Pileus Git - ~andy/csm213a-hw/blob - hw2/main.cpp

   1 #include "messages.h"
   2
   3 #include "mbed.h"
   4 #include "serial_irq.h"
   5 #include "serial_dma.h"
   6 #include "timer_dma.h"
   7
   8 /**
   9  * Mode of operation:
  10  *   Devices 1 and 2 synchronize clocks using serial messages.
  11  *
  12  *   1. Each serial message timestamped using the hardware timer capture
  13  *      registers in both the sender and receiver.
  14  *   2. The sender transmits the send timestamp during the next time-sync
  15  *      message.
  16  *   3. The receiver then compares the senders timestamp with it's own
  17  *      timestamp for the corresponding messages and calculates an offset.
  18  *   4. The offset is used to compensate the receivers local clock.
  19  *
  20  *   Time synchronization is performed in both directions.
  21  */
  22
  23 /****************
  24  * Testing vars *
  25  ****************/
  26
  27 uint32_t test_xmt_enab  = 0;
  28 uint64_t test_xmt_time0 = 0;
  29 uint64_t test_xmt_time1 = 0;
  30
  31 uint32_t test_rcv_enab  = 0;
  32 uint64_t test_rcv_time  = 0;
  33
  34 /*******************
  35  * Timer functions *
  36  *******************/
  37
  38 #define NSEC_PER_SEC 1000000000ULL
  39
  40 uint64_t time_last_local; // timestamp at last time sync
  41 uint64_t time_last_world; // offset at last time sync
  42
  43 /**
  44  * Generate time stamp for an async event:
  45  *   local: drift compensated wall-clock time
  46  *   world: nanoseconds in world time world
  47  *   valid: local timestamp at valid valid
  48  */
  49 //uint64_t time_to_local(uint64_t world, uint64_t valid)
  50 //{
  51 //      uint64_t now =
  52 //      local =  + (stamp);
  53 //}
  54
  55 /**
  56  * Generate time stamp for an async event:
  57  *   time:  drift compensated wall-clock time
  58  *   stamp: event timestamp from PIT Module
  59  */
  60 uint64_t time_to_world(uint64_t local)
  61 {
  62         uint64_t elapsed = local - time_last_local;
  63         return time_last_world + elapsed;
  64 }
  65
  66 /**
  67  * Compensate the Real-Time-Clock oscillator for
  68  * temperature and drift errors. Called at 1Hz and
  69  * synchronous to the RTC 1Hz output.
  70  */
  71 void time_rtc_comp(void)
  72 {
  73         // todo
  74 }
  75
  76 /**
  77  * Synchronize the timer internal state with updates
  78  * from an external time sync message.
  79  *   local: our internal timestamp for the event
  80  *   world: reference timestamp from the other device
  81  */
  82 void time_ext_init(uint64_t local, uint64_t world)
  83 {
  84         sirq_printf("initialize clocks: %d -> %d\r\n",
  85                         (int)(local/NSEC_PER_SEC),
  86                         (int)(world/NSEC_PER_SEC));
  87
  88         time_last_local = local;
  89         time_last_world = world;
  90 }
  91
  92 /**
  93  * Synchronize the timer internal state with updates
  94  * from an external time sync message.
