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  * Timer functions *
  25  *******************/
  26
  27 #define NSEC_PER_SEC 1000000000ULL
  28
  29 uint64_t time_last_local; // timestamp at last time sync
  30 uint64_t time_last_world; // offset at last time sync
  31
  32 /**
  33  * Generate time stamp for an async event:
  34  *   time:  drift compensated wall-clock time
  35  *   stamp: event timestamp from PIT Module
  36  */
  37 uint64_t time_to_world(uint64_t local)
  38 {
  39         uint64_t elapsed = local - time_last_local;
  40         return time_last_world + elapsed;
  41 }
  42
  43 /**
  44  * Synchronize the timer internal state with updates
  45  * from an external time sync message.
  46  *   local: our internal timestamp for the event
  47  *   world: reference timestamp from the other device
  48  */
  49 void time_ext_init(uint64_t local, uint64_t world)
  50 {
  51         sirq_printf("initialize clocks: %d -> %d\r\n",
  52                         (int)(local/NSEC_PER_SEC),
  53                         (int)(world/NSEC_PER_SEC));
  54
  55         time_last_local = local;
  56         time_last_world = world;
  57 }
  58
  59 /**
  60  * Synchronize the timer internal state with updates
  61  * from an external time sync message.
  62  *   local: our internal timestamp for the event
  63  *   world: reference timestamp from the other device
  64  */
  65 void time_ext_sync(uint64_t local, uint64_t world)
  66 {
  67         uint64_t guess = time_to_world(local);
  68
  69         time_last_local = local;
  70         time_last_world = (guess/2) + (world/2);
  71         //time_last_world = (guess * 3 / 4) + (world * 1 / 4);
  72         //time_last_world =
  73         //      (guess - (        guess / 2)) +
  74         //      (world - (world - world / 2));
  75         //time_last_world =
  76         //      (guess - (guess - guess / 4)) +
  77         //      (world - (        world / 4));
  78
  79         world = time_last_world;
  80
  81 //#ifdef VERBOSE
  82 #if 1
  83         uint64_t error = world > guess ? world - guess :
  84                          guess > world ? guess - world : 0;
  85         int      ahead = guess > world;
  86         sirq_printf("syncing clocks: %6d=%d.%04u -> %d.%04u (err: %s%ld.%09lu)\r\n",
  87                         (int)((local / NSEC_PER_SEC)),
  88                         (int)((guess / NSEC_PER_SEC)),
  89                         (int)((guess % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
  90                         (int)((world / NSEC_PER_SEC)),
  91                         (int)((world % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
  92                         ahead ? "-" : " ",
  93                         (int32_t )(error / (int64_t)NSEC_PER_SEC),
  94                         (uint32_t)(error % (int64_t)NSEC_PER_SEC));
  95 #endif
  96 //#endif
  97 }
  98
  99 void time_printf(const char *label, uint64_t local)
 100 {
 101         uint64_t world = time_to_world(local);
 102         sirq_printf("%s -- %d.%09u -> %d.%09u\r\n",
 103                         label,
 104                         (int)(local / NSEC_PER_SEC),
 105                         (int)(local % NSEC_PER_SEC),
 106                         (int)(world / NSEC_PER_SEC),
 107                         (int)(world % NSEC_PER_SEC));
 108 }
 109
 110 /*********************
 111  * Signal generation *
 112  *********************/
 113
 114 // for 24 Mhz clock, 24/1000 = 3/125
 115 // for 48 Mhz clock  48/1000 = 6/125
 116 // for 50 Mhz clock  50/1000 = 1/20  (FLL/2)
 117 #define EMIT_CLOCKS(nsec) ((uint16_t)((nsec)   / 20))
 118 #define EMIT_NSEC(clocks) ((uint16_t)((clocks) * 20))
 119
 120 static uint32_t *emit_pcr    = 0; // transmit pin name
 121
