644 (file)
@@ -12,7 +12,8 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
 
 ### Fixed
 - AC-Mode decoding for HitagS
-- Wrong UID at HitagS simulation 
+- Wrong UID at HitagS simulation
+- 'hf 15 sim' now works as expected (piwi)
 
 ### Added
 - Support Standard Communication Mode in HITAG S
@@ -24,6 +25,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
 - Added `hf fido` `assert` and `make` commands from fido2 protocol (authenticatorMakeCredential and authenticatorGetAssertion) (Merlok)
 - Added `lf paradox clone` to clone a Paradox card
 - Added `emv` commmands working for both contactless and smart cards (Merlok)
+- Added 'hf 15 snoop' (piwi)
 
 
 ## [v3.1.0][2018-10-10]
index 4b1264b6684abc375af7c0ca51967a82fc6730ab..e2f513115277b6a3b6bfadd9bae4b23b5a67e0dd 100644 (file)
@@ -36,8 +36,8 @@ static uint16_t BigBuf_hi = BIGBUF_SIZE;
 static uint8_t *emulator_memory = NULL;
 
 // trace related variables
-static uint16_t traceLen = 0;
-int tracing = 1; //Last global one.. todo static?
+static uint32_t traceLen = 0;
+static bool tracing = true;
 
 // get the address of BigBuf
 uint8_t *BigBuf_get_addr(void)
@@ -66,7 +66,7 @@ void BigBuf_Clear(void)
 // clear ALL of BigBuf
 void BigBuf_Clear_ext(bool verbose)
 {
-       memset(BigBuf,0,BIGBUF_SIZE);
+       memset(BigBuf, 0, BIGBUF_SIZE);
        if (verbose) 
                Dbprintf("Buffer cleared (%i bytes)",BIGBUF_SIZE);
 }
@@ -76,7 +76,7 @@ void BigBuf_Clear_EM(void){
 
 void BigBuf_Clear_keep_EM(void)
 {
-       memset(BigBuf,0,BigBuf_hi);
+       memset(BigBuf, 0, BigBuf_hi);
 }
 
 // allocate a chunk of memory from BigBuf. We allocate high memory first. The unallocated memory
@@ -162,8 +162,8 @@ bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_
 
        uint8_t *trace = BigBuf_get_addr();
 
-       uint16_t num_paritybytes = (iLen-1)/8 + 1;      // number of valid paritybytes in *parity
-       uint16_t duration = timestamp_end - timestamp_start;
+       uint32_t num_paritybytes = (iLen-1)/8 + 1;      // number of valid paritybytes in *parity
+       uint32_t duration = timestamp_end - timestamp_start;
 
        // Return when trace is full
        uint16_t max_traceLen = BigBuf_max_traceLen();
@@ -200,19 +200,23 @@ bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_
 
        // data bytes
        if (btBytes != NULL && iLen != 0) {
-               memcpy(trace + traceLen, btBytes, iLen);
+               for (int i = 0; i < iLen; i++) {
+                       trace[traceLen++] = *btBytes++;
+               }
        }
-       traceLen += iLen;
 
        // parity bytes
        if (num_paritybytes != 0) {
                if (parity != NULL) {
-                       memcpy(trace + traceLen, parity, num_paritybytes);
+                       for (int i = 0; i < num_paritybytes; i++) {
+                               trace[traceLen++] = *parity++;
+                       }
                } else {
-                       memset(trace + traceLen, 0x00, num_paritybytes);
+                       for (int i = 0; i < num_paritybytes; i++) {
+                               trace[traceLen++] = 0x00;
+                       }
                }
        }
-       traceLen += num_paritybytes;
 
        return true;
 }
@@ -259,8 +263,9 @@ int LogTraceHitag(const uint8_t * btBytes, int iBits, int iSamples, uint32_t dwP
        trace[traceLen++] = ((dwParity >> 24) & 0xff);
        trace[traceLen++] = iBits;
 
-       memcpy(trace + traceLen, btBytes, iLen);
-       traceLen += iLen;
+       for (int i = 0; i < iLen; i++) {
+               trace[traceLen++] = *btBytes++;
+       }
 
        return true;
 }
index 58c979dbd734925fa8b4697c4671d4a79f3826c9..1348ef0473124bb8317689c97d8a55bbad9fc8c3 100644 (file)
@@ -24,6 +24,7 @@
 #include "legicrfsim.h"
 #include "hitag2.h"
 #include "hitagS.h"
+#include "iso15693.h"
 #include "lfsampling.h"
 #include "BigBuf.h"
 #include "mifareutil.h"
@@ -1115,8 +1116,9 @@ void UsbPacketReceived(uint8_t *packet, int len)
                case CMD_ACQUIRE_RAW_ADC_SAMPLES_ISO_15693:
                        AcquireRawAdcSamplesIso15693();
                        break;
-               case CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693:
-                       RecordRawAdcSamplesIso15693();
+                       
+               case CMD_SNOOP_ISO_15693:
+                       SnoopIso15693();
                        break;
                        
                case CMD_ISO_15693_COMMAND:
index b9b1f3deaf4c59c4fea92be47a9db62203060c78..fad9e6eb7873ec6417be34be41cfb468d38121a4 100644 (file)
@@ -25,7 +25,6 @@
 
 extern const uint8_t OddByteParity[256];
 extern int rsamples;   // = 0;
-extern int tracing;    // = TRUE;
 extern uint8_t trigger;
 
 // This may be used (sparingly) to declare a function to be copied to
@@ -101,7 +100,6 @@ void RAMFUNC SnoopIso14443b(void);
 void SendRawCommand14443B(uint32_t, uint32_t, uint8_t, uint8_t[]);
 
 // Also used in iclass.c
-bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t len, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag);
 void GetParity(const uint8_t *pbtCmd, uint16_t len, uint8_t *parity);
 
 void RAMFUNC SniffMifare(uint8_t param);
@@ -150,15 +148,6 @@ void       OnSuccess();
 void   OnError(uint8_t reason);
 
 
-/// iso15693.h
-void RecordRawAdcSamplesIso15693(void);
-void AcquireRawAdcSamplesIso15693(void);
-void ReaderIso15693(uint32_t parameter);       // Simulate an ISO15693 reader - greg
-void SimTagIso15693(uint32_t parameter, uint8_t *uid); // simulate an ISO15693 tag - greg
-void BruteforceIso15693Afi(uint32_t speed); // find an AFI of a tag - atrox
-void DirectTag15693Command(uint32_t datalen,uint32_t speed, uint32_t recv, uint8_t data[]); // send arbitrary commands from CLI - atrox 
-void SetDebugIso15693(uint32_t flag);
-
 /// iclass.h
 void RAMFUNC SnoopIClass(void);
 void SimulateIClass(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint8_t *datain);
index 5aff6505654ca8e9cb3bed987c6ca0be2bbee5a0..0600067edd52c07d2aec566079d739a885fa49fc 100644 (file)
@@ -24,7 +24,7 @@ void SetupSpi(int mode);
 bool FpgaSetupSscDma(uint8_t *buf, uint16_t sample_count);
 void Fpga_print_status();
 int FpgaGetCurrent();
-#define FpgaDisableSscDma(void)        AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
+#define FpgaDisableSscDma(void) AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
 #define FpgaEnableSscDma(void) AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTEN;
 void SetAdcMuxFor(uint32_t whichGpio);
 
@@ -33,46 +33,47 @@ void SetAdcMuxFor(uint32_t whichGpio);
 #define FPGA_BITSTREAM_HF 2
 
 // Definitions for the FPGA commands.
-#define FPGA_CMD_SET_CONFREG                                           (1<<12)
-#define FPGA_CMD_SET_DIVISOR                                           (2<<12)
-#define FPGA_CMD_SET_USER_BYTE1                                                (3<<12)
+#define FPGA_CMD_SET_CONFREG                        (1<<12)
+#define FPGA_CMD_SET_DIVISOR                        (2<<12)
+#define FPGA_CMD_SET_USER_BYTE1                     (3<<12)
 // Definitions for the FPGA configuration word.
 // LF
-#define FPGA_MAJOR_MODE_LF_ADC                                         (0<<5)
-#define FPGA_MAJOR_MODE_LF_EDGE_DETECT                         (1<<5)
-#define FPGA_MAJOR_MODE_LF_PASSTHRU                                    (2<<5)
+#define FPGA_MAJOR_MODE_LF_ADC                      (0<<5)
+#define FPGA_MAJOR_MODE_LF_EDGE_DETECT              (1<<5)
+#define FPGA_MAJOR_MODE_LF_PASSTHRU                 (2<<5)
 // HF
-#define FPGA_MAJOR_MODE_HF_READER_TX                           (0<<5)
-#define FPGA_MAJOR_MODE_HF_READER_RX_XCORR                     (1<<5)
-#define FPGA_MAJOR_MODE_HF_SIMULATOR                           (2<<5)
-#define FPGA_MAJOR_MODE_HF_ISO14443A                           (3<<5)
-#define FPGA_MAJOR_MODE_HF_SNOOP                               (4<<5)
+#define FPGA_MAJOR_MODE_HF_READER_TX                (0<<5)
+#define FPGA_MAJOR_MODE_HF_READER_RX_XCORR          (1<<5)
+#define FPGA_MAJOR_MODE_HF_SIMULATOR                (2<<5)
+#define FPGA_MAJOR_MODE_HF_ISO14443A                (3<<5)
+#define FPGA_MAJOR_MODE_HF_SNOOP                    (4<<5)
 // BOTH
-#define FPGA_MAJOR_MODE_OFF                                                    (7<<5)
+#define FPGA_MAJOR_MODE_OFF                         (7<<5)
 // Options for LF_ADC
-#define FPGA_LF_ADC_READER_FIELD                                       (1<<0)
+#define FPGA_LF_ADC_READER_FIELD                    (1<<0)
 // Options for LF_EDGE_DETECT
-#define FPGA_CMD_SET_EDGE_DETECT_THRESHOLD                     FPGA_CMD_SET_USER_BYTE1
-#define FPGA_LF_EDGE_DETECT_READER_FIELD                       (1<<0)
-#define FPGA_LF_EDGE_DETECT_TOGGLE_MODE                                (1<<1)
+#define FPGA_CMD_SET_EDGE_DETECT_THRESHOLD          FPGA_CMD_SET_USER_BYTE1
+#define FPGA_LF_EDGE_DETECT_READER_FIELD            (1<<0)
+#define FPGA_LF_EDGE_DETECT_TOGGLE_MODE             (1<<1)
 // Options for the HF reader, tx to tag
-#define FPGA_HF_READER_TX_SHALLOW_MOD                          (1<<0)
+#define FPGA_HF_READER_TX_SHALLOW_MOD               (1<<0)
 // Options for the HF reader, correlating against rx from tag
-#define FPGA_HF_READER_RX_XCORR_848_KHZ                                (1<<0)
-#define FPGA_HF_READER_RX_XCORR_SNOOP                          (1<<1)
-#define FPGA_HF_READER_RX_XCORR_QUARTER_FREQ           (1<<2)
+#define FPGA_HF_READER_RX_XCORR_848_KHZ             (1<<0)
+#define FPGA_HF_READER_RX_XCORR_SNOOP               (1<<1)
+#define FPGA_HF_READER_RX_XCORR_QUARTER_FREQ        (1<<2)
+#define FPGA_HF_READER_RX_XCORR_AMPLITUDE           (1<<3)
 // Options for the HF simulated tag, how to modulate
-#define FPGA_HF_SIMULATOR_NO_MODULATION                                (0<<0)
-#define FPGA_HF_SIMULATOR_MODULATE_BPSK                                (1<<0)
-#define FPGA_HF_SIMULATOR_MODULATE_212K                                (2<<0)
-#define FPGA_HF_SIMULATOR_MODULATE_424K                                (4<<0)
-#define FPGA_HF_SIMULATOR_MODULATE_424K_8BIT           0x5//101
+#define FPGA_HF_SIMULATOR_NO_MODULATION             (0<<0)
+#define FPGA_HF_SIMULATOR_MODULATE_BPSK             (1<<0)
+#define FPGA_HF_SIMULATOR_MODULATE_212K             (2<<0)
+#define FPGA_HF_SIMULATOR_MODULATE_424K             (4<<0)
+#define FPGA_HF_SIMULATOR_MODULATE_424K_8BIT        0x5//101
 
