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bd20f8f4 1//-----------------------------------------------------------------------------
bd20f8f4 2// This code is licensed to you under the terms of the GNU GPL, version 2 or,
3// at your option, any later version. See the LICENSE.txt file for the text of
4// the license.
5//-----------------------------------------------------------------------------
d19929cb 6// Hitag2 emulation (preliminary test version)
bd20f8f4 7//
d19929cb 8// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
9//-----------------------------------------------------------------------------
10// Hitag2 complete rewrite of the code
11// - Fixed modulation/encoding issues
12// - Rewrote code for transponder emulation
13// - Added snooping of transponder communication
14// - Added reader functionality
15//
16// (c) 2012 Roel Verdult
bd20f8f4 17//-----------------------------------------------------------------------------
3742d905 18
e30c654b 19#include "proxmark3.h"
3742d905 20#include "apps.h"
f7e3ed82 21#include "util.h"
3742d905 22#include "hitag2.h"
9ab7a6c7 23#include "string.h"
aabb719d 24#include "BigBuf.h"
3742d905 25
d19929cb 26static bool bQuiet;
27
f71f4deb 28static bool bCrypto;
29static bool bAuthenticating;
30static bool bPwd;
31static bool bSuccessful;
3742d905 32
117d9ec2 33
47e18126 34
3742d905 35struct hitag2_tag {
36 uint32_t uid;
e30c654b 37 enum {
d19929cb 38 TAG_STATE_RESET = 0x01, // Just powered up, awaiting GetSnr
39 TAG_STATE_ACTIVATING = 0x02 , // In activation phase (password mode), sent UID, awaiting reader password
40 TAG_STATE_ACTIVATED = 0x03, // Activation complete, awaiting read/write commands
41 TAG_STATE_WRITING = 0x04, // In write command, awaiting sector contents to be written
3742d905 42 } state;
43 unsigned int active_sector;
d19929cb 44 byte_t crypto_active;
45 uint64_t cs;
46 byte_t sectors[12][4];
3742d905 47};
48
bde10a50 49static struct hitag2_tag tag = {
d19929cb 50 .state = TAG_STATE_RESET,
51 .sectors = { // Password mode: | Crypto mode:
52 [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID
53 [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key
54 [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved
55 [3] = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG
56 [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK
57 [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
58 [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: ....
59 [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
60 [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low
61 [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High
62 [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF
63 [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC
64 },
3742d905 65};
66
52244230
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67static enum {
68 WRITE_STATE_START = 0x0,
69 WRITE_STATE_PAGENUM_WRITTEN,
70 WRITE_STATE_PROG
71} writestate;
72
73
f71f4deb 74// ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces.
75// Historically it used to be FREE_BUFFER_SIZE, which was 2744.
76#define AUTH_TABLE_LENGTH 2744
77static byte_t* auth_table;
78static size_t auth_table_pos = 0;
79static size_t auth_table_len = AUTH_TABLE_LENGTH;
e30c654b 80
f71f4deb 81static byte_t password[4];
82static byte_t NrAr[8];
83static byte_t key[8];
52244230 84static byte_t writedata[4];
f71f4deb 85static uint64_t cipher_state;
3742d905 86
87/* Following is a modified version of cryptolib.com/ciphers/hitag2/ */
88// Software optimized 48-bit Philips/NXP Mifare Hitag2 PCF7936/46/47/52 stream cipher algorithm by I.C. Wiener 2006-2007.
89// For educational purposes only.
90// No warranties or guarantees of any kind.
91// This code is released into the public domain by its author.
92
93// Basic macros:
94
95#define u8 uint8_t
96#define u32 uint32_t
97#define u64 uint64_t
98#define rev8(x) ((((x)>>7)&1)+((((x)>>6)&1)<<1)+((((x)>>5)&1)<<2)+((((x)>>4)&1)<<3)+((((x)>>3)&1)<<4)+((((x)>>2)&1)<<5)+((((x)>>1)&1)<<6)+(((x)&1)<<7))
99#define rev16(x) (rev8 (x)+(rev8 (x>> 8)<< 8))
100#define rev32(x) (rev16(x)+(rev16(x>>16)<<16))
101#define rev64(x) (rev32(x)+(rev32(x>>32)<<32))
102#define bit(x,n) (((x)>>(n))&1)
103#define bit32(x,n) ((((x)[(n)>>5])>>((n)))&1)
104#define inv32(x,i,n) ((x)[(i)>>5]^=((u32)(n))<<((i)&31))
105#define rotl64(x, n) ((((u64)(x))<<((n)&63))+(((u64)(x))>>((0-(n))&63)))
106
107// Single bit Hitag2 functions:
108
109#define i4(x,a,b,c,d) ((u32)((((x)>>(a))&1)+(((x)>>(b))&1)*2+(((x)>>(c))&1)*4+(((x)>>(d))&1)*8))
110
111static const u32 ht2_f4a = 0x2C79; // 0010 1100 0111 1001
112static const u32 ht2_f4b = 0x6671; // 0110 0110 0111 0001
113static const u32 ht2_f5c = 0x7907287B; // 0111 1001 0000 0111 0010 1000 0111 1011
114
115static u32 _f20 (const u64 x)
116{
52244230
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117 u32 i5;
118
3742d905 119 i5 = ((ht2_f4a >> i4 (x, 1, 2, 4, 5)) & 1)* 1
52244230
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120 + ((ht2_f4b >> i4 (x, 7,11,13,14)) & 1)* 2
121 + ((ht2_f4b >> i4 (x,16,20,22,25)) & 1)* 4
122 + ((ht2_f4b >> i4 (x,27,28,30,32)) & 1)* 8
123 + ((ht2_f4a >> i4 (x,33,42,43,45)) & 1)*16;
e30c654b 124
3742d905 125 return (ht2_f5c >> i5) & 1;
126}
127
128static u64 _hitag2_init (const u64 key, const u32 serial, const u32 IV)
129{
130 u32 i;
131 u64 x = ((key & 0xFFFF) << 32) + serial;
e30c654b 132
3742d905 133 for (i = 0; i < 32; i++)
134 {
135 x >>= 1;
136 x += (u64) (_f20 (x) ^ (((IV >> i) ^ (key >> (i+16))) & 1)) << 47;
137 }
138 return x;
139}
140
141static u64 _hitag2_round (u64 *state)
142{
143 u64 x = *state;
e30c654b 144
3742d905 145 x = (x >> 1) +
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146 ((((x >> 0) ^ (x >> 2) ^ (x >> 3) ^ (x >> 6)
147 ^ (x >> 7) ^ (x >> 8) ^ (x >> 16) ^ (x >> 22)
148 ^ (x >> 23) ^ (x >> 26) ^ (x >> 30) ^ (x >> 41)
149 ^ (x >> 42) ^ (x >> 43) ^ (x >> 46) ^ (x >> 47)) & 1) << 47);
e30c654b 150
3742d905 151 *state = x;
152 return _f20 (x);
153}
154
3742d905 155static u32 _hitag2_byte (u64 * x)
156{
157 u32 i, c;
e30c654b 158
3742d905 159 for (i = 0, c = 0; i < 8; i++) c += (u32) _hitag2_round (x) << (i^7);
160 return c;
161}
162
f71f4deb 163static int hitag2_reset(void)
d19929cb 164{
165 tag.state = TAG_STATE_RESET;
166 tag.crypto_active = 0;
167 return 0;
168}
3742d905 169
f71f4deb 170static int hitag2_init(void)
d19929cb 171{
bde10a50 172// memcpy(&tag, &resetdata, sizeof(tag));
d19929cb 173 hitag2_reset();
174 return 0;
175}
3742d905 176
d19929cb 177static void hitag2_cipher_reset(struct hitag2_tag *tag, const byte_t *iv)
3742d905 178{