 122 static uint64_t  emit_start  = 0; // transmit start time (world time)
 123 static uint64_t  emit_period = 0; // transmit period
 124 static uint64_t  emit_due    = 0; // next transmit (world time)
 125
 126 static uint32_t  emit_slack  = 0; // how far ahead we need to schedule, in us
 127 static uint32_t  emit_worst  = 0; // worst-case latency in task table
 128
 129 void emit_init(int alt, PinName pin, PinMode mode)
 130 {
 131         // Find pin
 132         emit_pcr = (uint32_t*)(PORTA_BASE + pin);
 133
 134         // Enable clocks
 135         SIM->SCGC6            |= SIM_SCGC6_TPM1_MASK;
 136         SIM->SOPT2            |= SIM_SOPT2_TPMSRC(1);
 137
 138         // Debug print on SOPT2
 139         // -- mbed may set PLLFLL when configuring UART0
 140         sirq_printf("SOPT2: u0src=%d tpmsrc=%d %s %s clkos=%d %s\r\n",
 141                 (SIM->SOPT2 & SIM_SOPT2_UART0SRC_MASK)     >> SIM_SOPT2_UART0SRC_SHIFT,
 142                 (SIM->SOPT2 & SIM_SOPT2_TPMSRC_MASK)       >> SIM_SOPT2_TPMSRC_SHIFT,
 143                 (SIM->SOPT2 & SIM_SOPT2_UART0SRC_MASK)     ? "USBSRC" : "usbsrc",
 144                 (SIM->SOPT2 & SIM_SOPT2_PLLFLLSEL_MASK)    ? "PLL/2"  : "FLL",
 145                 (SIM->SOPT2 & SIM_SOPT2_CLKOUTSEL_MASK)    >> SIM_SOPT2_CLKOUTSEL_SHIFT,
 146                 (SIM->SOPT2 & SIM_SOPT2_RTCCLKOUTSEL_MASK) ? "RTCOS"  : "rtcos");
 147
 148         // Set pin mode
 149         emit_pcr[0]            = PORT_PCR_ISF_MASK
 150                                | PORT_PCR_MUX(alt)
 151                                | mode;
 152
 153         // Setup Timer/PWM Module
 154         TPM1->SC               = TPM_SC_TOF_MASK;
 155         TPM1->CNT              = TPM_CNT_COUNT(0);
 156         TPM1->MOD              = TPM_MOD_MOD(0xFFFF);
 157
 158         TPM1->CONTROLS[0].CnSC = TPM_CnSC_CHF_MASK    // clear flag
 159                                | TPM_CnSC_MSB_MASK    // set output highon match,
 160                                | TPM_CnSC_ELSB_MASK   // cleared on overflow
 161                                | TPM_CnSC_ELSA_MASK;  // ..
 162
 163         TPM1->STATUS           = TPM_STATUS_CH0F_MASK
 164                                | TPM_STATUS_TOF_MASK;
 165
 166         TPM1->CONF             = TPM_CONF_CSOO_MASK;
 167 }
 168
 169 void emit_enable(uint64_t start, uint64_t period)
 170 {
 171         const int slack_clocks = 0x8000; // tune based on emit_worst
 172
 173         emit_start  = start;
 174         emit_period = period;
 175         emit_due    = start + period;
 176
 177         // TODO - tune slack time
 178         // TODO - check clock power
 179         // TODO - TPM clock source
 180         emit_slack  = EMIT_NSEC(slack_clocks);
 181
 182         time_printf("emit scheduled", emit_due);
 183 }
 184
 185 void emit_schedule(uint64_t when)
 186 {
 187         uint64_t now    = time_to_world(tdma_time());
 188         uint64_t start  = when - now;     // transmit time
 189         uint64_t stop   = start + 100000; // 100 us pulse
 190
 191         // Disable timer
 192         TPM1->SC               = TPM_SC_TOF_MASK;
 193
 194         // Set transmit time
 195         TPM1->CONTROLS[0].CnV  = EMIT_CLOCKS(start);
 196         TPM1->MOD              = TPM_MOD_MOD(EMIT_CLOCKS(stop));
 197
 198         // Start the timer
 199         TPM1->SC               = TPM_SC_TOF_MASK
 200                                | TPM_SC_PS(0)
 201                                | TPM_SC_CMOD(1);
 202
 203         // Clock testing
 204         uint32_t test_tpm0 = TPM1->SC;
 205         uint32_t test_pit0 = PIT->CHANNEL[1].CVAL;
 206         for (int i = 0; i < 1000; i++)
 207                 asm("nop");
 208         uint32_t test_tpm1 = TPM1->SC;
 209         uint32_t test_pit1 = PIT->CHANNEL[1].CVAL;
