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CHG: better annotation for 'legic'
[proxmark3-svn] / armsrc / legicrf.c
1 //-----------------------------------------------------------------------------
2 // (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
3 //
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
6 // the license.
7 //-----------------------------------------------------------------------------
8 // LEGIC RF simulation code
9 //-----------------------------------------------------------------------------
10
11 #include "legicrf.h"
12
13 static struct legic_frame {
14 int bits;
15 uint32_t data;
16 } current_frame;
17
18 static enum {
19 STATE_DISCON,
20 STATE_IV,
21 STATE_CON,
22 } legic_state;
23
24 static crc_t legic_crc;
25 static int legic_read_count;
26 static uint32_t legic_prng_bc;
27 static uint32_t legic_prng_iv;
28
29 static int legic_phase_drift;
30 static int legic_frame_drift;
31 static int legic_reqresp_drift;
32
33 int timestamp;
34
35 AT91PS_TC timer;
36 AT91PS_TC prng_timer;
37
38 static void setup_timer(void) {
39 /* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
40 * this it won't be terribly accurate but should be good enough.
41 */
42 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
43 timer = AT91C_BASE_TC1;
44 timer->TC_CCR = AT91C_TC_CLKDIS;
45 timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;
46 timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
47
48 /*
49 * Set up Timer 2 to use for measuring time between frames in
50 * tag simulation mode. Runs 4x faster as Timer 1
51 */
52 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC2);
53 prng_timer = AT91C_BASE_TC2;
54 prng_timer->TC_CCR = AT91C_TC_CLKDIS;
55 prng_timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV2_CLOCK;
56 prng_timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
57 }
58
59 /* At TIMER_CLOCK3 (MCK/32) */
60 #define RWD_TIME_1 150 /* RWD_TIME_PAUSE off, 80us on = 100us */
61 #define RWD_TIME_0 90 /* RWD_TIME_PAUSE off, 40us on = 60us */
62 #define RWD_TIME_PAUSE 30 /* 20us */
63 #define RWD_TIME_FUZZ 20 /* rather generous 13us, since the peak detector + hysteresis fuzz quite a bit */
64 #define TAG_TIME_BIT 150 /* 100us for every bit */
65 #define TAG_TIME_WAIT 490 /* 490 time from RWD frame end to tag frame start, experimentally determined */
66
67 #define SIM_DIVISOR 586 /* prng_time/SIM_DIVISOR count prng needs to be forwared */
68 #define SIM_SHIFT 900 /* prng_time+SIM_SHIFT shift of delayed start */
69
70 #define SESSION_IV 0x55
71 #define OFFSET_LOG 1024
72
73 #define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
74
75 // ~ 258us + 100us*delay
76 #define WAIT_387 WAIT(387)
77 #define WAIT(delay) while(timer->TC_CV < (delay) );
78
79
80 // ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces.
81 // Historically it used to be FREE_BUFFER_SIZE, which was 2744.
82 #define LEGIC_CARD_MEMSIZE 1024
83 static uint8_t* cardmem;
84
85 /*
86 The new tracelog..
87 // Traceformat:
88 // 32 bits timestamp (little endian)
89 // 16 bits duration (little endian)
90 // 16 bits data length (little endian, Highest Bit used as readerToTag flag)
91 // y Bytes data
92 // x Bytes parity (one byte per 8 bytes data)
93 */
94
95 /* Generate Keystream */
96 static uint32_t get_key_stream(int skip, int count)
97 {
98 uint32_t key = 0;
99 int i;
100
101 // Use int to enlarge timer tc to 32bit
102 legic_prng_bc += prng_timer->TC_CV;
103
104 // reset the prng timer.
105 prng_timer->TC_CCR = AT91C_TC_SWTRG;
106 while(prng_timer->TC_CV > 1) ;
107
108 /* If skip == -1, forward prng time based */
109 if(skip == -1) {
110 i = (legic_prng_bc + SIM_SHIFT)/SIM_DIVISOR; /* Calculate Cycles based on timer */
111 i -= legic_prng_count(); /* substract cycles of finished frames */
112 i -= count; /* substract current frame length, rewind to beginning */
113 legic_prng_forward(i);
114 } else {
115 legic_prng_forward(skip);
116 }
117
118 i = (count == 6) ? -1 : legic_read_count;
119
120 /* Write Time Data into LOG */
121 // uint8_t *BigBuf = BigBuf_get_addr();
122 // BigBuf[OFFSET_LOG+128+i] = legic_prng_count();
123 // BigBuf[OFFSET_LOG+256+i*4] = (legic_prng_bc >> 0) & 0xff;
124 // BigBuf[OFFSET_LOG+256+i*4+1] = (legic_prng_bc >> 8) & 0xff;
125 // BigBuf[OFFSET_LOG+256+i*4+2] = (legic_prng_bc >>16) & 0xff;
126 // BigBuf[OFFSET_LOG+256+i*4+3] = (legic_prng_bc >>24) & 0xff;
127 // BigBuf[OFFSET_LOG+384+i] = count;
128
129 /* Generate KeyStream */
130 for(i=0; i<count; i++) {
131 key |= legic_prng_get_bit() << i;
132 legic_prng_forward(1);
133 }
134 return key;
135 }
136
137 /* Send a frame in tag mode, the FPGA must have been set up by
138 * LegicRfSimulate
139 */
140 static void frame_send_tag(uint16_t response, int bits, int crypt)
141 {
142 /* Bitbang the response */
143 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
144 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
145 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
146
147 /* Use time to crypt frame */
148 if(crypt) {
149 legic_prng_forward(2); /* TAG_TIME_WAIT -> shift by 2 */
150 int key = 0;
151 for(int i = 0; i < bits; i++) {
152 key |= legic_prng_get_bit() << i;
153 legic_prng_forward(1);
154 }
155 response = response ^ key;
156 }
157
158 /* Wait for the frame start */
159 //while(timer->TC_CV < (TAG_TIME_WAIT - 30)) ;
160 WAIT( TAG_TIME_WAIT - 30)
161
162 uint8_t bit = 0;
163 for(int i = 0; i < bits; i++) {
164 int nextbit = timer->TC_CV + TAG_TIME_BIT;
165 bit = response & 1;
166 response >>= 1;
167
168 if (bit)
169 AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
170 else
171 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
172
173 //while(timer->TC_CV < nextbit) ;
174 WAIT(nextbit)
175 }
176 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
177 }
178
179 // Starts Clock and waits until its reset
180 static void ResetClock(void){
181 timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
182 while(timer->TC_CV > 1) ;
183 }
184
185 /* Send a frame in reader mode, the FPGA must have been set up by
186 * LegicRfReader
187 */
188 static void frame_send_rwd(uint32_t data, uint8_t bits){
189
190 uint8_t bit = 0;
191 uint32_t starttime = 0, pause_end = 0, bit_end = 0, temp = data;
192 ResetClock();
193
194 for(int i = 0; i < bits; i++) {
195
196 starttime = timer->TC_CV;
197 pause_end = starttime + RWD_TIME_PAUSE;
198 bit = temp & 1;
199 temp >>= 1;
200
201 if(bit ^ legic_prng_get_bit())
202 bit_end = starttime + RWD_TIME_1;
203 else
204 bit_end = starttime + RWD_TIME_0;
205
206 /* RWD_TIME_PAUSE time off, then some time on, so that the complete bit time is
207 * RWD_TIME_x, where x is the bit to be transmitted */
208 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
209
210 WAIT( pause_end )
211
212 AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
213
214 // bit duration is longest. use this time to forward the lfsr
215 legic_prng_forward(1);
216
217 WAIT( bit_end )
218 }
219
220 // One final pause to mark the end of the frame
221 pause_end = timer->TC_CV + RWD_TIME_PAUSE;
222
223 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
224
225 WAIT(pause_end)
226
227 AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
228
229 // log
230 uint8_t cmdbytes[2] = { (data & 0xFF), 0 };
231 if ( bits > 8 ) {
232 cmdbytes[1] = (data >> 8 ) & 0xFF;
233 LogTrace(cmdbytes, 2, 0, timer->TC_CV, NULL, TRUE);
234 } else {
235 LogTrace(cmdbytes, 1, 0, timer->TC_CV, NULL, TRUE);
236 }
237 /* Reset the timer, to measure time until the start of the tag frame */
238 ResetClock();
239 }
240
241 /* Receive a frame from the card in reader emulation mode, the FPGA and
242 * timer must have been set up by LegicRfReader and frame_send_rwd.