bde10a50 179 uint64_t key = ((uint64_t)tag->sectors[2][2]) |
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180 ((uint64_t)tag->sectors[2][3] << 8) |
181 ((uint64_t)tag->sectors[1][0] << 16) |
182 ((uint64_t)tag->sectors[1][1] << 24) |
183 ((uint64_t)tag->sectors[1][2] << 32) |
184 ((uint64_t)tag->sectors[1][3] << 40);
bde10a50 185 uint32_t uid = ((uint32_t)tag->sectors[0][0]) |
52244230
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186 ((uint32_t)tag->sectors[0][1] << 8) |
187 ((uint32_t)tag->sectors[0][2] << 16) |
188 ((uint32_t)tag->sectors[0][3] << 24);
3742d905 189 uint32_t iv_ = (((uint32_t)(iv[0]))) |
52244230
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190 (((uint32_t)(iv[1])) << 8) |
191 (((uint32_t)(iv[2])) << 16) |
192 (((uint32_t)(iv[3])) << 24);
d19929cb 193 tag->cs = _hitag2_init(rev64(key), rev32(uid), rev32(iv_));
3742d905 194}
195
d19929cb 196static int hitag2_cipher_authenticate(uint64_t* cs, const byte_t *authenticator_is)
3742d905 197{
d19929cb 198 byte_t authenticator_should[4];
199 authenticator_should[0] = ~_hitag2_byte(cs);
200 authenticator_should[1] = ~_hitag2_byte(cs);
201 authenticator_should[2] = ~_hitag2_byte(cs);
202 authenticator_should[3] = ~_hitag2_byte(cs);
203 return (memcmp(authenticator_should, authenticator_is, 4) == 0);
3742d905 204}
205
d19929cb 206static int hitag2_cipher_transcrypt(uint64_t* cs, byte_t *data, unsigned int bytes, unsigned int bits)
3742d905 207{
208 int i;
d19929cb 209 for(i=0; i<bytes; i++) data[i] ^= _hitag2_byte(cs);
210 for(i=0; i<bits; i++) data[bytes] ^= _hitag2_round(cs) << (7-i);
3742d905 211 return 0;
212}
d19929cb 213
214// Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK)
215// TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz
216// Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier)
217// T0 = TIMER_CLOCK1 / 125000 = 192
218#define T0 192
219
220#define SHORT_COIL() LOW(GPIO_SSC_DOUT)
221#define OPEN_COIL() HIGH(GPIO_SSC_DOUT)
222
223#define HITAG_FRAME_LEN 20
224#define HITAG_T_STOP 36 /* T_EOF should be > 36 */
225#define HITAG_T_LOW 8 /* T_LOW should be 4..10 */
226#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
227#define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */
228//#define HITAG_T_EOF 40 /* T_EOF should be > 36 */
229#define HITAG_T_EOF 80 /* T_EOF should be > 36 */
230#define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */
231#define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */
232#define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */
52244230 233#define HITAG_T_PROG 614
d19929cb 234
235#define HITAG_T_TAG_ONE_HALF_PERIOD 10
236#define HITAG_T_TAG_TWO_HALF_PERIOD 25
237#define HITAG_T_TAG_THREE_HALF_PERIOD 41
238#define HITAG_T_TAG_FOUR_HALF_PERIOD 57
239
240#define HITAG_T_TAG_HALF_PERIOD 16
241#define HITAG_T_TAG_FULL_PERIOD 32
242
243#define HITAG_T_TAG_CAPTURE_ONE_HALF 13
244#define HITAG_T_TAG_CAPTURE_TWO_HALF 25
245#define HITAG_T_TAG_CAPTURE_THREE_HALF 41
246#define HITAG_T_TAG_CAPTURE_FOUR_HALF 57
247
248
249static void hitag_send_bit(int bit) {
250 LED_A_ON();
251 // Reset clock for the next bit
252 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
253
254 // Fixed modulation, earlier proxmark version used inverted signal
255 if(bit == 0) {
256 // Manchester: Unloaded, then loaded |__--|
257 LOW(GPIO_SSC_DOUT);
258 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
259 HIGH(GPIO_SSC_DOUT);
260 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
261 } else {
262 // Manchester: Loaded, then unloaded |--__|
263 HIGH(GPIO_SSC_DOUT);
264 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
265 LOW(GPIO_SSC_DOUT);
266 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
267 }
268 LED_A_OFF();
269}
270
271static void hitag_send_frame(const byte_t* frame, size_t frame_len)
272{
273 // Send start of frame
274 for(size_t i=0; i<5; i++) {
275 hitag_send_bit(1);
276 }
277
278 // Send the content of the frame
279 for(size_t i=0; i<frame_len; i++) {
280 hitag_send_bit((frame[i/8] >> (7-(i%8)))&1);
281 }
282
283 // Drop the modulation
284 LOW(GPIO_SSC_DOUT);
285}
286
f71f4deb 287
288static void hitag2_handle_reader_command(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen)
d19929cb 289{
290 byte_t rx_air[HITAG_FRAME_LEN];
291
292 // Copy the (original) received frame how it is send over the air
293 memcpy(rx_air,rx,nbytes(rxlen));
294
295 if(tag.crypto_active) {
296 hitag2_cipher_transcrypt(&(tag.cs),rx,rxlen/8,rxlen%8);
297 }
298
299 // Reset the transmission frame length
300 *txlen = 0;
301
302 // Try to find out which command was send by selecting on length (in bits)
303 switch (rxlen) {
304 // Received 11000 from the reader, request for UID, send UID
52244230
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305 case 05: {
306 // Always send over the air in the clear plaintext mode
307 if(rx_air[0] != 0xC0) {
308 // Unknown frame ?
309 return;
d19929cb 310 }
52244230
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311 *txlen = 32;
312 memcpy(tx,tag.sectors[0],4);
313 tag.crypto_active = 0;
314 }
d19929cb 315 break;
316
317 // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number
52244230
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318 case 10: {
319 unsigned int sector = (~( ((rx[0]<<2)&0x04) | ((rx[1]>>6)&0x03) ) & 0x07);
320 // Verify complement of sector index
321 if(sector != ((rx[0]>>3)&0x07)) {
322 //DbpString("Transmission error (read/write)");
323 return;
324 }
d19929cb 325
52244230
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326 switch (rx[0] & 0xC6) {
327 // Read command: 11xx x00y
328 case 0xC0:
329 memcpy(tx,tag.sectors[sector],4);
330 *txlen = 32;
331 break;
d19929cb 332
52244230
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333 // Inverted Read command: 01xx x10y
334 case 0x44:
335 for (size_t i=0; i<4; i++) {
336 tx[i] = tag.sectors[sector][i] ^ 0xff;
d19929cb 337 }
52244230
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338 *txlen = 32;
339 break;
340
341 // Write command: 10xx x01y
342 case 0x82:
343 // Prepare write, acknowledge by repeating command
344 memcpy(tx,rx,nbytes(rxlen));
345 *txlen = rxlen;
346 tag.active_sector = sector;
347 tag.state=TAG_STATE_WRITING;
348 break;
349
350 // Unknown command
351 default:
352 Dbprintf("Unknown command: %02x %02x",rx[0],rx[1]);
353 return;
354 break;
d19929cb 355 }
52244230 356 }
d19929cb 357 break;
358
359 // Writing data or Reader password
52244230
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360 case 32: {
361 if(tag.state == TAG_STATE_WRITING) {
362 // These are the sector contents to be written. We don't have to do anything else.