  95  *   local: our internal timestamp for the event
  96  *   world: reference timestamp from the other device
  97  */
  98 void time_ext_sync(uint64_t local, uint64_t world)
  99 {
 100         uint64_t guess = time_to_world(local);
 101
 102         time_last_local = local;
 103         time_last_world = (guess/2) + (world/2);
 104         //time_last_world = (guess * 3 / 4) + (world * 1 / 4);
 105         //time_last_world =
 106         //      (guess - (        guess / 2)) +
 107         //      (world - (world - world / 2));
 108         //time_last_world =
 109         //      (guess - (guess - guess / 4)) +
 110         //      (world - (        world / 4));
 111
 112         world = time_last_world;
 113
 114 //#ifdef VERBOSE
 115 #if 0
 116         uint64_t error = world > guess ? world - guess :
 117                          guess > world ? guess - world : 0;
 118         int      ahead = guess > world;
 119         sirq_printf("syncing clocks: %6d=%d.%04u -> %d.%04u (err: %s%ld.%09lu)\r\n",
 120                         (int)((local / NSEC_PER_SEC)),
 121                         (int)((guess / NSEC_PER_SEC)),
 122                         (int)((guess % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 123                         (int)((world / NSEC_PER_SEC)),
 124                         (int)((world % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 125                         ahead ? "-" : " ",
 126                         (int32_t )(error / (int64_t)NSEC_PER_SEC),
 127                         (uint32_t)(error % (int64_t)NSEC_PER_SEC));
 128 #endif
 129 //#endif
 130 }
 131
 132 void time_printf(const char *label, uint64_t local)
 133 {
 134         uint64_t world = time_to_world(local);
 135         sirq_printf("%s -- %d.%09u -> %d.%09u\r\n",
 136                         label,
 137                         (int)(local / NSEC_PER_SEC),
 138                         (int)(local % NSEC_PER_SEC),
 139                         (int)(world / NSEC_PER_SEC),
 140                         (int)(world % NSEC_PER_SEC));
 141 }
 142
 143 /*********************
 144  * Signal generation *
 145  *********************/
 146
 147 static uint32_t *emit_pcr    = 0; // transmit pin name
 148
 149 static uint64_t  emit_start  = 0; // transmit start time (world time)
 150 static uint64_t  emit_period = 0; // transmit period
 151 static uint64_t  emit_due    = 0; // next transmit (world time)
 152
 153 static uint32_t  emit_slack  = 0; // how far ahead we need to schedule
 154 static uint32_t  emit_worst  = 0; // worst-case latency in task table
 155
 156 void emit_init(int alt, PinName pin, PinMode mode)
 157 {
 158         // Find pin
 159         emit_pcr = (uint32_t*)(PORTA_BASE + pin);
 160
 161         // Enable clocks
 162         SIM->SCGC6            |= SIM_SCGC6_TPM0_MASK;
 163
 164         SIM->SOPT2            |= SIM_SOPT2_TPMSRC(1);
 165         SIM->SOPT4            |= SIM_SOPT4_TPM1CLKSEL_MASK;
 166
 167         // Set pin mode
 168         emit_pcr[0]            = PORT_PCR_ISF_MASK
 169                                | PORT_PCR_MUX(alt)
 170                                | mode;
 171
 172         // Setup Timer/PWM Module
 173         TPM0->SC               = TPM_SC_TOF_MASK
 174                                | TPM_SC_PS(1);        // 24 MHz clock ?
 175         TPM0->CNT              = TPM_CNT_COUNT(0);
 176         TPM0->MOD              = TPM_MOD_MOD(0xFFFF);
 177
 178         TPM0->CONTROLS[0].CnSC = TPM_CnSC_CHF_MASK    // clear flag
 179                                | TPM_CnSC_MSB_MASK    // pulse output on match
 180                                | TPM_CnSC_MSA_MASK    // ..
