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1 //-----------------------------------------------------------------------------
2 // (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
3 // 2016 Iceman
4 //
5 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
6 // at your option, any later version. See the LICENSE.txt file for the text of
7 // the license.
8 //-----------------------------------------------------------------------------
9 // LEGIC RF simulation code
10 //-----------------------------------------------------------------------------
11 #include "legicrf.h"
12
13 static struct legic_frame {
14 uint8_t 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 AT91PS_TC timer;
34 AT91PS_TC prng_timer;
35
36 /*
37 static void setup_timer(void) {
38 // Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
39 // this it won't be terribly accurate but should be good enough.
40 //
41 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
42 timer = AT91C_BASE_TC1;
43 timer->TC_CCR = AT91C_TC_CLKDIS;
44 timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;
45 timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
46
47 //
48 // Set up Timer 2 to use for measuring time between frames in
49 // tag simulation mode. Runs 4x faster as Timer 1
50 //
51 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC2);
52 prng_timer = AT91C_BASE_TC2;
53 prng_timer->TC_CCR = AT91C_TC_CLKDIS;
54 prng_timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV2_CLOCK;
55 prng_timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
56 }
57
58 AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
59 AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
60
61 // fast clock
62 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
63 AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz)/32 -- tick=1.5mks
64 AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_ACPA_CLEAR |
65 AT91C_TC_ACPC_SET | AT91C_TC_ASWTRG_SET;
66 AT91C_BASE_TC0->TC_RA = 1;
67 AT91C_BASE_TC0->TC_RC = 0xBFFF + 1; // 0xC000
68
69 */
70
71 // At TIMER_CLOCK3 (MCK/32)
72 // testing calculating in (us) microseconds.
73 #define RWD_TIME_1 120 // READER_TIME_PAUSE 20us off, 80us on = 100us 80 * 1.5 == 120ticks
74 #define RWD_TIME_0 60 // READER_TIME_PAUSE 20us off, 40us on = 60us 40 * 1.5 == 60ticks
75 #define RWD_TIME_PAUSE 30 // 20us == 20 * 1.5 == 30ticks */
76 #define TAG_BIT_PERIOD 142 // 100us == 100 * 1.5 == 150ticks
77 #define TAG_FRAME_WAIT 495 // 330us from READER frame end to TAG frame start. 330 * 1.5 == 495
78
79 #define RWD_TIME_FUZZ 20 // rather generous 13us, since the peak detector + hysteresis fuzz quite a bit
80
81 #define SIM_DIVISOR 586 /* prng_time/SIM_DIVISOR count prng needs to be forwared */
82 #define SIM_SHIFT 900 /* prng_time+SIM_SHIFT shift of delayed start */
83
84 #define OFFSET_LOG 1024
85
86 #define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
87
88 #ifndef SHORT_COIL
89 # define SHORT_COIL LOW(GPIO_SSC_DOUT);
90 #endif
91 #ifndef OPEN_COIL
92 # define OPEN_COIL HIGH(GPIO_SSC_DOUT);
93 #endif
94 #ifndef LINE_IN
95 # define LINE_IN \
96 do { \
97 AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN; \
98 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN; \
99 } while (0);
100 #endif
101 // Pause pulse, off in 20us / 30ticks,
102 // ONE / ZERO bit pulse,
103 // one == 80us / 120ticks
104 // zero == 40us / 60ticks
105 #ifndef COIL_PULSE
106 # define COIL_PULSE(x) \
107 do { \
108 SHORT_COIL; \
109 WaitTicks( (RWD_TIME_PAUSE) ); \
110 OPEN_COIL; \
111 WaitTicks((x)); \
112 } while (0);
113 #endif
114
115 // ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces.
116 // Historically it used to be FREE_BUFFER_SIZE, which was 2744.
117 #define LEGIC_CARD_MEMSIZE 1024
118 static uint8_t* cardmem;
119
120 static void frame_append_bit(struct legic_frame * const f, uint8_t bit) {
121 // Overflow, won't happen
122 if (f->bits >= 31) return;
123
124 f->data |= (bit << f->bits);
125 f->bits++;
126 }
127
128 static void frame_clean(struct legic_frame * const f) {
129 f->data = 0;
130 f->bits = 0;
131 }
132
133 // Prng works when waiting in 99.1us cycles.
134 // and while sending/receiving in bit frames (100, 60)
135 /*static void CalibratePrng( uint32_t time){
136 // Calculate Cycles based on timer 100us
137 uint32_t i = (time - sendFrameStop) / 100 ;
138
139 // substract cycles of finished frames
140 int k = i - legic_prng_count()+1;
141
142 // substract current frame length, rewind to beginning
143 if ( k > 0 )
144 legic_prng_forward(k);
145 }
146 */
147
148 /* Generate Keystream */
149 uint32_t get_key_stream(int skip, int count) {
150
151 int i;
152
153 // Use int to enlarge timer tc to 32bit
154 legic_prng_bc += prng_timer->TC_CV;
155
156 // reset the prng timer.
157
158 /* If skip == -1, forward prng time based */
159 if(skip == -1) {
160 i = (legic_prng_bc + SIM_SHIFT)/SIM_DIVISOR; /* Calculate Cycles based on timer */
161 i -= legic_prng_count(); /* substract cycles of finished frames */
162 i -= count; /* substract current frame length, rewind to beginning */
163 legic_prng_forward(i);
164 } else {
165 legic_prng_forward(skip);
166 }
167
168 i = (count == 6) ? -1 : legic_read_count;
169
170 /* Generate KeyStream */
171 return legic_prng_get_bits(count);
172 }
173
174 /* Send a frame in tag mode, the FPGA must have been set up by
175 * LegicRfSimulate
176 */
177 void frame_send_tag(uint16_t response, uint8_t bits) {
178
179 uint16_t mask = 1;
180
181 /* Bitbang the response */
182 SHORT_COIL;
183 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
184 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
185
186 /* TAG_FRAME_WAIT -> shift by 2 */
187 legic_prng_forward(2);
188 response ^= legic_prng_get_bits(bits);
189
190 /* Wait for the frame start */
191 WaitTicks( TAG_FRAME_WAIT );
192
193 for (; mask < BITMASK(bits); mask <<= 1) {
194 if (response & mask)
195 OPEN_COIL
196 else
197 SHORT_COIL
198 WaitTicks(TAG_BIT_PERIOD);
199 }
200 SHORT_COIL;
201 }
202
203 /* Send a frame in reader mode, the FPGA must have been set up by
204 * LegicRfReader
205 */
206 void frame_sendAsReader(uint32_t data, uint8_t bits){
207
208 uint32_t starttime = GET_TICKS, send = 0;
209 uint16_t mask = 1;
210
211 // xor lsfr onto data.