363 memcpy(tag.sectors[tag.active_sector],rx,nbytes(rxlen));
364 tag.state=TAG_STATE_RESET;
365 return;
366 } else {
367 // Received RWD password, respond with configuration and our password
368 if(memcmp(rx,tag.sectors[1],4) != 0) {
369 DbpString("Reader password is wrong");
d19929cb 370 return;
d19929cb 371 }
52244230
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372 *txlen = 32;
373 memcpy(tx,tag.sectors[3],4);
d19929cb 374 }
52244230 375 }
d19929cb 376 break;
377
378 // Received RWD authentication challenge and respnse
52244230
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379 case 64: {
380 // Store the authentication attempt
381 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
382 memcpy(auth_table+auth_table_len,rx,8);
383 auth_table_len += 8;
384 }
d19929cb 385
52244230
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386 // Reset the cipher state
387 hitag2_cipher_reset(&tag,rx);
388 // Check if the authentication was correct
389 if(!hitag2_cipher_authenticate(&(tag.cs),rx+4)) {
390 // The reader failed to authenticate, do nothing
391 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
392 return;
393 }
394 // Succesful, but commented out reporting back to the Host, this may delay to much.
395 // Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
d19929cb 396
52244230
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397 // Activate encryption algorithm for all further communication
398 tag.crypto_active = 1;
d19929cb 399
52244230
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400 // Use the tag password as response
401 memcpy(tx,tag.sectors[3],4);
402 *txlen = 32;
403 }
d19929cb 404 break;
405 }
406
47e18126 407// LogTraceHitag(rx,rxlen,0,0,false);
408// LogTraceHitag(tx,*txlen,0,0,true);
d19929cb 409
410 if(tag.crypto_active) {
411 hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen/8, *txlen%8);
412 }
413}
414
415static void hitag_reader_send_bit(int bit) {
416 LED_A_ON();
417 // Reset clock for the next bit
418 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
419
420 // Binary puls length modulation (BPLM) is used to encode the data stream
421 // This means that a transmission of a one takes longer than that of a zero
422
b8140ab1 423 // Enable modulation, which means, drop the field
d19929cb 424 HIGH(GPIO_SSC_DOUT);
425
426 // Wait for 4-10 times the carrier period
427 while(AT91C_BASE_TC0->TC_CV < T0*6);
428 // SpinDelayUs(8*8);
429
430 // Disable modulation, just activates the field again
431 LOW(GPIO_SSC_DOUT);
432
433 if(bit == 0) {
434 // Zero bit: |_-|
435 while(AT91C_BASE_TC0->TC_CV < T0*22);
436 // SpinDelayUs(16*8);
437 } else {
438 // One bit: |_--|
439 while(AT91C_BASE_TC0->TC_CV < T0*28);
440 // SpinDelayUs(22*8);
441 }
442 LED_A_OFF();
443}
444
f71f4deb 445
d19929cb 446static void hitag_reader_send_frame(const byte_t* frame, size_t frame_len)
447{
448 // Send the content of the frame
449 for(size_t i=0; i<frame_len; i++) {
450 hitag_reader_send_bit((frame[i/8] >> (7-(i%8)))&1);
451 }
452 // Send EOF
453 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
b8140ab1 454 // Enable modulation, which means, drop the field
d19929cb 455 HIGH(GPIO_SSC_DOUT);
456 // Wait for 4-10 times the carrier period
457 while(AT91C_BASE_TC0->TC_CV < T0*6);
458 // Disable modulation, just activates the field again
459 LOW(GPIO_SSC_DOUT);
460}
461
ed7bd3a3 462size_t blocknr;
463
f71f4deb 464static bool hitag2_password(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
d19929cb 465 // Reset the transmission frame length
466 *txlen = 0;
467
468 // Try to find out which command was send by selecting on length (in bits)
469 switch (rxlen) {
470 // No answer, try to resurrect
52244230
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471 case 0: {
472 // Stop if there is no answer (after sending password)
473 if (bPwd) {
474 DbpString("Password failed!");
475 return false;
476 }
477 *txlen = 5;
478 memcpy(tx,"\xc0",nbytes(*txlen));
479 } break;
d19929cb 480
481 // Received UID, tag password
52244230
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482 case 32: {
483 if (!bPwd) {
484 *txlen = 32;
485 memcpy(tx,password,4);
486 bPwd = true;
487 memcpy(tag.sectors[blocknr],rx,4);
488 blocknr++;
489 } else {
219a334d 490
491 if(blocknr == 1){
492 //store password in block1, the TAG answers with Block3, but we need the password in memory
493 memcpy(tag.sectors[blocknr],tx,4);
494 }else{
495 memcpy(tag.sectors[blocknr],rx,4);
496 }
497
498 blocknr++;
499 if (blocknr > 7) {
52244230
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500 DbpString("Read succesful!");
501 bSuccessful = true;
502 return false;
219a334d 503 }
504 *txlen = 10;
505 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
506 tx[1] = ((blocknr^7) << 6);
52244230
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507 }
508 } break;
d19929cb 509
510 // Unexpected response
52244230
HJ
511 default: {
512 Dbprintf("Uknown frame length: %d",rxlen);
513 return false;
514 } break;
515 }
516 return true;
517}
518
519static bool hitag2_write_page(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen)
520{
521 switch (writestate) {
522 case WRITE_STATE_START:
523 *txlen = 10;
524 tx[0] = 0x82 | (blocknr << 3) | ((blocknr^7) >> 2);
525 tx[1] = ((blocknr^7) << 6);
526 writestate = WRITE_STATE_PAGENUM_WRITTEN;
527 break;
528 case WRITE_STATE_PAGENUM_WRITTEN:
529 // Check if page number was received correctly
530 if ((rxlen == 10) &&
531 (rx[0] == (0x82 | (blocknr << 3) | ((blocknr^7) >> 2))) &&
532 (rx[1] == (((blocknr & 0x3) ^ 0x3) << 6))) {
533 *txlen = 32;
534 memset(tx, 0, HITAG_FRAME_LEN);
535 memcpy(tx, writedata, 4);
536 writestate = WRITE_STATE_PROG;
537 } else {
538 Dbprintf("hitag2_write_page: Page number was not received correctly: rxlen=%d rx=%02x%02x%02x%02x",
539 rxlen, rx[0], rx[1], rx[2], rx[3]);
540 bSuccessful = false;
d19929cb 541 return false;
52244230
HJ
542 }
543 break;
544 case WRITE_STATE_PROG:
545 if (rxlen == 0) {
546 bSuccessful = true;
547 } else {
548 bSuccessful = false;
549 Dbprintf("hitag2_write_page: unexpected rx data (%d) after page write", rxlen);
550 }
551 return false;
552 default:
553 DbpString("hitag2_write_page: Unknown state %d");
554 bSuccessful = false;
555 return false;
d19929cb 556 }
52244230 557
d19929cb 558 return true;
559}
560
52244230 561static bool hitag2_crypto(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen, bool write) {
bde10a50 562 // Reset the transmission frame length
563 *txlen = 0;
564
52244230 565 if(bCrypto) {
bde10a50 566 hitag2_cipher_transcrypt(&cipher_state,rx,rxlen/8,rxlen%8);
52244230
HJ
567
568 }
569
570 if (bCrypto && !bAuthenticating && write) {
571 if (!hitag2_write_page(rx, rxlen, tx, txlen)) {
572 return false;
573 }
bde10a50 574 }
52244230
HJ
575 else
576 {
bde10a50 577
578 // Try to find out which command was send by selecting on length (in bits)
579 switch (rxlen) {
52244230
HJ
580 // No answer, try to resurrect
581 case 0:
582 {
583 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