 181                                | TPM_CnSC_ELSA_MASK;  // pulse high
 182
 183         TPM0->CONTROLS[0].CnV  = 0xFFFF;              // time delay
 184
 185         TPM0->STATUS           = TPM_STATUS_CH0F_MASK
 186                                | TPM_STATUS_TOF_MASK;
 187
 188         TPM0->CONF             = TPM_CONF_CSOO_MASK;
 189 }
 190
 191 void emit_enable(uint64_t start, uint64_t period)
 192 {
 193         emit_start  = start;
 194         emit_period = period;
 195         emit_due    = start + period;
 196
 197         emit_slack  = 10000; // tune based on emit_worst
 198
 199         time_printf("emit scheduled", emit_due);
 200 }
 201
 202 void emit_schedule(uint64_t when)
 203 {
 204         uint64_t now   = time_to_world(tdma_time());
 205         uint16_t delay = (uint16_t)(when-now);
 206
 207         // Clear pending flags
 208         //emit_pcr[0]           |= PORT_PCR_ISF_MASK
 209
 210         // Disable timer
 211         TPM0->SC               = TPM_SC_TOF_MASK;
 212
 213         // Set transmit time
 214         TPM0->CNT              = TPM_CNT_COUNT(0);
 215         TPM0->CONTROLS[0].CnV  = delay;
 216
 217         // Start the timer
 218         TPM0->SC               = TPM_SC_TOF_MASK
 219                                | TPM_SC_CMOD(1);
 220
 221         // Debug
 222         //sirq_printf("emitting event\r\n");
 223 }
 224
 225 void emit_transmit(void)
 226 {
 227         static uint64_t prev;
 228
 229         // Get a fresh timestamp
 230         uint64_t world = time_to_world(tdma_time());
 231
 232         // Record how how much time we have to reschedule
 233         if (prev && world - prev > emit_worst)
 234                 emit_worst = prev;
 235
 236         // Schedule task if needed
 237         if (emit_due && emit_period &&
 238             world+emit_slack > emit_due) {
 239                 emit_schedule(emit_due);
 240                 emit_due += emit_period;
 241         }
 242 }
 243
 244 /************************
 245  * Serial I/O functions *
 246  ************************/
 247
 248 typedef struct {
 249         int      index;
 250         int      state;
 251         uint8_t  buffer[256];
 252 } parser_t;
 253
 254 static uint32_t serial_device_id   = 0;
 255
 256 const  uint64_t serial_sync_delay  = NSEC_PER_SEC / 100; // 1hz
 257 static uint64_t serial_sync_due    = 0;
 258
 259 static tdma_t  *serial_tdma_rcv    = NULL;
 260 static tdma_t  *serial_tdma_xmt    = NULL;
 261
 262 static uint64_t serial_prev_local  = 0;
 263 static uint64_t serial_prev_seq    = 0;
 264
 265 static uint64_t serial_xmt_local   = 0;
 266 static uint64_t serial_xmt_seq     = 0;
 267
 268 /**
 269  * Convert world to local time
 270  */
 271 uint64_t serial_read_time(ntime_t time)
 272 {
 273         return ((uint64_t)time.seconds) * NSEC_PER_SEC
 274              + ((uint64_t)time.nanosec);
 275 }
 276
 277 ntime_t serial_write_time(uint64_t time)
 278 {
 279         ntime_t buf = {};
 280         buf.seconds = time / NSEC_PER_SEC;
 281         buf.nanosec = time % NSEC_PER_SEC;
 282         return buf;
 283 }
 284
 285 /**
 286  * Output initialization message init message
 287  */
 288 void serial_send_init(uint16_t device, uint64_t local)
 289 {
 290 }
 291
 292 /**
 293  * Output time sync message
 294  */
 295 void serial_send_sync(sirq_t *port, uint64_t now)
 296 {
 297         if (serial_sync_due == 0 || now < serial_sync_due)
 298                 return; // not ready
 299
 300         //sirq_printf("sending sync\r\n");
 301
 302         // Calculate world time
 303         uint64_t local = 0;
 304         uint64_t world = time_to_world(serial_xmt_local);
 305
 306         // Message data
 307         header_t   head;
 308         sync_msg_t body;
 309
 310         // Transmit sync message
 311         head.header = MSG_HEADER;
 312         head.msgid  = MSG_ID_SYNC;
