1 //-----------------------------------------------------------------------------
2 // Jonathan Westhues, split Nov 2006
4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
5 // at your option, any later version. See the LICENSE.txt file for the text of
7 //-----------------------------------------------------------------------------
8 // Routines to support ISO 14443B. This includes both the reader software and
9 // the `fake tag' modes.
10 //-----------------------------------------------------------------------------
12 #include "proxmark3.h"
17 #include "iso14443crc.h"
19 #define RECEIVE_SAMPLES_TIMEOUT 2000
21 //=============================================================================
22 // An ISO 14443 Type B tag. We listen for commands from the reader, using
23 // a UART kind of thing that's implemented in software. When we get a
24 // frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
25 // If it's good, then we can do something appropriate with it, and send
27 //=============================================================================
29 //-----------------------------------------------------------------------------
30 // Code up a string of octets at layer 2 (including CRC, we don't generate
31 // that here) so that they can be transmitted to the reader. Doesn't transmit
32 // them yet, just leaves them ready to send in ToSend[].
33 //-----------------------------------------------------------------------------
34 static void CodeIso14443bAsTag(const uint8_t *cmd
, int len
)
40 // Transmit a burst of ones, as the initial thing that lets the
41 // reader get phase sync. This (TR1) must be > 80/fs, per spec,
42 // but tag that I've tried (a Paypass) exceeds that by a fair bit,
44 for(i
= 0; i
< 20; i
++) {
52 for(i
= 0; i
< 10; i
++) {
58 for(i
= 0; i
< 2; i
++) {
65 for(i
= 0; i
< len
; i
++) {
76 for(j
= 0; j
< 8; j
++) {
99 for(i
= 0; i
< 10; i
++) {
105 for(i
= 0; i
< 2; i
++) {
112 // Convert from last byte pos to length
116 //-----------------------------------------------------------------------------
117 // The software UART that receives commands from the reader, and its state
119 //-----------------------------------------------------------------------------
123 STATE_GOT_FALLING_EDGE_OF_SOF
,
124 STATE_AWAITING_START_BIT
,
125 STATE_RECEIVING_DATA
,
136 /* Receive & handle a bit coming from the reader.
138 * This function is called 4 times per bit (every 2 subcarrier cycles).
139 * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
142 * LED A -> ON once we have received the SOF and are expecting the rest.
143 * LED A -> OFF once we have received EOF or are in error state or unsynced
145 * Returns: true if we received a EOF
146 * false if we are still waiting for some more
148 static int Handle14443bUartBit(int bit
)
153 // we went low, so this could be the beginning
155 Uart
.state
= STATE_GOT_FALLING_EDGE_OF_SOF
;
161 case STATE_GOT_FALLING_EDGE_OF_SOF
:
163 if(Uart
.posCnt
== 2) { // sample every 4 1/fs in the middle of a bit
165 if(Uart
.bitCnt
> 9) {
166 // we've seen enough consecutive
167 // zeros that it's a valid SOF
170 Uart
.state
= STATE_AWAITING_START_BIT
;
171 LED_A_ON(); // Indicate we got a valid SOF
173 // didn't stay down long enough
174 // before going high, error
175 Uart
.state
= STATE_ERROR_WAIT
;
178 // do nothing, keep waiting
182 if(Uart
.posCnt
>= 4) Uart
.posCnt
= 0;
183 if(Uart
.bitCnt
> 12) {
184 // Give up if we see too many zeros without
186 Uart
.state
= STATE_ERROR_WAIT
;
190 case STATE_AWAITING_START_BIT
:
193 if(Uart
.posCnt
> 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
194 // stayed high for too long between
196 Uart
.state
= STATE_ERROR_WAIT
;
199 // falling edge, this starts the data byte
203 Uart
.state
= STATE_RECEIVING_DATA
;
207 case STATE_RECEIVING_DATA
:
209 if(Uart
.posCnt