243 *
244 * The LEGIC RF protocol from card to reader does not include explicit
245 * frame start/stop information or length information. The reader must
246 * know beforehand how many bits it wants to receive. (Notably: a card
247 * sending a stream of 0-bits is indistinguishable from no card present.)
248 *
249 * Receive methodology: There is a fancy correlator in hi_read_rx_xcorr, but
250 * I'm not smart enough to use it. Instead I have patched hi_read_tx to output
251 * the ADC signal with hysteresis on SSP_DIN. Bit-bang that signal and look
252 * for edges. Count the edges in each bit interval. If they are approximately
253 * 0 this was a 0-bit, if they are approximately equal to the number of edges
254 * expected for a 212kHz subcarrier, this was a 1-bit. For timing we use the
255 * timer that's still running from frame_send_rwd in order to get a synchronization
256 * with the frame that we just sent.
257 *
258 * FIXME: Because we're relying on the hysteresis to just do the right thing
259 * the range is severely reduced (and you'll probably also need a good antenna).
260 * So this should be fixed some time in the future for a proper receiver.
261 */
262 static void frame_receive_rwd(struct legic_frame * const f, int bits, int crypt)
263 {
264 uint32_t starttime = timer->TC_CV;
265
266 uint32_t the_bit = 1;
267 uint32_t data = 0;/* Use a bitmask to save on shifts */
268 int i, old_level = 0, edges = 0;
269 int next_bit_at = TAG_TIME_WAIT;
270 int level = 0;
271
272 if(bits > 32) bits = 32;
273
274 AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
275 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
276
277 /* we have some time now, precompute the cipher
278 * since we cannot compute it on the fly while reading */
279 legic_prng_forward(2);
280
281 if(crypt) {
282 for(i=0; i<bits; i++) {
283 data |= legic_prng_get_bit() << i;
284 legic_prng_forward(1);
285 }
286 }
287
288 // QUESTION: how long did those extra calls to logtrace take?
289 WAIT(next_bit_at)
290
291 next_bit_at += TAG_TIME_BIT;
292
293 for(i=0; i<bits; i++) {
294 edges = 0;
295 while(timer->TC_CV < next_bit_at) {
296 level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
297 if(level != old_level)
298 edges++;
299 old_level = level;
300 }
301 next_bit_at += TAG_TIME_BIT;
302
303 // We expect 42 edges
304 if(edges > 20 && edges < 60) {
305 data ^= the_bit;
306 }
307 the_bit <<= 1;
308 }
309
310 f->data = data;
311 f->bits = bits;
312
313 // log
314 uint8_t cmdbytes[] = { (data & 0xFF), (data >> 8) & 0xFF };
315 LogTrace(cmdbytes, 2, starttime, timer->TC_CV, NULL, FALSE);
316
317 // Reset the timer, to synchronize the next frame
318 ResetClock();
319 }
320
321 static void frame_append_bit(struct legic_frame * const f, int bit) {
322 // Overflow, won't happen
323 if (f->bits >= 31) return;
324
325 f->data |= (bit << f->bits);
326 f->bits++;
327 }
328
329 static void frame_clean(struct legic_frame * const f) {
330 f->data = 0;
331 f->bits = 0;
332 }
333
334 // Setup pm3 as a Legic Reader
335 static uint32_t perform_setup_phase_rwd(uint8_t iv) {
336
337 // Switch on carrier and let the tag charge for 1ms
338 AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
339 SpinDelay(20); // was 1ms before.
340
341 // no keystream yet
342 legic_prng_init(0);
343
344 frame_send_rwd(iv, 7);
345
346 legic_prng_init(iv);
347
348 frame_clean(&current_frame);
349
350 frame_receive_rwd(&current_frame, 6, 1);
351
352 // we wait anyways
353 legic_prng_forward(3);
354
355 WAIT(387)
356
357 // Send obsfuscated acknowledgment frame.
358 // 0x19 = MIM22
359 // 0x39 = MIM256, MIM1024
360 if ( current_frame.data == 0x0D ){
361 frame_send_rwd(0x19, 6);
362 }else{
363 frame_send_rwd(0x39, 6);
364 }
365
366 return current_frame.data;
367 }
368
369 static void LegicCommonInit(void) {
370
371 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
372 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
373 FpgaSetupSsc();
374 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
375
376 /* Bitbang the transmitter */
377 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
378 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
379 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
380
381 // reserve a cardmem, meaning we can use the tracelog function in bigbuff easier.
382 cardmem = BigBuf_malloc(LEGIC_CARD_MEMSIZE);
383 memset(cardmem, 0x00, LEGIC_CARD_MEMSIZE);
384
385 clear_trace();
386 set_tracing(TRUE);
387
388 setup_timer();
389
390 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
391 }
392
393 /* Switch off carrier, make sure tag is reset */
394 static void switch_off_tag_rwd(void) {
395 AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
396 SpinDelay(10);
397 WDT_HIT();
398 }
399
400 // calculate crc4 for a legic READ command
401 // 5,8,10 address size.