 210         uint32_t test_tpm  = test_tpm0 - test_tpm0;
 211         uint32_t test_pit  = test_pit1 - test_pit0;
 212         sirq_printf("pit/tpm: tpm=%04hx/%04hx=%d pit=%08x/%08x=%d\r\n",
 213                         test_tpm0, test_tpm1, test_tpm,
 214                         test_pit0, test_pit1, test_pit);
 215
 216         // Debug output
 217         //sirq_printf("emitting event\r\n");
 218 }
 219
 220 void emit_transmit(uint64_t local, uint64_t world)
 221 {
 222         static uint64_t prev = 0;
 223
 224         // Record how how much time we have to reschedule
 225         if (prev && (local-prev) > emit_worst)
 226                 emit_worst = (local-prev);
 227         prev = local;
 228
 229         // Schedule task if needed
 230         if (emit_due && emit_period &&
 231             world+emit_slack > emit_due) {
 232                 emit_schedule(emit_due);
 233                 emit_due += emit_period;
 234         }
 235 }
 236
 237 /************************
 238  * Serial I/O functions *
 239  ************************/
 240
 241 typedef struct {
 242         int      index;
 243         int      state;
 244         uint8_t  buffer[256];
 245 } parser_t;
 246
 247 static uint32_t serial_device_id   = 0;
 248
 249 const  uint64_t serial_sync_delay  = NSEC_PER_SEC / 100;
 250 static uint64_t serial_sync_due    = 0;
 251
 252 static tdma_t  *serial_tdma_rcv    = NULL;
 253 static tdma_t  *serial_tdma_xmt    = NULL;
 254
 255 /**
 256  * Convert world to local time
 257  */
 258 uint64_t serial_read_time(ntime_t time)
 259 {
 260         return ((uint64_t)time.seconds) * NSEC_PER_SEC
 261              + ((uint64_t)time.nanosec);
 262 }
 263
 264 ntime_t serial_write_time(uint64_t time)
 265 {
 266         ntime_t buf = {};
 267         buf.seconds = time / NSEC_PER_SEC;
 268         buf.nanosec = time % NSEC_PER_SEC;
 269         return buf;
 270 }
 271
 272 int serial_time_stamp(tdma_t *port, uint64_t *local, uint64_t *world,
 273                 const char *msg)
 274 {
 275         int valid = tdma_stamp(port, local);
 276         *world = time_to_world(*local);
 277
 278         if (!valid)
 279                 sirq_printf("%s -- missing\r\n", msg);
 280         //else
 281         //      time_printf(msg, current);
 282
 283         return valid;
 284 }
 285
 286 /**
 287  * Output initialization message init message
 288  */
 289 void serial_send_init(uint16_t device, uint64_t local)
 290 {
 291 }
 292
 293 /**
 294  * Output time sync message
 295  */
 296 void serial_send_sync(sirq_t *port, uint64_t now)
 297 {
 298         if (serial_sync_due == 0 || now < serial_sync_due)
 299                 return; // not ready
 300
 301         // Message data
 302         header_t   head;
 303         sync_msg_t body;
 304
 305         // Write header
 306         head.header = MSG_HEADER;
 307         head.msgid  = MSG_ID_SYNC;
 308         head.length = sizeof(body);
 309         head.cksum  = 0; // todo
 310
 311         tdma_stop(serial_tdma_rcv, 0);
 312         tdma_start(serial_tdma_xmt);
 313
 314         sirq_write(port, &head, sizeof(head));
 315
 316         tdma_stop(serial_tdma_xmt, 100);
 317         tdma_start(serial_tdma_rcv);
 318
 319         // Save transmit time
 320         uint64_t local = 0, world = 0;
 321         serial_time_stamp(serial_tdma_xmt, &local, &world,
 322                         "sync time transmit");
 323
 324         // Debug output
 325         //sirq_printf("sync time transmit\r\n");
 326         //time_printf("  local", local);
 327         //time_printf("  world", world);
 328
 329         // Write body with updated time and send
 330         body.time = serial_write_time(world);
 331
 332         sirq_write(port, &body, sizeof(body));
 333
 334         // Queue next transmit time