 // Options for ISO14443A
-#define FPGA_HF_ISO14443A_SNIFFER                                      (0<<0)
-#define FPGA_HF_ISO14443A_TAGSIM_LISTEN                                (1<<0)
-#define FPGA_HF_ISO14443A_TAGSIM_MOD                           (2<<0)
-#define FPGA_HF_ISO14443A_READER_LISTEN                                (3<<0)
-#define FPGA_HF_ISO14443A_READER_MOD                           (4<<0)
+#define FPGA_HF_ISO14443A_SNIFFER                   (0<<0)
+#define FPGA_HF_ISO14443A_TAGSIM_LISTEN             (1<<0)
+#define FPGA_HF_ISO14443A_TAGSIM_MOD                (2<<0)
+#define FPGA_HF_ISO14443A_READER_LISTEN             (3<<0)
+#define FPGA_HF_ISO14443A_READER_MOD                (4<<0)
 
 #endif
index 1591a062126b8fab9d2a88cb9ee093aa2ae7aa84..d27fc1c6f70ff533fe94b70e0590aae541a8100f 100644 (file)
@@ -751,12 +751,9 @@ void RAMFUNC SnoopIClass(void)
 
                        //if(!LogTrace(Uart.output,Uart.byteCnt, rsamples, Uart.parityBits,true)) break;
                        //if(!LogTrace(NULL, 0, Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, 0, true)) break;
-                       if(tracing)     {
-                               uint8_t parity[MAX_PARITY_SIZE];
-                               GetParity(Uart.output, Uart.byteCnt, parity);
-                               LogTrace(Uart.output,Uart.byteCnt, time_start, time_stop, parity, true);
-                       }
-
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       GetParity(Uart.output, Uart.byteCnt, parity);
+                       LogTrace(Uart.output,Uart.byteCnt, time_start, time_stop, parity, true);
 
                        /* And ready to receive another command. */
                    Uart.state = STATE_UNSYNCD;
@@ -779,11 +776,9 @@ void RAMFUNC SnoopIClass(void)
                        rsamples = samples - Demod.samples;
                    LED_B_ON();
 
-                       if(tracing)     {
-                               uint8_t parity[MAX_PARITY_SIZE];
-                               GetParity(Demod.output, Demod.len, parity);
-                               LogTrace(Demod.output, Demod.len, time_start, time_stop, parity, false);
-                       }
+                       uint8_t parity[MAX_PARITY_SIZE];
+                       GetParity(Demod.output, Demod.len, parity);
+                       LogTrace(Demod.output, Demod.len, time_start, time_stop, parity, false);
 
                    // And ready to receive another response.
                    memset(&Demod, 0, sizeof(Demod));
@@ -1322,20 +1317,17 @@ int doIClassSimulation( int simulationMode, uint8_t *reader_mac_buf)
                        t2r_time = GetCountSspClk();
                }
 
-               if (tracing) {
-                       uint8_t parity[MAX_PARITY_SIZE];
-                       GetParity(receivedCmd, len, parity);
-                       LogTrace(receivedCmd,len, (r2t_time-time_0)<< 4, (r2t_time-time_0) << 4, parity, true);
-
-                       if (trace_data != NULL) {
-                               GetParity(trace_data, trace_data_size, parity);
-                               LogTrace(trace_data, trace_data_size, (t2r_time-time_0) << 4, (t2r_time-time_0) << 4, parity, false);
-                       }
-                       if(!tracing) {
-                               DbpString("Trace full");
-                               //break;
-                       }
+               uint8_t parity[MAX_PARITY_SIZE];
+               GetParity(receivedCmd, len, parity);
+               LogTrace(receivedCmd,len, (r2t_time-time_0)<< 4, (r2t_time-time_0) << 4, parity, true);
 
+               if (trace_data != NULL) {
+                       GetParity(trace_data, trace_data_size, parity);
+                       LogTrace(trace_data, trace_data_size, (t2r_time-time_0) << 4, (t2r_time-time_0) << 4, parity, false);
+               }
+               if(!get_tracing()) {
+                       DbpString("Trace full");
+                       //break;
                }
        }
 
@@ -1509,11 +1501,9 @@ void ReaderTransmitIClass(uint8_t* frame, int len)
                LED_A_ON();
 
        // Store reader command in buffer
-       if (tracing) {
-               uint8_t par[MAX_PARITY_SIZE];
-               GetParity(frame, len, par);
-               LogTrace(frame, len, rsamples, rsamples, par, true);
-       }
+       uint8_t par[MAX_PARITY_SIZE];
+       GetParity(frame, len, par);
+       LogTrace(frame, len, rsamples, rsamples, par, true);
 }
 
 //-----------------------------------------------------------------------------
@@ -1569,11 +1559,9 @@ int ReaderReceiveIClass(uint8_t* receivedAnswer)
   int samples = 0;
   if (!GetIClassAnswer(receivedAnswer,160,&samples,0)) return false;
   rsamples += samples;
-  if (tracing) {
-       uint8_t parity[MAX_PARITY_SIZE];
-       GetParity(receivedAnswer, Demod.len, parity);
-       LogTrace(receivedAnswer,Demod.len,rsamples,rsamples,parity,false);
-  }
+  uint8_t parity[MAX_PARITY_SIZE];
+  GetParity(receivedAnswer, Demod.len, parity);
+  LogTrace(receivedAnswer,Demod.len,rsamples,rsamples,parity,false);
   if(samples == 0) return false;
   return Demod.len;
 }
@@ -1715,7 +1703,7 @@ void ReaderIClass(uint8_t arg0) {
                // if only looking for one card try 2 times if we missed it the first time
                if (try_once && tryCnt > 2) break; 
                tryCnt++;
-               if(!tracing) {
+               if(!get_tracing()) {
                        DbpString("Trace full");
                        break;
                }
@@ -1828,7 +1816,7 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
        
                WDT_HIT();
 
-               if(!tracing) {
+               if(!get_tracing()) {
                        DbpString("Trace full");
                        break;
                }
index 7bf8f5af7d110e4f440b933ebed4f5c1f8138052..f5fcc91c49dbdd530c2b2b0f74499c3634e3fda9 100644 (file)
@@ -1220,7 +1220,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
                        EmSendPrecompiledCmd(p_response);
                }
                
-               if (!tracing) {
+               if (!get_tracing()) {
                        Dbprintf("Trace Full. Simulation stopped.");
                        break;
                }
@@ -1619,9 +1619,7 @@ void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t
                LED_A_ON();
   
        // Log reader command in trace buffer
-       if (tracing) {
-               LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, true);
-       }
+       LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, true);
 }
 
 
@@ -1652,9 +1650,7 @@ void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
 static int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
 {
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) return false;
-       if (tracing) {
-               LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
-       }
+       LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
        return Demod.len;
 }
 
@@ -1662,9 +1658,7 @@ static int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t
 int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
 {
        if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) return false;
-       if (tracing) {
-               LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
-       }
+       LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
        return Demod.len;
 }
 
index cb8567fa570533ae8cee27283ca0e37f22429b78..76d7a0753845f3453de413fe6c0a5ff7e96c5edd 100644 (file)
@@ -386,10 +386,7 @@ void SimulateIso14443bTag(void)
                        break;
                }
 
-               if (tracing) {
-                       uint8_t parity[MAX_PARITY_SIZE];
-                       LogTrace(receivedCmd, len, 0, 0, parity, true);
-               }
+               LogTrace(receivedCmd, len, 0, 0, NULL, true);
 
                // Good, look at the command now.
                if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
@@ -463,10 +460,7 @@ void SimulateIso14443bTag(void)
                }
 
                // trace the response:
-               if (tracing) {
-                       uint8_t parity[MAX_PARITY_SIZE];
-                       LogTrace(resp, respLen, 0, 0, parity, false);
-               }
+               LogTrace(resp, respLen, 0, 0, NULL, false);
 
        }
 }
@@ -763,9 +757,8 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
 
        if (!quiet) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", maxBehindBy, samples, gotFrame, Demod.len, Demod.sumI, Demod.sumQ);
        //Tracing
-       if (tracing && Demod.len > 0) {
-               uint8_t parity[MAX_PARITY_SIZE];
-               LogTrace(Demod.output, Demod.len, 0, 0, parity, false);
+       if (Demod.len > 0) {
+               LogTrace(Demod.output, Demod.len, 0, 0, NULL, false);
        }
 }
 
@@ -858,10 +851,7 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 {
        CodeIso14443bAsReader(cmd, len);
        TransmitFor14443b();
-       if (tracing) {
-               uint8_t parity[MAX_PARITY_SIZE];
-               LogTrace(cmd,len, 0, 0, parity, true);
-       }
+       LogTrace(cmd,len, 0, 0, NULL, true);
 }
 
 /* Sends an APDU to the tag
@@ -1153,7 +1143,6 @@ void RAMFUNC SnoopIso14443b(void)
        upTo = dmaBuf;
        lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
-       uint8_t parity[MAX_PARITY_SIZE];
 
        bool TagIsActive = false;
        bool ReaderIsActive = false;
@@ -1198,9 +1187,7 @@ void RAMFUNC SnoopIso14443b(void)
                if (!TagIsActive) {                                                     // no need to try decoding reader data if the tag is sending
                        if(Handle14443bUartBit(ci & 0x01)) {
                                triggered = true;
-                               if(tracing) {
-                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
-                               }
+                               LogTrace(Uart.output, Uart.byteCnt, samples, samples, NULL, true);
                                /* And ready to receive another command. */
                                UartReset();
                                /* And also reset the demod code, which might have been */
@@ -1209,9 +1196,7 @@ void RAMFUNC SnoopIso14443b(void)
                        }
                        if(Handle14443bUartBit(cq & 0x01)) {
                                triggered = true;
-                               if(tracing) {
-                                       LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
-                               }
+                               LogTrace(Uart.output, Uart.byteCnt, samples, samples, NULL, true);
                                /* And ready to receive another command. */
                                UartReset();
                                /* And also reset the demod code, which might have been */
@@ -1223,13 +1208,8 @@ void RAMFUNC SnoopIso14443b(void)
 
                if(!ReaderIsActive && triggered) {                                              // no need to try decoding tag data if the reader is sending or not yet triggered
                        if(Handle14443bSamplesDemod(ci/2, cq/2)) {
-
                                //Use samples as a time measurement
-                               if(tracing)
-                               {
-                                       uint8_t parity[MAX_PARITY_SIZE];
-                                       LogTrace(Demod.output, Demod.len, samples, samples, parity, false);
-                               }
+                               LogTrace(Demod.output, Demod.len, samples, samples, NULL, false);
                                // And ready to receive another response.
                                DemodReset();
                        }
index da2aab69bfa1d6971bc3c3a88edac8340e7f88f2..f6868297ae33e02ecd9e1de6611729aeffa89fa2 100644 (file)
 // *) add anti-collision support for inventory-commands
 // *) read security status of a block
 // *) sniffing and simulation do not support two subcarrier modes.
-// *) remove or refactor code under "depricated"
+// *) remove or refactor code under "deprecated"
 // *) document all the functions
 
+#include "iso15693.h"
 
 #include "proxmark3.h"
 #include "util.h"
@@ -58,6 +59,7 @@
 #include "iso15693tools.h"
 #include "protocols.h"
 #include "cmd.h"
+#include "BigBuf.h"
 
 #define arraylen(x) (sizeof(x)/sizeof((x)[0]))
 
@@ -68,27 +70,20 @@ static int DEBUG = 0;
 // This section basicly contains transmission and receiving of bits
 ///////////////////////////////////////////////////////////////////////
 
-#define FrameSOF              Iso15693FrameSOF
-#define Logic0                Iso15693Logic0
-#define Logic1                Iso15693Logic1
-#define FrameEOF              Iso15693FrameEOF
-
 #define Crc(data,datalen)     Iso15693Crc(data,datalen)
 #define AddCrc(data,datalen)  Iso15693AddCrc(data,datalen)
 #define sprintUID(target,uid)  Iso15693sprintUID(target,uid)
 