402 static int LegicCRC(uint16_t byte_index, uint8_t value, uint8_t cmd_sz) {
403 crc_clear(&legic_crc);
404 crc_update(&legic_crc, LEGIC_READ, 1);
405 crc_update(&legic_crc, byte_index, cmd_sz-1);
406 crc_update(&legic_crc, value, 8);
407 return crc_finish(&legic_crc);
408 }
409
410 #define LEGIC_READ 0x01
411 #define LEGIC_WRITE 0x00
412
413 int legic_read_byte(int byte_index, int cmd_sz) {
414
415 int calcCrc = 0, crc = 0;
416 uint8_t byte = 0;
417 uint32_t cmd = (byte_index << 1) | LEGIC_READ;
418
419 WAIT_387
420
421 // send read command
422 frame_send_rwd(cmd, cmd_sz);
423
424 frame_clean(&current_frame);
425
426 // receive
427 frame_receive_rwd(&current_frame, 12, 1);
428
429 byte = current_frame.data & 0xff;
430 calcCrc = LegicCRC(byte_index, byte, cmd_sz);
431 crc = (current_frame.data >> 8);
432
433 if( calcCrc != crc ) {
434 Dbprintf("!!! crc mismatch: expected %x but got %x !!!", calcCrc, crc);
435 return -1;
436 }
437
438 // we wait anyways
439 legic_prng_forward(4);
440 return byte;
441 }
442
443 /*
444 * - assemble a write_cmd_frame with crc and send it
445 * - wait until the tag sends back an ACK ('1' bit unencrypted)
446 * - forward the prng based on the timing
447 */
448 //int legic_write_byte(int byte, int addr, int addr_sz, int PrngCorrection) {
449 int legic_write_byte(int byte, int addr, int addr_sz) {
450
451 //do not write UID, CRC at offset 0-4.
452 if(addr <= 0x04) return 0;
453
454 // crc
455 crc_clear(&legic_crc);
456 crc_update(&legic_crc, 0, 1); /* CMD_WRITE */
457 crc_update(&legic_crc, addr, addr_sz);
458 crc_update(&legic_crc, byte, 8);
459 uint32_t crc = crc_finish(&legic_crc);
460
461 // send write command
462 uint32_t cmd = ((crc <<(addr_sz+1+8)) //CRC
463 |(byte <<(addr_sz+1)) //Data
464 |(addr <<1) //Address
465 |(0x00 <<0)); //CMD = W
466 uint32_t cmd_sz = addr_sz+1+8+4; //crc+data+cmd
467
468 legic_prng_forward(2); /* we wait anyways */
469
470 while(timer->TC_CV < 387) ; /* ~ 258us */
471
472 frame_send_rwd(cmd, cmd_sz);
473
474 // wllm-rbnt doesnt have these
475 // AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
476 // AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
477
478 // wait for ack
479 int t, old_level = 0, edges = 0;
480 int next_bit_at = 0;
481
482 while(timer->TC_CV < 387) ; /* ~ 258us */
483
484 for( t = 0; t < 80; t++) {
485 edges = 0;
486 next_bit_at += TAG_TIME_BIT;
487 while(timer->TC_CV < next_bit_at) {
488 int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
489 if(level != old_level) {
490 edges++;
491 }
492 old_level = level;
493 }
494 if(edges > 20 && edges < 60) { /* expected are 42 edges */
495 int t = timer->TC_CV;
496 int c = t / TAG_TIME_BIT;
497
498 ResetClock();
499 legic_prng_forward(c);
500 return 0;
501 }
502 }
503
504 ResetClock();
505 return -1;
506 }
507
508 int LegicRfReader(int offset, int bytes, int iv) {
509
510 // ice_legic_setup();
511 // ice_legic_select_card();
512 // return 0;
513 int byte_index = 0, cmd_sz = 0, card_sz = 0;
514
515 LegicCommonInit();
516
517 if ( MF_DBGLEVEL >= 2) DbpString("setting up legic card");
518
519 uint32_t tag_type = perform_setup_phase_rwd(iv);
520
521 //we lose to mutch time with dprintf
522 switch_off_tag_rwd();
523
524 switch(tag_type) {
525 case 0x0d:
526 if ( MF_DBGLEVEL >= 2) DbpString("MIM22 card found, reading card ...");
527 cmd_sz = 6;
528 card_sz = 22;
529 break;
530 case 0x1d:
531 if ( MF_DBGLEVEL >= 2) DbpString("MIM256 card found, reading card ...");
532 cmd_sz = 9;
533 card_sz = 256;
534 break;
535 case 0x3d:
536 if ( MF_DBGLEVEL >= 2) DbpString("MIM1024 card found, reading card ...");
537 cmd_sz = 11;
538 card_sz = 1024;
539 break;
540 default:
541 if ( MF_DBGLEVEL >= 1) Dbprintf("Unknown card format: %x",tag_type);
542 return -1;
543 }
544 if(bytes == -1)
545 bytes = card_sz;
546
547 if(bytes+offset >= card_sz)
548 bytes = card_sz - offset;
549
550 perform_setup_phase_rwd(iv);
551
552 legic_prng_forward(2);
553
554 LED_B_ON();
555 while(byte_index < bytes) {
556 int r = legic_read_byte(byte_index+offset, cmd_sz);
557 if(r == -1 || BUTTON_PRESS()) {
558 switch_off_tag_rwd();
559 LEDsoff();
560 if ( MF_DBGLEVEL >= 2) DbpString("operation aborted");
561 return -1;
562 }
563 cardmem[byte_index] = r;
564 WDT_HIT();
565 byte_index++;
566 }
567
568 switch_off_tag_rwd();
569 LEDsoff();
570
571 if ( MF_DBGLEVEL >= 1) Dbprintf("Card read, use 'hf legic decode' or");
572 if ( MF_DBGLEVEL >= 1) Dbprintf("'data hexsamples %d' to view results", (bytes+7) & ~7);
573 return 0;
574 }
575
576 /*int _LegicRfWriter(int offset, int bytes, int addr_sz, uint8_t *BigBuf, int RoundBruteforceValue) {
577 int byte_index=0;
578
579 LED_B_ON();
580 perform_setup_phase_rwd(SESSION_IV);
581 //legic_prng_forward(2);
582 while(byte_index < bytes) {
583 int r;
584
585 //check if the DCF should be changed
586 if ( (offset == 0x05) && (bytes == 0x02) ) {
587 //write DCF in reverse order (addr 0x06 before 0x05)
588 r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz, RoundBruteforceValue);
589 //legic_prng_forward(1);
590 if(r == 0) {
591 byte_index++;
592 r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz, RoundBruteforceValue);
593 }
594 //legic_prng_forward(1);
595 }
596 else {
597 r = legic_write_byte(BigBuf[byte_index+offset], byte_index+offset, addr_sz, RoundBruteforceValue);
598 }
599 if((r != 0) || BUTTON_PRESS()) {
600 Dbprintf("operation aborted @ 0x%03.3x", byte_index);
601 switch_off_tag_rwd();
602 LED_B_OFF();
603 LED_C_OFF();
604 return -1;
605 }
606
607 WDT_HIT();
608 byte_index++;
609 if(byte_index & 0x10) LED_C_ON(); else LED_C_OFF();
610 }
611 LED_B_OFF();
612 LED_C_OFF();
613 DbpString("write successful");
614 return 0;
615 }*/
616
617 void LegicRfWriter(int offset, int bytes, int iv) {
618
619 int byte_index = 0, addr_sz = 0;
620
621 iv = (iv <=0 ) ? SESSION_IV : iv;
622
623 LegicCommonInit();
624
625 if ( MF_DBGLEVEL >= 2) DbpString("setting up legic card");
626
627 uint32_t tag_type = perform_setup_phase_rwd(iv);
628
629 switch_off_tag_rwd();
630
631 switch(tag_type) {
632 case 0x0d:
633 if(offset+bytes > 22) {
634 Dbprintf("Error: can not write to 0x%03.3x on MIM22", offset+bytes);
635 return;
636 }
637 addr_sz = 5;
638 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM22 card found, writing 0x%02.2x - 0x%02.2x ...", offset, offset+bytes);
639 break;
640 case 0x1d:
641 if(offset+bytes > 0x100) {
642 Dbprintf("Error: can not write to 0x%03.3x on MIM256", offset+bytes);
643 return;
644 }
645 addr_sz = 8;
646 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM256 card found, writing 0x%02.2x - 0x%02.2x ...", offset, offset+bytes);
647 break;
648 case 0x3d:
649 if(offset+bytes > 0x400) {
650 Dbprintf("Error: can not write to 0x%03.3x on MIM1024", offset+bytes);
651 return;
652 }
653 addr_sz = 10;
654 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM1024 card found, writing 0x%03.3x - 0x%03.3x ...", offset, offset+bytes);
655 break;
656 default:
657 Dbprintf("No or unknown card found, aborting");
658 return;
659 }
660
661 LED_B_ON();
662 perform_setup_phase_rwd(iv);
663 while(byte_index < bytes) {
664 int r;
665
666 //check if the DCF should be changed
667 if ( ((byte_index+offset) == 0x05) && (bytes >= 0x02) ) {
668 //write DCF in reverse order (addr 0x06 before 0x05)
669 r = legic_write_byte(cardmem[(0x06-byte_index)], (0x06-byte_index), addr_sz);
670
671 // write second byte on success...