== 2) {
210 // time to sample a bit
213 Uart
.shiftReg
|= 0x200;
217 if(Uart
.posCnt
>= 4) {
220 if(Uart
.bitCnt
== 10) {
221 if((Uart
.shiftReg
& 0x200) && !(Uart
.shiftReg
& 0x001))
223 // this is a data byte, with correct
224 // start and stop bits
225 Uart
.output
[Uart
.byteCnt
] = (Uart
.shiftReg
>> 1) & 0xff;
228 if(Uart
.byteCnt
>= Uart
.byteCntMax
) {
229 // Buffer overflowed, give up
231 Uart
.state
= STATE_ERROR_WAIT
;
233 // so get the next byte now
235 Uart
.state
= STATE_AWAITING_START_BIT
;
237 } else if(Uart
.shiftReg
== 0x000) {
238 // this is an EOF byte
239 LED_A_OFF(); // Finished receiving
240 if (Uart
.byteCnt
!= 0) {
244 Uart
.state
= STATE_ERROR_WAIT
;
248 Uart
.state
= STATE_ERROR_WAIT
;
253 case STATE_ERROR_WAIT
:
254 // We're all screwed up, so wait a little while
255 // for whatever went wrong to finish, and then
258 if(Uart
.posCnt
> 10) {
259 Uart
.state
= STATE_UNSYNCD
;
265 Uart
.state
= STATE_UNSYNCD
;
272 //-----------------------------------------------------------------------------
273 // Receive a command (from the reader to us, where we are the simulated tag),
274 // and store it in the given buffer, up to the given maximum length. Keeps
275 // spinning, waiting for a well-framed command, until either we get one
276 // (returns TRUE) or someone presses the pushbutton on the board (FALSE).
278 // Assume that we're called with the SSC (to the FPGA) and ADC path set
280 //-----------------------------------------------------------------------------
281 static int GetIso14443bCommandFromReader(uint8_t *received
, int *len
, int maxLen
)
286 // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
287 // only, since we are receiving, not transmitting).
288 // Signal field is off with the appropriate LED
290 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR
| FPGA_HF_SIMULATOR_NO_MODULATION
);
293 // Now run a `software UART' on the stream of incoming samples.
294 Uart
.output
= received
;
295 Uart
.byteCntMax
= maxLen
;
296 Uart
.state
= STATE_UNSYNCD
;
301 if(BUTTON_PRESS()) return FALSE
;
303 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_TXRDY
)) {
304 AT91C_BASE_SSC
->SSC_THR
= 0x00;
306 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_RXRDY
)) {
307 uint8_t b
= (uint8_t)AT91C_BASE_SSC
->SSC_RHR
;
310 for(i
= 0; i
< 8; i
++, mask
>>= 1) {
312 if(Handle14443bUartBit(bit
)) {
321 //-----------------------------------------------------------------------------
322 // Main loop of simulated tag: receive commands from reader, decide what
323 // response to send, and send it.
324 //-----------------------------------------------------------------------------
325 void SimulateIso14443bTag(void)
327 // the only command we understand is REQB, AFI=0, Select All, N=0:
328 static const uint8_t cmd1
[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
329 // ... and we respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
330 // supports only 106kBit/s in both directions, max frame size = 32Bytes,
331 // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
332 static const uint8_t response1
[] = {
333 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
334 0x00, 0x21, 0x85, 0x5e, 0xd7
340 // allocate command receive buffer
342 uint8_t *receivedCmd
= BigBuf_malloc(MAX_FRAME_SIZE
);
349 FpgaDownloadAndGo(FPGA_BITSTREAM_HF
);
351 // prepare the (only one) tag answer:
352 CodeIso14443bAsTag(response1
, sizeof(response1
));
353 uint8_t *resp1
= BigBuf_malloc(ToSendMax
);
354 memcpy(resp1
, ToSend
, ToSendMax
);
355 uint16_t resp1Len
= ToSendMax
;
357 // We need to listen to the high-frequency, peak-detected path.
358 SetAdcMuxFor(GPIO_MUXSEL_HIPKD
);
366 if(!GetIso14443bCommandFromReader(receivedCmd
, &len
, 100)) {
367 Dbprintf("button pressed, received %d commands", cmdsRecvd
);
371 // Good, look at the command now.