-// approximate amplitude=sqrt(ci^2+cq^2) by amplitude = max(|ci|,|cq|) + 1/2*min(|ci|,|cq|)
-#define AMPLITUDE(ci, cq) (MAX(ABS(ci), ABS(cq)) + MIN(ABS(ci), ABS(cq))/2)
-
 // buffers
-#define ISO15693_DMA_BUFFER_SIZE     128
-#define ISO15693_MAX_RESPONSE_LENGTH  36 // allows read single block with the maximum block size of 256bits. Read multiple blocks not supported yet
-#define ISO15693_MAX_COMMAND_LENGTH   45 // allows write single block with the maximum block size of 256bits. Write multiple blocks not supported yet
+#define ISO15693_DMA_BUFFER_SIZE        2048 // must be a power of 2
+#define ISO15693_MAX_RESPONSE_LENGTH     36 // allows read single block with the maximum block size of 256bits. Read multiple blocks not supported yet
+#define ISO15693_MAX_COMMAND_LENGTH      45 // allows write single block with the maximum block size of 256bits. Write multiple blocks not supported yet
 
 // timing. Delays in SSP_CLK ticks.
 #define DELAY_READER_TO_ARM            8
 #define DELAY_ARM_TO_READER            1
 #define DELAY_ISO15693_VCD_TO_VICC   132 // 132/423.75kHz = 311.5us from end of EOF to start of tag response
+#define DELAY_ISO15693_VICC_TO_VCD  1017 // 1017/3.39MHz = 300us between end of tag response and next reader command
 
 // ---------------------------
 // Signal Processing
@@ -271,11 +266,13 @@ static void CodeIso15693AsTag(uint8_t *cmd, int n)
 
 
 // Transmit the command (to the tag) that was placed in cmd[].
-static void TransmitTo15693Tag(const uint8_t *cmd, int len)
+static void TransmitTo15693Tag(const uint8_t *cmd, int len, uint32_t start_time)
 {
        FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
 
+       while (GetCountSspClk() < start_time);
+
        LED_B_ON();
     for(int c = 0; c < len; ) {
         if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
@@ -302,6 +299,7 @@ static void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t start
        }
 
        while (GetCountSspClk() < (start_time & 0xfffffff8)) ;
+
        AT91C_BASE_SSC->SSC_THR = 0x00; // clear TXRDY
 
        LED_C_ON();
@@ -329,7 +327,7 @@ static void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t start
 
 //=============================================================================
 // An ISO 15693 decoder for tag responses (one subcarrier only).
-// Uses cross correlation to identify the SOF, each bit, and EOF.
+// Uses cross correlation to identify each bit and EOF.
 // This function is called 8 times per bit (every 2 subcarrier cycles).
 // Subcarrier frequency fs is 424kHz, 1/fs = 2,36us,
 // i.e. function is called every 4,72us
@@ -341,16 +339,15 @@ static void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t start
 //          false if we are still waiting for some more
 //=============================================================================
 
-#define SUBCARRIER_DETECT_THRESHOLD    2
-#define SOF_CORRELATOR_LEN (1<<5)
+#define NOISE_THRESHOLD    30      // don't try to correlate noise
 
 typedef struct DecodeTag {
        enum {
-               STATE_TAG_UNSYNCD,
-               STATE_TAG_AWAIT_SOF_1,
-               STATE_TAG_AWAIT_SOF_2,
+               STATE_TAG_SOF_LOW,
+               STATE_TAG_SOF_HIGH,
+               STATE_TAG_SOF_HIGH_END,
                STATE_TAG_RECEIVING_DATA,
-               STATE_TAG_AWAIT_EOF
+               STATE_TAG_EOF
        }         state;
        int       bitCount;
        int       posCount;
@@ -361,84 +358,68 @@ typedef struct DecodeTag {
                SOF_PART2
        }         lastBit;
        uint16_t  shiftReg;
+       uint16_t  max_len;
        uint8_t   *output;
        int       len;
        int       sum1, sum2;
-       uint8_t   SOF_low;
-       uint8_t   SOF_high;
-       uint8_t   SOF_last;
-       int32_t   SOF_corr;
-       int32_t   SOF_corr_prev;
-       uint8_t   SOF_correlator[SOF_CORRELATOR_LEN];
 } DecodeTag_t;
 
-static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTag)
+
+static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint16_t amplitude, DecodeTag_t *DecodeTag)
 {
        switch(DecodeTag->state) {
-               case STATE_TAG_UNSYNCD:
-                       // initialize SOF correlator. We are looking for 12 samples low and 12 samples high.
-                       DecodeTag->SOF_low = 0;
-                       DecodeTag->SOF_high = 12;
-                       DecodeTag->SOF_last = 23;
-                       memset(DecodeTag->SOF_correlator, 0x00, DecodeTag->SOF_last + 1);
-                       DecodeTag->SOF_correlator[DecodeTag->SOF_last] = AMPLITUDE(ci,cq);
-                       DecodeTag->SOF_corr = DecodeTag->SOF_correlator[DecodeTag->SOF_last];
-                       DecodeTag->SOF_corr_prev = DecodeTag->SOF_corr;
-                       // initialize Decoder
-                       DecodeTag->posCount = 0;
-                       DecodeTag->bitCount = 0;
-                       DecodeTag->len = 0;
-                       DecodeTag->state = STATE_TAG_AWAIT_SOF_1;
-                       break;
-
-               case STATE_TAG_AWAIT_SOF_1:
-                       // calculate the correlation in real time. Look at differences only.
-                       DecodeTag->SOF_corr += DecodeTag->SOF_correlator[DecodeTag->SOF_low++];
-                       DecodeTag->SOF_corr -= 2*DecodeTag->SOF_correlator[DecodeTag->SOF_high++];
-                       DecodeTag->SOF_last++;
-                       DecodeTag->SOF_low &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_high &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_last &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_correlator[DecodeTag->SOF_last] = AMPLITUDE(ci,cq);
-                       DecodeTag->SOF_corr += DecodeTag->SOF_correlator[DecodeTag->SOF_last];
-
-                       // if correlation increases for 10 consecutive samples, we are close to maximum correlation
-                       if (DecodeTag->SOF_corr > DecodeTag->SOF_corr_prev + SUBCARRIER_DETECT_THRESHOLD) {
+               case STATE_TAG_SOF_LOW: 
+                       // waiting for 12 times low (11 times low is accepted as well)
+                       if (amplitude < NOISE_THRESHOLD) {
                                DecodeTag->posCount++;
                        } else {
-                               DecodeTag->posCount = 0;
+                               if (DecodeTag->posCount > 10) {
+                                       DecodeTag->posCount = 1;
+                                       DecodeTag->sum1 = 0;
+                                       DecodeTag->state = STATE_TAG_SOF_HIGH;
+                               } else {
+                                       DecodeTag->posCount = 0;
+                               }
                        }
-
-                       if (DecodeTag->posCount == 10) {        // correlation increased 10 times
-                               DecodeTag->state = STATE_TAG_AWAIT_SOF_2;
+                       break;
+                       
+               case STATE_TAG_SOF_HIGH:
+                       // waiting for 10 times high. Take average over the last 8
+                       if (amplitude > NOISE_THRESHOLD) {
+                               DecodeTag->posCount++;
+                               if (DecodeTag->posCount > 2) {
+                                       DecodeTag->sum1 += amplitude; // keep track of average high value
+                               }
+                               if (DecodeTag->posCount == 10) {
+                                       DecodeTag->sum1 >>= 4;        // calculate half of average high value (8 samples)
+                                       DecodeTag->state = STATE_TAG_SOF_HIGH_END;
+                               }
+                       } else { // high phase was too short
+                               DecodeTag->posCount = 1;
+                               DecodeTag->state = STATE_TAG_SOF_LOW;
                        }
-
-                       DecodeTag->SOF_corr_prev = DecodeTag->SOF_corr;
-
                        break;
 
-               case STATE_TAG_AWAIT_SOF_2:
-                       // calculate the correlation in real time. Look at differences only.
-                       DecodeTag->SOF_corr += DecodeTag->SOF_correlator[DecodeTag->SOF_low++];
-                       DecodeTag->SOF_corr -= 2*DecodeTag->SOF_correlator[DecodeTag->SOF_high++];
-                       DecodeTag->SOF_last++;
-                       DecodeTag->SOF_low &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_high &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_last &= (SOF_CORRELATOR_LEN-1);
-                       DecodeTag->SOF_correlator[DecodeTag->SOF_last] = AMPLITUDE(ci,cq);
-                       DecodeTag->SOF_corr += DecodeTag->SOF_correlator[DecodeTag->SOF_last];
-
-                       if (DecodeTag->SOF_corr >= DecodeTag->SOF_corr_prev) { // we are looking for the maximum correlation
-                               DecodeTag->SOF_corr_prev = DecodeTag->SOF_corr;
-                       } else {
-                               DecodeTag->lastBit = SOF_PART1;  // detected 1st part of SOF
-                               DecodeTag->sum1 = DecodeTag->SOF_correlator[DecodeTag->SOF_last];
+               case STATE_TAG_SOF_HIGH_END:
+                       // waiting for a falling edge
+                       if (amplitude < DecodeTag->sum1) {   // signal drops below 50% average high: a falling edge
+                               DecodeTag->lastBit = SOF_PART1;  // detected 1st part of SOF (12 samples low and 12 samples high)
+                               DecodeTag->shiftReg = 0;
+                               DecodeTag->bitCount = 0;
+                               DecodeTag->len = 0;
+                               DecodeTag->sum1 = amplitude;
                                DecodeTag->sum2 = 0;
                                DecodeTag->posCount = 2;
                                DecodeTag->state = STATE_TAG_RECEIVING_DATA;
                                LED_C_ON();
+                       } else {
+                               DecodeTag->posCount++;
+                               if (DecodeTag->posCount > 13) { // high phase too long
+                                       DecodeTag->posCount = 0;
+                                       DecodeTag->state = STATE_TAG_SOF_LOW;
+                                       LED_C_OFF();
+                               }
                        }
-
                        break;
 
                case STATE_TAG_RECEIVING_DATA:
@@ -446,23 +427,27 @@ static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTa
                                DecodeTag->sum1 = 0;
                                DecodeTag->sum2 = 0;
                        }
-
                        if (DecodeTag->posCount <= 4) {
-                               DecodeTag->sum1 += AMPLITUDE(ci, cq);
+                               DecodeTag->sum1 += amplitude;
                        } else {
-                               DecodeTag->sum2 += AMPLITUDE(ci, cq);
+                               DecodeTag->sum2 += amplitude;
                        }
-
                        if (DecodeTag->posCount == 8) {
-                               int16_t corr_1 = (DecodeTag->sum2 - DecodeTag->sum1) / 4;
-                               int16_t corr_0 = (DecodeTag->sum1 - DecodeTag->sum2) / 4;
-                               int16_t corr_EOF = (DecodeTag->sum1 + DecodeTag->sum2) / 8;
+                               int32_t corr_1 = DecodeTag->sum2 - DecodeTag->sum1;
+                               int32_t corr_0 = -corr_1;
+                               int32_t corr_EOF = (DecodeTag->sum1 + DecodeTag->sum2) / 2;
                                if (corr_EOF > corr_0 && corr_EOF > corr_1) {
-                                       DecodeTag->state = STATE_TAG_AWAIT_EOF;
+                                       if (DecodeTag->lastBit == LOGIC0) {  // this was already part of EOF
+                                               DecodeTag->state = STATE_TAG_EOF;
+                                       } else {
+                                               DecodeTag->posCount = 0;
+                                               DecodeTag->state = STATE_TAG_SOF_LOW;
+                                               LED_C_OFF();
+                                       }
                                } else if (corr_1 > corr_0) {
                                        // logic 1
                                        if (DecodeTag->lastBit == SOF_PART1) { // still part of SOF
-                                               DecodeTag->lastBit = SOF_PART2;
+                                               DecodeTag->lastBit = SOF_PART2;    // SOF completed
                                        } else {
                                                DecodeTag->lastBit = LOGIC1;
                                                DecodeTag->shiftReg >>= 1;
@@ -471,6 +456,12 @@ static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTa
                                                if (DecodeTag->bitCount == 8) {
                                                        DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
                                                        DecodeTag->len++;
+                                                       if (DecodeTag->len > DecodeTag->max_len) {
+                                                               // buffer overflow, give up
+                                                               DecodeTag->posCount = 0;
+                                                               DecodeTag->state = STATE_TAG_SOF_LOW;
+                                                               LED_C_OFF();
+                                                       }
                                                        DecodeTag->bitCount = 0;
                                                        DecodeTag->shiftReg = 0;
                                                }
@@ -478,7 +469,8 @@ static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTa
                                } else {
                                        // logic 0
                                        if (DecodeTag->lastBit == SOF_PART1) { // incomplete SOF
-                                               DecodeTag->state = STATE_TAG_UNSYNCD;
+                                               DecodeTag->posCount = 0;
+                                               DecodeTag->state = STATE_TAG_SOF_LOW;
                                                LED_C_OFF();
                                        } else {
                                                DecodeTag->lastBit = LOGIC0;
@@ -487,6 +479,12 @@ static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTa
                                                if (DecodeTag->bitCount == 8) {
                                                        DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
                                                        DecodeTag->len++;
+                                                       if (DecodeTag->len > DecodeTag->max_len) {
+                                                               // buffer overflow, give up
+                                                               DecodeTag->posCount = 0;
+                                                               DecodeTag->state = STATE_TAG_SOF_LOW;
+                                                               LED_C_OFF();
+                                                       }
                                                        DecodeTag->bitCount = 0;
                                                        DecodeTag->shiftReg = 0;
                                                }
@@ -497,89 +495,106 @@ static int Handle15693SamplesFromTag(int8_t ci, int8_t cq, DecodeTag_t *DecodeTa
                        DecodeTag->posCount++;
                        break;
 