672 if(r == 0) {
673 byte_index++;
674 r = legic_write_byte(cardmem[(0x06-byte_index)], (0x06-byte_index), addr_sz);
675 }
676 }
677 else {
678 r = legic_write_byte(cardmem[byte_index+offset], byte_index+offset, addr_sz);
679 }
680
681 if((r != 0) || BUTTON_PRESS()) {
682 Dbprintf("operation aborted @ 0x%03.3x", byte_index);
683 switch_off_tag_rwd();
684 LEDsoff();
685 return;
686 }
687
688 WDT_HIT();
689 byte_index++;
690 }
691 LEDsoff();
692 if ( MF_DBGLEVEL >= 1) DbpString("write successful");
693 }
694
695 void LegicRfRawWriter(int address, int byte, int iv) {
696
697 int byte_index = 0, addr_sz = 0;
698
699 iv = (iv <= 0) ? SESSION_IV : iv;
700
701 LegicCommonInit();
702
703 if ( MF_DBGLEVEL >= 2) DbpString("setting up legic card");
704
705 uint32_t tag_type = perform_setup_phase_rwd(iv);
706
707 switch_off_tag_rwd();
708
709 switch(tag_type) {
710 case 0x0d:
711 if(address > 22) {
712 Dbprintf("Error: can not write to 0x%03.3x on MIM22", address);
713 return;
714 }
715 addr_sz = 5;
716 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM22 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", address, byte);
717 break;
718 case 0x1d:
719 if(address > 0x100) {
720 Dbprintf("Error: can not write to 0x%03.3x on MIM256", address);
721 return;
722 }
723 addr_sz = 8;
724 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM256 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", address, byte);
725 break;
726 case 0x3d:
727 if(address > 0x400) {
728 Dbprintf("Error: can not write to 0x%03.3x on MIM1024", address);
729 return;
730 }
731 addr_sz = 10;
732 if ( MF_DBGLEVEL >= 2) Dbprintf("MIM1024 card found, writing at addr 0x%03.3x - value 0x%03.3x ...", address, byte);
733 break;
734 default:
735 Dbprintf("No or unknown card found, aborting");
736 return;
737 }
738
739 Dbprintf("integer value: %d address: %d addr_sz: %d", byte, address, addr_sz);
740 LED_B_ON();
741
742 perform_setup_phase_rwd(iv);
743 //legic_prng_forward(2);
744
745 int r = legic_write_byte(byte, address, addr_sz);
746
747 if((r != 0) || BUTTON_PRESS()) {
748 Dbprintf("operation aborted @ 0x%03.3x (%1d)", byte_index, r);
749 switch_off_tag_rwd();
750 LEDsoff();
751 return;
752 }
753
754 LEDsoff();
755 if ( MF_DBGLEVEL >= 1) DbpString("write successful");
756 }
757
758 /* Handle (whether to respond) a frame in tag mode
759 * Only called when simulating a tag.
760 */
761 static void frame_handle_tag(struct legic_frame const * const f)
762 {
763 uint8_t *BigBuf = BigBuf_get_addr();
764
765 /* First Part of Handshake (IV) */
766 if(f->bits == 7) {
767
768 LED_C_ON();
769
770 prng_timer->TC_CCR = AT91C_TC_SWTRG;
771 while(prng_timer->TC_CV > 1) ;
772
773 legic_prng_init(f->data);
774 frame_send_tag(0x3d, 6, 1); /* 0x3d^0x26 = 0x1b */
775 legic_state = STATE_IV;
776 legic_read_count = 0;
777 legic_prng_bc = 0;
778 legic_prng_iv = f->data;
779
780 /* TIMEOUT */
781 ResetClock();
782
783 //while(timer->TC_CV < 280);
784 WAIT(280)
785 return;
786 }
787
788 /* 0x19==??? */
789 if(legic_state == STATE_IV) {
790 int local_key = get_key_stream(3, 6);
791 int xored = 0x39 ^ local_key;
792 if((f->bits == 6) && (f->data == xored)) {
793 legic_state = STATE_CON;
794
795 /* TIMEOUT */
796 ResetClock();
797
798 //while(timer->TC_CV < 200);
799 WAIT(200)
800
801 return;
802 } else {
803 legic_state = STATE_DISCON;
804 LED_C_OFF();
805 Dbprintf("iv: %02x frame: %02x key: %02x xored: %02x", legic_prng_iv, f->data, local_key, xored);
806 return;
807 }
808 }
809
810 /* Read */
811 if(f->bits == 11) {
812 if(legic_state == STATE_CON) {
813 int key = get_key_stream(2, 11); //legic_phase_drift, 11);
814 int addr = f->data ^ key; addr = addr >> 1;
815 int data = BigBuf[addr];
816 int hash = LegicCRC(addr, data, 11) << 8;
817 BigBuf[OFFSET_LOG+legic_read_count] = (uint8_t)addr;
818 legic_read_count++;
819
820 //Dbprintf("Data:%03.3x, key:%03.3x, addr: %03.3x, read_c:%u", f->data, key, addr, read_c);
821 legic_prng_forward(legic_reqresp_drift);
822
823 frame_send_tag(hash | data, 12, 1);
824
825 /* TIMEOUT */
826 ResetClock();
827
828 legic_prng_forward(2);
829 //while(timer->TC_CV < 180);
830 WAIT(180)
831
832 return;
833 }
834 }
835
836 /* Write */
837 if(f->bits == 23) {
838 int key = get_key_stream(-1, 23); //legic_frame_drift, 23);
839 int addr = f->data ^ key; addr = addr >> 1; addr = addr & 0x3ff;
840 int data = f->data ^ key; data = data >> 11; data = data & 0xff;
841
842 /* write command */
843 legic_state = STATE_DISCON;
844 LED_C_OFF();
845 Dbprintf("write - addr: %x, data: %x", addr, data);
846 return;
847 }
848
849 if(legic_state != STATE_DISCON) {
850 Dbprintf("Unexpected: sz:%u, Data:%03.3x, State:%u, Count:%u", f->bits, f->data, legic_state, legic_read_count);
851 int i;
852 Dbprintf("IV: %03.3x", legic_prng_iv);
853 for(i = 0; i<legic_read_count; i++) {
854 Dbprintf("Read Nb: %u, Addr: %u", i, BigBuf[OFFSET_LOG+i]);
855 }
856
857 for(i = -1; i<legic_read_count; i++) {
858 uint32_t t;
859 t = BigBuf[OFFSET_LOG+256+i*4];
860 t |= BigBuf[OFFSET_LOG+256+i*4+1] << 8;
861 t |= BigBuf[OFFSET_LOG+256+i*4+2] <<16;
862 t |= BigBuf[OFFSET_LOG+256+i*4+3] <<24;
863
864 Dbprintf("Cycles: %u, Frame Length: %u, Time: %u",
865 BigBuf[OFFSET_LOG+128+i],