212 send = data ^ legic_prng_get_bits(bits);
213
214 for (; mask < BITMASK(bits); mask <<= 1) {
215 if (send & mask)
216 COIL_PULSE(RWD_TIME_1)
217 else
218 COIL_PULSE(RWD_TIME_0)
219 }
220
221 // Final pause to mark the end of the frame
222 COIL_PULSE(0);
223
224 // log
225 uint8_t cmdbytes[] = {bits, BYTEx(data, 0), BYTEx(data, 1), BYTEx(send, 0), BYTEx(send, 1)};
226 LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, TRUE);
227 }
228
229 /* Receive a frame from the card in reader emulation mode, the FPGA and
230 * timer must have been set up by LegicRfReader and frame_sendAsReader.
231 *
232 * The LEGIC RF protocol from card to reader does not include explicit
233 * frame start/stop information or length information. The reader must
234 * know beforehand how many bits it wants to receive. (Notably: a card
235 * sending a stream of 0-bits is indistinguishable from no card present.)
236 *
237 * Receive methodology: There is a fancy correlator in hi_read_rx_xcorr, but
238 * I'm not smart enough to use it. Instead I have patched hi_read_tx to output
239 * the ADC signal with hysteresis on SSP_DIN. Bit-bang that signal and look
240 * for edges. Count the edges in each bit interval. If they are approximately
241 * 0 this was a 0-bit, if they are approximately equal to the number of edges
242 * expected for a 212kHz subcarrier, this was a 1-bit. For timing we use the
243 * timer that's still running from frame_sendAsReader in order to get a synchronization
244 * with the frame that we just sent.
245 *
246 * FIXME: Because we're relying on the hysteresis to just do the right thing
247 * the range is severely reduced (and you'll probably also need a good antenna).
248 * So this should be fixed some time in the future for a proper receiver.
249 */
250 static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
251
252 if ( bits > 32 ) return;
253
254 uint8_t i = bits, edges = 0;
255 uint32_t the_bit = 1, next_bit_at = 0, data = 0;
256 uint32_t old_level = 0;
257 volatile uint32_t level = 0;
258
259 frame_clean(f);
260
261 /* Bitbang the receiver */
262 LINE_IN;
263
264 // calibrate the prng.
265 legic_prng_forward(2);
266 data = legic_prng_get_bits(bits);
267
268 //FIXED time between sending frame and now listening frame. 330us
269 uint32_t starttime = GET_TICKS;
270 // its about 9+9 ticks delay from end-send to here.
271 WaitTicks( 477 );
272
273 next_bit_at = GET_TICKS + TAG_BIT_PERIOD;
274
275 while ( i-- ){
276 edges = 0;
277 while ( GET_TICKS < next_bit_at) {
278
279 level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
280
281 if (level != old_level)
282 ++edges;
283
284 old_level = level;
285 }
286
287 next_bit_at += TAG_BIT_PERIOD;
288
289 // We expect 42 edges (ONE)
290 if ( edges > 20 )
291 data ^= the_bit;
292
293 the_bit <<= 1;
294 }
295
296 // output
297 f->data = data;
298 f->bits = bits;
299
300 // log
301 uint8_t cmdbytes[] = {bits, BYTEx(data, 0), BYTEx(data, 1)};
302 LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, FALSE);
303 }
304
305 // Setup pm3 as a Legic Reader
306 static uint32_t setup_phase_reader(uint8_t iv) {
307
308 // Switch on carrier and let the tag charge for 1ms
309 HIGH(GPIO_SSC_DOUT);
310 WaitUS(5000);
311
312 ResetTicks();
313
314 // no keystream yet
315 legic_prng_init(0);
316
317 // send IV handshake
318 frame_sendAsReader(iv, 7);
319
320 // Now both tag and reader has same IV. Prng can start.
321 legic_prng_init(iv);
322
323 frame_receiveAsReader(&current_frame, 6);
324
325 // 292us (438t) - fixed delay before sending ack.
326 // minus log and stuff 100tick?
327 WaitTicks(338);
328 legic_prng_forward(3);
329
330 // Send obsfuscated acknowledgment frame.
331 // 0x19 = 0x18 MIM22, 0x01 LSB READCMD
332 // 0x39 = 0x38 MIM256, MIM1024 0x01 LSB READCMD
333 switch ( current_frame.data ) {
334 case 0x0D: frame_sendAsReader(0x19, 6); break;
335 case 0x1D:
336 case 0x3D: frame_sendAsReader(0x39, 6); break;
337 default: break;
338 }
339
340 legic_prng_forward(2);
341 return current_frame.data;
342 }
343
344 static void LegicCommonInit(void) {
345
346 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
347 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
348 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
349
350 /* Bitbang the transmitter */
351 LOW(GPIO_SSC_DOUT);
352 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
353 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
354
355 // reserve a cardmem, meaning we can use the tracelog function in bigbuff easier.
356 cardmem = BigBuf_get_EM_addr();
357 memset(cardmem, 0x00, LEGIC_CARD_MEMSIZE);
358
359 clear_trace();
360 set_tracing(TRUE);
361 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
362
363 StartTicks();
364 }
365
366 // Switch off carrier, make sure tag is reset
367 static void switch_off_tag_rwd(void) {
368 LOW(GPIO_SSC_DOUT);
369 WaitUS(20);
370 WDT_HIT();
371 }
372
373 // calculate crc4 for a legic READ command
374 static uint32_t legic4Crc(uint8_t cmd, uint16_t byte_index, uint8_t value, uint8_t cmd_sz) {
375 crc_clear(&legic_crc);
376 uint32_t temp = (value << cmd_sz) | (byte_index << 1) | cmd;
377 crc_update(&legic_crc, temp, cmd_sz + 8 );
378 return crc_finish(&legic_crc);
379 }
380
381 int legic_read_byte( uint16_t index, uint8_t cmd_sz) {
382
383 uint8_t byte, crc, calcCrc = 0;
384 uint32_t cmd = (index << 1) | LEGIC_READ;
385
386 // 90ticks = 60us (should be 100us but crc calc takes time.)