-               case STATE_TAG_AWAIT_EOF:
-                       if (DecodeTag->lastBit == LOGIC0) {  // this was already part of EOF
-                               LED_C_OFF();
-                               return true;
+               case STATE_TAG_EOF:
+                       if (DecodeTag->posCount == 1) {
+                               DecodeTag->sum1 = 0;
+                               DecodeTag->sum2 = 0;
+                       }
+                       if (DecodeTag->posCount <= 4) {
+                               DecodeTag->sum1 += amplitude;
                        } else {
-                               DecodeTag->state = STATE_TAG_UNSYNCD;
-                               LED_C_OFF();
+                               DecodeTag->sum2 += amplitude;
                        }
+                       if (DecodeTag->posCount == 8) {
+                               int32_t corr_1 = DecodeTag->sum2 - DecodeTag->sum1;
+                               int32_t corr_0 = -corr_1;
+                               int32_t corr_EOF = (DecodeTag->sum1 + DecodeTag->sum2) / 2;
+                               if (corr_EOF > corr_0 || corr_1 > corr_0) {
+                                       DecodeTag->posCount = 0;
+                                       DecodeTag->state = STATE_TAG_SOF_LOW;
+                                       LED_C_OFF();
+                               } else {
+                                       LED_C_OFF();
+                                       return true;
+                               }
+                       }
+                       DecodeTag->posCount++;
                        break;
 
-               default:
-                       DecodeTag->state = STATE_TAG_UNSYNCD;
-                       LED_C_OFF();
-                       break;
        }
 
        return false;
 }
 
 
-static void DecodeTagInit(DecodeTag_t *DecodeTag, uint8_t *data)
+static void DecodeTagInit(DecodeTag_t *DecodeTag, uint8_t *data, uint16_t max_len)
 {
+       DecodeTag->posCount = 0;
+       DecodeTag->state = STATE_TAG_SOF_LOW;
        DecodeTag->output = data;
-       DecodeTag->state = STATE_TAG_UNSYNCD;
+       DecodeTag->max_len = max_len;
+}
+
+
+static void DecodeTagReset(DecodeTag_t *DecodeTag)
+{
+       DecodeTag->posCount = 0;
+       DecodeTag->state = STATE_TAG_SOF_LOW;
 }
 
+
 /*
  *  Receive and decode the tag response, also log to tracebuffer
  */
-static int GetIso15693AnswerFromTag(uint8_t* response, int timeout)
+static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int timeout)
 {
-       int maxBehindBy = 0;
-       int lastRxCounter, samples = 0;
-       int8_t ci, cq;
+       int samples = 0;
        bool gotFrame = false;
 
-       uint16_t dmaBuf[ISO15693_DMA_BUFFER_SIZE];
-
+       uint16_t *dmaBuf = (uint16_t*)BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE*sizeof(uint16_t));
+       
        // the Decoder data structure
-       DecodeTag_t DecodeTag;
-       DecodeTagInit(&DecodeTag, response);
+       DecodeTag_t DecodeTag = { 0 };
+       DecodeTagInit(&DecodeTag, response, max_len);
 
        // wait for last transfer to complete
        while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
 
        // And put the FPGA in the appropriate mode
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
 
        // Setup and start DMA.
        FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
        FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
        uint16_t *upTo = dmaBuf;
-       lastRxCounter = ISO15693_DMA_BUFFER_SIZE;
 
        for(;;) {
-               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO15693_DMA_BUFFER_SIZE-1);
-               if(behindBy > maxBehindBy) {
-                       maxBehindBy = behindBy;
-               }
+               uint16_t behindBy = ((uint16_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
 
-               if (behindBy < 1) continue;
+               if (behindBy == 0) continue;
 
-               ci = (int8_t)(*upTo >> 8);
-               cq = (int8_t)(*upTo & 0xff);
+               uint16_t tagdata = *upTo++;
 
-               upTo++;
-               lastRxCounter--;
                if(upTo >= dmaBuf + ISO15693_DMA_BUFFER_SIZE) {                // we have read all of the DMA buffer content.
                        upTo = dmaBuf;                                             // start reading the circular buffer from the beginning
-                       lastRxCounter += ISO15693_DMA_BUFFER_SIZE;
+                       if(behindBy > (9*ISO15693_DMA_BUFFER_SIZE/10)) {
+                               Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy);
+                               break;
+                       }
                }
                if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
                        AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
                }
+
                samples++;
 
-               if (Handle15693SamplesFromTag(ci, cq, &DecodeTag)) {
+               if (Handle15693SamplesFromTag(tagdata, &DecodeTag)) {
                        gotFrame = true;
                        break;
                }
 
-               if(samples > timeout && DecodeTag.state < STATE_TAG_RECEIVING_DATA) {
+               if (samples > timeout && DecodeTag.state < STATE_TAG_RECEIVING_DATA) {
                        DecodeTag.len = 0;
                        break;
                }
@@ -587,11 +602,12 @@ static int GetIso15693AnswerFromTag(uint8_t* response, int timeout)
        }
 
        FpgaDisableSscDma();
+       BigBuf_free();
+       
+       if (DEBUG) Dbprintf("samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
+                           samples, gotFrame, DecodeTag.state, DecodeTag.len, DecodeTag.bitCount, DecodeTag.posCount);
 
-       if (DEBUG) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
-                           maxBehindBy, samples, gotFrame, DecodeTag.state, DecodeTag.len, DecodeTag.bitCount, DecodeTag.posCount);
-
-       if (tracing && DecodeTag.len > 0) {
+       if (DecodeTag.len > 0) {
                LogTrace(DecodeTag.output, DecodeTag.len, 0, 0, NULL, false);
        }
 
@@ -636,14 +652,32 @@ typedef struct DecodeReader {
 } DecodeReader_t;
 
 
-static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader)
+static void DecodeReaderInit(DecodeReader_t* DecodeReader, uint8_t *data, uint16_t max_len)
+{
+       DecodeReader->output = data;
+       DecodeReader->byteCountMax = max_len;
+       DecodeReader->state = STATE_READER_UNSYNCD;
+       DecodeReader->byteCount = 0;
+       DecodeReader->bitCount = 0;
+       DecodeReader->posCount = 1;
+       DecodeReader->shiftReg = 0;
+}
+
+
+static void DecodeReaderReset(DecodeReader_t* DecodeReader)
+{
+       DecodeReader->state = STATE_READER_UNSYNCD;
+}
+
+
+static int inline __attribute__((always_inline)) Handle15693SampleFromReader(uint8_t bit, DecodeReader_t *restrict DecodeReader)
 {
        switch(DecodeReader->state) {
                case STATE_READER_UNSYNCD:
                        if(!bit) {
                                // we went low, so this could be the beginning of a SOF
-                               DecodeReader->state = STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF;
                                DecodeReader->posCount = 1;
+                               DecodeReader->state = STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF;
                        }
                        break;
 
@@ -651,13 +685,13 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                        DecodeReader->posCount++;
                        if(bit) { // detected rising edge
                                if(DecodeReader->posCount < 4) { // rising edge too early (nominally expected at 5)
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                } else { // SOF
                                        DecodeReader->state = STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF;
                                }
                        } else {
                                if(DecodeReader->posCount > 5) { // stayed low for too long
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                } else {
                                        // do nothing, keep waiting
                                }
@@ -668,19 +702,19 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                        DecodeReader->posCount++;
                        if(!bit) { // detected a falling edge
                                if (DecodeReader->posCount < 20) {         // falling edge too early (nominally expected at 21 earliest)
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                } else if (DecodeReader->posCount < 23) {  // SOF for 1 out of 4 coding
                                        DecodeReader->Coding = CODING_1_OUT_OF_4;
                                        DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
                                } else if (DecodeReader->posCount < 28) {  // falling edge too early (nominally expected at 29 latest)
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                } else {                                 // SOF for 1 out of 4 coding
                                        DecodeReader->Coding = CODING_1_OUT_OF_256;
                                        DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
                                }
                        } else {
                                if(DecodeReader->posCount > 29) { // stayed high for too long
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                } else {
                                        // do nothing, keep waiting
                                }
@@ -692,7 +726,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                        if (bit) { // detected rising edge
                                if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
                                        if (DecodeReader->posCount < 32) { // rising edge too early (nominally expected at 33)
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        } else {
                                                DecodeReader->posCount = 1;
                                                DecodeReader->bitCount = 0;
@@ -703,7 +737,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                        }
                                } else { // CODING_1_OUT_OF_4
                                        if (DecodeReader->posCount < 24) { // rising edge too early (nominally expected at 25)
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        } else {
                                                DecodeReader->state = STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4;
                                        }
@@ -711,13 +745,13 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                        } else {
                                if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
                                        if (DecodeReader->posCount > 34) { // signal stayed low for too long
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        } else {
                                                // do nothing, keep waiting
                                        }
                                } else { // CODING_1_OUT_OF_4
                                        if (DecodeReader->posCount > 26) { // signal stayed low for too long
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        } else {
                                                // do nothing, keep waiting
                                        }
@@ -739,7 +773,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                        // do nothing, keep waiting
                                }
                        } else { // unexpected falling edge
-                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                        }
                        break;
 
@@ -761,7 +795,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                int corr11 = (DecodeReader->sum1 + DecodeReader->sum2) / 2;
                                if (corr01 > corr11 && corr01 > corr10) { // EOF
                                        LED_B_OFF(); // Finished receiving
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        if (DecodeReader->byteCount != 0) {
                                                return true;
                                        }
@@ -775,9 +809,10 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                        if (DecodeReader->byteCount > DecodeReader->byteCountMax) {
                                                // buffer overflow, give up
                                                LED_B_OFF();
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                               DecodeReaderReset(DecodeReader);
                                        }
                                        DecodeReader->bitCount = 0;
+                                       DecodeReader->shiftReg = 0;
                                } else {
                                        DecodeReader->bitCount++;
                                }
@@ -802,7 +837,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                int corr11 = (DecodeReader->sum1 + DecodeReader->sum2) / 2;
                                if (corr01 > corr11 && corr01 > corr10) { // EOF
                                        LED_B_OFF(); // Finished receiving
-                                       DecodeReader->state = STATE_READER_UNSYNCD;
+                                       DecodeReaderReset(DecodeReader);
                                        if (DecodeReader->byteCount != 0) {
                                                return true;
                                        }
@@ -815,7 +850,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
                                        if (DecodeReader->byteCount > DecodeReader->byteCountMax) {
                                                // buffer overflow, give up
                                                LED_B_OFF();
-                                               DecodeReader->state = STATE_READER_UNSYNCD;
+                                               DecodeReaderReset(DecodeReader);
                                        }
                                }
                                DecodeReader->bitCount++;
@@ -824,7 +859,7 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
 
                default:
                        LED_B_OFF();
-                       DecodeReader->state = STATE_READER_UNSYNCD;
+                       DecodeReaderReset(DecodeReader);
                        break;
        }
 