 313         head.length = sizeof(body);
 314         head.cksum  = 0; // todo
 315
 316         body.seq          = serial_xmt_seq;
 317         body.time.seconds = world / NSEC_PER_SEC;
 318         body.time.nanosec = world % NSEC_PER_SEC;
 319
 320         tdma_stop(serial_tdma_rcv);
 321
 322         test_xmt_enab  = 1;
 323         test_xmt_time0 = 0;
 324         test_xmt_time1 = 0;
 325
 326         tdma_start(serial_tdma_xmt);
 327         sirq_write(port, &head, sizeof(head));
 328         sirq_write(port, &body, sizeof(body));
 329         tdma_stop(serial_tdma_xmt);
 330
 331         // save transmit time
 332         //local = test_xmt_time1;
 333         int valid = tdma_stamp(serial_tdma_xmt, &local);
 334         if (!valid) {
 335                 sirq_printf("sync transmit time -- missed\r\n");
 336         } else {
 337                 //time_printf("sync transmit time ", local);
 338                 //time_printf("sync transmit test0", test_xmt_time0);
 339                 //time_printf("sync transmit test1", test_xmt_time1);
 340         }
 341
 342         tdma_start(serial_tdma_rcv);
 343
 344         serial_xmt_seq  += 1;
 345         serial_sync_due  = 0;
 346         serial_xmt_local = local;
 347 }
 348
 349 /**
 350  * Output external event received message
 351  *   event: id of the received event
 352  *   time:  compensated timestamp of the event
 353  */
 354 void serial_send_event(uint16_t event, uint64_t local)
 355 {
 356 //      uint64_t world = time_to_world(local);
 357
 358         // Message data
 359 #if 0
 360         header_t    head;
 361         event_msg_t body;
 362
 363         ntime_t time = {};
 364         time.seconds = (uint32_t)(world / NSEC_PER_SEC);
 365         time.nanosec = (uint32_t)(world % NSEC_PER_SEC);
 366
 367         sirq_printf("event received - %08x:%08x - %u.%09u\r\n",
 368                 (uint32_t)(local >> 32), (uint32_t)local,
 369                 time.seconds, time.nanosec);
 370
 371         // Transmit sync message
 372         head.header = MSG_HEADER;
 373         head.msgid  = MSG_ID_SYNC;
 374         head.length = sizeof(body);
 375         head.cksum  = 0; // todo
 376
 377         body.seq          = serial_xmt_seq;
 378         body.time.seconds = world / NSEC_PER_SEC;
 379         body.time.nanosec = world % NSEC_PER_SEC;
 380
 381         tdma_stop(serial_tdma_rcv);
 382
 383         test_xmt_enab  = 1;
 384         test_xmt_time0 = 0;
 385         test_xmt_time1 = 0;
 386
 387         tdma_start(serial_tdma_xmt);
 388         sirq_write(port, &head, sizeof(head));
 389         sirq_write(port, &body, sizeof(body));
 390         tdma_stop(serial_tdma_xmt);
 391 #endif
 392 }
 393
 394 /**
 395  * Handle init message
 396  */
 397 void serial_handle_init(init_msg_t *msg)
 398 {
 399         sirq_printf("initialize: %s %s %s %s %s\r\n",
 400                 msg->valid & MSG_VALID_DEVICE ? "DEV"    : "dev",
 401                 msg->valid & MSG_VALID_START  ? "START"  : "start",
 402                 msg->valid & MSG_VALID_PERIOD ? "PERIOD" : "period",
 403                 msg->valid & MSG_VALID_WORLD  ? "WORLD"  : "world",
 404                 msg->valid & MSG_VALID_SYNC   ? "SYNC"   : "sync");
 405         sirq_printf("  dev    -- %d\r\n", msg->device);
 406         time_printf("  start ", serial_read_time(msg->start));
 407         time_printf("  period", serial_read_time(msg->period));
 408         time_printf("  world ", serial_read_time(msg->world));
 409
 410         if (msg->valid & MSG_VALID_DEVICE)
 411                 serial_device_id = msg->device;
 412
 413         if (msg->valid & MSG_VALID_START ||
 414             msg->valid & MSG_VALID_PERIOD) {
 415                 uint64_t start  = serial_read_time(msg->start);
 416                 uint64_t period = serial_read_time(msg->period);