387 //WaitTicks(330); // 330ticks prng(4) - works
388 WaitTicks(240); // 240ticks prng(3) - works
389
390 frame_sendAsReader(cmd, cmd_sz);
391 frame_receiveAsReader(&current_frame, 12);
392
393 // CRC check.
394 byte = BYTEx(current_frame.data, 0);
395 crc = BYTEx(current_frame.data, 1);
396 calcCrc = legic4Crc(LEGIC_READ, index, byte, cmd_sz);
397
398 if( calcCrc != crc ) {
399 Dbprintf("!!! crc mismatch: expected %x but got %x !!!", calcCrc, crc);
400 return -1;
401 }
402
403 legic_prng_forward(3);
404 return byte;
405 }
406
407 /*
408 * - assemble a write_cmd_frame with crc and send it
409 * - wait until the tag sends back an ACK ('1' bit unencrypted)
410 * - forward the prng based on the timing
411 */
412 int legic_write_byte(uint16_t index, uint8_t byte, uint8_t addr_sz) {
413
414 // crc
415 crc_clear(&legic_crc);
416 crc_update(&legic_crc, 0, 1); /* CMD_WRITE */
417 crc_update(&legic_crc, index, addr_sz);
418 crc_update(&legic_crc, byte, 8);
419 uint32_t crc = crc_finish(&legic_crc);
420 uint32_t crc2 = legic4Crc(LEGIC_WRITE, index, byte, addr_sz+1);
421 if ( crc != crc2 ) {
422 Dbprintf("crc is missmatch");
423 return 1;
424 }
425 // send write command
426 uint32_t cmd = ((crc <<(addr_sz+1+8)) //CRC
427 |(byte <<(addr_sz+1)) //Data
428 |(index <<1) //index
429 | LEGIC_WRITE); //CMD = Write
430
431 uint32_t cmd_sz = addr_sz+1+8+4; //crc+data+cmd
432
433 legic_prng_forward(2);
434
435 WaitTicks(330);
436
437 frame_sendAsReader(cmd, cmd_sz);
438
439 /* Bitbang the receiver */
440 LINE_IN;
441
442 int t, old_level = 0, edges = 0;
443 int next_bit_at = 0;
444
445 // ACK 3.6ms = 3600us * 1.5 = 5400ticks.
446 WaitTicks(5360);
447
448 for( t = 0; t < 80; ++t) {
449 edges = 0;
450 next_bit_at += TAG_BIT_PERIOD;
451 while(timer->TC_CV < next_bit_at) {
452 volatile uint32_t level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
453 if(level != old_level)
454 edges++;
455
456 old_level = level;
457 }
458 /* expected are 42 edges (ONE) */
459 if(edges > 20 ) {
460 int t = timer->TC_CV;
461 int c = t / TAG_BIT_PERIOD;
462
463 ResetTimer(timer);
464 legic_prng_forward(c);
465 return 0;
466 }
467 }
468
469 return -1;
470 }
471
472 int LegicRfReader(uint16_t offset, uint16_t len, uint8_t iv) {
473
474 uint16_t i = 0;
475 uint8_t isOK = 1;
476 legic_card_select_t card;
477
478 LegicCommonInit();
479
480 if ( legic_select_card_iv(&card, iv) ) {
481 isOK = 0;
482 goto OUT;
483 }
484
485 switch_off_tag_rwd();
486
487 if (len + offset >= card.cardsize)
488 len = card.cardsize - offset;
489
490 setup_phase_reader(iv);
491
492 LED_B_ON();
493 while (i < len) {
494 int r = legic_read_byte(offset + i, card.cmdsize);
495
496 if (r == -1 || BUTTON_PRESS()) {
497 if ( MF_DBGLEVEL >= 2) DbpString("operation aborted");
498 isOK = 0;
499 goto OUT;
500 }
501 cardmem[i++] = r;
502 WDT_HIT();
503 }
504
505 OUT:
506 WDT_HIT();
507 switch_off_tag_rwd();
508 LEDsoff();
509 cmd_send(CMD_ACK, isOK, len, 0, cardmem, len);
510 return 0;
511 }
512
513 void LegicRfWriter(uint16_t offset, uint16_t len, uint8_t iv, uint8_t *data) {
514
515 uint8_t isOK = 1;
516
517 // UID not is writeable.
518 if ( offset <= 4 ) {
519 isOK = 0;
520 goto OUT;
521 }
522
523 legic_card_select_t card;
524
525 LegicCommonInit();
526
527 if ( legic_select_card_iv(&card, iv) ) {
528 isOK = 0;
529 goto OUT;
530 }
531
532 if (len + offset >= card.cardsize)
533 len = card.cardsize - offset;
534
535 setup_phase_reader(iv);
536
537 LED_B_ON();
538 int r = 0;
539 // how about we write backwards instead. no need for this extra DCF check.
540 // index = len - cardsize
541 // stops uid 01234,
542 /*
543 len = 20
544 offset = 5
545
546 index = 20+5 = 25
547 if ( index > cardsize ) return -1;
548
549 loop
550 write( data[index], index , card.addrsize);
551 --index;
552 end loop
553 */
554 uint16_t index = len;
555 while(index > 4) {
556
557 r = legic_write_byte( index, data[ index ], card.addrsize);
558
559 if ( r ) {
560 Dbprintf("operation aborted @ 0x%03.3x", index);
561 isOK = 0;
562 goto OUT;
563 }
564 --index;
565 WDT_HIT();
566 }
567
568 OUT:
569 cmd_send(CMD_ACK, isOK, 0,0,0,0);
570 switch_off_tag_rwd();
571 LEDsoff();
572 }
573
574 int legic_select_card_iv(legic_card_select_t *p_card, uint8_t iv){
575
576 if ( p_card == NULL ) return 1;
577
578 p_card->tagtype = setup_phase_reader(iv);
579
580 switch(p_card->tagtype) {
581 case 0x0d:
582 p_card->cmdsize = 6;
583 p_card->addrsize = 5;
584 p_card->cardsize = 22;
585 break;
586 case 0x1d:
587 p_card->cmdsize = 9;
588 p_card->addrsize = 8;
589 p_card->cardsize = 256;
590 break;
591 case 0x3d:
592 p_card->cmdsize = 11;
593 p_card->addrsize = 10;
594 p_card->cardsize = 1024;
595 break;
596 default:
597 p_card->cmdsize = 0;
598 p_card->addrsize = 0;
599 p_card->cardsize = 0;
600 return 2;
601 }
602 return 0;
603 }
604 int legic_select_card(legic_card_select_t *p_card){
605 return legic_select_card_iv(p_card, 0x01);
606 }
607
608 //-----------------------------------------------------------------------------
609 // Work with emulator memory
610 //
611 // Note: we call FpgaDownloadAndGo(FPGA_BITSTREAM_HF) here although FPGA is not
612 // involved in dealing with emulator memory. But if it is called later, it might
613 // destroy the Emulator Memory.