373 if(len
== sizeof(cmd1
) && memcmp(receivedCmd
, cmd1
, len
) == 0) {
374 resp
= resp1
; respLen
= resp1Len
;
376 Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len
, cmdsRecvd
);
377 // And print whether the CRC fails, just for good measure
378 ComputeCrc14443(CRC_14443_B
, receivedCmd
, len
-2, &b1
, &b2
);
379 if(b1
!= receivedCmd
[len
-2] || b2
!= receivedCmd
[len
-1]) {
380 // Not so good, try again.
381 DbpString("+++CRC fail");
383 DbpString("CRC passes");
390 if(cmdsRecvd
> 0x30) {
391 DbpString("many commands later...");
395 if(respLen
<= 0) continue;
398 // Signal field is off with the appropriate LED
400 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR
| FPGA_HF_SIMULATOR_MODULATE_BPSK
);
401 AT91C_BASE_SSC
->SSC_THR
= 0xff;
404 // Transmit the response.
407 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_TXRDY
)) {
410 AT91C_BASE_SSC
->SSC_THR
= b
;
417 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_RXRDY
)) {
418 volatile uint8_t b
= (uint8_t)AT91C_BASE_SSC
->SSC_RHR
;
425 //=============================================================================
426 // An ISO 14443 Type B reader. We take layer two commands, code them
427 // appropriately, and then send them to the tag. We then listen for the
428 // tag's response, which we leave in the buffer to be demodulated on the
430 //=============================================================================
435 DEMOD_PHASE_REF_TRAINING
,
436 DEMOD_AWAITING_FALLING_EDGE_OF_SOF
,
437 DEMOD_GOT_FALLING_EDGE_OF_SOF
,
438 DEMOD_AWAITING_START_BIT
,
439 DEMOD_RECEIVING_DATA
,
445 /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
457 * Handles reception of a bit from the tag
459 * This function is called 2 times per bit (every 4 subcarrier cycles).
460 * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us
463 * LED C -> ON once we have received the SOF and are expecting the rest.
464 * LED C -> OFF once we have received EOF or are unsynced
466 * Returns: true if we received a EOF
467 * false if we are still waiting for some more
470 static RAMFUNC
int Handle14443bSamplesDemod(int ci
, int cq
)
474 // The soft decision on the bit uses an estimate of just the
475 // quadrant of the reference angle, not the exact angle.
476 #define MAKE_SOFT_DECISION() { \
477 if(Demod.sumI > 0) { \
482 if(Demod.sumQ > 0) { \
489 #define SUBCARRIER_DETECT_THRESHOLD 8
491 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
492 /* #define CHECK_FOR_SUBCARRIER() { \
502 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
503 #define CHECK_FOR_SUBCARRIER() { \
505 if(cq < 0) { /* ci < 0, cq < 0 */ \
507 v = -cq - (ci >> 1); \
509 v = -ci - (cq >> 1); \
511 } else { /* ci < 0, cq >= 0 */ \
513 v = -ci + (cq >> 1); \
515 v = cq - (ci >> 1); \
519 if(cq < 0) { /* ci >= 0, cq < 0 */ \
521 v = ci - (cq >> 1); \
523 v = -cq + (ci >> 1); \
525 } else { /* ci >= 0, cq >= 0 */ \
527 v = ci + (cq >> 1); \
529 v = cq + (ci >> 1); \
535 switch(Demod
.state
) {
537 CHECK_FOR_SUBCARRIER();
538 if(v
> SUBCARRIER_DETECT_THRESHOLD
) { // subcarrier detected
539 Demod
.state
= DEMOD_PHASE_REF_TRAINING
;
546 case DEMOD_PHASE_REF_TRAINING
:
547 if(Demod
.posCount
< 8) {
548 CHECK_FOR_SUBCARRIER();