584 if (bCrypto) {
585 // Failed during authentication
586 if (bAuthenticating) {
587 DbpString("Authentication failed!");
588 return false;
fc8c5cdd 589 } else {
52244230
HJ
590 // Failed reading a block, could be (read/write) locked, skip block and re-authenticate
591 if (blocknr == 1) {
592 // Write the low part of the key in memory
593 memcpy(tag.sectors[1],key+2,4);
594 } else if (blocknr == 2) {
595 // Write the high part of the key in memory
596 tag.sectors[2][0] = 0x00;
597 tag.sectors[2][1] = 0x00;
598 tag.sectors[2][2] = key[0];
599 tag.sectors[2][3] = key[1];
600 } else {
601 // Just put zero's in the memory (of the unreadable block)
602 memset(tag.sectors[blocknr],0x00,4);
603 }
604 blocknr++;
605 bCrypto = false;
606 }
607 } else {
608 *txlen = 5;
609 memcpy(tx,"\xc0",nbytes(*txlen));
610 }
611 break;
612 }
613 // Received UID, crypto tag answer
614 case 32: {
615 if (!bCrypto) {
616 uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40;
617 uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24;
618 Dbprintf("hitag2_crypto: key=0x%x%x uid=0x%x", (uint32_t) ((rev64(ui64key)) >> 32), (uint32_t) ((rev64(ui64key)) & 0xffffffff), rev32(ui32uid));
619 cipher_state = _hitag2_init(rev64(ui64key), rev32(ui32uid), 0);
620 memset(tx,0x00,4);
621 memset(tx+4,0xff,4);
622 hitag2_cipher_transcrypt(&cipher_state, tx+4, 4, 0);
623 *txlen = 64;
624 bCrypto = true;
625 bAuthenticating = true;
626 } else {
627 // Check if we received answer tag (at)
628 if (bAuthenticating) {
629 bAuthenticating = false;
630 if (write) {
631 if (!hitag2_write_page(rx, rxlen, tx, txlen)) {
632 return false;
633 }
634 break;
635 }
bde10a50 636 } else {
52244230
HJ
637 // Store the received block
638 memcpy(tag.sectors[blocknr],rx,4);
639 blocknr++;
bde10a50 640 }
52244230
HJ
641
642 if (blocknr > 7) {
643 DbpString("Read succesful!");
644 bSuccessful = true;
645 return false;
646 } else {
647 *txlen = 10;
648 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
649 tx[1] = ((blocknr^7) << 6);
650 }
651 }
652 } break;
bde10a50 653
52244230
HJ
654 // Unexpected response
655 default: {
656 Dbprintf("Uknown frame length: %d",rxlen);
657 return false;
658 } break;
659 }
bde10a50 660 }
bde10a50 661
52244230
HJ
662 if(bCrypto) {
663 // We have to return now to avoid double encryption
664 if (!bAuthenticating) {
665 hitag2_cipher_transcrypt(&cipher_state,tx,*txlen/8,*txlen%8);
666 }
bde10a50 667 }
668
669 return true;
670}
671
672
f71f4deb 673static bool hitag2_authenticate(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
d19929cb 674 // Reset the transmission frame length
675 *txlen = 0;
676
677 // Try to find out which command was send by selecting on length (in bits)
678 switch (rxlen) {
679 // No answer, try to resurrect
52244230
HJ
680 case 0: {
681 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
682 if (bCrypto) {
683 DbpString("Authentication failed!");
684 return false;
685 }
686 *txlen = 5;
687 memcpy(tx,"\xc0",nbytes(*txlen));
688 } break;
d19929cb 689
690 // Received UID, crypto tag answer
52244230
HJ
691 case 32: {
692 if (!bCrypto) {
693 *txlen = 64;
694 memcpy(tx,NrAr,8);
695 bCrypto = true;
696 } else {
697 DbpString("Authentication succesful!");
698 // We are done... for now
699 return false;
700 }
701 } break;
d19929cb 702
703 // Unexpected response
52244230
HJ
704 default: {
705 Dbprintf("Uknown frame length: %d",rxlen);
706 return false;
707 } break;
d19929cb 708 }
709
710 return true;
711}
712
117d9ec2 713
f71f4deb 714static bool hitag2_test_auth_attempts(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
117d9ec2 715
d19929cb 716 // Reset the transmission frame length
717 *txlen = 0;
718
719 // Try to find out which command was send by selecting on length (in bits)
720 switch (rxlen) {
52244230
HJ
721 // No answer, try to resurrect
722 case 0: {
723 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
724 if (bCrypto) {
725 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
43751d2a 726
52244230
HJ
727 // Removing failed entry from authentiations table
728 memcpy(auth_table+auth_table_pos,auth_table+auth_table_pos+8,8);
729 auth_table_len -= 8;
f71f4deb 730
52244230
HJ
731 // Return if we reached the end of the authentications table
732 bCrypto = false;
733 if (auth_table_pos == auth_table_len) {
734 return false;
d19929cb 735 }
52244230
HJ
736
737 // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry)
738 memcpy(NrAr,auth_table+auth_table_pos,8);
739 }
740 *txlen = 5;
741 memcpy(tx,"\xc0",nbytes(*txlen));
742 } break;
d19929cb 743
52244230
HJ
744 // Received UID, crypto tag answer, or read block response
745 case 32: {
746 if (!bCrypto) {
747 *txlen = 64;
748 memcpy(tx,NrAr,8);
749 bCrypto = true;
750 } else {
751 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
752 bCrypto = false;
753 if ((auth_table_pos+8) == auth_table_len) {
754 return false;
d19929cb 755 }
52244230
HJ
756 auth_table_pos += 8;
757 memcpy(NrAr,auth_table+auth_table_pos,8);
758 }
759 } break;
d19929cb 760
52244230
HJ
761 default: {
762 Dbprintf("Uknown frame length: %d",rxlen);
763 return false;
764 } break;
d19929cb 765 }
766
767 return true;
768}
769
f86d6b55 770static bool hitag2_read_uid(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
771 // Reset the transmission frame length
772 *txlen = 0;
773
774 // Try to find out which command was send by selecting on length (in bits)
775 switch (rxlen) {
776 // No answer, try to resurrect
52244230
HJ
777 case 0: {
778 // Just starting or if there is no answer
779 *txlen = 5;
780 memcpy(tx,"\xc0",nbytes(*txlen));
781 } break;
f86d6b55 782 // Received UID
52244230
HJ
783 case 32: {
784 // Check if we received answer tag (at)
785 if (bAuthenticating) {
786 bAuthenticating = false;
787 } else {
788 // Store the received block
789 memcpy(tag.sectors[blocknr],rx,4);
790 blocknr++;
791 }
792 if (blocknr > 0) {
793 //DbpString("Read successful!");
794 bSuccessful = true;
f86d6b55 795 return false;
52244230
HJ
796 }
797 } break;
798 // Unexpected response
799 default: {
800 Dbprintf("Uknown frame length: %d",rxlen);
801 return false;
802 } break;
f86d6b55 803 }
804 return true;
805}
f71f4deb 806
d19929cb 807void SnoopHitag(uint32_t type) {
808 int frame_count;
809 int response;
810 int overflow;
811 bool rising_edge;
812 bool reader_frame;
813 int lastbit;
814 bool bSkip;
815 int tag_sof;
816 byte_t rx[HITAG_FRAME_LEN];
817 size_t rxlen=0;
818
09ffd16e 819 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
820
821 // Clean up trace and prepare it for storing frames
822 set_tracing(TRUE);
823 clear_trace();
824
d19929cb 825 auth_table_len = 0;
826 auth_table_pos = 0;
09ffd16e 827
f71f4deb 828 BigBuf_free();
52244230 829 auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH);
d19929cb 830 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
f71f4deb 831
d19929cb 832 DbpString("Starting Hitag2 snoop");
833 LED_D_ON();
834
835 // Set up eavesdropping mode, frequency divisor which will drive the FPGA
836 // and analog mux selection.