614 //-----------------------------------------------------------------------------
615 // arg0 = offset
616 // arg1 = num of bytes
617 void LegicEMemSet(uint32_t arg0, uint32_t arg1, uint8_t *data) {
618 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
619 legic_emlset_mem(data, arg0, arg1);
620 }
621 // arg0 = offset
622 // arg1 = num of bytes
623 void LegicEMemGet(uint32_t arg0, uint32_t arg1) {
624 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
625 uint8_t buf[USB_CMD_DATA_SIZE] = {0x00};
626 legic_emlget_mem(buf, arg0, arg1);
627 LED_B_ON();
628 cmd_send(CMD_ACK, arg0, arg1, 0, buf, USB_CMD_DATA_SIZE);
629 LED_B_OFF();
630 }
631 void legic_emlset_mem(uint8_t *data, int offset, int numofbytes) {
632 cardmem = BigBuf_get_EM_addr();
633 memcpy(cardmem + offset, data, numofbytes);
634 }
635 void legic_emlget_mem(uint8_t *data, int offset, int numofbytes) {
636 cardmem = BigBuf_get_EM_addr();
637 memcpy(data, cardmem + offset, numofbytes);
638 }
639
640 void LegicRfInfo(void){
641
642 int r;
643
644 uint8_t buf[sizeof(legic_card_select_t)] = {0x00};
645 legic_card_select_t *card = (legic_card_select_t*) buf;
646
647 LegicCommonInit();
648
649 if ( legic_select_card(card) ) {
650 cmd_send(CMD_ACK,0,0,0,0,0);
651 goto OUT;
652 }
653
654 // read UID bytes
655 for ( uint8_t i = 0; i < sizeof(card->uid); ++i) {
656 r = legic_read_byte(i, card->cmdsize);
657 if ( r == -1 ) {
658 cmd_send(CMD_ACK,0,0,0,0,0);
659 goto OUT;
660 }
661 card->uid[i] = r & 0xFF;
662 }
663
664 // MCC byte.
665 r = legic_read_byte(4, card->cmdsize);
666 uint32_t calc_mcc = CRC8Legic(card->uid, 4);;
667 if ( r != calc_mcc) {
668 cmd_send(CMD_ACK,0,0,0,0,0);
669 goto OUT;
670 }
671
672 // OK
673 cmd_send(CMD_ACK, 1, 0, 0, buf, sizeof(legic_card_select_t));
674
675 OUT:
676 switch_off_tag_rwd();
677 LEDsoff();
678 }
679
680 /* Handle (whether to respond) a frame in tag mode
681 * Only called when simulating a tag.
682 */
683 static void frame_handle_tag(struct legic_frame const * const f)
684 {
685 // log
686 //uint8_t cmdbytes[] = {bits, BYTEx(data, 0), BYTEx(data, 1)};
687 //LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, FALSE);
688
689 cardmem = BigBuf_get_EM_addr();
690
691 /* First Part of Handshake (IV) */
692 if(f->bits == 7) {
693
694 LED_C_ON();
695
696 // Reset prng timer
697 ResetTimer(prng_timer);
698
699 // IV from reader.
700 legic_prng_init(f->data);
701
702 // We should have three tagtypes with three different answers.
703 frame_send_tag(0x3d, 6); /* 0x3d^0x26 = 0x1B */
704
705 legic_state = STATE_IV;
706 legic_read_count = 0;
707 legic_prng_bc = 0;
708 legic_prng_iv = f->data;
709
710
711 ResetTimer(timer);
712 WaitUS(280);
713 return;
714 }
715
716 /* 0x19==??? */
717 if(legic_state == STATE_IV) {
718 uint32_t local_key = get_key_stream(3, 6);
719 int xored = 0x39 ^ local_key;
720 if((f->bits == 6) && (f->data == xored)) {
721 legic_state = STATE_CON;
722
723 ResetTimer(timer);
724 WaitUS(200);
725 return;
726
727 } else {
728 legic_state = STATE_DISCON;
729 LED_C_OFF();
730 Dbprintf("iv: %02x frame: %02x key: %02x xored: %02x", legic_prng_iv, f->data, local_key, xored);
731 return;
732 }
733 }
734
735 /* Read */
736 if(f->bits == 11) {
737 if(legic_state == STATE_CON) {
738 uint32_t key = get_key_stream(2, 11); //legic_phase_drift, 11);
739 uint16_t addr = f->data ^ key;
740 addr >>= 1;
741 uint8_t data = cardmem[addr];
742 int hash = legic4Crc(LEGIC_READ, addr, data, 11) << 8;
743
744 legic_read_count++;
745 legic_prng_forward(legic_reqresp_drift);
746
747 frame_send_tag(hash | data, 12);
748 ResetTimer(timer);
749 legic_prng_forward(2);
750 WaitTicks(330);
751 return;
752 }
753 }
754
755 /* Write */
756 if(f->bits == 23) {
757 uint32_t key = get_key_stream(-1, 23); //legic_frame_drift, 23);
758 uint16_t addr = f->data ^ key;
759 addr >>= 1;
760 addr &= 0x3ff;
761 uint32_t data = f->data ^ key;
762 data >>= 11;
763 data &= 0xff;
764
765 cardmem[addr] = data;
766 /* write command */
767 legic_state = STATE_DISCON;
768 LED_C_OFF();
769 Dbprintf("write - addr: %x, data: %x", addr, data);
770 // should send a ACK within 3.5ms too
771 return;
772 }
773
774 if(legic_state != STATE_DISCON) {
775 Dbprintf("Unexpected: sz:%u, Data:%03.3x, State:%u, Count:%u", f->bits, f->data, legic_state, legic_read_count);
776 Dbprintf("IV: %03.3x", legic_prng_iv);
777 }
778
779 legic_state = STATE_DISCON;
780 legic_read_count = 0;
781 SpinDelay(10);
782 LED_C_OFF();
783 return;
784 }
785
786 /* Read bit by bit untill full frame is received
787 * Call to process frame end answer
788 */
789 static void emit(int bit) {
790
791 switch (bit) {
792 case 1:
793 frame_append_bit(&current_frame, 1);
794 break;
795 case 0:
796 frame_append_bit(&current_frame, 0);
797 break;
798 default:
799 if(current_frame.bits <= 4) {
800 frame_clean(&current_frame);
801 } else {
802 frame_handle_tag(&current_frame);
803 frame_clean(&current_frame);
804 }
805 WDT_HIT();
806 break;
807 }
808 }
809
810 void LegicRfSimulate(int phase, int frame, int reqresp)
811 {
812 /* ADC path high-frequency peak detector, FPGA in high-frequency simulator mode,
813 * modulation mode set to 212kHz subcarrier. We are getting the incoming raw
814 * envelope waveform on DIN and should send our response on DOUT.
