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  *   local: drift compensated wall-clock time
  35  *   world: nanoseconds in world time world
  36  *   valid: local timestamp at valid valid
  37  */
  38 //uint64_t time_to_local(uint64_t world, uint64_t valid)
  39 //{
  40 //      uint64_t now =
  41 //      local =  + (stamp);
  42 //}
  43
  44 /**
  45  * Generate time stamp for an async event:
  46  *   time:  drift compensated wall-clock time
  47  *   stamp: event timestamp from PIT Module
  48  */
  49 uint64_t time_to_world(uint64_t local)
  50 {
  51         uint64_t elapsed = local - time_last_local;
  52         return time_last_world + elapsed;
  53 }
  54
  55 /**
  56  * Compensate the Real-Time-Clock oscillator for
  57  * temperature and drift errors. Called at 1Hz and
  58  * synchronous to the RTC 1Hz output.
  59  */
  60 void time_rtc_comp(void)
  61 {
  62         // todo
  63 }
  64
  65 /**
  66  * Synchronize the timer internal state with updates
  67  * from an external time sync message.
  68  *   local: our internal timestamp for the event
  69  *   world: reference timestamp from the other device
  70  */
  71 void time_ext_init(uint64_t local, uint64_t world)
  72 {
  73         sirq_printf("initialize clocks: %d -> %d\r\n",
  74                         (int)(local/NSEC_PER_SEC),
  75                         (int)(world/NSEC_PER_SEC));
  76
  77         time_last_local = local;
  78         time_last_world = world;
  79 }
  80
  81 /**
  82  * Synchronize the timer internal state with updates
  83  * from an external time sync message.
  84  *   local: our internal timestamp for the event
  85  *   world: reference timestamp from the other device
  86  */
  87 void time_ext_sync(uint64_t local, uint64_t world)
  88 {
  89         uint64_t guess = time_to_world(local);
  90
  91         time_last_local = local;
  92         time_last_world = (guess/2) + (world/2);
  93         //time_last_world = (guess * 3 / 4) + (world * 1 / 4);
  94         //time_last_world =
  95         //      (guess - (        guess / 2)) +
  96         //      (world - (world - world / 2));
  97         //time_last_world =
  98         //      (guess - (guess - guess / 4)) +
  99         //      (world - (        world / 4));
 100
 101         world = time_last_world;
 102
 103 //#ifdef VERBOSE
 104 #if 1
 105         uint64_t error = world > guess ? world - guess :
 106                          guess > world ? guess - world : 0;
 107         int      ahead = guess > world;
 108         sirq_printf("syncing clocks: %6d=%d.%04u -> %d.%04u (err: %s%ld.%09lu)\r\n",
 109                         (int)((local / NSEC_PER_SEC)),
 110                         (int)((guess / NSEC_PER_SEC)),
 111                         (int)((guess % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 112                         (int)((world / NSEC_PER_SEC)),
 113                         (int)((world % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 114                         ahead ? "-" : " ",
 115                         (int32_t )(error / (int64_t)NSEC_PER_SEC),
 116                         (uint32_t)(error % (int64_t)NSEC_PER_SEC));
 117 #endif
 118 //#endif
 119 }
 120
 121 void time_printf(const char *label, uint64_t local)
 122 {
 123         uint64_t world = time_to_world(local);
 124         sirq_printf("%s -- %d.%09u -> %d.%09u\r\n",
 125                         label,
 126                         (int)(local / NSEC_PER_SEC),
 127                         (int)(local % NSEC_PER_SEC),
 128                         (int)(world / NSEC_PER_SEC),
 129                         (int)(world % NSEC_PER_SEC));
 130 }
 131
 132 /*********************
 133  * Signal generation *
 134  *********************/
 135
 136 static uint32_t *emit_pcr    = 0; // transmit pin name
 137
 138 static uint64_t  emit_start  = 0; // transmit start time (world time)
 139 static uint64_t  emit_period = 0; // transmit period
 140 static uint64_t  emit_due    = 0; // next transmit (world time)
 141
 142 static uint32_t  emit_slack  = 0; // how far ahead we need to schedule, in us
 143 static uint32_t  emit_worst  = 0; // worst-case latency in task table
 144
 145 void emit_init(int alt, PinName pin, PinMode mode)
 146 {
 147         // Find pin
 148         emit_pcr = (uint32_t*)(PORTA_BASE + pin);
 149
 150         // Enable clocks
 151         SIM->SCGC6            |= SIM_SCGC6_TPM0_MASK;
 152
 153         SIM->SOPT2            |= SIM_SOPT2_TPMSRC(1);
 154         SIM->SOPT4            |= SIM_SOPT4_TPM1CLKSEL_MASK;
 155
 156         // Set pin mode
 157         emit_pcr[0]            = PORT_PCR_ISF_MASK
 158                                | PORT_PCR_MUX(alt)
 159                                | mode;
 160
 161         // Setup Timer/PWM Module
 162         TPM0->SC               = TPM_SC_TOF_MASK
 163                                | TPM_SC_PS(1);        // 24 MHz clock ?