866 BigBuf[OFFSET_LOG+384+i],
867 t);
868 }
869 }
870 legic_state = STATE_DISCON;
871 legic_read_count = 0;
872 SpinDelay(10);
873 LED_C_OFF();
874 return;
875 }
876
877 /* Read bit by bit untill full frame is received
878 * Call to process frame end answer
879 */
880 static void emit(int bit) {
881
882 switch (bit) {
883 case 1:
884 frame_append_bit(&current_frame, 1);
885 break;
886 case 0:
887 frame_append_bit(&current_frame, 0);
888 break;
889 default:
890 if(current_frame.bits <= 4) {
891 frame_clean(&current_frame);
892 } else {
893 frame_handle_tag(&current_frame);
894 frame_clean(&current_frame);
895 }
896 WDT_HIT();
897 break;
898 }
899 }
900
901 void LegicRfSimulate(int phase, int frame, int reqresp)
902 {
903 /* ADC path high-frequency peak detector, FPGA in high-frequency simulator mode,
904 * modulation mode set to 212kHz subcarrier. We are getting the incoming raw
905 * envelope waveform on DIN and should send our response on DOUT.
906 *
907 * The LEGIC RF protocol is pulse-pause-encoding from reader to card, so we'll
908 * measure the time between two rising edges on DIN, and no encoding on the
909 * subcarrier from card to reader, so we'll just shift out our verbatim data
910 * on DOUT, 1 bit is 100us. The time from reader to card frame is still unclear,
911 * seems to be 300us-ish.
912 */
913
914 legic_phase_drift = phase;
915 legic_frame_drift = frame;
916 legic_reqresp_drift = reqresp;
917
918 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
919 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
920 FpgaSetupSsc();
921 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_212K);
922
923 /* Bitbang the receiver */
924 AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
925 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
926
927 setup_timer();
928 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
929
930 int old_level = 0;
931 int active = 0;
932 legic_state = STATE_DISCON;
933
934 LED_B_ON();
935 DbpString("Starting Legic emulator, press button to end");
936
937 while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
938 int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
939 int time = timer->TC_CV;
940
941 if(level != old_level) {
942 if(level == 1) {
943 timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
944
945 if (FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
946 /* 1 bit */
947 emit(1);
948 active = 1;
949 LED_A_ON();
950 } else if (FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
951 /* 0 bit */
952 emit(0);
953 active = 1;
954 LED_A_ON();
955 } else if (active) {
956 /* invalid */
957 emit(-1);
958 active = 0;
959 LED_A_OFF();
960 }
961 }
962 }
963
964 /* Frame end */
965 if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
966 emit(-1);
967 active = 0;
968 LED_A_OFF();
969 }
970
971 if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA)) {
972 timer->TC_CCR = AT91C_TC_CLKDIS;
973 }
974
975 old_level = level;
976 WDT_HIT();
977 }
978 if ( MF_DBGLEVEL >= 1) DbpString("Stopped");
979 LEDsoff();
980 }
981
982 //-----------------------------------------------------------------------------
983 //-----------------------------------------------------------------------------
984
985
986 //-----------------------------------------------------------------------------
987 // Code up a string of octets at layer 2 (including CRC, we don't generate
988 // that here) so that they can be transmitted to the reader. Doesn't transmit
989 // them yet, just leaves them ready to send in ToSend[].
990 //-----------------------------------------------------------------------------
991 // static void CodeLegicAsTag(const uint8_t *cmd, int len)
992 // {
993 // int i;
994
995 // ToSendReset();
996
997 // // Transmit a burst of ones, as the initial thing that lets the
998 // // reader get phase sync. This (TR1) must be > 80/fs, per spec,
999 // // but tag that I've tried (a Paypass) exceeds that by a fair bit,
1000 // // so I will too.
1001 // for(i = 0; i < 20; i++) {
1002 // ToSendStuffBit(1);
1003 // ToSendStuffBit(1);
1004 // ToSendStuffBit(1);
1005 // ToSendStuffBit(1);
1006 // }
1007
1008 // // Send SOF.
1009 // for(i = 0; i < 10; i++) {
1010 // ToSendStuffBit(0);
1011 // ToSendStuffBit(0);
1012 // ToSendStuffBit(0);
1013 // ToSendStuffBit(0);
1014 // }
1015 // for(i = 0; i < 2; i++) {
1016 // ToSendStuffBit(1);
1017 // ToSendStuffBit(1);
1018 // ToSendStuffBit(1);
1019 // ToSendStuffBit(1);
1020 // }
1021
1022 // for(i = 0; i < len; i++) {
1023 // int j;
1024 // uint8_t b = cmd[i];
1025
1026 // // Start bit
1027 // ToSendStuffBit(0);
1028 // ToSendStuffBit(0);
1029 // ToSendStuffBit(0);
1030 // ToSendStuffBit(0);
1031
1032 // // Data bits
1033 // for(j = 0; j < 8; j++) {
1034 // if(b & 1) {
1035 // ToSendStuffBit(1);
1036 // ToSendStuffBit(1);
1037 // ToSendStuffBit(1);
1038 // ToSendStuffBit(1);
1039 // } else {
1040 // ToSendStuffBit(0);
1041 // ToSendStuffBit(0);
1042 // ToSendStuffBit(0);
1043 // ToSendStuffBit(0);
1044 // }
1045 // b >>= 1;
1046 // }
1047
1048 // // Stop bit
1049 // ToSendStuffBit(1);
1050 // ToSendStuffBit(1);
1051 // ToSendStuffBit(1);
1052 // ToSendStuffBit(1);
1053 // }
1054
1055 // // Send EOF.