815 *
816 * The LEGIC RF protocol is pulse-pause-encoding from reader to card, so we'll
817 * measure the time between two rising edges on DIN, and no encoding on the
818 * subcarrier from card to reader, so we'll just shift out our verbatim data
819 * on DOUT, 1 bit is 100us. The time from reader to card frame is still unclear,
820 * seems to be 300us-ish.
821 */
822
823 int old_level = 0, active = 0;
824 legic_state = STATE_DISCON;
825
826 legic_phase_drift = phase;
827 legic_frame_drift = frame;
828 legic_reqresp_drift = reqresp;
829
830 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
831 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
832 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_212K);
833
834 /* Bitbang the receiver */
835 LINE_IN;
836
837 // need a way to determine which tagtype we are simulating
838
839 // hook up emulator memory
840 cardmem = BigBuf_get_EM_addr();
841
842 clear_trace();
843 set_tracing(TRUE);
844
845 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
846
847 StartTicks();
848
849 LED_B_ON();
850 DbpString("Starting Legic emulator, press button to end");
851
852 while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
853 volatile uint32_t level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
854
855 uint32_t time = GET_TICKS;
856
857 if (level != old_level) {
858
859 if (level) {
860
861 ResetTicks();
862
863 if (FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
864 /* 1 bit */
865 emit(1);
866 active = 1;
867 LED_A_ON();
868 } else if (FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
869 /* 0 bit */
870 emit(0);
871 active = 1;
872 LED_A_ON();
873 } else if (active) {
874 /* invalid */
875 emit(-1);
876 active = 0;
877 LED_A_OFF();
878 }
879 }
880 }
881
882 /* Frame end */
883 if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
884 emit(-1);
885 active = 0;
886 LED_A_OFF();
887 }
888
889 /*
890 * Disable the counter, Then wait for the clock to acknowledge the
891 * shutdown in its status register. Reading the SR has the
892 * side-effect of clearing any pending state in there.
893 */
894 if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA))
895 StopTicks();
896
897 old_level = level;
898 WDT_HIT();
899 }
900
901 WDT_HIT();
902 switch_off_tag_rwd();
903 LEDsoff();
904 cmd_send(CMD_ACK, 1, 0, 0, 0, 0);
905 }
906
907 //-----------------------------------------------------------------------------
908 // Code up a string of octets at layer 2 (including CRC, we don't generate
909 // that here) so that they can be transmitted to the reader. Doesn't transmit
910 // them yet, just leaves them ready to send in ToSend[].
911 //-----------------------------------------------------------------------------
912 // static void CodeLegicAsTag(const uint8_t *cmd, int len)
913 // {
914 // int i;
915
916 // ToSendReset();
917
918 // // Transmit a burst of ones, as the initial thing that lets the
919 // // reader get phase sync. This (TR1) must be > 80/fs, per spec,
920 // // but tag that I've tried (a Paypass) exceeds that by a fair bit,
921 // // so I will too.
922 // for(i = 0; i < 20; i++) {
923 // ToSendStuffBit(1);
924 // ToSendStuffBit(1);
925 // ToSendStuffBit(1);
926 // ToSendStuffBit(1);
927 // }
928
929 // // Send SOF.
930 // for(i = 0; i < 10; i++) {
931 // ToSendStuffBit(0);
932 // ToSendStuffBit(0);
933 // ToSendStuffBit(0);
934 // ToSendStuffBit(0);
935 // }
936 // for(i = 0; i < 2; i++) {
937 // ToSendStuffBit(1);
938 // ToSendStuffBit(1);
939 // ToSendStuffBit(1);
940 // ToSendStuffBit(1);
941 // }
942
943 // for(i = 0; i < len; i++) {
944 // int j;
945 // uint8_t b = cmd[i];
946
947 // // Start bit
948 // ToSendStuffBit(0);
949 // ToSendStuffBit(0);
950 // ToSendStuffBit(0);
951 // ToSendStuffBit(0);
952
953 // // Data bits
954 // for(j = 0; j < 8; j++) {
955 // if(b & 1) {
956 // ToSendStuffBit(1);
957 // ToSendStuffBit(1);
958 // ToSendStuffBit(1);
959 // ToSendStuffBit(1);
960 // } else {
961 // ToSendStuffBit(0);
962 // ToSendStuffBit(0);
963 // ToSendStuffBit(0);
964 // ToSendStuffBit(0);
965 // }
966 // b >>= 1;
967 // }
968
969 // // Stop bit
970 // ToSendStuffBit(1);
971 // ToSendStuffBit(1);
972 // ToSendStuffBit(1);
973 // ToSendStuffBit(1);
974 // }
975
976 // // Send EOF.