@@ -832,18 +867,6 @@ static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader
 }
 
 
-static void DecodeReaderInit(uint8_t *data, uint16_t max_len, DecodeReader_t* DecodeReader)
-{
-       DecodeReader->output = data;
-       DecodeReader->byteCountMax = max_len;
-       DecodeReader->state = STATE_READER_UNSYNCD;
-       DecodeReader->byteCount = 0;
-       DecodeReader->bitCount = 0;
-       DecodeReader->posCount = 0;
-       DecodeReader->shiftReg = 0;
-}
-
-
 //-----------------------------------------------------------------------------
 // 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
@@ -856,16 +879,15 @@ static void DecodeReaderInit(uint8_t *data, uint16_t max_len, DecodeReader_t* De
 
 static int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eof_time)
 {
-       int maxBehindBy = 0;
-       int lastRxCounter, samples = 0;
+       int samples = 0;
        bool gotFrame = false;
        uint8_t b;
 
-       uint8_t dmaBuf[ISO15693_DMA_BUFFER_SIZE];
+       uint8_t *dmaBuf = BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE);
 
        // the decoder data structure
        DecodeReader_t DecodeReader = {0};
-       DecodeReaderInit(received, max_len, &DecodeReader);
+       DecodeReaderInit(&DecodeReader, received, max_len);
 
        // wait for last transfer to complete
        while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
@@ -883,21 +905,19 @@ static int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint3
        // Setup and start DMA.
        FpgaSetupSscDma(dmaBuf, ISO15693_DMA_BUFFER_SIZE);
        uint8_t *upTo = dmaBuf;
-       lastRxCounter = ISO15693_DMA_BUFFER_SIZE;
 
        for(;;) {
-               int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO15693_DMA_BUFFER_SIZE-1);
-               if(behindBy > maxBehindBy) {
-                       maxBehindBy = behindBy;
-               }
+               uint16_t behindBy = ((uint8_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
 
-               if (behindBy < 1) continue;
+               if (behindBy == 0) continue;
 
                b = *upTo++;
-               lastRxCounter--;
                if(upTo >= dmaBuf + ISO15693_DMA_BUFFER_SIZE) {                // we have read all of the DMA buffer content.
                        upTo = dmaBuf;                                             // start reading the circular buffer from the beginning
-                       lastRxCounter += ISO15693_DMA_BUFFER_SIZE;
+                       if(behindBy > (9*ISO15693_DMA_BUFFER_SIZE/10)) {
+                               Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy);
+                               break;
+                       }
                }
                if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
                        AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
@@ -927,11 +947,12 @@ static int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint3
 
 
        FpgaDisableSscDma();
+       BigBuf_free_keep_EM();
+       
+       if (DEBUG) Dbprintf("samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
+                           samples, gotFrame, DecodeReader.state, DecodeReader.byteCount, DecodeReader.bitCount, DecodeReader.posCount);
 
-       if (DEBUG) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
-                           maxBehindBy, samples, gotFrame, DecodeReader.state, DecodeReader.byteCount, DecodeReader.bitCount, DecodeReader.posCount);
-
-       if (tracing && DecodeReader.byteCount > 0) {
+       if (DecodeReader.byteCount > 0) {
                LogTrace(DecodeReader.output, DecodeReader.byteCount, 0, 0, NULL, true);
        }
 
@@ -939,7 +960,29 @@ static int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint3
 }
 
 
-static void BuildIdentifyRequest(void);
+// Encode (into the ToSend buffers) an identify request, which is the first
+// thing that you must send to a tag to get a response.
+static void BuildIdentifyRequest(void)
+{
+       uint8_t cmd[5];
+
+       uint16_t crc;
+       // one sub-carrier, inventory, 1 slot, fast rate
+       // AFI is at bit 5 (1<<4) when doing an INVENTORY
+       cmd[0] = (1 << 2) | (1 << 5) | (1 << 1);
+       // inventory command code
+       cmd[1] = 0x01;
+       // no mask
+       cmd[2] = 0x00;
+       //Now the CRC
+       crc = Crc(cmd, 3);
+       cmd[3] = crc & 0xff;
+       cmd[4] = crc >> 8;
+
+       CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+
 //-----------------------------------------------------------------------------
 // Start to read an ISO 15693 tag. We send an identify request, then wait
 // for the response. The response is not demodulated, just left in the buffer
@@ -980,18 +1023,12 @@ void AcquireRawAdcSamplesIso15693(void)
        while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
 
        FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
 
        for(int c = 0; c < 4000; ) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       uint16_t iq = AT91C_BASE_SSC->SSC_RHR;
-                       // The samples are correlations against I and Q versions of the
-                       // tone that the tag AM-modulates. We just want power,
-                       // so abs(I) + abs(Q) is close to what we want.
-                       int8_t i = (int8_t)(iq >> 8);
-                       int8_t q = (int8_t)(iq & 0xff);
-                       uint8_t r = AMPLITUDE(i, q);
-                       dest[c++] = r;
+                       uint16_t r = AT91C_BASE_SSC->SSC_RHR;
+                       dest[c++] = r >> 5;
                }
        }
 
@@ -1000,49 +1037,139 @@ void AcquireRawAdcSamplesIso15693(void)
 }
 
 
-// TODO: there is no trigger condition. The 14000 samples represent a time frame of 66ms.
-// It is unlikely that we get something meaningful.
-// TODO: Currently we only record tag answers. Add tracing of reader commands.
-// TODO: would we get something at all? The carrier is switched on...
-void RecordRawAdcSamplesIso15693(void)
+void SnoopIso15693(void)
 {
-       LEDsoff();
-       LED_A_ON();
+       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+       BigBuf_free();
 
-       uint8_t *dest = BigBuf_get_addr();
+       clear_trace();
+       set_tracing(true);
 
-       FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-       // Setup SSC
-       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
 
-       // Start from off (no field generated)
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-       SpinDelay(200);
+       // The DMA buffer, used to stream samples from the FPGA
+       uint16_t* dmaBuf = (uint16_t*)BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE*sizeof(uint16_t));
+       uint16_t *upTo;
+
+       // Count of samples received so far, so that we can include timing
+       // information in the trace buffer.
+       int samples = 0;
+
+       DecodeTag_t DecodeTag = {0};
+       uint8_t response[ISO15693_MAX_RESPONSE_LENGTH];
+       DecodeTagInit(&DecodeTag, response, sizeof(response));
 
+       DecodeReader_t DecodeReader = {0};;
+       uint8_t cmd[ISO15693_MAX_COMMAND_LENGTH];
+       DecodeReaderInit(&DecodeReader, cmd, sizeof(cmd));
+
+       // Print some debug information about the buffer sizes
+       if (DEBUG) {
+               Dbprintf("Snooping buffers initialized:");
+               Dbprintf("  Trace:         %i bytes", BigBuf_max_traceLen());
+               Dbprintf("  Reader -> tag: %i bytes", ISO15693_MAX_COMMAND_LENGTH);
+               Dbprintf("  tag -> Reader: %i bytes", ISO15693_MAX_RESPONSE_LENGTH);
+               Dbprintf("  DMA:           %i bytes", ISO15693_DMA_BUFFER_SIZE * sizeof(uint16_t));
+       }
+       Dbprintf("Snoop started. Press button to stop.");
+       
+       // Signal field is off, no reader signal, no tag signal
+       LEDsoff();
+       // And put the FPGA in the appropriate mode
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_SNOOP | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
-       SpinDelay(100);
+       // Setup for the DMA.
+       FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       upTo = dmaBuf;
+       FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
 
-       LED_D_ON();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+       bool TagIsActive = false;
+       bool ReaderIsActive = false;
+       bool ExpectTagAnswer = false;
 
-       for(int c = 0; c < 14000;) {
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       uint16_t iq = AT91C_BASE_SSC->SSC_RHR;
-                       // The samples are correlations against I and Q versions of the
-                       // tone that the tag AM-modulates. We just want power,
-                       // so abs(I) + abs(Q) is close to what we want.
-                       int8_t i = (int8_t)(iq >> 8);
-                       int8_t q = (int8_t)(iq & 0xff);
-                       uint8_t r = AMPLITUDE(i, q);
-                       dest[c++] = r;
+       // And now we loop, receiving samples.
+       for(;;) {
+               uint16_t behindBy = ((uint16_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
+
+               if (behindBy == 0) continue;
+
+               uint16_t snoopdata = *upTo++;
+
+               if(upTo >= dmaBuf + ISO15693_DMA_BUFFER_SIZE) {                    // we have read all of the DMA buffer content.
+                       upTo = dmaBuf;                                                 // start reading the circular buffer from the beginning
+                       if(behindBy > (9*ISO15693_DMA_BUFFER_SIZE/10)) {
+                               Dbprintf("About to blow circular buffer - aborted! behindBy=%d, samples=%d", behindBy, samples);
+                               break;
+                       }
+                       if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+                               AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+                               AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
+                               WDT_HIT();
+                               if(BUTTON_PRESS()) {
+                                       DbpString("Snoop stopped.");
+                                       break;
+                               }
+                       }
+               }
+               samples++;
+               
+               if (!TagIsActive) {                                            // no need to try decoding reader data if the tag is sending
+                       if (Handle15693SampleFromReader(snoopdata & 0x02, &DecodeReader)) {
+                               FpgaDisableSscDma();
+                               ExpectTagAnswer = true;
+                               LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+                               /* And ready to receive another command. */
+                               DecodeReaderReset(&DecodeReader);
+                               /* And also reset the demod code, which might have been */
+                               /* false-triggered by the commands from the reader. */
+                               DecodeTagReset(&DecodeTag);
+                               upTo = dmaBuf;
+                               FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+                       }
+                       if (Handle15693SampleFromReader(snoopdata & 0x01, &DecodeReader)) {
+                               FpgaDisableSscDma();
+                               ExpectTagAnswer = true;
+                               LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+                               /* And ready to receive another command. */
+                               DecodeReaderReset(&DecodeReader);
+                               /* And also reset the demod code, which might have been */
+                               /* false-triggered by the commands from the reader. */
+                               DecodeTagReset(&DecodeTag);
+                               upTo = dmaBuf;
+                               FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+                       }
+                       ReaderIsActive = (DecodeReader.state >= STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF);
                }
+
+               if (!ReaderIsActive && ExpectTagAnswer) {                                               // no need to try decoding tag data if the reader is currently sending or no answer expected yet
+                       if (Handle15693SamplesFromTag(snoopdata >> 2, &DecodeTag)) {
+                               FpgaDisableSscDma();
+                               //Use samples as a time measurement
+                               LogTrace(DecodeTag.output, DecodeTag.len, samples, samples, NULL, false);
+                               // And ready to receive another response.
+                               DecodeTagReset(&DecodeTag);
+                               DecodeReaderReset(&DecodeReader);
+                               ExpectTagAnswer = false;
+                               upTo = dmaBuf;
+                               FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+                       }
+                       TagIsActive = (DecodeTag.state >= STATE_TAG_RECEIVING_DATA);
+               }
+
        }
 
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-       LED_D_OFF();
-       Dbprintf("finished recording");
-       LED_A_OFF();
+       FpgaDisableSscDma();
+       BigBuf_free();
+       
+       LEDsoff();
+
+       DbpString("Snoop statistics:");
+       Dbprintf("  ExpectTagAnswer: %d", ExpectTagAnswer);
+       Dbprintf("  DecodeTag State: %d", DecodeTag.state);
+       Dbprintf("  DecodeTag byteCnt: %d", DecodeTag.len);
+       Dbprintf("  DecodeReader State: %d", DecodeReader.state);
+       Dbprintf("  DecodeReader byteCnt: %d", DecodeReader.byteCount);
+       Dbprintf("  Trace length: %d", BigBuf_get_traceLen());
 }
 
 
@@ -1072,27 +1199,6 @@ static void Iso15693InitReader() {
 // This section basically contains transmission and receiving of bits
 ///////////////////////////////////////////////////////////////////////
 