549 if (v
> SUBCARRIER_DETECT_THRESHOLD
) {
550 // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
551 // note: synchronization time > 80 1/fs
555 } else { // subcarrier lost
556 Demod
.state
= DEMOD_UNSYNCD
;
559 Demod
.state
= DEMOD_AWAITING_FALLING_EDGE_OF_SOF
;
563 case DEMOD_AWAITING_FALLING_EDGE_OF_SOF
:
564 MAKE_SOFT_DECISION();
565 if(v
< 0) { // logic '0' detected
566 Demod
.state
= DEMOD_GOT_FALLING_EDGE_OF_SOF
;
567 Demod
.posCount
= 0; // start of SOF sequence
569 if(Demod
.posCount
> 200/4) { // maximum length of TR1 = 200 1/fs
570 Demod
.state
= DEMOD_UNSYNCD
;
576 case DEMOD_GOT_FALLING_EDGE_OF_SOF
:
578 MAKE_SOFT_DECISION();
580 if(Demod
.posCount
< 9*2) { // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
581 Demod
.state
= DEMOD_UNSYNCD
;
583 LED_C_ON(); // Got SOF
584 Demod
.state
= DEMOD_AWAITING_START_BIT
;
587 /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
593 if(Demod
.posCount
> 12*2) { // low phase of SOF too long (> 12 etu)
594 Demod
.state
= DEMOD_UNSYNCD
;
600 case DEMOD_AWAITING_START_BIT
:
602 MAKE_SOFT_DECISION();
604 if(Demod
.posCount
> 3*2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
605 Demod
.state
= DEMOD_UNSYNCD
;
608 } else { // start bit detected
610 Demod
.posCount
= 1; // this was the first half
613 Demod
.state
= DEMOD_RECEIVING_DATA
;
617 case DEMOD_RECEIVING_DATA
:
618 MAKE_SOFT_DECISION();
619 if(Demod
.posCount
== 0) { // first half of bit
622 } else { // second half of bit
625 /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
626 if(Demod.thisBit > 0) {
627 Demod.metric += Demod.thisBit;
629 Demod.metric -= Demod.thisBit;
634 Demod
.shiftReg
>>= 1;
635 if(Demod
.thisBit
> 0) { // logic '1'
636 Demod
.shiftReg
|= 0x200;
640 if(Demod
.bitCount
== 10) {
641 uint16_t s
= Demod
.shiftReg
;
642 if((s
& 0x200) && !(s
& 0x001)) { // stop bit == '1', start bit == '0'
643 uint8_t b
= (s
>> 1);
644 Demod
.output
[Demod
.len
] = b
;
646 Demod
.state
= DEMOD_AWAITING_START_BIT
;
648 Demod
.state
= DEMOD_UNSYNCD
;
651 // This is EOF (start, stop and all data bits == '0'
661 Demod
.state
= DEMOD_UNSYNCD
;
670 static void DemodReset()
672 // Clear out the state of the "UART" that receives from the tag.
674 Demod
.state
= DEMOD_UNSYNCD
;
676 memset(Demod
.output
, 0x00, MAX_FRAME_SIZE
);
680 static void DemodInit(uint8_t *data
)
687 static void UartReset()
689 Uart
.byteCntMax
= MAX_FRAME_SIZE
;
690 Uart
.state
= STATE_UNSYNCD
;
696 static void UartInit(uint8_t *data
)
704 * Demodulate the samples we received from the tag, also log to tracebuffer
705 * quiet: set to 'TRUE' to disable debug output
707 static void GetSamplesFor14443bDemod(int n
, bool quiet
)
710 bool gotFrame
= FALSE
;
711 int lastRxCounter
, ci
, cq
, samples
= 0;
713 // Allocate memory from BigBuf for some buffers
714 // free all previous allocations first
717 // The response (tag -> reader) that we're receiving.
718 uint8_t *receivedResponse
= BigBuf_malloc(MAX_FRAME_SIZE
);
720 // The DMA buffer, used to stream samples from the FPGA
721 int8_t *dmaBuf
= (int8_t*) BigBuf_malloc(DMA_BUFFER_SIZE
);
723 // Set up the demodulator for tag -> reader responses.
724 DemodInit(receivedResponse
);
726 // Setup and start DMA.