977 // for(i = 0; i < 10; i++) {
978 // ToSendStuffBit(0);
979 // ToSendStuffBit(0);
980 // ToSendStuffBit(0);
981 // ToSendStuffBit(0);
982 // }
983 // for(i = 0; i < 2; i++) {
984 // ToSendStuffBit(1);
985 // ToSendStuffBit(1);
986 // ToSendStuffBit(1);
987 // ToSendStuffBit(1);
988 // }
989
990 // // Convert from last byte pos to length
991 // ToSendMax++;
992 // }
993
994 //-----------------------------------------------------------------------------
995 // The software UART that receives commands from the reader, and its state
996 // variables.
997 //-----------------------------------------------------------------------------
998 /*
999 static struct {
1000 enum {
1001 STATE_UNSYNCD,
1002 STATE_GOT_FALLING_EDGE_OF_SOF,
1003 STATE_AWAITING_START_BIT,
1004 STATE_RECEIVING_DATA
1005 } state;
1006 uint16_t shiftReg;
1007 int bitCnt;
1008 int byteCnt;
1009 int byteCntMax;
1010 int posCnt;
1011 uint8_t *output;
1012 } Uart;
1013 */
1014 /* Receive & handle a bit coming from the reader.
1015 *
1016 * This function is called 4 times per bit (every 2 subcarrier cycles).
1017 * Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
1018 *
1019 * LED handling:
1020 * LED A -> ON once we have received the SOF and are expecting the rest.
1021 * LED A -> OFF once we have received EOF or are in error state or unsynced
1022 *
1023 * Returns: true if we received a EOF
1024 * false if we are still waiting for some more
1025 */
1026 // static RAMFUNC int HandleLegicUartBit(uint8_t bit)
1027 // {
1028 // switch(Uart.state) {
1029 // case STATE_UNSYNCD:
1030 // if(!bit) {
1031 // // we went low, so this could be the beginning of an SOF
1032 // Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
1033 // Uart.posCnt = 0;
1034 // Uart.bitCnt = 0;
1035 // }
1036 // break;
1037
1038 // case STATE_GOT_FALLING_EDGE_OF_SOF:
1039 // Uart.posCnt++;
1040 // if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
1041 // if(bit) {
1042 // if(Uart.bitCnt > 9) {
1043 // // we've seen enough consecutive
1044 // // zeros that it's a valid SOF
1045 // Uart.posCnt = 0;
1046 // Uart.byteCnt = 0;
1047 // Uart.state = STATE_AWAITING_START_BIT;
1048 // LED_A_ON(); // Indicate we got a valid SOF
1049 // } else {
1050 // // didn't stay down long enough
1051 // // before going high, error
1052 // Uart.state = STATE_UNSYNCD;
1053 // }
1054 // } else {
1055 // // do nothing, keep waiting
1056 // }
1057 // Uart.bitCnt++;
1058 // }
1059 // if(Uart.posCnt >= 4) Uart.posCnt = 0;
1060 // if(Uart.bitCnt > 12) {
1061 // // Give up if we see too many zeros without
1062 // // a one, too.
1063 // LED_A_OFF();
1064 // Uart.state = STATE_UNSYNCD;
1065 // }
1066 // break;
1067
1068 // case STATE_AWAITING_START_BIT:
1069 // Uart.posCnt++;
1070 // if(bit) {
1071 // if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
1072 // // stayed high for too long between
1073 // // characters, error
1074 // Uart.state = STATE_UNSYNCD;
1075 // }
1076 // } else {
1077 // // falling edge, this starts the data byte
1078 // Uart.posCnt = 0;
1079 // Uart.bitCnt = 0;
1080 // Uart.shiftReg = 0;
1081 // Uart.state = STATE_RECEIVING_DATA;
1082 // }
1083 // break;
1084
1085 // case STATE_RECEIVING_DATA:
1086 // Uart.posCnt++;
1087 // if(Uart.posCnt == 2) {
1088 // // time to sample a bit
1089 // Uart.shiftReg >>= 1;
1090 // if(bit) {
1091 // Uart.shiftReg |= 0x200;
1092 // }
1093 // Uart.bitCnt++;
1094 // }
1095 // if(Uart.posCnt >= 4) {
1096 // Uart.posCnt = 0;
1097 // }
1098 // if(Uart.bitCnt == 10) {
1099 // if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
1100 // {
1101 // // this is a data byte, with correct
1102 // // start and stop bits
1103 // Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
1104 // Uart.byteCnt++;
1105
1106 // if(Uart.byteCnt >= Uart.byteCntMax) {
1107 // // Buffer overflowed, give up
1108 // LED_A_OFF();
1109 // Uart.state = STATE_UNSYNCD;
1110 // } else {
1111 // // so get the next byte now
1112 // Uart.posCnt = 0;
1113 // Uart.state = STATE_AWAITING_START_BIT;
1114 // }
1115 // } else if (Uart.shiftReg == 0x000) {
1116 // // this is an EOF byte
1117 // LED_A_OFF(); // Finished receiving
1118 // Uart.state = STATE_UNSYNCD;
1119 // if (Uart.byteCnt != 0) {
1120 // return TRUE;
1121 // }
1122 // } else {
1123 // // this is an error
1124 // LED_A_OFF();
1125 // Uart.state = STATE_UNSYNCD;
1126 // }
1127 // }
1128 // break;
1129
1130 // default:
1131 // LED_A_OFF();
1132 // Uart.state = STATE_UNSYNCD;
1133 // break;
1134 // }
1135
1136 // return FALSE;
1137 // }
1138 /*
1139
1140 static void UartReset() {
1141 Uart.byteCntMax = 3;
1142 Uart.state = STATE_UNSYNCD;
1143 Uart.byteCnt = 0;
1144 Uart.bitCnt = 0;
1145 Uart.posCnt = 0;
1146 memset(Uart.output, 0x00, 3);
1147 }
1148 */
1149 // static void UartInit(uint8_t *data) {
1150 // Uart.output = data;
1151 // UartReset();
1152 // }
1153
1154 //=============================================================================
1155 // An LEGIC reader. We take layer two commands, code them
1156 // appropriately, and then send them to the tag. We then listen for the
1157 // tag's response, which we leave in the buffer to be demodulated on the
1158 // PC side.