1056 // for(i = 0; i < 10; i++) {
1057 // ToSendStuffBit(0);
1058 // ToSendStuffBit(0);
1059 // ToSendStuffBit(0);
1060 // ToSendStuffBit(0);
1061 // }
1062 // for(i = 0; i < 2; i++) {
1063 // ToSendStuffBit(1);
1064 // ToSendStuffBit(1);
1065 // ToSendStuffBit(1);
1066 // ToSendStuffBit(1);
1067 // }
1068
1069 // // Convert from last byte pos to length
1070 // ToSendMax++;
1071 // }
1072
1073 //-----------------------------------------------------------------------------
1074 // The software UART that receives commands from the reader, and its state
1075 // variables.
1076 //-----------------------------------------------------------------------------
1077 static struct {
1078 enum {
1079 STATE_UNSYNCD,
1080 STATE_GOT_FALLING_EDGE_OF_SOF,
1081 STATE_AWAITING_START_BIT,
1082 STATE_RECEIVING_DATA
1083 } state;
1084 uint16_t shiftReg;
1085 int bitCnt;
1086 int byteCnt;
1087 int byteCntMax;
1088 int posCnt;
1089 uint8_t *output;
1090 } Uart;
1091
1092 /* Receive & handle a bit coming from the reader.
1093 *
1094 * This function is called 4 times per bit (every 2 subcarrier cycles).
1095 * Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
1096 *
1097 * LED handling:
1098 * LED A -> ON once we have received the SOF and are expecting the rest.
1099 * LED A -> OFF once we have received EOF or are in error state or unsynced
1100 *
1101 * Returns: true if we received a EOF
1102 * false if we are still waiting for some more
1103 */
1104 // static RAMFUNC int HandleLegicUartBit(uint8_t bit)
1105 // {
1106 // switch(Uart.state) {
1107 // case STATE_UNSYNCD:
1108 // if(!bit) {
1109 // // we went low, so this could be the beginning of an SOF
1110 // Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
1111 // Uart.posCnt = 0;
1112 // Uart.bitCnt = 0;
1113 // }
1114 // break;
1115
1116 // case STATE_GOT_FALLING_EDGE_OF_SOF:
1117 // Uart.posCnt++;
1118 // if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
1119 // if(bit) {
1120 // if(Uart.bitCnt > 9) {
1121 // // we've seen enough consecutive
1122 // // zeros that it's a valid SOF
1123 // Uart.posCnt = 0;
1124 // Uart.byteCnt = 0;
1125 // Uart.state = STATE_AWAITING_START_BIT;
1126 // LED_A_ON(); // Indicate we got a valid SOF
1127 // } else {
1128 // // didn't stay down long enough
1129 // // before going high, error
1130 // Uart.state = STATE_UNSYNCD;
1131 // }
1132 // } else {
1133 // // do nothing, keep waiting
1134 // }
1135 // Uart.bitCnt++;
1136 // }
1137 // if(Uart.posCnt >= 4) Uart.posCnt = 0;
1138 // if(Uart.bitCnt > 12) {
1139 // // Give up if we see too many zeros without
1140 // // a one, too.
1141 // LED_A_OFF();
1142 // Uart.state = STATE_UNSYNCD;
1143 // }
1144 // break;
1145
1146 // case STATE_AWAITING_START_BIT:
1147 // Uart.posCnt++;
1148 // if(bit) {
1149 // if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
1150 // // stayed high for too long between
1151 // // characters, error
1152 // Uart.state = STATE_UNSYNCD;
1153 // }
1154 // } else {
1155 // // falling edge, this starts the data byte
1156 // Uart.posCnt = 0;
1157 // Uart.bitCnt = 0;
1158 // Uart.shiftReg = 0;
1159 // Uart.state = STATE_RECEIVING_DATA;
1160 // }
1161 // break;
1162
1163 // case STATE_RECEIVING_DATA:
1164 // Uart.posCnt++;
1165 // if(Uart.posCnt == 2) {
1166 // // time to sample a bit
1167 // Uart.shiftReg >>= 1;
1168 // if(bit) {
1169 // Uart.shiftReg |= 0x200;
1170 // }
1171 // Uart.bitCnt++;
1172 // }
1173 // if(Uart.posCnt >= 4) {
1174 // Uart.posCnt = 0;
1175 // }
1176 // if(Uart.bitCnt == 10) {
1177 // if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
1178 // {
1179 // // this is a data byte, with correct
1180 // // start and stop bits
1181 // Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
1182 // Uart.byteCnt++;
1183
1184 // if(Uart.byteCnt >= Uart.byteCntMax) {
1185 // // Buffer overflowed, give up
1186 // LED_A_OFF();
1187 // Uart.state = STATE_UNSYNCD;
1188 // } else {
1189 // // so get the next byte now
1190 // Uart.posCnt = 0;
1191 // Uart.state = STATE_AWAITING_START_BIT;
1192 // }
1193 // } else if (Uart.shiftReg == 0x000) {
1194 // // this is an EOF byte
1195 // LED_A_OFF(); // Finished receiving
1196 // Uart.state = STATE_UNSYNCD;
1197 // if (Uart.byteCnt != 0) {
1198 // return TRUE;
1199 // }
1200 // } else {
1201 // // this is an error
1202 // LED_A_OFF();
1203 // Uart.state = STATE_UNSYNCD;
1204 // }
1205 // }
1206 // break;
1207
1208 // default:
1209 // LED_A_OFF();
1210 // Uart.state = STATE_UNSYNCD;
1211 // break;
1212 // }
1213
1214 // return FALSE;
1215 // }
1216
1217
1218 static void UartReset() {
1219 Uart.byteCntMax = 3;
1220 Uart.state = STATE_UNSYNCD;
1221 Uart.byteCnt = 0;
1222 Uart.bitCnt = 0;
1223 Uart.posCnt = 0;
1224 memset(Uart.output, 0x00, 3);
1225 }
1226
1227 // static void UartInit(uint8_t *data) {
1228 // Uart.output = data;
1229 // UartReset();
1230 // }
1231
1232 //=============================================================================
1233 // An LEGIC reader. We take layer two commands, code them
1234 // appropriately, and then send them to the tag. We then listen for the
1235 // tag's response, which we leave in the buffer to be demodulated on the
1236 // PC side.
1237 //=============================================================================
1238
1239 static struct {
1240 enum {
1241 DEMOD_UNSYNCD,
1242 DEMOD_PHASE_REF_TRAINING,
1243 DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
1244 DEMOD_GOT_FALLING_EDGE_OF_SOF,
1245 DEMOD_AWAITING_START_BIT,
1246 DEMOD_RECEIVING_DATA
1247 } state;
1248 int bitCount;
1249 int posCount;
1250 int thisBit;
1251 uint16_t shiftReg;
1252 uint8_t *output;
1253 int len;
1254 int sumI;
1255 int sumQ;
1256 } Demod;
1257
1258 /*
1259 * Handles reception of a bit from the tag
1260 *
1261 * This function is called 2 times per bit (every 4 subcarrier cycles).
1262 * Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
1263 *
1264 * LED handling:
1265 * LED C -> ON once we have received the SOF and are expecting the rest.