024b97c5 837 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE);
d19929cb 838 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
839 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
840 RELAY_OFF();
841
842 // Configure output pin that is connected to the FPGA (for modulating)
843 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
844 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
845
846 // Disable modulation, we are going to eavesdrop, not modulate ;)
847 LOW(GPIO_SSC_DOUT);
848
849 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
850 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
851 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
852
f71f4deb 853 // Disable timer during configuration
d19929cb 854 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
855
856 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
857 // external trigger rising edge, load RA on rising edge of TIOA.
858 uint32_t t1_channel_mode = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH;
859 AT91C_BASE_TC1->TC_CMR = t1_channel_mode;
860
861 // Enable and reset counter
862 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
863
864 // Reset the received frame, frame count and timing info
d19929cb 865 frame_count = 0;
866 response = 0;
867 overflow = 0;
868 reader_frame = false;
869 lastbit = 1;
870 bSkip = true;
871 tag_sof = 4;
872
873 while(!BUTTON_PRESS()) {
874 // Watchdog hit
875 WDT_HIT();
876
877 // Receive frame, watch for at most T0*EOF periods
878 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
879 // Check if rising edge in modulation is detected
880 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
881 // Retrieve the new timing values
882 int ra = (AT91C_BASE_TC1->TC_RA/T0);
883
884 // Find out if we are dealing with a rising or falling edge
885 rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0;
886
887 // Shorter periods will only happen with reader frames
888 if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) {
889 // Switch from tag to reader capture
890 LED_C_OFF();
891 reader_frame = true;
892 memset(rx,0x00,sizeof(rx));
893 rxlen = 0;
894 }
895
896 // Only handle if reader frame and rising edge, or tag frame and falling edge
897 if (reader_frame != rising_edge) {
52244230 898 overflow += ra;
d19929cb 899 continue;
900 }
901
902 // Add the buffered timing values of earlier captured edges which were skipped
903 ra += overflow;
904 overflow = 0;
905
906 if (reader_frame) {
907 LED_B_ON();
908 // Capture reader frame
909 if(ra >= HITAG_T_STOP) {
910 if (rxlen != 0) {
911 //DbpString("wierd0?");
912 }
913 // Capture the T0 periods that have passed since last communication or field drop (reset)
914 response = (ra - HITAG_T_LOW);
915 } else if(ra >= HITAG_T_1_MIN ) {
916 // '1' bit
917 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
918 rxlen++;
919 } else if(ra >= HITAG_T_0_MIN) {
920 // '0' bit
921 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
922 rxlen++;
923 } else {
924 // Ignore wierd value, is to small to mean anything
925 }
926 } else {
927 LED_C_ON();
928 // Capture tag frame (manchester decoding using only falling edges)
929 if(ra >= HITAG_T_EOF) {
930 if (rxlen != 0) {
931 //DbpString("wierd1?");
932 }
933 // Capture the T0 periods that have passed since last communication or field drop (reset)
934 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
935 response = ra-HITAG_T_TAG_HALF_PERIOD;
936 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
937 // Manchester coding example |-_|_-|-_| (101)
938 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
939 rxlen++;
940 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
941 rxlen++;
942 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
943 // Manchester coding example |_-|...|_-|-_| (0...01)
944 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
945 rxlen++;
946 // We have to skip this half period at start and add the 'one' the second time
947 if (!bSkip) {
948 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
949 rxlen++;
950 }
951 lastbit = !lastbit;
952 bSkip = !bSkip;
953 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
954 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
955 if (tag_sof) {
956 // Ignore bits that are transmitted during SOF
957 tag_sof--;
958 } else {
959 // bit is same as last bit
960 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
961 rxlen++;
962 }
963 } else {
964 // Ignore wierd value, is to small to mean anything
965 }
966 }
967 }
968 }
969
970 // Check if frame was captured
971 if(rxlen > 0) {
972 frame_count++;
47e18126 973 if (!LogTraceHitag(rx,rxlen,response,0,reader_frame)) {
d19929cb 974 DbpString("Trace full");
975 break;
976 }
977
978 // Check if we recognize a valid authentication attempt
979 if (nbytes(rxlen) == 8) {
980 // Store the authentication attempt
981 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
982 memcpy(auth_table+auth_table_len,rx,8);
983 auth_table_len += 8;
984 }
985 }
986
987 // Reset the received frame and response timing info
988 memset(rx,0x00,sizeof(rx));
989 response = 0;
990 reader_frame = false;
991 lastbit = 1;
992 bSkip = true;
993 tag_sof = 4;
994 overflow = 0;
995
996 LED_B_OFF();
997 LED_C_OFF();
998 } else {
999 // Save the timer overflow, will be 0 when frame was received
1000 overflow += (AT91C_BASE_TC1->TC_CV/T0);
1001 }
1002 // Reset the frame length
1003 rxlen = 0;
1004 // Reset the timer to restart while-loop that receives frames
1005 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
1006 }
52244230 1007 LED_A_ON();
d19929cb 1008 LED_B_OFF();
1009 LED_C_OFF();
1010 LED_D_OFF();
1011 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
52244230 1012 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
d19929cb 1013 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
52244230 1014 LED_A_OFF();
d19929cb 1015
1016// Dbprintf("frame received: %d",frame_count);
1017// Dbprintf("Authentication Attempts: %d",(auth_table_len/8));
1018// DbpString("All done");
1019}
1020
1021void SimulateHitagTag(bool tag_mem_supplied, byte_t* data) {
1022 int frame_count;
1023 int response;
1024 int overflow;
1025 byte_t rx[HITAG_FRAME_LEN];
1026 size_t rxlen=0;
1027 byte_t tx[HITAG_FRAME_LEN];
1028 size_t txlen=0;
1029 bool bQuitTraceFull = false;
1030 bQuiet = false;
1031
09ffd16e 1032 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1033
1034 // Clean up trace and prepare it for storing frames
1035 set_tracing(TRUE);
1036 clear_trace();
1037
d19929cb 1038 auth_table_len = 0;
1039 auth_table_pos = 0;
52244230 1040 byte_t* auth_table;
f71f4deb 1041 BigBuf_free();
52244230 1042 auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH);
d19929cb 1043 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
1044
1045 DbpString("Starting Hitag2 simulation");
1046 LED_D_ON();
1047 hitag2_init();
1048
1049 if (tag_mem_supplied) {
1050 DbpString("Loading hitag2 memory...");
1051 memcpy((byte_t*)tag.sectors,data,48);
1052 }
1053
1054 uint32_t block = 0;
1055 for (size_t i=0; i<12; i++) {
1056 for (size_t j=0; j<4; j++) {
1057 block <<= 8;
1058 block |= tag.sectors[i][j];
1059 }
1060 Dbprintf("| %d | %08x |",i,block);
1061 }
1062
1063 // Set up simulator mode, frequency divisor which will drive the FPGA
1064 // and analog mux selection.
28598e80 1065 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT);
d19929cb 1066 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1067 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1068 RELAY_OFF();
1069
1070 // Configure output pin that is connected to the FPGA (for modulating)
1071 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
1072 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
1073
1074 // Disable modulation at default, which means release resistance
1075 LOW(GPIO_SSC_DOUT);
1076
1077 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
1078 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
1079
1080 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
1081 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1082 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1083
52244230 1084 // Disable timer during configuration
d19929cb 1085 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1086
3fe4ff4f 1087 // Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
d19929cb 1088 // external trigger rising edge, load RA on rising edge of TIOA.