1159 //=============================================================================
1160 /*
1161 static struct {
1162 enum {
1163 DEMOD_UNSYNCD,
1164 DEMOD_PHASE_REF_TRAINING,
1165 DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
1166 DEMOD_GOT_FALLING_EDGE_OF_SOF,
1167 DEMOD_AWAITING_START_BIT,
1168 DEMOD_RECEIVING_DATA
1169 } state;
1170 int bitCount;
1171 int posCount;
1172 int thisBit;
1173 uint16_t shiftReg;
1174 uint8_t *output;
1175 int len;
1176 int sumI;
1177 int sumQ;
1178 } Demod;
1179 */
1180 /*
1181 * Handles reception of a bit from the tag
1182 *
1183 * This function is called 2 times per bit (every 4 subcarrier cycles).
1184 * Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
1185 *
1186 * LED handling:
1187 * LED C -> ON once we have received the SOF and are expecting the rest.
1188 * LED C -> OFF once we have received EOF or are unsynced
1189 *
1190 * Returns: true if we received a EOF
1191 * false if we are still waiting for some more
1192 *
1193 */
1194
1195 /*
1196 static RAMFUNC int HandleLegicSamplesDemod(int ci, int cq)
1197 {
1198 int v = 0;
1199 int ai = ABS(ci);
1200 int aq = ABS(cq);
1201 int halfci = (ai >> 1);
1202 int halfcq = (aq >> 1);
1203
1204 switch(Demod.state) {
1205 case DEMOD_UNSYNCD:
1206
1207 CHECK_FOR_SUBCARRIER()
1208
1209 if(v > SUBCARRIER_DETECT_THRESHOLD) { // subcarrier detected
1210 Demod.state = DEMOD_PHASE_REF_TRAINING;
1211 Demod.sumI = ci;
1212 Demod.sumQ = cq;
1213 Demod.posCount = 1;
1214 }
1215 break;
1216
1217 case DEMOD_PHASE_REF_TRAINING:
1218 if(Demod.posCount < 8) {
1219
1220 CHECK_FOR_SUBCARRIER()
1221
1222 if (v > SUBCARRIER_DETECT_THRESHOLD) {
1223 // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
1224 // note: synchronization time > 80 1/fs
1225 Demod.sumI += ci;
1226 Demod.sumQ += cq;
1227 ++Demod.posCount;
1228 } else {
1229 // subcarrier lost
1230 Demod.state = DEMOD_UNSYNCD;
1231 }
1232 } else {
1233 Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
1234 }
1235 break;
1236
1237 case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
1238
1239 MAKE_SOFT_DECISION()
1240
1241 //Dbprintf("ICE: %d %d %d %d %d", v, Demod.sumI, Demod.sumQ, ci, cq );
1242 // logic '0' detected
1243 if (v <= 0) {
1244
1245 Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
1246
1247 // start of SOF sequence
1248 Demod.posCount = 0;
1249 } else {
1250 // maximum length of TR1 = 200 1/fs
1251 if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
1252 }
1253 ++Demod.posCount;
1254 break;
1255
1256 case DEMOD_GOT_FALLING_EDGE_OF_SOF:
1257 ++Demod.posCount;
1258
1259 MAKE_SOFT_DECISION()
1260
1261 if(v > 0) {
1262 // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
1263 if(Demod.posCount < 10*2) {
1264 Demod.state = DEMOD_UNSYNCD;
1265 } else {
1266 LED_C_ON(); // Got SOF
1267 Demod.state = DEMOD_AWAITING_START_BIT;
1268 Demod.posCount = 0;
1269 Demod.len = 0;
1270 }
1271 } else {
1272 // low phase of SOF too long (> 12 etu)
1273 if(Demod.posCount > 13*2) {
1274 Demod.state = DEMOD_UNSYNCD;
1275 LED_C_OFF();
1276 }
1277 }
1278 break;
1279
1280 case DEMOD_AWAITING_START_BIT:
1281 ++Demod.posCount;
1282
1283 MAKE_SOFT_DECISION()
1284
1285 if(v > 0) {
1286 // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
1287 if(Demod.posCount > 3*2) {
1288 Demod.state = DEMOD_UNSYNCD;
1289 LED_C_OFF();
1290 }
1291 } else {
1292 // start bit detected
1293 Demod.bitCount = 0;
1294 Demod.posCount = 1; // this was the first half
1295 Demod.thisBit = v;
1296 Demod.shiftReg = 0;
1297 Demod.state = DEMOD_RECEIVING_DATA;
1298 }
1299 break;
1300
1301 case DEMOD_RECEIVING_DATA:
1302
1303 MAKE_SOFT_DECISION()
1304
1305 if(Demod.posCount == 0) {
1306 // first half of bit
1307 Demod.thisBit = v;
1308 Demod.posCount = 1;
1309 } else {
1310 // second half of bit
1311 Demod.thisBit += v;
1312 Demod.shiftReg >>= 1;
1313 // logic '1'
1314 if(Demod.thisBit > 0)
1315 Demod.shiftReg |= 0x200;
1316
1317 ++Demod.bitCount;
1318
1319 if(Demod.bitCount == 10) {
1320
1321 uint16_t s = Demod.shiftReg;
1322
1323 if((s & 0x200) && !(s & 0x001)) {
1324 // stop bit == '1', start bit == '0'
1325 uint8_t b = (s >> 1);
1326 Demod.output[Demod.len] = b;
1327 ++Demod.len;
1328 Demod.state = DEMOD_AWAITING_START_BIT;
1329 } else {
1330 Demod.state = DEMOD_UNSYNCD;
1331 LED_C_OFF();
1332
1333 if(s == 0x000) {
1334 // This is EOF (start, stop and all data bits == '0'
1335 return TRUE;
1336 }
1337 }
1338 }
1339 Demod.posCount = 0;
1340 }
1341 break;
1342
1343 default:
1344 Demod.state = DEMOD_UNSYNCD;
1345 LED_C_OFF();
1346 break;
1347 }
1348 return FALSE;
1349 }
1350 */
1351 /*
1352 // Clear out the state of the "UART" that receives from the tag.