727 FpgaSetupSscDma((uint8_t*) dmaBuf
, DMA_BUFFER_SIZE
);
729 int8_t *upTo
= dmaBuf
;
730 lastRxCounter
= DMA_BUFFER_SIZE
;
732 // Signal field is ON with the appropriate LED:
734 // And put the FPGA in the appropriate mode
735 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR
| FPGA_HF_READER_RX_XCORR_848_KHZ
);
738 int behindBy
= lastRxCounter
- AT91C_BASE_PDC_SSC
->PDC_RCR
;
739 if(behindBy
> max
) max
= behindBy
;
741 while(((lastRxCounter
-AT91C_BASE_PDC_SSC
->PDC_RCR
) & (DMA_BUFFER_SIZE
-1)) > 2) {
745 if(upTo
>= dmaBuf
+ DMA_BUFFER_SIZE
) {
747 AT91C_BASE_PDC_SSC
->PDC_RNPR
= (uint32_t) upTo
;
748 AT91C_BASE_PDC_SSC
->PDC_RNCR
= DMA_BUFFER_SIZE
;
751 if(lastRxCounter
<= 0) {
752 lastRxCounter
+= DMA_BUFFER_SIZE
;
757 if(Handle14443bSamplesDemod(ci
, cq
)) {
763 if(samples
> n
|| gotFrame
) {
768 AT91C_BASE_PDC_SSC
->PDC_PTCR
= AT91C_PDC_RXTDIS
;
770 if (!quiet
) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", max
, samples
, gotFrame
, Demod
.len
, Demod
.sumI
, Demod
.sumQ
);
772 if (tracing
&& Demod
.len
> 0) {
773 uint8_t parity
[MAX_PARITY_SIZE
];
774 //GetParity(Demod.output, Demod.len, parity);
775 LogTrace(Demod
.output
, Demod
.len
, 0, 0, parity
, FALSE
);
780 //-----------------------------------------------------------------------------
781 // Transmit the command (to the tag) that was placed in ToSend[].
782 //-----------------------------------------------------------------------------
783 static void TransmitFor14443b(void)
789 while(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_TXRDY
)) {
790 AT91C_BASE_SSC
->SSC_THR
= 0xff;
793 // Signal field is ON with the appropriate Red LED
795 // Signal we are transmitting with the Green LED
797 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX
| FPGA_HF_READER_TX_SHALLOW_MOD
);
799 for(c
= 0; c
< 10;) {
800 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_TXRDY
)) {
801 AT91C_BASE_SSC
->SSC_THR
= 0xff;
804 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_RXRDY
)) {
805 volatile uint32_t r
= AT91C_BASE_SSC
->SSC_RHR
;
813 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_TXRDY
)) {
814 AT91C_BASE_SSC
->SSC_THR
= ToSend
[c
];
820 if(AT91C_BASE_SSC
->SSC_SR
& (AT91C_SSC_RXRDY
)) {
821 volatile uint32_t r
= AT91C_BASE_SSC
->SSC_RHR
;
826 LED_B_OFF(); // Finished sending
830 //-----------------------------------------------------------------------------
831 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
832 // so that it is ready to transmit to the tag using TransmitFor14443b().
833 //-----------------------------------------------------------------------------
834 static void CodeIso14443bAsReader(const uint8_t *cmd
, int len
)
841 // Establish initial reference level
842 for(i
= 0; i
< 40; i
++) {
846 for(i
= 0; i
< 10; i
++) {
850 for(i
= 0; i
< len
; i
++) {
858 for(j
= 0; j
< 8; j
++) {
869 for(i
= 0; i
< 10; i
++) {
872 for(i
= 0; i
< 8; i
++) {
876 // And then a little more, to make sure that the last character makes
877 // it out before we switch to rx mode.
878 for(i
= 0; i
< 24; i
++) {
882 // Convert from last character reference to length
888 Convenience function to encode, transmit and trace iso 14443b comms
890 static void CodeAndTransmit14443bAsReader(const uint8_t *cmd
, int len
)
892 CodeIso14443bAsReader(cmd
, len
);
895 uint8_t parity
[MAX_PARITY_SIZE
];
896 GetParity(cmd
, len
, parity
);
897 LogTrace(cmd
,len
, 0, 0, parity
, TRUE
);
902 //-----------------------------------------------------------------------------
903 // Read a SRI512 ISO 14443B tag.
905 // SRI512 tags are just simple memory tags, here we're looking at making a dump
906 // of the contents of the memory. No anticollision algorithm is done, we assume
907 // we have a single tag in the field.