1089 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING;
1090
d19929cb 1091 // Reset the received frame, frame count and timing info
1092 memset(rx,0x00,sizeof(rx));
1093 frame_count = 0;
1094 response = 0;
1095 overflow = 0;
3fe4ff4f 1096
1097 // Enable and reset counter
1098 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
d19929cb 1099
1100 while(!BUTTON_PRESS()) {
1101 // Watchdog hit
1102 WDT_HIT();
1103
1104 // Receive frame, watch for at most T0*EOF periods
1105 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
1106 // Check if rising edge in modulation is detected
1107 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1108 // Retrieve the new timing values
1109 int ra = (AT91C_BASE_TC1->TC_RA/T0) + overflow;
1110 overflow = 0;
1111
1112 // Reset timer every frame, we have to capture the last edge for timing
1113 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1114
1115 LED_B_ON();
1116
1117 // Capture reader frame
1118 if(ra >= HITAG_T_STOP) {
1119 if (rxlen != 0) {
1120 //DbpString("wierd0?");
1121 }
1122 // Capture the T0 periods that have passed since last communication or field drop (reset)
1123 response = (ra - HITAG_T_LOW);
1124 } else if(ra >= HITAG_T_1_MIN ) {
1125 // '1' bit
1126 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1127 rxlen++;
1128 } else if(ra >= HITAG_T_0_MIN) {
1129 // '0' bit
1130 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1131 rxlen++;
1132 } else {
1133 // Ignore wierd value, is to small to mean anything
1134 }
1135 }
1136 }
1137
1138 // Check if frame was captured
1139 if(rxlen > 4) {
1140 frame_count++;
1141 if (!bQuiet) {
47e18126 1142 if (!LogTraceHitag(rx,rxlen,response,0,true)) {
d19929cb 1143 DbpString("Trace full");
1144 if (bQuitTraceFull) {
1145 break;
1146 } else {
1147 bQuiet = true;
1148 }
1149 }
1150 }
1151
1152 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1153 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1154
1155 // Process the incoming frame (rx) and prepare the outgoing frame (tx)
1156 hitag2_handle_reader_command(rx,rxlen,tx,&txlen);
1157
1158 // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit,
1159 // not that since the clock counts since the rising edge, but T_Wait1 is
1160 // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low)
1161 // periods. The gap time T_Low varies (4..10). All timer values are in
1162 // terms of T0 units
1163 while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_WAIT_1-HITAG_T_LOW));
1164
1165 // Send and store the tag answer (if there is any)
1166 if (txlen) {
1167 // Transmit the tag frame
1168 hitag_send_frame(tx,txlen);
1169 // Store the frame in the trace
1170 if (!bQuiet) {
47e18126 1171 if (!LogTraceHitag(tx,txlen,0,0,false)) {
d19929cb 1172 DbpString("Trace full");
1173 if (bQuitTraceFull) {
1174 break;
1175 } else {
1176 bQuiet = true;
1177 }
1178 }
1179 }
1180 }
1181
1182 // Reset the received frame and response timing info
1183 memset(rx,0x00,sizeof(rx));
1184 response = 0;
1185
1186 // Enable and reset external trigger in timer for capturing future frames
1187 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1188 LED_B_OFF();
1189 }
1190 // Reset the frame length
1191 rxlen = 0;
1192 // Save the timer overflow, will be 0 when frame was received
1193 overflow += (AT91C_BASE_TC1->TC_CV/T0);
1194 // Reset the timer to restart while-loop that receives frames
1195 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
1196 }
1197 LED_B_OFF();
1198 LED_D_OFF();
1199 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1200 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1201 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
3fe4ff4f 1202
1203 DbpString("Sim Stopped");
1204
d19929cb 1205}
1206
1207void ReaderHitag(hitag_function htf, hitag_data* htd) {
1208 int frame_count;
1209 int response;
1210 byte_t rx[HITAG_FRAME_LEN];
1211 size_t rxlen=0;
1212 byte_t txbuf[HITAG_FRAME_LEN];
1213 byte_t* tx = txbuf;
1214 size_t txlen=0;
1215 int lastbit;
1216 bool bSkip;
1217 int reset_sof;
1218 int tag_sof;
1219 int t_wait = HITAG_T_WAIT_MAX;
1220 bool bStop;
1221 bool bQuitTraceFull = false;
ab4da50d 1222
f71f4deb 1223 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1224 // Reset the return status
1225 bSuccessful = false;
ab4da50d 1226
d19929cb 1227 // Clean up trace and prepare it for storing frames
3000dc4e
MHS
1228 set_tracing(TRUE);
1229 clear_trace();
117d9ec2 1230
f86d6b55 1231 //DbpString("Starting Hitag reader family");
d19929cb 1232
1233 // Check configuration
1234 switch(htf) {
52244230
HJ
1235 case RHT2F_PASSWORD: {
1236 Dbprintf("List identifier in password mode");
1237 memcpy(password,htd->pwd.password,4);
1238 blocknr = 0;
1239 bQuitTraceFull = false;
1240 bQuiet = false;
1241 bPwd = false;
1242 } break;
1243 case RHT2F_AUTHENTICATE: {
1244 DbpString("Authenticating using nr,ar pair:");
1245 memcpy(NrAr,htd->auth.NrAr,8);
1246 Dbhexdump(8,NrAr,false);
1247 bQuiet = false;
1248 bCrypto = false;
1249 bAuthenticating = false;
1250 bQuitTraceFull = true;
1251 } break;
1252 case RHT2F_CRYPTO:
1253 {
1254 DbpString("Authenticating using key:");
1255 memcpy(key,htd->crypto.key,6); //HACK; 4 or 6?? I read both in the code.
1256 Dbhexdump(6,key,false);
1257 blocknr = 0;
1258 bQuiet = false;
1259 bCrypto = false;
1260 bAuthenticating = false;
1261 bQuitTraceFull = true;
1262 } break;
1263 case RHT2F_TEST_AUTH_ATTEMPTS: {
1264 Dbprintf("Testing %d authentication attempts",(auth_table_len/8));
1265 auth_table_pos = 0;
1266 memcpy(NrAr, auth_table, 8);
1267 bQuitTraceFull = false;
1268 bQuiet = false;
1269 bCrypto = false;
1270 } break;
1271 case RHT2F_UID_ONLY: {
1272 blocknr = 0;
1273 bQuiet = false;
1274 bCrypto = false;
1275 bAuthenticating = false;
1276 bQuitTraceFull = true;
1277 } break;
1278 default: {
1279 Dbprintf("Error, unknown function: %d",htf);
1280 return;
1281 } break;
1282 }
1283
1284 LED_D_ON();
1285 hitag2_init();
1286
1287 // Configure output and enable pin that is connected to the FPGA (for modulating)
1288 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
1289 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
1290
1291 // Set fpga in edge detect with reader field, we can modulate as reader now
1292 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
1293
1294 // Set Frequency divisor which will drive the FPGA and analog mux selection
1295 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1296 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1297 RELAY_OFF();
1298
1299 // Disable modulation at default, which means enable the field
1300 LOW(GPIO_SSC_DOUT);
1301
1302 // Give it a bit of time for the resonant antenna to settle.
1303 SpinDelay(30);
1304
1305 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
1306 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
1307
1308 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames
1309 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1310 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1311
1312 // Disable timer during configuration
1313 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1314
1315 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
1316 // external trigger rising edge, load RA on falling edge of TIOA.
1317 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
1318
1319 // Enable and reset counters
1320 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1321 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1322
1323 // Reset the received frame, frame count and timing info
1324 frame_count = 0;
1325 response = 0;
1326 lastbit = 1;
1327 bStop = false;
1328
1329 // Tag specific configuration settings (sof, timings, etc.)