 164         TPM0->CNT              = TPM_CNT_COUNT(0);
 165         TPM0->MOD              = TPM_MOD_MOD(0xFFFF);
 166
 167         TPM0->CONTROLS[0].CnSC = TPM_CnSC_CHF_MASK    // clear flag
 168                                | TPM_CnSC_MSB_MASK    // pulse output on match
 169                                | TPM_CnSC_MSA_MASK    // ..
 170                                | TPM_CnSC_ELSA_MASK;  // pulse high
 171
 172         TPM0->CONTROLS[0].CnV  = 0xFFFF;              // time delay
 173
 174         TPM0->STATUS           = TPM_STATUS_CH0F_MASK
 175                                | TPM_STATUS_TOF_MASK;
 176
 177         TPM0->CONF             = TPM_CONF_CSOO_MASK;
 178 }
 179
 180 void emit_enable(uint64_t start, uint64_t period)
 181 {
 182         const int slack_tick = 0xC000; // tune based on emit_worst
 183
 184         emit_start  = start;
 185         emit_period = period;
 186         emit_due    = start + period;
 187
 188         emit_slack  = slack_tick * 1000 / 24;
 189
 190         time_printf("emit scheduled", emit_due);
 191 }
 192
 193 void emit_schedule(uint64_t when)
 194 {
 195         uint64_t now   = time_to_world(tdma_time());
 196         uint16_t delay = (uint16_t)(when-now);
 197
 198         // Clear pending flags
 199         //emit_pcr[0]           |= PORT_PCR_ISF_MASK
 200
 201         // Disable timer
 202         TPM0->SC               = TPM_SC_TOF_MASK;
 203
 204         // Set transmit time
 205         TPM0->CNT              = TPM_CNT_COUNT(0);
 206         TPM0->CONTROLS[0].CnV  = delay;
 207
 208         // Start the timer
 209         TPM0->SC               = TPM_SC_TOF_MASK
 210                                | TPM_SC_CMOD(1);
 211
 212         // Debug
 213         sirq_printf("emitting event\r\n");
 214 }
 215
 216 void emit_transmit(uint64_t local, uint64_t world)
 217 {
 218         static uint64_t prev = 0;
 219
 220         // Record how how much time we have to reschedule
 221         if (prev && (local-prev) > emit_worst)
 222                 emit_worst = (local-prev);
 223         prev = local;
 224
 225         // Schedule task if needed
 226         if (emit_due && emit_period &&
 227             world+emit_slack > emit_due) {
 228                 emit_schedule(emit_due);
 229                 emit_due += emit_period;
 230         }
 231 }
 232
 233 /************************
 234  * Serial I/O functions *
 235  ************************/
 236
 237 typedef struct {
 238         int      index;
 239         int      state;
 240         uint8_t  buffer[256];
 241 } parser_t;
 242
 243 static uint32_t serial_device_id   = 0;
 244
 245 const  uint64_t serial_sync_delay  = NSEC_PER_SEC / 100; // 1hz
 246 static uint64_t serial_sync_due    = 0;
 247
 248 static tdma_t  *serial_tdma_rcv    = NULL;
 249 static tdma_t  *serial_tdma_xmt    = NULL;
 250
 251 static uint64_t serial_prev_local  = 0;
 252 static uint64_t serial_prev_seq    = 0;
 253
 254 static uint64_t serial_xmt_local   = 0;
 255 static uint64_t serial_xmt_seq     = 0;
 256
 257 /**
 258  * Convert world to local time
 259  */
 260 uint64_t serial_read_time(ntime_t time)
 261 {
 262         return ((uint64_t)time.seconds) * NSEC_PER_SEC
 263              + ((uint64_t)time.nanosec);
 264 }
 265
 266 ntime_t serial_write_time(uint64_t time)
 267 {
 268         ntime_t buf = {};
 269         buf.seconds = time / NSEC_PER_SEC;
 270         buf.nanosec = time % NSEC_PER_SEC;
 271         return buf;
 272 }
 273
 274 /**
 275  * Output initialization message init message
 276  */
 277 void serial_send_init(uint16_t device, uint64_t local)
 278 {
 279 }
 280
 281 /**
 282  * Output time sync message
 283  */
 284 void serial_send_sync(sirq_t *port, uint64_t now)
 285 {
 286         if (serial_sync_due == 0 || now < serial_sync_due)
 287                 return; // not ready
 288
 289         //sirq_printf("sending sync\r\n");
 290
 291         // Calculate world time