 335         serial_sync_due  = 0;
 336 }
 337
 338 /**
 339  * Output external event received message
 340  *   event: id of the received event
 341  *   time:  compensated timestamp of the event
 342  */
 343 void serial_send_event(sirq_t *port, uint16_t event, uint64_t local)
 344 {
 345         time_printf("event received", local);
 346
 347         // Convert timestamp
 348         uint64_t world = time_to_world(local);
 349         ntime_t  ltime = serial_write_time(local);
 350         ntime_t  wtime = serial_write_time(world);
 351
 352         // Message data
 353         header_t    head = {};
 354         event_msg_t body = {};
 355
 356         // Transmit sync message
 357         head.header = MSG_HEADER;
 358         head.msgid  = MSG_ID_EVENT;
 359         head.length = sizeof(body);
 360         head.cksum  = 0; // todo
 361
 362         body.device = serial_device_id;
 363         body.event  = event;
 364         body.world  = wtime;
 365         body.local  = ltime;
 366
 367         // Transmit message to BBB
 368         sirq_write(port, &head, sizeof(head));
 369         sirq_write(port, &body, sizeof(body));
 370 }
 371
 372 /**
 373  * Handle init message
 374  */
 375 void serial_handle_init(init_msg_t *msg)
 376 {
 377         sirq_printf("initialize: %s %s %s %s %s\r\n",
 378                 msg->valid & MSG_VALID_DEVICE ? "DEV"    : "dev",
 379                 msg->valid & MSG_VALID_START  ? "START"  : "start",
 380                 msg->valid & MSG_VALID_PERIOD ? "PERIOD" : "period",
 381                 msg->valid & MSG_VALID_WORLD  ? "WORLD"  : "world",
 382                 msg->valid & MSG_VALID_SYNC   ? "SYNC"   : "sync");
 383         sirq_printf("  dev    -- %d\r\n", msg->device);
 384         time_printf("  start ", serial_read_time(msg->start));
 385         time_printf("  period", serial_read_time(msg->period));
 386         time_printf("  world ", serial_read_time(msg->world));
 387
 388         if (msg->valid & MSG_VALID_DEVICE)
 389                 serial_device_id = msg->device;
 390
 391         if (msg->valid & MSG_VALID_START ||
 392             msg->valid & MSG_VALID_PERIOD) {
 393                 uint64_t start  = serial_read_time(msg->start);
 394                 uint64_t period = serial_read_time(msg->period);
 395                 emit_enable(start, period);
 396         }
 397
 398         if (msg->valid & MSG_VALID_WORLD) {
 399                 uint64_t world = serial_read_time(msg->world);
 400                 uint64_t local = tdma_time();
 401                 time_ext_init(local, world);
 402         }
 403
 404         if (msg->valid & MSG_VALID_SYNC)
 405                 serial_sync_due = tdma_time() + serial_sync_delay;
 406 }
 407
 408 /**
 409  * Handle sync message
 410  */
 411 void serial_handle_sync(sync_msg_t *msg)
 412 {
 413         // Read receive timestamp
 414         uint64_t local = 0, world = 0;
 415         serial_time_stamp(serial_tdma_rcv, &local, &world,
 416                         "sync time receive ");
 417         tdma_stop(serial_tdma_rcv, 0);
 418
 419         // Lookup reference time from message
 420         uint64_t reference = serial_read_time(msg->time);
 421
 422         // Debug output
 423         //sirq_printf("sync time receive\r\n");
 424         //time_printf("  local", local);
 425         //time_printf("  world", world);
 426         //time_printf("  ref  ", reference);
 427
 428         // Synchronize the clocks
 429         time_ext_sync(local, reference);
 430
 431         // Queue transmit to other board
 432         serial_sync_due   = tdma_time() + serial_sync_delay;
 433 }
 434
 435 /**
 436  * Handle event message
 437  */
 438 void serial_handle_event(event_msg_t *msg)
 439 {
 440 }
 441
 442 /**
 443  * Deliver message
 444  */