909 // I tried to be systematic and check every answer of the tag, every CRC, etc...
910 //-----------------------------------------------------------------------------
911 void ReadSTMemoryIso14443b(uint32_t dwLast
)
918 FpgaDownloadAndGo(FPGA_BITSTREAM_HF
);
919 // Make sure that we start from off, since the tags are stateful;
920 // confusing things will happen if we don't reset them between reads.
922 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF
);
925 SetAdcMuxFor(GPIO_MUXSEL_HIPKD
);
928 // Now give it time to spin up.
929 // Signal field is on with the appropriate LED
932 FPGA_MAJOR_MODE_HF_READER_RX_XCORR
| FPGA_HF_READER_RX_XCORR_848_KHZ
);
935 // First command: wake up the tag using the INITIATE command
936 uint8_t cmd1
[] = {0x06, 0x00, 0x97, 0x5b};
938 CodeAndTransmit14443bAsReader(cmd1
, sizeof(cmd1
));
940 GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT
, TRUE
);
943 if (Demod
.len
== 0) {
944 DbpString("No response from tag");
947 Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %02x %02x %02x",
948 Demod
.output
[0], Demod
.output
[1], Demod
.output
[2]);
950 // There is a response, SELECT the uid
951 DbpString("Now SELECT tag:");
952 cmd1
[0] = 0x0E; // 0x0E is SELECT
953 cmd1
[1] = Demod
.output
[0];
954 ComputeCrc14443(CRC_14443_B
, cmd1
, 2, &cmd1
[2], &cmd1
[3]);
955 CodeAndTransmit14443bAsReader(cmd1
, sizeof(cmd1
));
958 GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT
, TRUE
);
960 if (Demod
.len
!= 3) {
961 Dbprintf("Expected 3 bytes from tag, got %d", Demod
.len
);
964 // Check the CRC of the answer:
965 ComputeCrc14443(CRC_14443_B
, Demod
.output
, 1 , &cmd1
[2], &cmd1
[3]);
966 if(cmd1
[2] != Demod
.output
[1] || cmd1
[3] != Demod
.output
[2]) {
967 DbpString("CRC Error reading select response.");
970 // Check response from the tag: should be the same UID as the command we just sent:
971 if (cmd1
[1] != Demod
.output
[0]) {
972 Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1
[1], Demod
.output
[0]);
975 // Tag is now selected,
976 // First get the tag's UID:
978 ComputeCrc14443(CRC_14443_B
, cmd1
, 1 , &cmd1
[1], &cmd1
[2]);
979 CodeAndTransmit14443bAsReader(cmd1
, 3); // Only first three bytes for this one
982 GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT
, TRUE
);
984 if (Demod
.len
!= 10) {
985 Dbprintf("Expected 10 bytes from tag, got %d", Demod
.len
);
988 // The check the CRC of the answer (use cmd1 as temporary variable):
989 ComputeCrc14443(CRC_14443_B
, Demod
.output
, 8, &cmd1
[2], &cmd1
[3]);
990 if(cmd1
[2] != Demod
.output
[8] || cmd1
[3] != Demod
.output
[9]) {
991 Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
992 (cmd1
[2]<<8)+cmd1
[3], (Demod
.output
[8]<<8)+Demod
.output
[9]);
993 // Do not return;, let's go on... (we should retry, maybe ?)
995 Dbprintf("Tag UID (64 bits): %08x %08x",
996 (Demod
.output
[7]<<24) + (Demod
.output
[6]<<16) + (Demod
.output
[5]<<8) + Demod
.output
[4],
997 (Demod
.output
[3]<<24) + (Demod
.output
[2]<<16) + (Demod
.output
[1]<<8) + Demod
.output
[0]);
999 // Now loop to read all 16 blocks, address from 0 to last block
1000 Dbprintf("Tag memory dump, block 0 to %d", dwLast
);
1006 DbpString("System area block (0xff):");
1010 ComputeCrc14443(CRC_14443_B
, cmd1
, 2, &cmd1
[2], &cmd1
[3]);
1011 CodeAndTransmit14443bAsReader(cmd1
, sizeof(cmd1
));
1014 GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT
, TRUE
);
1016 if (Demod
.len
!= 6) { // Check if we got an answer from the tag
1017 DbpString("Expected 6 bytes from tag, got less...");
1020 // The check the CRC of the answer (use cmd1 as temporary variable):
1021 ComputeCrc14443(CRC_14443_B
, Demod
.output
, 4, &cmd1
[2], &cmd1
[3]);
1022 if(cmd1
[2] != Demod
.output
[4] || cmd1
[3] != Demod
.output
[5]) {
1023 Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
1024 (cmd1
[2]<<8)+cmd1
[3], (Demod
.output
[4]<<8)+Demod
.output
[5]);
1025 // Do not return;, let's go on... (we should retry, maybe ?)