1330 if (htf < 10){
1331 // hitagS settings
1332 reset_sof = 1;
1333 t_wait = 200;
1334 //DbpString("Configured for hitagS reader");
1335 } else if (htf < 20) {
1336 // hitag1 settings
1337 reset_sof = 1;
1338 t_wait = 200;
1339 //DbpString("Configured for hitag1 reader");
1340 } else if (htf < 30) {
1341 // hitag2 settings
1342 reset_sof = 4;
1343 t_wait = HITAG_T_WAIT_2;
1344 //DbpString("Configured for hitag2 reader");
1345 } else {
1346 Dbprintf("Error, unknown hitag reader type: %d",htf);
1347 return;
1348 }
1349 uint8_t attempt_count=0;
1350 while(!bStop && !BUTTON_PRESS()) {
1351 // Watchdog hit
1352 WDT_HIT();
1353
1354 // Check if frame was captured and store it
1355 if(rxlen > 0) {
1356 frame_count++;
1357 if (!bQuiet) {
1358 if (!LogTraceHitag(rx,rxlen,response,0,false)) {
1359 DbpString("Trace full");
1360 if (bQuitTraceFull) {
1361 break;
1362 } else {
1363 bQuiet = true;
1364 }
1365 }
1366 }
1367 }
1368
1369 // By default reset the transmission buffer
1370 tx = txbuf;
1371 switch(htf) {
d19929cb 1372 case RHT2F_PASSWORD: {
52244230 1373 bStop = !hitag2_password(rx,rxlen,tx,&txlen);
d19929cb 1374 } break;
1375 case RHT2F_AUTHENTICATE: {
52244230 1376 bStop = !hitag2_authenticate(rx,rxlen,tx,&txlen);
bde10a50 1377 } break;
bde10a50 1378 case RHT2F_CRYPTO: {
52244230 1379 bStop = !hitag2_crypto(rx,rxlen,tx,&txlen, false);
d19929cb 1380 } break;
d19929cb 1381 case RHT2F_TEST_AUTH_ATTEMPTS: {
52244230 1382 bStop = !hitag2_test_auth_attempts(rx,rxlen,tx,&txlen);
d19929cb 1383 } break;
f86d6b55 1384 case RHT2F_UID_ONLY: {
52244230
HJ
1385 bStop = !hitag2_read_uid(rx, rxlen, tx, &txlen);
1386 attempt_count++; //attempt 3 times to get uid then quit
1387 if (!bStop && attempt_count == 3) bStop = true;
f86d6b55 1388 } break;
d19929cb 1389 default: {
1390 Dbprintf("Error, unknown function: %d",htf);
1391 return;
1392 } break;
52244230
HJ
1393 }
1394
1395 // Send and store the reader command
1396 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1397 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1398
1399 // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
1400 // Since the clock counts since the last falling edge, a 'one' means that the
1401 // falling edge occured halfway the period. with respect to this falling edge,
1402 // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
1403 // All timer values are in terms of T0 units
1404 while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
1405
1406 //Dbprintf("DEBUG: Sending reader frame");
1407
1408 // Transmit the reader frame
1409 hitag_reader_send_frame(tx,txlen);
1410
1411 // Enable and reset external trigger in timer for capturing future frames
1412 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1413
1414 // Add transmitted frame to total count
1415 if(txlen > 0) {
1416 frame_count++;
1417 if (!bQuiet) {
1418 // Store the frame in the trace
1419 if (!LogTraceHitag(tx,txlen,HITAG_T_WAIT_2,0,true)) {
1420 if (bQuitTraceFull) {
1421 break;
1422 } else {
1423 bQuiet = true;
1424 }
1425 }
1426 }
1427 }
1428
1429 // Reset values for receiving frames
1430 memset(rx,0x00,sizeof(rx));
1431 rxlen = 0;
1432 lastbit = 1;
1433 bSkip = true;
1434 tag_sof = reset_sof;
1435 response = 0;
1436 //Dbprintf("DEBUG: Waiting to receive frame");
1437 uint32_t errorCount = 0;
1438
1439 // Receive frame, watch for at most T0*EOF periods
1440 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
1441 // Check if falling edge in tag modulation is detected
1442 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1443 // Retrieve the new timing values
1444 int ra = (AT91C_BASE_TC1->TC_RA/T0);
1445
1446 // Reset timer every frame, we have to capture the last edge for timing
1447 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
1448
1449 LED_B_ON();
1450
1451 // Capture tag frame (manchester decoding using only falling edges)
1452 if(ra >= HITAG_T_EOF) {
1453 if (rxlen != 0) {
1454 //Dbprintf("DEBUG: Wierd1");
1455 }
1456 // Capture the T0 periods that have passed since last communication or field drop (reset)
1457 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
1458 response = ra-HITAG_T_TAG_HALF_PERIOD;
1459 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
1460 // Manchester coding example |-_|_-|-_| (101)
1461
1462 //need to test to verify we don't exceed memory...
1463 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1464 // break;
1465 //}
1466 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1467 rxlen++;
1468 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1469 rxlen++;
1470 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
1471 // Manchester coding example |_-|...|_-|-_| (0...01)
1472
1473 //need to test to verify we don't exceed memory...
1474 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1475 // break;
1476 //}
1477 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1478 rxlen++;
1479 // We have to skip this half period at start and add the 'one' the second time
1480 if (!bSkip) {
1481 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1482 rxlen++;
1483 }
1484 lastbit = !lastbit;
1485 bSkip = !bSkip;
1486 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
1487 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
1488
1489 //need to test to verify we don't exceed memory...
1490 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1491 // break;
1492 //}
1493 if (tag_sof) {
1494 // Ignore bits that are transmitted during SOF
1495 tag_sof--;
1496 } else {
1497 // bit is same as last bit
1498 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
1499 rxlen++;
1500 }
1501 } else {
1502 //Dbprintf("DEBUG: Wierd2");
1503 errorCount++;
1504 // Ignore wierd value, is to small to mean anything
1505 }
1506 }
1507 //if we saw over 100 wierd values break it probably isn't hitag...
1508 if (errorCount >100) break;
1509 // We can break this loop if we received the last bit from a frame
1510 if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) {
1511 if (rxlen>0) break;
1512 }
1513 }
1514 }
1515 //Dbprintf("DEBUG: Done waiting for frame");
1516
1517 LED_B_OFF();
1518 LED_D_OFF();
1519 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1520 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1521 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1522 //Dbprintf("frame received: %d",frame_count);
1523 //DbpString("All done");
1524 cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48);
1525}
1526
1527void WriterHitag(hitag_function htf, hitag_data* htd, int page) {
1528 int frame_count;
1529 int response;
1530 byte_t rx[HITAG_FRAME_LEN];
1531 size_t rxlen=0;
1532 byte_t txbuf[HITAG_FRAME_LEN];
1533 byte_t* tx = txbuf;
1534 size_t txlen=0;
1535 int lastbit;
1536 bool bSkip;
1537 int reset_sof;
1538 int tag_sof;
1539 int t_wait = HITAG_T_WAIT_MAX;
1540 bool bStop;
1541 bool bQuitTraceFull = false;
1542
1543 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1544 // Reset the return status
1545 bSuccessful = false;
1546
1547 // Clean up trace and prepare it for storing frames
1548 set_tracing(TRUE);
1549 clear_trace();
1550
1551 //DbpString("Starting Hitag reader family");
1552
1553 // Check configuration
1554 switch(htf) {
1555 case WHT2F_CRYPTO:
1556 {
1557 DbpString("Authenticating using key:");
1558 memcpy(key,htd->crypto.key,6); //HACK; 4 or 6?? I read both in the code.