1266 * LED C -> OFF once we have received EOF or are unsynced
1267 *
1268 * Returns: true if we received a EOF
1269 * false if we are still waiting for some more
1270 *
1271 */
1272
1273 #ifndef SUBCARRIER_DETECT_THRESHOLD
1274 # define SUBCARRIER_DETECT_THRESHOLD 8
1275 #endif
1276
1277 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
1278 #ifndef CHECK_FOR_SUBCARRIER
1279 # define CHECK_FOR_SUBCARRIER() { v = MAX(ai, aq) + MIN(halfci, halfcq); }
1280 #endif
1281
1282 // The soft decision on the bit uses an estimate of just the
1283 // quadrant of the reference angle, not the exact angle.
1284 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
1285 #define MAKE_SOFT_DECISION() { \
1286 if(Demod.sumI > 0) \
1287 v = ci; \
1288 else \
1289 v = -ci; \
1290 \
1291 if(Demod.sumQ > 0) \
1292 v += cq; \
1293 else \
1294 v -= cq; \
1295 \
1296 }
1297
1298 static RAMFUNC int HandleLegicSamplesDemod(int ci, int cq)
1299 {
1300 int v = 0;
1301 int ai = ABS(ci);
1302 int aq = ABS(cq);
1303 int halfci = (ai >> 1);
1304 int halfcq = (aq >> 1);
1305
1306 switch(Demod.state) {
1307 case DEMOD_UNSYNCD:
1308
1309 CHECK_FOR_SUBCARRIER()
1310
1311 if(v > SUBCARRIER_DETECT_THRESHOLD) { // subcarrier detected
1312 Demod.state = DEMOD_PHASE_REF_TRAINING;
1313 Demod.sumI = ci;
1314 Demod.sumQ = cq;
1315 Demod.posCount = 1;
1316 }
1317 break;
1318
1319 case DEMOD_PHASE_REF_TRAINING:
1320 if(Demod.posCount < 8) {
1321
1322 CHECK_FOR_SUBCARRIER()
1323
1324 if (v > SUBCARRIER_DETECT_THRESHOLD) {
1325 // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
1326 // note: synchronization time > 80 1/fs
1327 Demod.sumI += ci;
1328 Demod.sumQ += cq;
1329 ++Demod.posCount;
1330 } else {
1331 // subcarrier lost
1332 Demod.state = DEMOD_UNSYNCD;
1333 }
1334 } else {
1335 Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
1336 }
1337 break;
1338
1339 case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
1340
1341 MAKE_SOFT_DECISION()
1342
1343 //Dbprintf("ICE: %d %d %d %d %d", v, Demod.sumI, Demod.sumQ, ci, cq );
1344 // logic '0' detected
1345 if (v <= 0) {
1346
1347 Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
1348
1349 // start of SOF sequence
1350 Demod.posCount = 0;
1351 } else {
1352 // maximum length of TR1 = 200 1/fs
1353 if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
1354 }
1355 ++Demod.posCount;
1356 break;
1357
1358 case DEMOD_GOT_FALLING_EDGE_OF_SOF:
1359 ++Demod.posCount;
1360
1361 MAKE_SOFT_DECISION()
1362
1363 if(v > 0) {
1364 // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
1365 if(Demod.posCount < 10*2) {
1366 Demod.state = DEMOD_UNSYNCD;
1367 } else {
1368 LED_C_ON(); // Got SOF
1369 Demod.state = DEMOD_AWAITING_START_BIT;
1370 Demod.posCount = 0;
1371 Demod.len = 0;
1372 }
1373 } else {
1374 // low phase of SOF too long (> 12 etu)
1375 if(Demod.posCount > 13*2) {
1376 Demod.state = DEMOD_UNSYNCD;
1377 LED_C_OFF();
1378 }
1379 }
1380 break;
1381
1382 case DEMOD_AWAITING_START_BIT:
1383 ++Demod.posCount;
1384
1385 MAKE_SOFT_DECISION()
1386
1387 if(v > 0) {
1388 // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
1389 if(Demod.posCount > 3*2) {
1390 Demod.state = DEMOD_UNSYNCD;
1391 LED_C_OFF();
1392 }
1393 } else {
1394 // start bit detected
1395 Demod.bitCount = 0;
1396 Demod.posCount = 1; // this was the first half
1397 Demod.thisBit = v;
1398 Demod.shiftReg = 0;
1399 Demod.state = DEMOD_RECEIVING_DATA;
1400 }
1401 break;
1402
1403 case DEMOD_RECEIVING_DATA:
1404
1405 MAKE_SOFT_DECISION()
1406
1407 if(Demod.posCount == 0) {
1408 // first half of bit
1409 Demod.thisBit = v;
1410 Demod.posCount = 1;
1411 } else {
1412 // second half of bit
1413 Demod.thisBit += v;
1414 Demod.shiftReg >>= 1;
1415 // logic '1'
1416 if(Demod.thisBit > 0)
1417 Demod.shiftReg |= 0x200;
1418
1419 ++Demod.bitCount;
1420
1421 if(Demod.bitCount == 10) {
1422
1423 uint16_t s = Demod.shiftReg;
1424
1425 if((s & 0x200) && !(s & 0x001)) {
1426 // stop bit == '1', start bit == '0'
1427 uint8_t b = (s >> 1);
1428 Demod.output[Demod.len] = b;
1429 ++Demod.len;
1430 Demod.state = DEMOD_AWAITING_START_BIT;
1431 } else {
1432 Demod.state = DEMOD_UNSYNCD;
1433 LED_C_OFF();
1434
1435 if(s == 0x000) {
1436 // This is EOF (start, stop and all data bits == '0'
1437 return TRUE;
1438 }
1439 }
1440 }
1441 Demod.posCount = 0;
1442 }
1443 break;
1444
1445 default:
1446 Demod.state = DEMOD_UNSYNCD;
1447 LED_C_OFF();
1448 break;
1449 }
1450 return FALSE;
1451 }
1452
1453 // Clear out the state of the "UART" that receives from the tag.
1454 static void DemodReset() {
1455 Demod.len = 0;
1456 Demod.state = DEMOD_UNSYNCD;
1457 Demod.posCount = 0;
1458 Demod.sumI = 0;
1459 Demod.sumQ = 0;
1460 Demod.bitCount = 0;
1461 Demod.thisBit = 0;
1462 Demod.shiftReg = 0;
1463 memset(Demod.output, 0x00, 3);
1464 }
1465
1466 static void DemodInit(uint8_t *data) {
1467 Demod.output = data;
1468 DemodReset();
1469 }
1470
1471 /*
1472 * Demodulate the samples we received from the tag, also log to tracebuffer
1473 * quiet: set to 'TRUE' to disable debug output
1474 */
1475 #define LEGIC_DMA_BUFFER_SIZE 256
1476 static void GetSamplesForLegicDemod(int n, bool quiet)
1477 {
1478 int max = 0;
1479 bool gotFrame = FALSE;
1480 int lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
1481 int ci, cq, samples = 0;
1482
1483 BigBuf_free();
1484
1485 // And put the FPGA in the appropriate mode
1486 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_QUARTER_FREQ);
1487
1488 // The response (tag -> reader) that we're receiving.
1489 // Set up the demodulator for tag -> reader responses.