 292         uint64_t local = 0;
 293         uint64_t world = time_to_world(serial_xmt_local);
 294
 295         // Message data
 296         header_t   head;
 297         sync_msg_t body;
 298
 299         // Transmit sync message
 300         head.header = MSG_HEADER;
 301         head.msgid  = MSG_ID_SYNC;
 302         head.length = sizeof(body);
 303         head.cksum  = 0; // todo
 304
 305         body.seq          = serial_xmt_seq;
 306         body.time.seconds = world / NSEC_PER_SEC;
 307         body.time.nanosec = world % NSEC_PER_SEC;
 308
 309         tdma_stop(serial_tdma_rcv);
 310
 311         tdma_start(serial_tdma_xmt);
 312         sirq_write(port, &head, sizeof(head));
 313         sirq_write(port, &body, sizeof(body));
 314         tdma_stop(serial_tdma_xmt);
 315
 316         // save transmit time
 317         int valid = tdma_stamp(serial_tdma_xmt, &local);
 318         if (!valid)
 319                 sirq_printf("sync transmit time -- missed\r\n");
 320         else
 321                 //time_printf("sync transmit time ", local);
 322
 323         tdma_start(serial_tdma_rcv);
 324
 325         serial_xmt_seq  += 1;
 326         serial_sync_due  = 0;
 327         serial_xmt_local = local;
 328 }
 329
 330 /**
 331  * Output external event received message
 332  *   event: id of the received event
 333  *   time:  compensated timestamp of the event
 334  */
 335 void serial_send_event(uint16_t event, uint64_t local)
 336 {
 337 //      uint64_t world = time_to_world(local);
 338
 339         // Message data
 340 #if 0
 341         header_t    head;
 342         event_msg_t body;
 343
 344         ntime_t time = {};
 345         time.seconds = (uint32_t)(world / NSEC_PER_SEC);
 346         time.nanosec = (uint32_t)(world % NSEC_PER_SEC);
 347
 348         sirq_printf("event received - %08x:%08x - %u.%09u\r\n",
 349                 (uint32_t)(local >> 32), (uint32_t)local,
 350                 time.seconds, time.nanosec);
 351
 352         // Transmit sync message
 353         head.header = MSG_HEADER;
 354         head.msgid  = MSG_ID_SYNC;
 355         head.length = sizeof(body);
 356         head.cksum  = 0; // todo
 357
 358         body.seq          = serial_xmt_seq;
 359         body.time.seconds = world / NSEC_PER_SEC;
 360         body.time.nanosec = world % NSEC_PER_SEC;
 361
 362         tdma_stop(serial_tdma_rcv);
 363
 364         tdma_start(serial_tdma_xmt);
 365         sirq_write(port, &head, sizeof(head));
 366         sirq_write(port, &body, sizeof(body));
 367         tdma_stop(serial_tdma_xmt);
 368 #endif
 369 }
 370
 371 /**
 372  * Handle init message
 373  */
 374 void serial_handle_init(init_msg_t *msg)
 375 {
 376         sirq_printf("initialize: %s %s %s %s %s\r\n",
 377                 msg->valid & MSG_VALID_DEVICE ? "DEV"    : "dev",
 378                 msg->valid & MSG_VALID_START  ? "START"  : "start",
 379                 msg->valid & MSG_VALID_PERIOD ? "PERIOD" : "period",
 380                 msg->valid & MSG_VALID_WORLD  ? "WORLD"  : "world",
 381                 msg->valid & MSG_VALID_SYNC   ? "SYNC"   : "sync");
 382         sirq_printf("  dev    -- %d\r\n", msg->device);
 383         time_printf("  start ", serial_read_time(msg->start));
 384         time_printf("  period", serial_read_time(msg->period));
 385         time_printf("  world ", serial_read_time(msg->world));
 386
 387         if (msg->valid & MSG_VALID_DEVICE)
 388                 serial_device_id = msg->device;
 389
 390         if (msg->valid & MSG_VALID_START ||
 391             msg->valid & MSG_VALID_PERIOD) {
 392                 uint64_t start  = serial_read_time(msg->start);
 393                 uint64_t period = serial_read_time(msg->period);
 394                 emit_enable(start, period);
 395         }
 396
 397         if (msg->valid & MSG_VALID_WORLD) {
 398                 uint64_t world = serial_read_time(msg->world);