1559 memcpy(writedata, htd->crypto.data, 4);
1560 Dbhexdump(6,key,false);
1561 blocknr = page;
1562 bQuiet = false;
1563 bCrypto = false;
1564 bAuthenticating = false;
1565 bQuitTraceFull = true;
1566 writestate = WRITE_STATE_START;
1567 } break;
1568 default: {
1569 Dbprintf("Error, unknown function: %d",htf);
1570 return;
1571 } break;
d19929cb 1572 }
1573
1574 LED_D_ON();
1575 hitag2_init();
1576
1577 // Configure output and enable pin that is connected to the FPGA (for modulating)
1578 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
1579 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
1580
1581 // Set fpga in edge detect with reader field, we can modulate as reader now
1582 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
1583
1584 // Set Frequency divisor which will drive the FPGA and analog mux selection
1585 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1586 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1587 RELAY_OFF();
1588
1589 // Disable modulation at default, which means enable the field
1590 LOW(GPIO_SSC_DOUT);
1591
1592 // Give it a bit of time for the resonant antenna to settle.
1593 SpinDelay(30);
1594
1595 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
1596 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
1597
1598 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames
1599 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1600 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1601
52244230 1602 // Disable timer during configuration
d19929cb 1603 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1604
1605 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
1606 // external trigger rising edge, load RA on falling edge of TIOA.
1607 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
1608
1609 // Enable and reset counters
1610 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1611 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1612
1613 // Reset the received frame, frame count and timing info
1614 frame_count = 0;
1615 response = 0;
1616 lastbit = 1;
1617 bStop = false;
1618
52244230
HJ
1619 // Tag specific configuration settings (sof, timings, etc.)
1620 if (htf < 10){
1621 // hitagS settings
1622 reset_sof = 1;
1623 t_wait = 200;
1624 //DbpString("Configured for hitagS reader");
1625 } else if (htf < 20) {
1626 // hitag1 settings
1627 reset_sof = 1;
1628 t_wait = 200;
1629 //DbpString("Configured for hitag1 reader");
1630 } else if (htf < 30) {
1631 // hitag2 settings
1632 reset_sof = 4;
1633 t_wait = HITAG_T_WAIT_2;
1634 //DbpString("Configured for hitag2 reader");
d19929cb 1635 } else {
52244230
HJ
1636 Dbprintf("Error, unknown hitag reader type: %d",htf);
1637 return;
1638 }
d19929cb 1639 while(!bStop && !BUTTON_PRESS()) {
1640 // Watchdog hit
1641 WDT_HIT();
1642
1643 // Check if frame was captured and store it
1644 if(rxlen > 0) {
1645 frame_count++;
1646 if (!bQuiet) {
47e18126 1647 if (!LogTraceHitag(rx,rxlen,response,0,false)) {
d19929cb 1648 DbpString("Trace full");
1649 if (bQuitTraceFull) {
1650 break;
1651 } else {
1652 bQuiet = true;
1653 }
1654 }
1655 }
1656 }
1657
1658 // By default reset the transmission buffer
1659 tx = txbuf;
1660 switch(htf) {
52244230
HJ
1661 case WHT2F_CRYPTO: {
1662 bStop = !hitag2_crypto(rx,rxlen,tx,&txlen, true);
1663 } break;
1664 default: {
1665 Dbprintf("Error, unknown function: %d",htf);
1666 return;
1667 } break;
d19929cb 1668 }
1669
1670 // Send and store the reader command
1671 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1672 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1673
1674 // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
1675 // Since the clock counts since the last falling edge, a 'one' means that the
1676 // falling edge occured halfway the period. with respect to this falling edge,
1677 // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
1678 // All timer values are in terms of T0 units
1679 while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
921e6399 1680
52244230 1681 //Dbprintf("DEBUG: Sending reader frame");
d19929cb 1682
1683 // Transmit the reader frame
1684 hitag_reader_send_frame(tx,txlen);
1685
52244230 1686 // Enable and reset external trigger in timer for capturing future frames
d19929cb 1687 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1688
1689 // Add transmitted frame to total count
1690 if(txlen > 0) {
1691 frame_count++;
1692 if (!bQuiet) {
1693 // Store the frame in the trace
47e18126 1694 if (!LogTraceHitag(tx,txlen,HITAG_T_WAIT_2,0,true)) {
d19929cb 1695 if (bQuitTraceFull) {
1696 break;
1697 } else {
1698 bQuiet = true;
1699 }
1700 }
1701 }
1702 }
52244230 1703
d19929cb 1704 // Reset values for receiving frames
1705 memset(rx,0x00,sizeof(rx));
1706 rxlen = 0;
1707 lastbit = 1;
1708 bSkip = true;
1709 tag_sof = reset_sof;
1710 response = 0;
52244230 1711 //Dbprintf("DEBUG: Waiting to receive frame");
921e6399 1712 uint32_t errorCount = 0;
1713
d19929cb 1714 // Receive frame, watch for at most T0*EOF periods
1715 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
1716 // Check if falling edge in tag modulation is detected
1717 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1718 // Retrieve the new timing values
1719 int ra = (AT91C_BASE_TC1->TC_RA/T0);
1720
1721 // Reset timer every frame, we have to capture the last edge for timing
1722 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
1723
1724 LED_B_ON();
52244230 1725
d19929cb 1726 // Capture tag frame (manchester decoding using only falling edges)
1727 if(ra >= HITAG_T_EOF) {
1728 if (rxlen != 0) {
921e6399 1729 //Dbprintf("DEBUG: Wierd1");
d19929cb 1730 }
1731 // Capture the T0 periods that have passed since last communication or field drop (reset)
1732 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
1733 response = ra-HITAG_T_TAG_HALF_PERIOD;
1734 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
1735 // Manchester coding example |-_|_-|-_| (101)
921e6399 1736
1737 //need to test to verify we don't exceed memory...
1738 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1739 // break;
1740 //}
d19929cb 1741 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1742 rxlen++;
1743 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1744 rxlen++;
1745 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
1746 // Manchester coding example |_-|...|_-|-_| (0...01)
921e6399 1747
1748 //need to test to verify we don't exceed memory...
1749 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1750 // break;
1751 //}
d19929cb 1752 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1753 rxlen++;
1754 // We have to skip this half period at start and add the 'one' the second time
1755 if (!bSkip) {
1756 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1757 rxlen++;
1758 }
1759 lastbit = !lastbit;
1760 bSkip = !bSkip;
1761 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
1762 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
921e6399 1763
1764 //need to test to verify we don't exceed memory...
1765 //if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) {
1766 // break;
1767 //}
d19929cb 1768 if (tag_sof) {
1769 // Ignore bits that are transmitted during SOF
1770 tag_sof--;
1771 } else {
1772 // bit is same as last bit
1773 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
1774 rxlen++;
1775 }
1776 } else {
52244230
HJ
1777 //Dbprintf("DEBUG: Wierd2");
1778 errorCount++;
d19929cb 1779 // Ignore wierd value, is to small to mean anything
1780 }
1781 }
921e6399 1782 //if we saw over 100 wierd values break it probably isn't hitag...
1783 if (errorCount >100) break;
d19929cb 1784 // We can break this loop if we received the last bit from a frame
1785 if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) {
1786 if (rxlen>0) break;
1787 }
1788 }
52244230
HJ
1789
1790 // Wait some extra time for flash to be programmed
1791 if ((rxlen == 0) && (writestate == WRITE_STATE_PROG))
1792 {
1793 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
1794 while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_PROG - HITAG_T_WAIT_MAX));
1795 }
d19929cb 1796 }
921e6399 1797 //Dbprintf("DEBUG: Done waiting for frame");
1798
d19929cb 1799 LED_B_OFF();
1800 LED_D_OFF();
1801 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1802 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1803 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
f86d6b55 1804 //Dbprintf("frame received: %d",frame_count);
4c16ae80 1805 //DbpString("All done");
1806 cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48);
d19929cb 1807}
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