 445 void serial_deliver(int msgid, void *body)
 446 {
 447         switch (msgid) {
 448                 case MSG_ID_INIT:
 449                         //sirq_printf("received init msg\r\n");
 450                         serial_handle_init((init_msg_t*)body);
 451                         break;
 452                 case MSG_ID_SYNC:
 453                         //sirq_printf("received sync msg\r\n");
 454                         serial_handle_sync((sync_msg_t*)body);
 455                         break;
 456                 case MSG_ID_EVENT:
 457                         //sirq_printf("received event msg\r\n");
 458                         serial_handle_event((event_msg_t*)body);
 459                         break;
 460         }
 461 }
 462
 463 /**
 464  * Process serial receive messages
 465  */
 466 void serial_receive(parser_t *parser, int byte)
 467 {
 468         //sirq_printf("serial_receive - %02x\r\n", byte);
 469
 470         // Lookup pointers
 471         header_t *head = (header_t*)parser->buffer;
 472         void     *body = (void*)(head+1);
 473         const int max_length = sizeof(parser->buffer)-sizeof(header_t);
 474
 475         // Process uart messages
 476         parser->buffer[parser->index++] = byte;
 477         switch (parser->state) {
 478                 case 0: // Search
 479                         if (parser->index == sizeof(uint16_t)) {
 480                                 if (head->header == MSG_HEADER) {
 481                                         parser->state = 1;
 482                                 } else {
 483                                         parser->buffer[0] = parser->buffer[1];
 484                                         parser->index = 1;
 485                                 }
 486                         }
 487                         break;
 488                 case 1: // Header
 489                         if (parser->index == sizeof(header_t)) {
 490                                 if (head->length <= max_length &&
 491                                     head->msgid  <= MSG_MAX_ID) {
 492                                         parser->state = 2;
 493                                 } else {
 494                                         parser->index = 0;
 495                                         parser->state = 0;
 496                                 }
 497                         }
 498                         break;
 499                 case 2: // Data
 500                         if (parser->index == (int)sizeof(header_t)+head->length) {
 501                                 serial_deliver(head->msgid, body);
 502                                 parser->index = 0;
 503                                 parser->state = 0;
 504                         }
 505                         break;
 506         }
 507 }
 508
 509 /********************
 510  * Data definitions *
 511  ********************/
 512
 513 // LEDs
 514 DigitalOut led1(LED1);
 515 DigitalOut led2(LED2);
 516
 517 // Message Parsers
 518 parser_t   parser_dbg;
 519 parser_t   parser_bbb;
 520 parser_t   parser_mbed;
 521
 522 // Serial IRQ
 523 sirq_t    *sirq_dbg;
 524 sirq_t    *sirq_bbb;
 525 sirq_t    *sirq_mbed;
 526
 527 // Timer DMA
 528 tdma_t    *tdma_evt;
 529 tdma_t    *tdma_rcv;
 530 tdma_t    *tdma_xmt;
 531
 532 /*********
 533  * Tasks *
 534  *********/
 535
 536 void task_serial(uint64_t local, uint64_t world)
 537 {
 538         while (sirq_ready(sirq_dbg)) {
 539                 //sirq_printf("serial recv - dbg\r\n");
 540                 serial_receive(&parser_dbg,  sirq_getc(sirq_dbg));
 541         }
 542
 543         while (sirq_ready(sirq_bbb)) {
 544                 //sirq_printf("serial recv - bbb\r\n");
 545                 serial_receive(&parser_bbb,  sirq_getc(sirq_bbb));