 417                 emit_enable(start, period);
 418         }
 419
 420         if (msg->valid & MSG_VALID_WORLD) {
 421                 uint64_t world = serial_read_time(msg->world);
 422                 uint64_t local = tdma_time();
 423                 time_ext_init(local, world);
 424         }
 425
 426         if (msg->valid & MSG_VALID_SYNC)
 427                 serial_sync_due = tdma_time() + serial_sync_delay;
 428 }
 429
 430 /**
 431  * Handle sync message
 432  */
 433 void serial_handle_sync(sync_msg_t *msg)
 434 {
 435         // Read receive timestamp for next time sync message
 436         uint64_t current = 0;
 437         int valid = tdma_stamp(serial_tdma_rcv, &current);
 438         if (!valid)
 439                 sirq_printf("sync receive time  -- missing\r\n");
 440         //else
 441         //      time_printf("sync receive time ", current);
 442         tdma_stop(serial_tdma_rcv);
 443
 444         // Lookup times
 445         uint64_t world = ((uint64_t)msg->time.seconds) * NSEC_PER_SEC
 446                        + ((uint64_t)msg->time.nanosec);
 447
 448         // Valid times timestamp
 449         if (serial_prev_seq == (msg->seq-1)) {
 450                 uint64_t local = serial_prev_local;
 451                 time_ext_sync(local, world);
 452         }
 453
 454         // Queue transmit to other board
 455         serial_sync_due   = tdma_time() + serial_sync_delay;
 456
 457         // Update states
 458         serial_prev_local = current;
 459         serial_prev_seq   = msg->seq;
 460 }
 461
 462 /**
 463  * Handle event message
 464  */
 465 void serial_handle_event(event_msg_t *msg)
 466 {
 467 }
 468
 469 /**
 470  * Deliver message
 471  */
 472 void serial_deliver(int msgid, void *body)
 473 {
 474         switch (msgid) {
 475                 case MSG_ID_INIT:
 476                         //sirq_printf("received init msg\r\n");
 477                         serial_handle_init((init_msg_t*)body);
 478                         break;
 479                 case MSG_ID_SYNC:
 480                         //sirq_printf("received sync msg\r\n");
 481                         serial_handle_sync((sync_msg_t*)body);
 482                         break;
 483                 case MSG_ID_EVENT:
 484                         //sirq_printf("received event msg\r\n");
 485                         serial_handle_event((event_msg_t*)body);
 486                         break;
 487         }
 488 }
 489
 490 /**
 491  * Process serial receive messages
 492  */
 493 void serial_receive(parser_t *parser, int byte)
 494 {
 495         //sirq_printf("serial_receive - %02x\r\n", byte);
 496
 497         // Lookup pointers
 498         header_t *head = (header_t*)parser->buffer;
 499         void     *body = (void*)(head+1);
 500         const int max_length = sizeof(parser->buffer)-sizeof(header_t);
 501
 502         // Process uart messages
 503         parser->buffer[parser->index++] = byte;
 504         switch (parser->state) {
 505                 case 0: // Search
 506                         if (parser->index == sizeof(uint16_t)) {
 507                                 if (head->header == MSG_HEADER) {
 508                                         parser->state = 1;
 509                                 } else {
 510                                         parser->buffer[0] = parser->buffer[1];
 511                                         parser->index = 1;
 512                                 }
 513                         }
 514                         break;
 515                 case 1: // Header
 516                         if (parser->index == sizeof(header_t)) {
 517                                 if (head->length <= max_length &&
 518                                     head->msgid  <= MSG_MAX_ID) {
 519                                         parser->state = 2;