 399                 uint64_t local = tdma_time();
 400                 time_ext_init(local, world);
 401         }
 402
 403         if (msg->valid & MSG_VALID_SYNC)
 404                 serial_sync_due = tdma_time() + serial_sync_delay;
 405 }
 406
 407 /**
 408  * Handle sync message
 409  */
 410 void serial_handle_sync(sync_msg_t *msg)
 411 {
 412         // Read receive timestamp for next time sync message
 413         uint64_t current = 0;
 414         int valid = tdma_stamp(serial_tdma_rcv, &current);
 415         if (!valid)
 416                 sirq_printf("sync receive time  -- missing\r\n");
 417         //else
 418         //      time_printf("sync receive time ", current);
 419         tdma_stop(serial_tdma_rcv);
 420
 421         // Lookup times
 422         uint64_t world = ((uint64_t)msg->time.seconds) * NSEC_PER_SEC
 423                        + ((uint64_t)msg->time.nanosec);
 424
 425         // Valid times timestamp
 426         if (serial_prev_seq == (msg->seq-1)) {
 427                 uint64_t local = serial_prev_local;
 428                 time_ext_sync(local, world);
 429         }
 430
 431         // Queue transmit to other board
 432         serial_sync_due   = tdma_time() + serial_sync_delay;
 433
 434         // Update states
 435         serial_prev_local = current;
 436         serial_prev_seq   = msg->seq;
 437 }
 438
 439 /**
 440  * Handle event message
 441  */
 442 void serial_handle_event(event_msg_t *msg)
 443 {
 444 }
 445
 446 /**
 447  * Deliver message
 448  */
 449 void serial_deliver(int msgid, void *body)
 450 {
 451         switch (msgid) {
 452                 case MSG_ID_INIT:
 453                         //sirq_printf("received init msg\r\n");
 454                         serial_handle_init((init_msg_t*)body);
 455                         break;
 456                 case MSG_ID_SYNC:
 457                         //sirq_printf("received sync msg\r\n");
 458                         serial_handle_sync((sync_msg_t*)body);
 459                         break;
 460                 case MSG_ID_EVENT:
 461                         //sirq_printf("received event msg\r\n");
 462                         serial_handle_event((event_msg_t*)body);
 463                         break;
 464         }
 465 }
 466
 467 /**
 468  * Process serial receive messages
 469  */
 470 void serial_receive(parser_t *parser, int byte)
 471 {
 472         //sirq_printf("serial_receive - %02x\r\n", byte);
 473
 474         // Lookup pointers
 475         header_t *head = (header_t*)parser->buffer;
 476         void     *body = (void*)(head+1);
 477         const int max_length = sizeof(parser->buffer)-sizeof(header_t);
 478
 479         // Process uart messages
 480         parser->buffer[parser->index++] = byte;
 481         switch (parser->state) {
 482                 case 0: // Search
 483                         if (parser->index == sizeof(uint16_t)) {
 484                                 if (head->header == MSG_HEADER) {
 485                                         parser->state = 1;
 486                                 } else {
 487                                         parser->buffer[0] = parser->buffer[1];
 488                                         parser->index = 1;
 489                                 }
 490                         }
 491                         break;
 492                 case 1: // Header
 493                         if (parser->index == sizeof(header_t)) {
 494                                 if (head->length <= max_length &&
 495                                     head->msgid  <= MSG_MAX_ID) {
 496                                         parser->state = 2;
 497                                 } else {
 498                                         parser->index = 0;
 499                                         parser->state = 0;
 500                                 }