1027 // Now print out the memory location:
1028 Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i
,
1029 (Demod
.output
[3]<<24) + (Demod
.output
[2]<<16) + (Demod
.output
[1]<<8) + Demod
.output
[0],
1030 (Demod
.output
[4]<<8)+Demod
.output
[5]);
1039 //=============================================================================
1040 // Finally, the `sniffer' combines elements from both the reader and
1041 // simulated tag, to show both sides of the conversation.
1042 //=============================================================================
1044 //-----------------------------------------------------------------------------
1045 // Record the sequence of commands sent by the reader to the tag, with
1046 // triggering so that we start recording at the point that the tag is moved
1048 //-----------------------------------------------------------------------------
1050 * Memory usage for this function, (within BigBuf)
1051 * Last Received command (reader->tag) - MAX_FRAME_SIZE
1052 * Last Received command (tag->reader) - MAX_FRAME_SIZE
1053 * DMA Buffer - DMA_BUFFER_SIZE
1054 * Demodulated samples received - all the rest
1056 void RAMFUNC
SnoopIso14443b(void)
1058 // We won't start recording the frames that we acquire until we trigger;
1059 // a good trigger condition to get started is probably when we see a
1060 // response from the tag.
1061 int triggered
= TRUE
; // TODO: set and evaluate trigger condition
1063 FpgaDownloadAndGo(FPGA_BITSTREAM_HF
);
1069 // The DMA buffer, used to stream samples from the FPGA
1070 int8_t *dmaBuf
= (int8_t*) BigBuf_malloc(DMA_BUFFER_SIZE
);
1074 int maxBehindBy
= 0;
1076 // Count of samples received so far, so that we can include timing
1077 // information in the trace buffer.
1080 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE
));
1081 UartInit(BigBuf_malloc(MAX_FRAME_SIZE
));
1083 // Print some debug information about the buffer sizes
1084 Dbprintf("Snooping buffers initialized:");
1085 Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen());
1086 Dbprintf(" Reader -> tag: %i bytes", MAX_FRAME_SIZE
);
1087 Dbprintf(" tag -> Reader: %i bytes", MAX_FRAME_SIZE
);
1088 Dbprintf(" DMA: %i bytes", DMA_BUFFER_SIZE
);
1090 // Signal field is off, no reader signal, no tag signal
1093 // And put the FPGA in the appropriate mode
1094 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR
| FPGA_HF_READER_RX_XCORR_848_KHZ
| FPGA_HF_READER_RX_XCORR_SNOOP
);
1095 SetAdcMuxFor(GPIO_MUXSEL_HIPKD
);
1097 // Setup for the DMA.
1100 lastRxCounter
= DMA_BUFFER_SIZE
;
1101 FpgaSetupSscDma((uint8_t*) dmaBuf
, DMA_BUFFER_SIZE
);
1102 uint8_t parity
[MAX_PARITY_SIZE
];
1104 bool TagIsActive
= FALSE
;
1105 bool ReaderIsActive
= FALSE
;
1107 // And now we loop, receiving samples.