 520                                 } else {
 521                                         parser->index = 0;
 522                                         parser->state = 0;
 523                                 }
 524                         }
 525                         break;
 526                 case 2: // Data
 527                         if (parser->index == (int)sizeof(header_t)+head->length) {
 528                                 serial_deliver(head->msgid, body);
 529                                 parser->index = 0;
 530                                 parser->state = 0;
 531                         }
 532                         break;
 533         }
 534 }
 535
 536 /********************
 537  * Data definitions *
 538  ********************/
 539
 540 // LEDs
 541 DigitalOut led1(LED1);
 542 DigitalOut led2(LED2);
 543
 544 // Message Parsers
 545 parser_t   parser_dbg;
 546 parser_t   parser_bbb;
 547 parser_t   parser_mbed;
 548
 549 // Serial IRQ
 550 sirq_t    *sirq_dbg;
 551 sirq_t    *sirq_bbb;
 552 sirq_t    *sirq_mbed;
 553
 554 // Timer DMA
 555 tdma_t    *tdma_evt;
 556 tdma_t    *tdma_rcv;
 557 tdma_t    *tdma_xmt;
 558
 559 /*********
 560  * Tasks *
 561  *********/
 562
 563 void task_serial(uint64_t local, uint64_t world)
 564 {
 565         while (sirq_ready(sirq_dbg)) {
 566                 //sirq_printf("serial recv - dbg\r\n");
 567                 serial_receive(&parser_dbg,  sirq_getc(sirq_dbg));
 568         }
 569
 570         while (sirq_ready(sirq_bbb)) {
 571                 //sirq_printf("serial recv - bbb\r\n");
 572                 serial_receive(&parser_bbb,  sirq_getc(sirq_bbb));
 573         }
 574
 575         while (sirq_ready(sirq_mbed)) {
 576                 //sirq_printf("serial recv - mbed\r\n");
 577                 serial_receive(&parser_mbed, sirq_getc(sirq_mbed));
 578         }
 579 }
 580
 581 void task_events(uint64_t local, uint64_t world)
 582 {
 583         uint64_t event = 0;
 584
 585 #ifdef VERBOSE
 586         if (tdma_stamp(tdma_evt, &event)) {
 587                 sirq_printf("event received - evt\r\n");
 588         if (tdma_stamp(tdma_rcv, &event))
 589                 sirq_printf("event received - rcv\r\n");
 590         if (tdma_stamp(tdma_xmt, &event))
 591                 sirq_printf("event received - xmt\r\n");
 592 #endif
 593
 594         if (tdma_stamp(tdma_evt, &event))
 595                 serial_send_event(0, event);
 596         tdma_stop(tdma_evt);
 597         tdma_start(tdma_evt);
 598 }
 599
 600 void task_sync(uint64_t local, uint64_t world)
 601 {
 602         serial_send_sync(sirq_mbed, local);
 603 }
 604
 605 void task_leds(uint64_t local, uint64_t world)
 606 {
 607         static uint32_t which = 0;
 608         led1 = (which == 0);
 609         led2 = (which == 1);
 610         which ^= 1;
 611 }
 612
 613 void task_emit(uint64_t local, uint64_t world)
 614 {
 615         emit_transmit();
 616 }
 617
 618 void task_debug(uint64_t local, uint64_t world)
 619 {
 620         //tdma_debug(tdma_rcv);
 621         //tdma_debug(tdma_xmt);
 622
 623         //sirq_debug(sirq_mbed);
 624
 625 #ifdef VERBOSE
 626         sirq_printf("background - %6u.%02u -> %u.%02u\r\n",
 627                         (uint32_t)(local / NSEC_PER_SEC),
 628                         (uint32_t)(local % NSEC_PER_SEC / 10000000),
 629                         (uint32_t)(world / NSEC_PER_SEC),
 630                         (uint32_t)(world % NSEC_PER_SEC / 10000000));
 631 #endif
 632 }
 633
 634 /********
 635  * Main *
 636  ********/
 637
 638 #define N_ELEM(x) (sizeof(x) / sizeof((x)[0]))
 639
 640 extern void test_main(void);
 641 extern serial_t stdio_uart;
 642
 643 static struct {
 644         void (*task)(uint64_t, uint64_t);
 645         uint64_t period;
 646         uint64_t due;
 647 } tasks[] = {
 648         { task_serial, 0          }, // always