 501                         }
 502                         break;
 503                 case 2: // Data
 504                         if (parser->index == (int)sizeof(header_t)+head->length) {
 505                                 serial_deliver(head->msgid, body);
 506                                 parser->index = 0;
 507                                 parser->state = 0;
 508                         }
 509                         break;
 510         }
 511 }
 512
 513 /********************
 514  * Data definitions *
 515  ********************/
 516
 517 // LEDs
 518 DigitalOut led1(LED1);
 519 DigitalOut led2(LED2);
 520
 521 // Message Parsers
 522 parser_t   parser_dbg;
 523 parser_t   parser_bbb;
 524 parser_t   parser_mbed;
 525
 526 // Serial IRQ
 527 sirq_t    *sirq_dbg;
 528 sirq_t    *sirq_bbb;
 529 sirq_t    *sirq_mbed;
 530
 531 // Timer DMA
 532 tdma_t    *tdma_evt;
 533 tdma_t    *tdma_rcv;
 534 tdma_t    *tdma_xmt;
 535
 536 /*********
 537  * Tasks *
 538  *********/
 539
 540 void task_serial(uint64_t local, uint64_t world)
 541 {
 542         while (sirq_ready(sirq_dbg)) {
 543                 //sirq_printf("serial recv - dbg\r\n");
 544                 serial_receive(&parser_dbg,  sirq_getc(sirq_dbg));
 545         }
 546
 547         while (sirq_ready(sirq_bbb)) {
 548                 //sirq_printf("serial recv - bbb\r\n");
 549                 serial_receive(&parser_bbb,  sirq_getc(sirq_bbb));
 550         }
 551
 552         while (sirq_ready(sirq_mbed)) {
 553                 //sirq_printf("serial recv - mbed\r\n");
 554                 serial_receive(&parser_mbed, sirq_getc(sirq_mbed));
 555         }
 556 }
 557
 558 void task_events(uint64_t local, uint64_t world)
 559 {
 560         uint64_t event = 0;
 561
 562 #ifdef VERBOSE
 563         if (tdma_stamp(tdma_evt, &event)) {
 564                 sirq_printf("event received - evt\r\n");
 565         if (tdma_stamp(tdma_rcv, &event))
 566                 sirq_printf("event received - rcv\r\n");
 567         if (tdma_stamp(tdma_xmt, &event))
 568                 sirq_printf("event received - xmt\r\n");
 569 #endif
 570
 571         if (tdma_stamp(tdma_evt, &event))
 572                 serial_send_event(0, event);
 573         tdma_stop(tdma_evt);
 574         tdma_start(tdma_evt);
 575 }
 576
 577 void task_sync(uint64_t local, uint64_t world)
 578 {
 579         serial_send_sync(sirq_mbed, local);
 580 }
 581
 582 void task_leds(uint64_t local, uint64_t world)
 583 {
 584         static uint32_t which = 0;
 585         led1 = (which == 0);
 586         led2 = (which == 1);
 587         which ^= 1;
 588 }
 589
 590 void task_emit(uint64_t local, uint64_t world)
 591 {
 592         emit_transmit(local, world);
 593 }
 594
 595 void task_debug(uint64_t local, uint64_t world)
 596 {
 597         //tdma_debug(tdma_rcv);
 598         //tdma_debug(tdma_xmt);
 599
 600         //sirq_debug(sirq_mbed);
 601
 602 #ifdef VERBOSE
 603         sirq_printf("background - %6u.%02u -> %u.%02u\r\n",
 604                         (uint32_t)(local / NSEC_PER_SEC),
 605                         (uint32_t)(local % NSEC_PER_SEC / 10000000),
 606                         (uint32_t)(world / NSEC_PER_SEC),
 607                         (uint32_t)(world % NSEC_PER_SEC / 10000000));
 608 #endif
 609 }
 610
 611 /********
 612  * Main *
 613  ********/
 614
 615 #define N_ELEM(x) (sizeof(x) / sizeof((x)[0]))
 616
 617 extern void test_main(void);
 618 extern serial_t stdio_uart;
 619
 620 static struct {
 621         void (*task)(uint64_t, uint64_t);
 622         uint64_t period;
 623         uint64_t due;
 624 } tasks[] = {
 625         { task_serial, 0          }, // always
 626         { task_events, 1000000000 }, // always -- testing
 627         { task_sync,   0          }, // always
 628         { task_emit,   0          }, // always
 629         { task_leds,   100000000  }, // 10hz
 630         { task_debug,  1000000000 }, // 1hz