1109 int behindBy
= (lastRxCounter
- AT91C_BASE_PDC_SSC
->PDC_RCR
) &
1110 (DMA_BUFFER_SIZE
-1);
1111 if(behindBy
> maxBehindBy
) {
1112 maxBehindBy
= behindBy
;
1115 if(behindBy
< 2) continue;
1121 if(upTo
>= dmaBuf
+ DMA_BUFFER_SIZE
) {
1123 lastRxCounter
+= DMA_BUFFER_SIZE
;
1124 AT91C_BASE_PDC_SSC
->PDC_RNPR
= (uint32_t) dmaBuf
;
1125 AT91C_BASE_PDC_SSC
->PDC_RNCR
= DMA_BUFFER_SIZE
;
1127 if(behindBy
> (9*DMA_BUFFER_SIZE
/10)) { // TODO: understand whether we can increase/decrease as we want or not?
1128 Dbprintf("blew circular buffer! behindBy=%d", behindBy
);
1132 DbpString("Reached trace limit");
1135 if(BUTTON_PRESS()) {
1136 DbpString("cancelled");
1143 if (!TagIsActive
) { // no need to try decoding reader data if the tag is sending
1144 if(Handle14443bUartBit(ci
& 0x01)) {
1145 if(triggered
&& tracing
) {
1146 //GetParity(Uart.output, Uart.byteCnt, parity);
1147 LogTrace(Uart
.output
, Uart
.byteCnt
, samples
, samples
, parity
, TRUE
);
1149 /* And ready to receive another command. */
1151 /* And also reset the demod code, which might have been */
1152 /* false-triggered by the commands from the reader. */
1155 if(Handle14443bUartBit(cq
& 0x01)) {
1156 if(triggered
&& tracing
) {
1157 //GetParity(Uart.output, Uart.byteCnt, parity);
1158 LogTrace(Uart
.output
, Uart
.byteCnt
, samples
, samples
, parity
, TRUE
);
1160 /* And ready to receive another command. */
1162 /* And also reset the demod code, which might have been */
1163 /* false-triggered by the commands from the reader. */
1166 ReaderIsActive
= (Uart
.state
!= STATE_UNSYNCD
);
1169 if(!ReaderIsActive
) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time
1170 if(Handle14443bSamplesDemod(ci
& 0xFE, cq
& 0xFE)) {
1172 //Use samples as a time measurement
1175 uint8_t parity
[MAX_PARITY_SIZE
];
1176 //GetParity(Demod.output, Demod.len, parity);
1177 LogTrace(Demod
.output
, Demod
.len
, samples
, samples
, parity
, FALSE
);
1181 // And ready to receive another response.
1184 TagIsActive
= (Demod
.state
> DEMOD_GOT_FALLING_EDGE_OF_SOF
);
1189 FpgaDisableSscDma();
1191 AT91C_BASE_PDC_SSC
->PDC_PTCR
= AT91C_PDC_RXTDIS
;
1192 DbpString("Snoop statistics:");
1193 Dbprintf(" Max behind by: %i", maxBehindBy
);
1194 Dbprintf(" Uart State: %x", Uart
.state
);
1195 Dbprintf(" Uart ByteCnt: %i", Uart
.byteCnt
);
1196 Dbprintf(" Uart ByteCntMax: %i", Uart
.byteCntMax
);
1197 Dbprintf(" Trace length: %i", BigBuf_get_traceLen());
1202 * Send raw command to tag ISO14443B
1204 * datalen len of buffer data
1205 * recv bool when true wait for data from tag and send to client
1206 * powerfield bool leave the field on when true
1207 * data buffer with byte to send
1213 void SendRawCommand14443B(uint32_t datalen
, uint32_t recv
, uint8_t powerfield
, uint8_t data
[])
1215 FpgaDownloadAndGo(FPGA_BITSTREAM_HF
);
1216 SetAdcMuxFor(GPIO_MUXSEL_HIPKD
);
1221 /* if(!powerfield) {
1222 // Make sure that we start from off, since the tags are stateful;
1223 // confusing things will happen if we don't reset them between reads.
1224 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1230 // if(!GETBIT(GPIO_LED_D)) { // if field is off
1231 // FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
1232 // // Signal field is on with the appropriate LED
1237 CodeAndTransmit14443bAsReader(data
, datalen
);
1240 GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT
, TRUE
);
1241 uint16_t iLen
= MIN(Demod
.len
, USB_CMD_DATA_SIZE
);
1242 cmd_send(CMD_ACK
, iLen
, 0, 0, Demod
.output
, iLen
);
1246 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF
);