 546         }
 547
 548         while (sirq_ready(sirq_mbed)) {
 549                 //sirq_printf("serial recv - mbed\r\n");
 550                 serial_receive(&parser_mbed, sirq_getc(sirq_mbed));
 551         }
 552 }
 553
 554 void task_events(uint64_t local, uint64_t world)
 555 {
 556         uint64_t event = 0;
 557
 558 #ifdef VERBOSE
 559         if (tdma_stamp(tdma_evt, &event)) {
 560                 sirq_printf("event received - evt\r\n");
 561         if (tdma_stamp(tdma_rcv, &event))
 562                 sirq_printf("event received - rcv\r\n");
 563         if (tdma_stamp(tdma_xmt, &event))
 564                 sirq_printf("event received - xmt\r\n");
 565 #endif
 566
 567         if (tdma_stamp(tdma_evt, &event))
 568                 serial_send_event(sirq_bbb, 0, event);
 569         tdma_stop(tdma_evt, 0);
 570         tdma_start(tdma_evt);
 571 }
 572
 573 void task_sync(uint64_t local, uint64_t world)
 574 {
 575         serial_send_sync(sirq_mbed, local);
 576 }
 577
 578 void task_leds(uint64_t local, uint64_t world)
 579 {
 580         static uint32_t which = 0;
 581         led1 = (which == 0);
 582         led2 = (which == 1);
 583         which ^= 1;
 584 }
 585
 586 void task_emit(uint64_t local, uint64_t world)
 587 {
 588         emit_transmit(local, world);
 589 }
 590
 591 void task_debug(uint64_t local, uint64_t world)
 592 {
 593         //tdma_debug(tdma_rcv);
 594         //tdma_debug(tdma_xmt);
 595
 596         //sirq_debug(sirq_mbed);
 597
 598         serial_send_event(sirq_bbb, 1, local);
 599
 600 #ifdef VERBOSE
 601         sirq_printf("background - %6u.%02u -> %u.%02u\r\n",
 602                         (uint32_t)(local / NSEC_PER_SEC),
 603                         (uint32_t)(local % NSEC_PER_SEC / 10000000),
 604                         (uint32_t)(world / NSEC_PER_SEC),
 605                         (uint32_t)(world % NSEC_PER_SEC / 10000000));
 606 #endif
 607 }
 608
 609 /********
 610  * Main *
 611  ********/
 612
 613 #define N_ELEM(x) (sizeof(x) / sizeof((x)[0]))
 614
 615 extern void test_main(void);
 616 extern serial_t stdio_uart;
 617
 618 static struct {
 619         void (*task)(uint64_t, uint64_t);
 620         uint64_t period;
 621         uint64_t due;
 622 } tasks[] = {
 623         { task_serial, 0          }, // always
 624         { task_events, 0          }, // always -- testing
 625         { task_sync,   0          }, // always
 626         { task_emit,   0          }, // always
 627         { task_leds,   100000000  }, // 10hz
 628         { task_debug,  1000000000 }, // 1hz
 629 };
 630
 631 void background(void)
 632 {
 633         // Debugging
 634         uint64_t local = tdma_time();
 635         uint64_t world = time_to_world(local);
 636
 637         // Run the scheduler
 638         for (unsigned i = 0; i < N_ELEM(tasks); i++) {
 639                 if (local >= tasks[i].due) {
 640                         tasks[i].task(local, world);
 641                         tasks[i].due += tasks[i].period;
 642                 }
 643         }
 644 }
 645
 646 int main(int argc, char **argv)
 647 {
 648         tdma_init();
 649         emit_init(3, PTE20, PullDown);
 650
 651         //pin = 1;
 652
 653         // Open serial ports
 654         sirq_dbg   = sirq_open(SIRQ_UART0, USBTX, USBRX, 115200); // to pc
 655         sirq_bbb   = sirq_open(SIRQ_UART1, PTE0,  PTE1,  115200); // to bbb
 656         sirq_mbed  = sirq_open(SIRQ_UART2, PTD3,  PTD2,  115200); // to mbed
 657
 658         // Setup timers
 659         tdma_evt   = tdma_open(TDMA_CHAN0, 3, PTC9,  PullDown); // async event
 660
 661         // mbed time sync
 662         tdma_rcv   = tdma_open(TDMA_CHAN2, 3, PTD2,  PullUp);   // time sync rcv
 663         tdma_xmt   = tdma_open(TDMA_CHAN3, 3, PTD3,  PullUp);   // time sync xmt