-// Encode (into the ToSend buffers) an identify request, which is the first
-// thing that you must send to a tag to get a response.
-static void BuildIdentifyRequest(void)
-{
-       uint8_t cmd[5];
-
-       uint16_t crc;
-       // one sub-carrier, inventory, 1 slot, fast rate
-       // AFI is at bit 5 (1<<4) when doing an INVENTORY
-       cmd[0] = (1 << 2) | (1 << 5) | (1 << 1);
-       // inventory command code
-       cmd[1] = 0x01;
-       // no mask
-       cmd[2] = 0x00;
-       //Now the CRC
-       crc = Crc(cmd, 3);
-       cmd[3] = crc & 0xff;
-       cmd[4] = crc >> 8;
-
-       CodeIso15693AsReader(cmd, sizeof(cmd));
-}
 
 // uid is in transmission order (which is reverse of display order)
 static void BuildReadBlockRequest(uint8_t *uid, uint8_t blockNumber )
@@ -1100,12 +1206,11 @@ static void BuildReadBlockRequest(uint8_t *uid, uint8_t blockNumber )
        uint8_t cmd[13];
 
        uint16_t crc;
-       // If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-       // followed by teh block data
-       // one sub-carrier, inventory, 1 slot, fast rate
-       cmd[0] = (1 << 6)| (1 << 5) | (1 << 1); // no SELECT bit, ADDR bit, OPTION bit
+       // If we set the Option_Flag in this request, the VICC will respond with the security status of the block
+       // followed by the block data
+       cmd[0] = ISO15693_REQ_OPTION | ISO15693_REQ_ADDRESS | ISO15693_REQ_DATARATE_HIGH; 
        // READ BLOCK command code
-       cmd[1] = 0x20;
+       cmd[1] = ISO15693_READBLOCK;
        // UID may be optionally specified here
        // 64-bit UID
        cmd[2] = uid[0];
@@ -1117,7 +1222,7 @@ static void BuildReadBlockRequest(uint8_t *uid, uint8_t blockNumber )
        cmd[8] = uid[6];
        cmd[9] = uid[7]; // 0xe0; // always e0 (not exactly unique)
        // Block number to read
-       cmd[10] = blockNumber;//0x00;
+       cmd[10] = blockNumber;
        //Now the CRC
        crc = Crc(cmd, 11); // the crc needs to be calculated over 11 bytes
        cmd[11] = crc & 0xff;
@@ -1156,10 +1261,9 @@ static void BuildInventoryResponse(uint8_t *uid)
 // Universal Method for sending to and recv bytes from a tag
 //     init ... should we initialize the reader?
 //     speed ... 0 low speed, 1 hi speed
-//     **recv will return you a pointer to the received data
-//     If you do not need the answer use NULL for *recv[]
+//     *recv will contain the tag's answer
 //     return: lenght of received data
-int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t **recv) {
+int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t *recv, uint16_t max_recv_len, uint32_t start_time) {
 
        LED_A_ON();
        LED_B_OFF();
@@ -1168,8 +1272,6 @@ int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t **recv
        if (init) Iso15693InitReader();
 
        int answerLen=0;
-       uint8_t *answer = BigBuf_get_addr() + 4000;
-       if (recv != NULL) memset(answer, 0, 100);
 
        if (!speed) {
                // low speed (1 out of 256)
@@ -1179,11 +1281,11 @@ int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t **recv
                CodeIso15693AsReader(send, sendlen);
        }
 
-       TransmitTo15693Tag(ToSend,ToSendMax);
+       TransmitTo15693Tag(ToSend, ToSendMax, start_time);
+
        // Now wait for a response
-       if (recv!=NULL) {
-               answerLen = GetIso15693AnswerFromTag(answer, 100);
-               *recv=answer;
+       if (recv != NULL) {
+               answerLen = GetIso15693AnswerFromTag(recv, max_recv_len, DELAY_ISO15693_VCD_TO_VICC * 2);
        }
 
        LED_A_OFF();
@@ -1202,46 +1304,46 @@ void DbdecodeIso15693Answer(int len, uint8_t *d) {
        char status[DBD15STATLEN+1]={0};
        uint16_t crc;
 
-       if (len>3) {
-               if (d[0]&(1<<3))
-                       strncat(status,"ProtExt ",DBD15STATLEN);
-               if (d[0]&1) {
+       if (len > 3) {
+               if (d[0] & ISO15693_RES_EXT)
+                       strncat(status,"ProtExt ", DBD15STATLEN);
+               if (d[0] & ISO15693_RES_ERROR) {
                        // error
-                       strncat(status,"Error ",DBD15STATLEN);
+                       strncat(status,"Error ", DBD15STATLEN);
                        switch (d[1]) {
                                case 0x01:
-                                       strncat(status,"01:notSupp",DBD15STATLEN);
+                                       strncat(status,"01:notSupp", DBD15STATLEN);
                                        break;
                                case 0x02:
-                                       strncat(status,"02:notRecog",DBD15STATLEN);
+                                       strncat(status,"02:notRecog", DBD15STATLEN);
                                        break;
                                case 0x03:
-                                       strncat(status,"03:optNotSupp",DBD15STATLEN);
+                                       strncat(status,"03:optNotSupp", DBD15STATLEN);
                                        break;
                                case 0x0f:
-                                       strncat(status,"0f:noInfo",DBD15STATLEN);
+                                       strncat(status,"0f:noInfo", DBD15STATLEN);
                                        break;
                                case 0x10:
-                                       strncat(status,"10:dontExist",DBD15STATLEN);
+                                       strncat(status,"10:doesn'tExist", DBD15STATLEN);
                                        break;
                                case 0x11:
-                                       strncat(status,"11:lockAgain",DBD15STATLEN);
+                                       strncat(status,"11:lockAgain", DBD15STATLEN);
                                        break;
                                case 0x12:
-                                       strncat(status,"12:locked",DBD15STATLEN);
+                                       strncat(status,"12:locked", DBD15STATLEN);
                                        break;
                                case 0x13:
-                                       strncat(status,"13:progErr",DBD15STATLEN);
+                                       strncat(status,"13:progErr", DBD15STATLEN);
                                        break;
                                case 0x14:
-                                       strncat(status,"14:lockErr",DBD15STATLEN);
+                                       strncat(status,"14:lockErr", DBD15STATLEN);
                                        break;
                                default:
-                                       strncat(status,"unknownErr",DBD15STATLEN);
+                                       strncat(status,"unknownErr", DBD15STATLEN);
                        }
-                       strncat(status," ",DBD15STATLEN);
+                       strncat(status," ", DBD15STATLEN);
                } else {
-                       strncat(status,"NoErr ",DBD15STATLEN);
+                       strncat(status,"NoErr ", DBD15STATLEN);
                }
 
                crc=Crc(d,len-2);
@@ -1266,6 +1368,7 @@ void SetDebugIso15693(uint32_t debug) {
        return;
 }
 
+
 //-----------------------------------------------------------------------------
 // Simulate an ISO15693 reader, perform anti-collision and then attempt to read a sector
 // all demodulation performed in arm rather than host. - greg
@@ -1275,13 +1378,14 @@ void ReaderIso15693(uint32_t parameter)
        LEDsoff();
        LED_A_ON();
 
-       int answerLen1 = 0;
+       set_tracing(true);
+       
+       int answerLen = 0;
        uint8_t TagUID[8] = {0x00};
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
 
-       uint8_t *answer1 = BigBuf_get_addr() + 4000;
-       memset(answer1, 0x00, 200);
+       uint8_t answer[ISO15693_MAX_RESPONSE_LENGTH];
 
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        // Setup SSC
@@ -1295,37 +1399,39 @@ void ReaderIso15693(uint32_t parameter)
        LED_D_ON();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
        SpinDelay(200);
+       StartCountSspClk();
+
 
        // FIRST WE RUN AN INVENTORY TO GET THE TAG UID
        // THIS MEANS WE CAN PRE-BUILD REQUESTS TO SAVE CPU TIME
 
        // Now send the IDENTIFY command
        BuildIdentifyRequest();
-
-       TransmitTo15693Tag(ToSend,ToSendMax);
+       TransmitTo15693Tag(ToSend, ToSendMax, 0);
 
        // Now wait for a response
-       answerLen1 = GetIso15693AnswerFromTag(answer1, 100) ;
+       answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC * 2) ;
+       uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD;
 
-       if (answerLen1 >=12) // we should do a better check than this
+       if (answerLen >=12) // we should do a better check than this
        {
-               TagUID[0] = answer1[2];
-               TagUID[1] = answer1[3];
-               TagUID[2] = answer1[4];
-               TagUID[3] = answer1[5];
-               TagUID[4] = answer1[6];
-               TagUID[5] = answer1[7];
-               TagUID[6] = answer1[8]; // IC Manufacturer code
-               TagUID[7] = answer1[9]; // always E0
+               TagUID[0] = answer[2];
+               TagUID[1] = answer[3];
+               TagUID[2] = answer[4];
+               TagUID[3] = answer[5];
+               TagUID[4] = answer[6];
+               TagUID[5] = answer[7];
+               TagUID[6] = answer[8]; // IC Manufacturer code
+               TagUID[7] = answer[9]; // always E0
 
        }
 
-       Dbprintf("%d octets read from IDENTIFY request:", answerLen1);
-       DbdecodeIso15693Answer(answerLen1, answer1);
-       Dbhexdump(answerLen1, answer1, false);
+       Dbprintf("%d octets read from IDENTIFY request:", answerLen);
+       DbdecodeIso15693Answer(answerLen, answer);
+       Dbhexdump(answerLen, answer, false);
 
        // UID is reverse
-       if (answerLen1 >= 12)
+       if (answerLen >= 12)
                Dbprintf("UID = %02hX%02hX%02hX%02hX%02hX%02hX%02hX%02hX",
                        TagUID[7],TagUID[6],TagUID[5],TagUID[4],
                        TagUID[3],TagUID[2],TagUID[1],TagUID[0]);
@@ -1340,18 +1446,21 @@ void ReaderIso15693(uint32_t parameter)
        // Dbhexdump(answerLen3,answer3,true);
 
        // read all pages
-       if (answerLen1 >= 12 && DEBUG) {
-               uint8_t *answer2 = BigBuf_get_addr() + 4100;
+       if (answerLen >= 12 && DEBUG) {
+
+               // debugptr = BigBuf_get_addr();
+
                int i = 0;
                while (i < 32) {  // sanity check, assume max 32 pages
                        BuildReadBlockRequest(TagUID, i);
-                       TransmitTo15693Tag(ToSend, ToSendMax);
-                       int answerLen2 = GetIso15693AnswerFromTag(answer2, 100);
-                       if (answerLen2 > 0) {
-                               Dbprintf("READ SINGLE BLOCK %d returned %d octets:", i, answerLen2);
-                               DbdecodeIso15693Answer(answerLen2, answer2);
-                               Dbhexdump(answerLen2, answer2, false);
-                               if ( *((uint32_t*) answer2) == 0x07160101 ) break; // exit on NoPageErr
+                       TransmitTo15693Tag(ToSend, ToSendMax, start_time);
+                       int answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC * 2);
+                       start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD;
+                       if (answerLen > 0) {
+                               Dbprintf("READ SINGLE BLOCK %d returned %d octets:", i, answerLen);
+                               DbdecodeIso15693Answer(answerLen, answer);
+                               Dbhexdump(answerLen, answer, false);
+                               if ( *((uint32_t*) answer) == 0x07160101 ) break; // exit on NoPageErr
                        }
                        i++;
                }
@@ -1412,12 +1521,14 @@ void BruteforceIso15693Afi(uint32_t speed)
        LEDsoff();
        LED_A_ON();
 
-       uint8_t data[20];
-       uint8_t *recv=data;
+       uint8_t data[6];
+       uint8_t recv[ISO15693_MAX_RESPONSE_LENGTH];
+       
        int datalen=0, recvlen=0;
 
        Iso15693InitReader();
-
+       StartCountSspClk();
+       
        // first without AFI
        // Tags should respond without AFI and with AFI=0 even when AFI is active
 