 631 };
 632
 633 void background(void)
 634 {
 635         // Debugging
 636         uint64_t local = tdma_time();
 637         uint64_t world = time_to_world(local);
 638
 639         // Run the scheduler
 640         for (unsigned i = 0; i < N_ELEM(tasks); i++) {
 641                 if (local >= tasks[i].due) {
 642                         tasks[i].task(local, world);
 643                         tasks[i].due += tasks[i].period;
 644                 }
 645         }
 646 }
 647
 648 int main(int argc, char **argv)
 649 {
 650         tdma_init();
 651         emit_init(4, PTC1, PullDown);
 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,  PullUp); // 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         // Test clocks
 679         //MCG->C1    = 0x05; // was 0x1A
 680         //MCG->C2    = 0x2C; // was 0x24
 681         //MCG->C3    = 0x91; // was 0x91
 682         //MCG->C4    = 0x10; // was 0x10
 683         //MCG->C5    = 0x01; // was 0x01
 684         //MCG->C6    = 0x40; // was 0x40
 685         //MCG->S     = 0x6E; // was 0x6E
 686         //MCG->SC    = 0x02; // was 0x02
 687         //MCG->ATCVH = 0x00; // was 0x00
 688         //MCG->ATCVL = 0x00; // was 0x00
 689         //MCG->C7    = 0x00; // was 0x00
 690         //MCG->C8    = 0x80; // was 0x80
 691         //MCG->C9    = 0x00; // was 0x00
 692         //MCG->C10   = 0x00; // was 0x00
 693
 694         //sirq_printf("MGC - C1    %02hx\r\n", MCG->C1);     // 1A
 695         //sirq_printf("MGC - C2    %02hx\r\n", MCG->C2);     // 24
 696         //sirq_printf("MGC - C3    %02hx\r\n", MCG->C3);     // 91
 697         //sirq_printf("MGC - C4    %02hx\r\n", MCG->C4);     // 10
 698         //sirq_printf("MGC - C5    %02hx\r\n", MCG->C5);     // 01
 699         //sirq_printf("MGC - C6    %02hx\r\n", MCG->C6);     // 40
 700         //sirq_printf("MGC - S     %02hx\r\n", MCG->S);      // 6E
 701         //sirq_printf("MGC - SC    %02hx\r\n", MCG->SC);     // 02
 702         //sirq_printf("MGC - ATCVH %02hx\r\n", MCG->ATCVH);  // 00
 703         //sirq_printf("MGC - ATCVL %02hx\r\n", MCG->ATCVL);  // 00
 704         //sirq_printf("MGC - C7    %02hx\r\n", MCG->C7);     // 00
 705         //sirq_printf("MGC - C8    %02hx\r\n", MCG->C8);     // 80
 706         //sirq_printf("MGC - C9    %02hx\r\n", MCG->C9);     // 00
 707         //sirq_printf("MGC - C10   %02hx\r\n", MCG->C10);    // 00
 708
 709         // Run background loop
 710         while (true)
 711                 background();
 712
 713         // Performance testing
 714         //uint64_t prev = 0, due = 0;
 715         //uint64_t worst[10] = {};
 716         //int      count = 0;
 717         //while (true) {
 718         //      uint64_t local = tdma_time();
 719         //      if (prev && (local-prev) > worst[count])
 720         //              worst[count] = (local-prev);
 721         //      prev = local;
 722         //      if (local > due) {
 723         //              if (count == 5) {
 724         //                      static char str[] = "background background background\r\n";
 725         //                      sirq_write(sirq_dbg, str, sizeof(str));
 726         //              }
 727         //              if (count == 9) {
 728         //                      sirq_printf("background\r\n");
 729         //                      for (int i = 0; i < 10; i++) {
 730         //                              sirq_printf("  worst[%d] = 0.%09u\r\n",
 731         //                                              i, worst[i]);
 732         //                              worst[i] = 0;
 733         //                      }
 734         //              }
 735         //              due += NSEC_PER_SEC;
 736         //              count = (count + 1) % 10;
 737         //      }
 738         //}
 739
 740         // Run tests
 741         //test_main();
 742
 743         return 0;
 744 }