 664
 665         // host time sync
 666         //tdma_rcv   = tdma_open(TDMA_CHAN2, 2, USBRX, PullUp); // time sync rcv
 667         //tdma_xmt   = tdma_open(TDMA_CHAN3, 2, USBTX, PullUp); // time sync xmt
 668
 669         // start timers
 670         tdma_start(tdma_evt);
 671         tdma_start(tdma_rcv);
 672         tdma_start(tdma_xmt);
 673
 674         // Serial timestamping
 675         serial_tdma_rcv = tdma_rcv;
 676         serial_tdma_xmt = tdma_xmt;
 677
 678         // configure crystal oscilator for high gain operation
 679         MCG->C2 |= MCG_C2_HGO0_MASK;
 680
 681         // Test clocks
 682         //MCG->C1    = 0x05; // was 0x1A
 683         //MCG->C2    = 0x2C; // was 0x24
 684         //MCG->C3    = 0x91; // was 0x91
 685         //MCG->C4    = 0x10; // was 0x10
 686         //MCG->C5    = 0x01; // was 0x01
 687         //MCG->C6    = 0x40; // was 0x40
 688         //MCG->S     = 0x6E; // was 0x6E
 689         //MCG->SC    = 0x02; // was 0x02
 690         //MCG->ATCVH = 0x00; // was 0x00
 691         //MCG->ATCVL = 0x00; // was 0x00
 692         //MCG->C7    = 0x00; // was 0x00
 693         //MCG->C8    = 0x80; // was 0x80
 694         //MCG->C9    = 0x00; // was 0x00
 695         //MCG->C10   = 0x00; // was 0x00
 696
 697         //sirq_printf("MGC - C1    %02hx\r\n", MCG->C1);     // 1A
 698         //sirq_printf("MGC - C2    %02hx\r\n", MCG->C2);     // 24
 699         //sirq_printf("MGC - C3    %02hx\r\n", MCG->C3);     // 91
 700         //sirq_printf("MGC - C4    %02hx\r\n", MCG->C4);     // 10
 701         //sirq_printf("MGC - C5    %02hx\r\n", MCG->C5);     // 01
 702         //sirq_printf("MGC - C6    %02hx\r\n", MCG->C6);     // 40
 703         //sirq_printf("MGC - S     %02hx\r\n", MCG->S);      // 6E
 704         //sirq_printf("MGC - SC    %02hx\r\n", MCG->SC);     // 02
 705         //sirq_printf("MGC - ATCVH %02hx\r\n", MCG->ATCVH);  // 00
 706         //sirq_printf("MGC - ATCVL %02hx\r\n", MCG->ATCVL);  // 00
 707         //sirq_printf("MGC - C7    %02hx\r\n", MCG->C7);     // 00
 708         //sirq_printf("MGC - C8    %02hx\r\n", MCG->C8);     // 80
 709         //sirq_printf("MGC - C9    %02hx\r\n", MCG->C9);     // 00
 710         //sirq_printf("MGC - C10   %02hx\r\n", MCG->C10);    // 00
 711
 712         // Run background loop
 713         while (true)
 714                 background();
 715
 716         // Performance testing
 717         //uint64_t prev = 0, due = 0;
 718         //uint64_t worst[10] = {};
 719         //int      count = 0;
 720         //while (true) {
 721         //      uint64_t local = tdma_time();
 722         //      if (prev && (local-prev) > worst[count])
 723         //              worst[count] = (local-prev);
 724         //      prev = local;
 725         //      if (local > due) {
 726         //              if (count == 5) {
 727         //                      static char str[] = "background background background\r\n";
 728         //                      sirq_write(sirq_dbg, str, sizeof(str));
 729         //              }
 730         //              if (count == 9) {
 731         //                      sirq_printf("background\r\n");
 732         //                      for (int i = 0; i < 10; i++) {
 733         //                              sirq_printf("  worst[%d] = 0.%09u\r\n",
 734         //                                              i, worst[i]);
 735         //                              worst[i] = 0;
 736         //                      }
 737         //              }
 738         //              due += NSEC_PER_SEC;
 739         //              count = (count + 1) % 10;
 740         //      }
 741         //}
 742
 743         // Run tests
 744         //test_main();
 745
 746         return 0;
 747 }