@@ -1425,10 +1536,11 @@ void BruteforceIso15693Afi(uint32_t speed)
        data[1] = ISO15693_INVENTORY;
        data[2] = 0; // mask length
        datalen = AddCrc(data,3);
-       recvlen = SendDataTag(data, datalen, false, speed, &recv);
+       recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), 0);
+       uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VCD_TO_VICC;
        WDT_HIT();
        if (recvlen>=12) {
-               Dbprintf("NoAFI UID=%s",sprintUID(NULL,&recv[2]));
+               Dbprintf("NoAFI UID=%s", sprintUID(NULL, &recv[2]));
        }
 
        // now with AFI
@@ -1438,13 +1550,14 @@ void BruteforceIso15693Afi(uint32_t speed)
        data[2] = 0; // AFI
        data[3] = 0; // mask length
 
-       for (int i=0;i<256;i++) {
-               data[2]=i & 0xFF;
-               datalen=AddCrc(data,4);
-               recvlen=SendDataTag(data, datalen, false, speed, &recv);
+       for (int i = 0; i < 256; i++) {
+               data[2] = i & 0xFF;
+               datalen = AddCrc(data,4);
+               recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), start_time);
+               start_time = GetCountSspClk() + DELAY_ISO15693_VCD_TO_VICC;
                WDT_HIT();
-               if (recvlen>=12) {
-                       Dbprintf("AFI=%i UID=%s", i, sprintUID(NULL,&recv[2]));
+               if (recvlen >= 12) {
+                       Dbprintf("AFI=%i UID=%s", i, sprintUID(NULL, &recv[2]));
                }
        }
        Dbprintf("AFI Bruteforcing done.");
@@ -1456,26 +1569,27 @@ void BruteforceIso15693Afi(uint32_t speed)
 // Allows to directly send commands to the tag via the client
 void DirectTag15693Command(uint32_t datalen, uint32_t speed, uint32_t recv, uint8_t data[]) {
 
-       int recvlen=0;
-       uint8_t *recvbuf = BigBuf_get_addr();
+       int recvlen = 0;
+       uint8_t recvbuf[ISO15693_MAX_RESPONSE_LENGTH];
 
        LED_A_ON();
 
        if (DEBUG) {
-               Dbprintf("SEND");
+               Dbprintf("SEND:");
                Dbhexdump(datalen, data, false);
        }
 
-       recvlen = SendDataTag(data, datalen, true, speed, (recv?&recvbuf:NULL));
+       recvlen = SendDataTag(data, datalen, true, speed, (recv?recvbuf:NULL), sizeof(recvbuf), 0);
 
        if (recv) {
-               cmd_send(CMD_ACK, recvlen>48?48:recvlen, 0, 0, recvbuf, 48);
-
                if (DEBUG) {
-                       Dbprintf("RECV");
-                       DbdecodeIso15693Answer(recvlen,recvbuf);
+                       Dbprintf("RECV:");
                        Dbhexdump(recvlen, recvbuf, false);
+                       DbdecodeIso15693Answer(recvlen, recvbuf);
                }
+
+               cmd_send(CMD_ACK, recvlen>ISO15693_MAX_RESPONSE_LENGTH?ISO15693_MAX_RESPONSE_LENGTH:recvlen, 0, 0, recvbuf, ISO15693_MAX_RESPONSE_LENGTH);
+
        }
 
        // for the time being, switch field off to protect rdv4.0
diff --git a/armsrc/iso15693.h b/armsrc/iso15693.h
new file mode 100644 (file)
index 0000000..e5b78a8
--- /dev/null
@@ -0,0 +1,24 @@
+//-----------------------------------------------------------------------------
+// Piwi - October 2018
+//
+// 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 15693.
+//-----------------------------------------------------------------------------
+
+#ifndef __ISO15693_H
+#define __ISO15693_H
+
+#include <stdint.h>
+
+void SnoopIso15693(void);
+void AcquireRawAdcSamplesIso15693(void);
+void ReaderIso15693(uint32_t parameter);
+void SimTagIso15693(uint32_t parameter, uint8_t *uid);
+void BruteforceIso15693Afi(uint32_t speed);
+void DirectTag15693Command(uint32_t datalen,uint32_t speed, uint32_t recv, uint8_t data[]); 
+void SetDebugIso15693(uint32_t flag);
+
+#endif
index 56b1cb3d2913b79899a0c38351d07cbfabfb1e5e..744a95d298e6d9c1b8516781e9c6672718a089f3 100644 (file)
@@ -264,7 +264,7 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
 
                uint8_t parityBits = parityBytes[j>>3];
                if (protocol != ISO_14443B && (isResponse || protocol == ISO_14443A) && (oddparity8(frame[j]) != ((parityBits >> (7-(j&0x0007))) & 0x01))) {
-                       snprintf(line[j/16]+(( j % 16) * 4),110, "%02x! ", frame[j]);
+                       snprintf(line[j/16]+(( j % 16) * 4), 110, " %02x!", frame[j]);
                } else {
                        snprintf(line[j/16]+(( j % 16) * 4), 110, " %02x ", frame[j]);
                }
@@ -281,14 +281,11 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
                }
        }
 
-       if(data_len == 0)
-       {
-               if(data_len == 0){
-                       sprintf(line[0],"<empty trace - possible error>");
-               }
+       if (data_len == 0) {
+               sprintf(line[0]," <empty trace - possible error>");
        }
-       //--- Draw the CRC column
 
+       //--- Draw the CRC column
        char *crc = (crcStatus == 0 ? "!crc" : (crcStatus == 1 ? " ok " : "    "));
 
        EndOfTransmissionTimestamp = timestamp + duration;
index e5f4af31cc9fa08ae8029fa9726ec6fd8fc857f7..da83ccafd4b9b73b5d110121d39c4e085c585e5f 100644 (file)
 #include "protocols.h"
 #include "cmdmain.h"
 
-#define FrameSOF              Iso15693FrameSOF
-#define Logic0                                         Iso15693Logic0
-#define Logic1                                         Iso15693Logic1
-#define FrameEOF                                       Iso15693FrameEOF
-
 #define Crc(data,datalen)     Iso15693Crc(data,datalen)
 #define AddCrc(data,datalen)  Iso15693AddCrc(data,datalen)
 #define sprintUID(target,uid)  Iso15693sprintUID(target,uid)
 
+// SOF defined as
+// 1) Unmodulated time of 56.64us
+// 2) 24 pulses of 423.75khz
+// 3) logic '1' (unmodulated for 18.88us followed by 8 pulses of 423.75khz)
+
+static const int Iso15693FrameSOF[] = {
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+        1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+        1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+       -1, -1, -1, -1,
+       -1, -1, -1, -1,
+        1,  1,  1,  1,
+        1,  1,  1,  1
+};
+static const int Iso15693Logic0[] = {
+        1,  1,  1,  1,
+        1,  1,  1,  1,
+       -1, -1, -1, -1,
+       -1, -1, -1, -1
+};
+static const int Iso15693Logic1[] = {
+       -1, -1, -1, -1,
+       -1, -1, -1, -1,
+        1,  1,  1,  1,
+        1,  1,  1,  1
+};
+
+// EOF defined as
+// 1) logic '0' (8 pulses of 423.75khz followed by unmodulated for 18.88us)
+// 2) 24 pulses of 423.75khz
+// 3) Unmodulated time of 56.64us
+
+static const int Iso15693FrameEOF[] = {
+        1,  1,  1,  1,
+        1,  1,  1,  1,
+       -1, -1, -1, -1,
+       -1, -1, -1, -1,
+        1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+        1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+
 // structure and database for uid -> tagtype lookups 
 typedef struct { 
        uint64_t uid;
@@ -293,8 +332,8 @@ int CmdHF15Demod(const char *Cmd)
        // First, correlate for SOF
        for (i = 0; i < 200; i++) {
                int corr = 0;
-               for (j = 0; j < arraylen(FrameSOF); j += skip) {
-                       corr += FrameSOF[j] * GraphBuffer[i + (j / skip)];
+               for (j = 0; j < arraylen(Iso15693FrameSOF); j += skip) {
+                       corr += Iso15693FrameSOF[j] * GraphBuffer[i + (j / skip)];
                }
                if (corr > max) {
                        max = corr;
@@ -302,28 +341,28 @@ int CmdHF15Demod(const char *Cmd)
                }
        }
        PrintAndLog("SOF at %d, correlation %d", maxPos,
-               max / (arraylen(FrameSOF) / skip));
+               max / (arraylen(Iso15693FrameSOF) / skip));
        
-       i = maxPos + arraylen(FrameSOF) / skip;
+       i = maxPos + arraylen(Iso15693FrameSOF) / skip;
        int k = 0;
        uint8_t outBuf[20];
        memset(outBuf, 0, sizeof(outBuf));
        uint8_t mask = 0x01;
        for (;;) {
                        int corr0 = 0, corr00 = 0, corr01 = 0, corr1 = 0, corrEOF = 0;
-                       for(j = 0; j < arraylen(Logic0); j += skip) {
-                               corr0 += Logic0[j]*GraphBuffer[i+(j/skip)];
+                       for(j = 0; j < arraylen(Iso15693Logic0); j += skip) {
+                               corr0 += Iso15693Logic0[j]*GraphBuffer[i+(j/skip)];
                        }
                        corr01 = corr00 = corr0;
-                       for(j = 0; j < arraylen(Logic0); j += skip) {
-                               corr00 += Logic0[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
-                               corr01 += Logic1[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
+                       for(j = 0; j < arraylen(Iso15693Logic0); j += skip) {
+                               corr00 += Iso15693Logic0[j]*GraphBuffer[i+arraylen(Iso15693Logic0)/skip+(j/skip)];
+                               corr01 += Iso15693Logic1[j]*GraphBuffer[i+arraylen(Iso15693Logic0)/skip+(j/skip)];
                        }
-                       for(j = 0; j < arraylen(Logic1); j += skip) {
-                               corr1 += Logic1[j]*GraphBuffer[i+(j/skip)];
+                       for(j = 0; j < arraylen(Iso15693Logic1); j += skip) {
+                               corr1 += Iso15693Logic1[j]*GraphBuffer[i+(j/skip)];
                        }
-                       for(j = 0; j < arraylen(FrameEOF); j += skip) {
-                               corrEOF += FrameEOF[j]*GraphBuffer[i+(j/skip)];
+                       for(j = 0; j < arraylen(Iso15693FrameEOF); j += skip) {
+                               corrEOF += Iso15693FrameEOF[j]*GraphBuffer[i+(j/skip)];
                        }
                        // Even things out by the length of the target waveform.
                        corr00 *= 2;
@@ -335,17 +374,17 @@ int CmdHF15Demod(const char *Cmd)
                                PrintAndLog("EOF at %d", i);
                                break;
                } else if (corr1 > corr0) {
-                       i += arraylen(Logic1) / skip;
+                       i += arraylen(Iso15693Logic1) / skip;
                        outBuf[k] |= mask;
                } else {
-                       i += arraylen(Logic0) / skip;
+                       i += arraylen(Iso15693Logic0) / skip;
                }
                mask <<= 1;
                if (mask == 0) {
                        k++;
                        mask = 0x01;
                }
-               if ((i + (int)arraylen(FrameEOF)) >= GraphTraceLen) {
+               if ((i + (int)arraylen(Iso15693FrameEOF)) >= GraphTraceLen) {
                        PrintAndLog("ran off end!");
                        break;
                }
@@ -374,10 +413,9 @@ int CmdHF15Read(const char *Cmd)
 }
 
 // Record Activity without enabling carrier
-// TODO: currently it DOES enable the carrier
-int CmdHF15Record(const char *Cmd)
+int CmdHF15Snoop(const char *Cmd)
 {
-       UsbCommand c = {CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693};
+       UsbCommand c = {CMD_SNOOP_ISO_15693};
        SendCommand(&c);
        return 0;
 }
@@ -514,7 +552,7 @@ static command_t CommandTable15[] =
        {"help",    CmdHF15Help,    1, "This help"},
        {"demod",   CmdHF15Demod,   1, "Demodulate ISO15693 from tag"},
        {"read",    CmdHF15Read,    0, "Read HF tag (ISO 15693)"},
-       {"record",  CmdHF15Record,  0, "Record Samples (ISO 15693)"}, // atrox
+       {"snoop",   CmdHF15Snoop,   0, "Eavesdrop ISO 15693 communications"},
        {"reader",  CmdHF15Reader,  0, "Act like an ISO15693 reader"},
        {"sim",     CmdHF15Sim,     0, "Fake an ISO15693 tag"},
        {"cmd",     CmdHF15Cmd,     0, "Send direct commands to ISO15693 tag"},
index 96095fba51e13717a00ff359f050eb48441e657d..d9f59cc69893122880f7e45c7a090d653620e54c 100644 (file)
@@ -14,57 +14,4 @@ int Iso15693AddCrc(uint8_t *req, int n);
 char* Iso15693sprintUID(char *target,uint8_t *uid);
 unsigned short iclass_crc16(char *data_p, unsigned short length);
 