1353 static void DemodReset() {
1354 Demod.len = 0;
1355 Demod.state = DEMOD_UNSYNCD;
1356 Demod.posCount = 0;
1357 Demod.sumI = 0;
1358 Demod.sumQ = 0;
1359 Demod.bitCount = 0;
1360 Demod.thisBit = 0;
1361 Demod.shiftReg = 0;
1362 memset(Demod.output, 0x00, 3);
1363 }
1364
1365 static void DemodInit(uint8_t *data) {
1366 Demod.output = data;
1367 DemodReset();
1368 }
1369 */
1370
1371 /*
1372 * Demodulate the samples we received from the tag, also log to tracebuffer
1373 * quiet: set to 'TRUE' to disable debug output
1374 */
1375
1376 /*
1377 #define LEGIC_DMA_BUFFER_SIZE 256
1378
1379 static void GetSamplesForLegicDemod(int n, bool quiet)
1380 {
1381 int max = 0;
1382 bool gotFrame = FALSE;
1383 int lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
1384 int ci, cq, samples = 0;
1385
1386 BigBuf_free();
1387
1388 // And put the FPGA in the appropriate mode
1389 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_QUARTER_FREQ);
1390
1391 // The response (tag -> reader) that we're receiving.
1392 // Set up the demodulator for tag -> reader responses.
1393 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
1394
1395 // The DMA buffer, used to stream samples from the FPGA
1396 int8_t *dmaBuf = (int8_t*) BigBuf_malloc(LEGIC_DMA_BUFFER_SIZE);
1397 int8_t *upTo = dmaBuf;
1398
1399 // Setup and start DMA.
1400 if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, LEGIC_DMA_BUFFER_SIZE) ){
1401 if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
1402 return;
1403 }
1404
1405 // Signal field is ON with the appropriate LED:
1406 LED_D_ON();
1407 for(;;) {
1408 int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
1409 if(behindBy > max) max = behindBy;
1410
1411 while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (LEGIC_DMA_BUFFER_SIZE-1)) > 2) {
1412 ci = upTo[0];
1413 cq = upTo[1];
1414 upTo += 2;
1415 if(upTo >= dmaBuf + LEGIC_DMA_BUFFER_SIZE) {
1416 upTo = dmaBuf;
1417 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
1418 AT91C_BASE_PDC_SSC->PDC_RNCR = LEGIC_DMA_BUFFER_SIZE;
1419 }
1420 lastRxCounter -= 2;
1421 if(lastRxCounter <= 0)
1422 lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
1423
1424 samples += 2;
1425
1426 gotFrame = HandleLegicSamplesDemod(ci , cq );
1427 if ( gotFrame )
1428 break;
1429 }
1430
1431 if(samples > n || gotFrame)
1432 break;
1433 }
1434
1435 FpgaDisableSscDma();
1436
1437 if (!quiet && Demod.len == 0) {
1438 Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d",
1439 max,
1440 samples,
1441 gotFrame,
1442 Demod.len,
1443 Demod.sumI,
1444 Demod.sumQ
1445 );
1446 }
1447
1448 //Tracing
1449 if (Demod.len > 0) {
1450 uint8_t parity[MAX_PARITY_SIZE] = {0x00};
1451 LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
1452 }
1453 }
1454
1455 */
1456
1457 //-----------------------------------------------------------------------------
1458 // Transmit the command (to the tag) that was placed in ToSend[].
1459 //-----------------------------------------------------------------------------
1460 /*
1461 static void TransmitForLegic(void)
1462 {
1463 int c;
1464
1465 FpgaSetupSsc();
1466
1467 while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))
1468 AT91C_BASE_SSC->SSC_THR = 0xff;
1469
1470 // Signal field is ON with the appropriate Red LED
1471 LED_D_ON();
1472
1473 // Signal we are transmitting with the Green LED
1474 LED_B_ON();
1475 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1476
1477 for(c = 0; c < 10;) {
1478 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1479 AT91C_BASE_SSC->SSC_THR = 0xff;
1480 c++;
1481 }
1482 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1483 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
1484 (void)r;
1485 }
1486 WDT_HIT();
1487 }
1488
1489 c = 0;
1490 for(;;) {
1491 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1492 AT91C_BASE_SSC->SSC_THR = ToSend[c];
1493 legic_prng_forward(1); // forward the lfsr
1494 c++;
1495 if(c >= ToSendMax) {
1496 break;
1497 }
1498 }
1499 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1500 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
1501 (void)r;
1502 }
1503 WDT_HIT();
1504 }
1505 LED_B_OFF();
1506 }
1507 */
1508
1509 //-----------------------------------------------------------------------------
1510 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
1511 // so that it is ready to transmit to the tag using TransmitForLegic().
1512 //-----------------------------------------------------------------------------
1513 /*
1514 static void CodeLegicBitsAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
1515 {
1516 int i, j;
1517 uint8_t b;
1518
1519 ToSendReset();
1520
1521 // Send SOF
1522 for(i = 0; i < 7; i++)
1523 ToSendStuffBit(1);
1524
1525
1526 for(i = 0; i < cmdlen; i++) {
1527 // Start bit
1528 ToSendStuffBit(0);
1529
1530 // Data bits
1531 b = cmd[i];
1532 for(j = 0; j < bits; j++) {
1533 if(b & 1) {
1534 ToSendStuffBit(1);
1535 } else {
1536 ToSendStuffBit(0);
1537 }
1538 b >>= 1;
1539 }
1540 }
1541
1542 // Convert from last character reference to length
1543 ++ToSendMax;
1544 }
1545 */
1546 /**
1547 Convenience function to encode, transmit and trace Legic comms
1548 **/
1549 /*
1550 static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
1551 {
1552 CodeLegicBitsAsReader(cmd, cmdlen, bits);
1553 TransmitForLegic();
1554 if (tracing) {
1555 uint8_t parity[1] = {0x00};
1556 LogTrace(cmd, cmdlen, 0, 0, parity, TRUE);
1557 }
1558 }
1559
1560 */
1561 // Set up LEGIC communication
1562 /*
1563 void ice_legic_setup() {
1564
1565 // standard things.
1566 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1567 BigBuf_free(); BigBuf_Clear_ext(false);
1568 clear_trace();
1569 set_tracing(TRUE);
1570 DemodReset();
1571 UartReset();
1572
1573 // Set up the synchronous serial port
1574 FpgaSetupSsc();
1575
1576 // connect Demodulated Signal to ADC:
1577 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1578
1579 // Signal field is on with the appropriate LED
1580 LED_D_ON();
1581 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1582 SpinDelay(20);
1583 // Start the timer
1584 //StartCountSspClk();
1585
1586 // initalize CRC
1587 crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
1588
1589 // initalize prng
1590 legic_prng_init(0);
1591 }
1592 */
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