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