-//-----------------------------------------------------------------------------
-// Map a sequence of octets (~layer 2 command) into the set of bits to feed
-// to the FPGA, to transmit that command to the tag.
-// Mode: highspeed && one subcarrier (ASK)
-//-----------------------------------------------------------------------------
-
-       // The sampling rate is 106.353 ksps/s, for T = 18.8 us
-
-       // SOF defined as
-       // 1) Unmodulated time of 56.64us
-       // 2) 24 pulses of 423.75khz
-       // 3) logic '1' (unmodulated for 18.88us followed by 8 pulses of 423.75khz)
-
-       static const int Iso15693FrameSOF[] = {
-               -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-               -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-                1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-                1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-               -1, -1, -1, -1,
-               -1, -1, -1, -1,
-                1,  1,  1,  1,
-                1,  1,  1,  1
-       };
-       static const int Iso15693Logic0[] = {
-                1,  1,  1,  1,
-                1,  1,  1,  1,
-               -1, -1, -1, -1,
-               -1, -1, -1, -1
-       };
-       static const int Iso15693Logic1[] = {
-               -1, -1, -1, -1,
-               -1, -1, -1, -1,
-                1,  1,  1,  1,
-                1,  1,  1,  1
-       };
-
-       // EOF defined as
-       // 1) logic '0' (8 pulses of 423.75khz followed by unmodulated for 18.88us)
-       // 2) 24 pulses of 423.75khz
-       // 3) Unmodulated time of 56.64us
-
-       static const int Iso15693FrameEOF[] = {
-                1,  1,  1,  1,
-                1,  1,  1,  1,
-               -1, -1, -1, -1,
-               -1, -1, -1, -1,
-                1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-                1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-               -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-               -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
-       };
-
-
 #endif
index bd296174f0978d3214bae003d25a7063bff60021..f16fd0614fbd2614e713a29da5f47a29094953e5 100644 (file)
Binary files a/fpga/fpga_hf.bit and b/fpga/fpga_hf.bit differ
index f99a43dde9ea33360176d40ffe1803e280016805..5d55cb89e6e696f3ff55588a81f080dd35e2aa39 100644 (file)
@@ -75,6 +75,8 @@ wire hi_read_rx_xcorr_848 = conf_word[0];
 wire hi_read_rx_xcorr_snoop = conf_word[1];
 // divide subcarrier frequency by 4
 wire hi_read_rx_xcorr_quarter = conf_word[2];
+// send amplitude only instead of ci/cq pair
+wire hi_read_rx_xcorr_amplitude = conf_word[3];
 
 // For the high-frequency simulated tag: what kind of modulation to use.
 wire [2:0] hi_simulate_mod_type = conf_word[2:0];
@@ -102,7 +104,7 @@ hi_read_rx_xcorr hrxc(
        hrxc_ssp_frame, hrxc_ssp_din, ssp_dout, hrxc_ssp_clk,
        cross_hi, cross_lo,
        hrxc_dbg,
-       hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter
+       hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter, hi_read_rx_xcorr_amplitude
 );
 
 hi_simulate hs(
index 8233960f5df3ff6cd65cddff1cb403f032340d5a..503c8d67bebe4c5db583d2e976586ae784e3945a 100644 (file)
@@ -10,7 +10,7 @@ module hi_read_rx_xcorr(
     ssp_frame, ssp_din, ssp_dout, ssp_clk,
     cross_hi, cross_lo,
     dbg,
-    xcorr_is_848, snoop, xcorr_quarter_freq
+    xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude
 );
     input pck0, ck_1356meg, ck_1356megb;
     output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
@@ -20,7 +20,7 @@ module hi_read_rx_xcorr(
     output ssp_frame, ssp_din, ssp_clk;
     input cross_hi, cross_lo;
     output dbg;
-    input xcorr_is_848, snoop, xcorr_quarter_freq;
+    input xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude;
 
 // Carrier is steady on through this, unless we're snooping.
 assign pwr_hi = ck_1356megb & (~snoop);
@@ -83,11 +83,46 @@ reg signed [13:0] corr_q_accum;
 // we will report maximum 8 significant bits
 reg signed [7:0] corr_i_out;
 reg signed [7:0] corr_q_out;
+
 // clock and frame signal for communication to ARM
 reg ssp_clk;
 reg ssp_frame;
 
 
+
+// the amplitude of the subcarrier is sqrt(ci^2 + cq^2).
+// approximate by amplitude = max(|ci|,|cq|) + 1/2*min(|ci|,|cq|)
+reg [13:0] corr_amplitude, abs_ci, abs_cq, max_ci_cq, min_ci_cq;
+
+
+always @(corr_i_accum or corr_q_accum)
+begin
+       if (corr_i_accum[13] == 1'b0)
+               abs_ci <= corr_i_accum;
+       else
+               abs_ci <= -corr_i_accum;
+       
+       if (corr_q_accum[13] == 1'b0)
+               abs_cq <= corr_q_accum;
+       else
+               abs_cq <= -corr_q_accum;
+       
+       if (abs_ci > abs_cq)
+       begin
+               max_ci_cq <= abs_ci;
+               min_ci_cq <= abs_cq;
+       end
+       else
+       begin
+               max_ci_cq <= abs_cq;
+               min_ci_cq <= abs_ci;
+       end
+
+       corr_amplitude <= max_ci_cq + min_ci_cq/2;
+
+end
+
+
 // The subcarrier reference signals
 reg subcarrier_I;
 reg subcarrier_Q;
@@ -110,52 +145,75 @@ begin
                        subcarrier_Q = ~(corr_i_cnt[4] ^ corr_i_cnt[3]);
                end
 end
-       
+
+
 // ADC data appears on the rising edge, so sample it on the falling edge
 always @(negedge adc_clk)
 begin
     // 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.
+    // versions of our reference signal, and keep the (signed) results or the
+    // resulting amplitude to send out later over the SSP.
     if(corr_i_cnt == 6'd0)
     begin
         if(snoop)
         begin
-                       // Send 7 most significant bits of tag signal (signed), plus 1 bit reader signal
-                       if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
-                               corr_i_out <= {corr_i_accum[11:5], after_hysteresis_prev_prev};
-                       else // truncate to maximum value
-                               if (corr_i_accum[13] == 1'b0)
-                                       corr_i_out <= {7'b0111111, after_hysteresis_prev_prev};
-                               else
-                                       corr_i_out <= {7'b1000000, after_hysteresis_prev_prev};
-                       if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
-                               corr_q_out <= {corr_q_accum[11:5], after_hysteresis_prev};
-                       else // truncate to maximum value
-                               if (corr_q_accum[13] == 1'b0)
-                                       corr_q_out <= {7'b0111111, after_hysteresis_prev};
-                               else
-                                       corr_q_out <= {7'b1000000, after_hysteresis_prev};
-                       after_hysteresis_prev_prev <= after_hysteresis;
+                       if (hi_read_rx_xcorr_amplitude)
+                       begin
+                               // send amplitude plus 2 bits reader signal
+                               corr_i_out <= corr_amplitude[13:6];
+                               corr_q_out <= {corr_amplitude[5:0], after_hysteresis_prev_prev, after_hysteresis_prev};
+                       end     
+                       else
+                       begin
+                               // Send 7 most significant bits of in phase tag signal (signed), plus 1 bit reader signal
+                               if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
+                                       corr_i_out <= {corr_i_accum[11:5], after_hysteresis_prev_prev};
+                               else // truncate to maximum value
+                                       if (corr_i_accum[13] == 1'b0)
+                                               corr_i_out <= {7'b0111111, after_hysteresis_prev_prev};
+                                       else
+                                               corr_i_out <= {7'b1000000, after_hysteresis_prev_prev};
+                               // Send 7 most significant bits of quadrature phase tag signal (signed), plus 1 bit reader signal
+                               if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
+                                       corr_q_out <= {corr_q_accum[11:5], after_hysteresis_prev};
+                               else // truncate to maximum value
+                                       if (corr_q_accum[13] == 1'b0)
+                                               corr_q_out <= {7'b0111111, after_hysteresis_prev};
+                                       else
+                                               corr_q_out <= {7'b1000000, after_hysteresis_prev};
+                       end
         end
         else
         begin
-            // Send 8 bits of tag signal
-                       if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
-                               corr_i_out <= corr_i_accum[11:4];
-                       else // truncate to maximum value
-                               if (corr_i_accum[13] == 1'b0)
-                                       corr_i_out <= 8'b01111111;
-                               else
-                                       corr_i_out <= 8'b10000000;
-                       if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
-                               corr_q_out <= corr_q_accum[11:4];
-                       else // truncate to maximum value
-                               if (corr_q_accum[13] == 1'b0)
-                                       corr_q_out <= 8'b01111111;
-                               else
-                                       corr_q_out <= 8'b10000000;
+                       if (hi_read_rx_xcorr_amplitude)
+                       begin
+                               // send amplitude
+                               corr_i_out <= {2'b00, corr_amplitude[13:8]};
+                               corr_q_out <= corr_amplitude[7:0];
+                       end     
+                       else
+                       begin
+                               // Send 8 bits of in phase tag signal
+                               if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
+                                       corr_i_out <= corr_i_accum[11:4];
+                               else // truncate to maximum value
+                                       if (corr_i_accum[13] == 1'b0)
+                                               corr_i_out <= 8'b01111111;
+                                       else
+                                               corr_i_out <= 8'b10000000;
+                               // Send 8 bits of quadrature phase tag signal
+                               if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
+                                       corr_q_out <= corr_q_accum[11:4];
+                               else // truncate to maximum value
+                                       if (corr_q_accum[13] == 1'b0)
+                                               corr_q_out <= 8'b01111111;
+                                       else
+                                               corr_q_out <= 8'b10000000;
+                       end
         end
+
+               // for each Q/I pair report two reader signal samples when sniffing. Store the 1st.
+               after_hysteresis_prev_prev <= after_hysteresis;
                // Initialize next correlation. 
                // Both I and Q reference signals are high when corr_i_nct == 0. Therefore need to accumulate.
         corr_i_accum <= $signed({1'b0,adc_d});
@@ -172,16 +230,16 @@ begin
             corr_q_accum <= corr_q_accum + $signed({1'b0,adc_d});
         else
             corr_q_accum <= corr_q_accum - $signed({1'b0,adc_d});
-
     end
 
-       // for each Q/I pair report two reader signal samples when sniffing
+       // for each Q/I pair report two reader signal samples when sniffing. Store the 2nd.
     if(corr_i_cnt == 6'd32)
         after_hysteresis_prev <= after_hysteresis;
 
     // Then the result from last time is serialized and send out to the ARM.
     // We get one report each cycle, and each report is 16 bits, so the
-    // ssp_clk should be the adc_clk divided by 64/16 = 4.
+    // ssp_clk should be the adc_clk divided by 64/16 = 4. 
+       // ssp_clk frequency = 13,56MHz / 4 = 3.39MHz
 
     if(corr_i_cnt[1:0] == 2'b10)
         ssp_clk <= 1'b0;
index e73aa2a757b636b134793416597a32082ce4494b..785435f03d0539a30ac19d6f90e8d1ec61dc3f9d 100644 (file)
@@ -125,7 +125,7 @@ typedef struct{
 #define CMD_ISO_14443B_COMMAND                                            0x0305
 #define CMD_READER_ISO_15693                                              0x0310
 #define CMD_SIMTAG_ISO_15693                                              0x0311
-#define CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693                              0x0312
+#define CMD_SNOOP_ISO_15693                                               0x0312
 #define CMD_ISO_15693_COMMAND                                             0x0313
 #define CMD_ISO_15693_COMMAND_DONE                                        0x0314
 #define CMD_ISO_15693_FIND_AFI                                            0x0315
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