1490 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
1491
1492 // The DMA buffer, used to stream samples from the FPGA
1493 int8_t *dmaBuf = (int8_t*) BigBuf_malloc(LEGIC_DMA_BUFFER_SIZE);
1494 int8_t *upTo = dmaBuf;
1495
1496 // Setup and start DMA.
1497 if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, LEGIC_DMA_BUFFER_SIZE) ){
1498 if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
1499 return;
1500 }
1501
1502 // Signal field is ON with the appropriate LED:
1503 LED_D_ON();
1504 for(;;) {
1505 int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
1506 if(behindBy > max) max = behindBy;
1507
1508 while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (LEGIC_DMA_BUFFER_SIZE-1)) > 2) {
1509 ci = upTo[0];
1510 cq = upTo[1];
1511 upTo += 2;
1512 if(upTo >= dmaBuf + LEGIC_DMA_BUFFER_SIZE) {
1513 upTo = dmaBuf;
1514 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
1515 AT91C_BASE_PDC_SSC->PDC_RNCR = LEGIC_DMA_BUFFER_SIZE;
1516 }
1517 lastRxCounter -= 2;
1518 if(lastRxCounter <= 0)
1519 lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
1520
1521 samples += 2;
1522
1523 gotFrame = HandleLegicSamplesDemod(ci , cq );
1524 if ( gotFrame )
1525 break;
1526 }
1527
1528 if(samples > n || gotFrame)
1529 break;
1530 }
1531
1532 FpgaDisableSscDma();
1533
1534 if (!quiet && Demod.len == 0) {
1535 Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d",
1536 max,
1537 samples,
1538 gotFrame,
1539 Demod.len,
1540 Demod.sumI,
1541 Demod.sumQ
1542 );
1543 }
1544
1545 //Tracing
1546 if (Demod.len > 0) {
1547 uint8_t parity[MAX_PARITY_SIZE] = {0x00};
1548 LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
1549 }
1550 }
1551 //-----------------------------------------------------------------------------
1552 // Transmit the command (to the tag) that was placed in ToSend[].
1553 //-----------------------------------------------------------------------------
1554 static void TransmitForLegic(void)
1555 {
1556 int c;
1557
1558 FpgaSetupSsc();
1559
1560 while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))
1561 AT91C_BASE_SSC->SSC_THR = 0xff;
1562
1563 // Signal field is ON with the appropriate Red LED
1564 LED_D_ON();
1565
1566 // Signal we are transmitting with the Green LED
1567 LED_B_ON();
1568 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1569
1570 for(c = 0; c < 10;) {
1571 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1572 AT91C_BASE_SSC->SSC_THR = 0xff;
1573 c++;
1574 }
1575 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1576 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
1577 (void)r;
1578 }
1579 WDT_HIT();
1580 }
1581
1582 c = 0;
1583 for(;;) {
1584 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1585 AT91C_BASE_SSC->SSC_THR = ToSend[c];
1586 legic_prng_forward(1); // forward the lfsr
1587 c++;
1588 if(c >= ToSendMax) {
1589 break;
1590 }
1591 }
1592 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1593 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
1594 (void)r;
1595 }
1596 WDT_HIT();
1597 }
1598 LED_B_OFF();
1599 }
1600
1601
1602 //-----------------------------------------------------------------------------
1603 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
1604 // so that it is ready to transmit to the tag using TransmitForLegic().
1605 //-----------------------------------------------------------------------------
1606 static void CodeLegicBitsAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
1607 {
1608 int i, j;
1609 uint8_t b;
1610
1611 ToSendReset();
1612
1613 // Send SOF
1614 for(i = 0; i < 7; i++)
1615 ToSendStuffBit(1);
1616
1617
1618 for(i = 0; i < cmdlen; i++) {
1619 // Start bit
1620 ToSendStuffBit(0);
1621
1622 // Data bits
1623 b = cmd[i];
1624 for(j = 0; j < bits; j++) {
1625 if(b & 1) {
1626 ToSendStuffBit(1);
1627 } else {
1628 ToSendStuffBit(0);
1629 }
1630 b >>= 1;
1631 }
1632 }
1633
1634 // Convert from last character reference to length
1635 ++ToSendMax;
1636 }
1637
1638 /**
1639 Convenience function to encode, transmit and trace Legic comms
1640 **/
1641 static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
1642 {
1643 CodeLegicBitsAsReader(cmd, cmdlen, bits);
1644 TransmitForLegic();
1645 if (tracing) {
1646 uint8_t parity[1] = {0x00};
1647 LogTrace(cmd, cmdlen, 0, 0, parity, TRUE);
1648 }
1649 }
1650
1651 int ice_legic_select_card()
1652 {
1653 //int cmd_size=0, card_size=0;
1654 uint8_t wakeup[] = { 0x7F };
1655 uint8_t getid[] = {0x19};
1656
1657 legic_prng_init(SESSION_IV);
1658
1659 // first, wake up the tag, 7bits
1660 CodeAndTransmitLegicAsReader(wakeup, sizeof(wakeup), 7);
1661
1662 GetSamplesForLegicDemod(1000, TRUE);
1663
1664 // frame_clean(&current_frame);
1665 //frame_receive_rwd(&current_frame, 6, 1);
1666
1667 legic_prng_forward(1); /* we wait anyways */
1668
1669 //while(timer->TC_CV < 387) ; /* ~ 258us */
1670 //frame_send_rwd(0x19, 6);
1671 CodeAndTransmitLegicAsReader(getid, sizeof(getid), 8);
1672 GetSamplesForLegicDemod(1000, TRUE);
1673
1674 //if (Demod.len < 14) return 2;
1675 Dbprintf("CARD TYPE: %02x LEN: %d", Demod.output[0], Demod.len);
1676
1677 switch(Demod.output[0]) {
1678 case 0x1d:
1679 DbpString("MIM 256 card found");
1680 // cmd_size = 9;
1681 // card_size = 256;
1682 break;
1683 case 0x3d:
1684 DbpString("MIM 1024 card found");
1685 // cmd_size = 11;
1686 // card_size = 1024;
1687 break;
1688 default:
1689 return -1;
1690 }
1691
1692 // if(bytes == -1)
1693 // bytes = card_size;
1694
1695 // if(bytes + offset >= card_size)
1696 // bytes = card_size - offset;
1697
1698 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1699 set_tracing(FALSE);
1700 return 1;
1701 }
1702
1703 // Set up LEGIC communication
1704 void ice_legic_setup() {
1705
1706 // standard things.
1707 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1708 BigBuf_free(); BigBuf_Clear_ext(false);
1709 clear_trace();
1710 set_tracing(TRUE);
1711 DemodReset();
1712 UartReset();
1713
1714 // Set up the synchronous serial port
1715 FpgaSetupSsc();
1716
1717 // connect Demodulated Signal to ADC:
1718 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1719
1720 // Signal field is on with the appropriate LED
1721 LED_D_ON();
1722 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1723 SpinDelay(20);
1724 // Start the timer
1725 //StartCountSspClk();
1726
1727 // initalize CRC
1728 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
1729
1730 // initalize prng
1731 legic_prng_init(0);
1732 }
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