 649         { task_events, 1000000000 }, // always -- testing
 650         { task_sync,   0          }, // always
 651         { task_emit,   0          }, // always
 652         { task_leds,   100000000  }, // 10hz
 653         { task_debug,  1000000000 }, // 1hz
 654 };
 655
 656 void background(void)
 657 {
 658         // Debugging
 659         uint64_t local = tdma_time();
 660         uint64_t world = time_to_world(local);
 661
 662         // Run the scheduler
 663         for (unsigned i = 0; i < N_ELEM(tasks); i++) {
 664                 if (local >= tasks[i].due) {
 665                         tasks[i].task(local, world);
 666                         tasks[i].due += tasks[i].period;
 667                 }
 668         }
 669 }
 670
 671 int main(int argc, char **argv)
 672 {
 673         tdma_init();
 674         emit_init(4, PTC1, PullDown);
 675
 676         // Open serial ports
 677         sirq_dbg   = sirq_open(SIRQ_UART0, USBTX, USBRX, 115200); // to pc
 678         sirq_bbb   = sirq_open(SIRQ_UART1, PTE0,  PTE1,  115200); // to bbb
 679         sirq_mbed  = sirq_open(SIRQ_UART2, PTD3,  PTD2,  115200); // to mbed
 680
 681         // Setup timers
 682         tdma_evt   = tdma_open(TDMA_CHAN0, 3, PTC9,  PullUp); // async event
 683
 684         // mbed time sync
 685         tdma_rcv   = tdma_open(TDMA_CHAN2, 3, PTD2,  PullUp);   // time sync rcv
 686         tdma_xmt   = tdma_open(TDMA_CHAN3, 3, PTD3,  PullUp);   // time sync xmt
 687
 688         // host time sync
 689         //tdma_rcv   = tdma_open(TDMA_CHAN2, 2, USBRX, PullUp); // time sync rcv
 690         //tdma_xmt   = tdma_open(TDMA_CHAN3, 2, USBTX, PullUp); // time sync xmt
 691
 692         // start timers
 693         tdma_start(tdma_evt);
 694         tdma_start(tdma_rcv);
 695         tdma_start(tdma_xmt);
 696
 697         // Serial timestamping
 698         serial_tdma_rcv = tdma_rcv;
 699         serial_tdma_xmt = tdma_xmt;
 700
 701         // Test clocks
 702         //MCG->C1    = 0x05; // was 0x1A
 703         //MCG->C2    = 0x2C; // was 0x24
 704         //MCG->C3    = 0x91; // was 0x91
 705         //MCG->C4    = 0x10; // was 0x10
 706         //MCG->C5    = 0x01; // was 0x01
 707         //MCG->C6    = 0x40; // was 0x40
 708         //MCG->S     = 0x6E; // was 0x6E
 709         //MCG->SC    = 0x02; // was 0x02
 710         //MCG->ATCVH = 0x00; // was 0x00
 711         //MCG->ATCVL = 0x00; // was 0x00
 712         //MCG->C7    = 0x00; // was 0x00
 713         //MCG->C8    = 0x80; // was 0x80
 714         //MCG->C9    = 0x00; // was 0x00
 715         //MCG->C10   = 0x00; // was 0x00
 716
 717         //sirq_printf("MGC - C1    %02hx\r\n", MCG->C1);     // 1A
 718         //sirq_printf("MGC - C2    %02hx\r\n", MCG->C2);     // 24
 719         //sirq_printf("MGC - C3    %02hx\r\n", MCG->C3);     // 91
 720         //sirq_printf("MGC - C4    %02hx\r\n", MCG->C4);     // 10
 721         //sirq_printf("MGC - C5    %02hx\r\n", MCG->C5);     // 01
 722         //sirq_printf("MGC - C6    %02hx\r\n", MCG->C6);     // 40
 723         //sirq_printf("MGC - S     %02hx\r\n", MCG->S);      // 6E
 724         //sirq_printf("MGC - SC    %02hx\r\n", MCG->SC);     // 02
 725         //sirq_printf("MGC - ATCVH %02hx\r\n", MCG->ATCVH);  // 00
 726         //sirq_printf("MGC - ATCVL %02hx\r\n", MCG->ATCVL);  // 00
 727         //sirq_printf("MGC - C7    %02hx\r\n", MCG->C7);     // 00
 728         //sirq_printf("MGC - C8    %02hx\r\n", MCG->C8);     // 80
 729         //sirq_printf("MGC - C9    %02hx\r\n", MCG->C9);     // 00
 730         //sirq_printf("MGC - C10   %02hx\r\n", MCG->C10);    // 00
 731
 732         // Run background loop
 733         printf("hello");
 734         while (true)
 735                 background();
 736
 737         // Run tests
 738         //test_main();
 739
 740         return 0;
 741 }