4 #include "serial_irq.h"
5 #include "serial_dma.h"
10 * Devices 1 and 2 synchronize clocks using serial messages.
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
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.
20 * Time synchronization is performed in both directions.
27 #define NSEC_PER_SEC 1000000000ULL
29 uint64_t time_last_local; // timestamp at last time sync
30 uint64_t time_last_world; // offset at last time sync
33 * Generate time stamp for an async event:
34 * time: drift compensated wall-clock time
35 * stamp: event timestamp from PIT Module
37 uint64_t time_to_world(uint64_t local)
39 uint64_t elapsed = local - time_last_local;
40 return time_last_world + elapsed;
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
49 void time_ext_init(uint64_t local, uint64_t world)
51 sirq_printf("initialize clocks: %d -> %d\r\n",
52 (int)(local/NSEC_PER_SEC),
53 (int)(world/NSEC_PER_SEC));
55 time_last_local = local;
56 time_last_world = world;
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
65 void time_ext_sync(uint64_t local, uint64_t world)
67 uint64_t guess = time_to_world(local);
69 time_last_local = local;
70 time_last_world = (guess/2) + (world/2);
71 //time_last_world = (guess * 3 / 4) + (world * 1 / 4);
73 // (guess - ( guess / 2)) +
74 // (world - (world - world / 2));
76 // (guess - (guess - guess / 4)) +
77 // (world - ( world / 4));
79 world = time_last_world;
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)),
93 (int32_t )(error / (int64_t)NSEC_PER_SEC),
94 (uint32_t)(error % (int64_t)NSEC_PER_SEC));
99 void time_printf(const char *label, uint64_t local)
101 uint64_t world = time_to_world(local);
102 sirq_printf("%s -- %d.%09u -> %d.%09u\r\n",
104 (int)(local / NSEC_PER_SEC),
105 (int)(local % NSEC_PER_SEC),
106 (int)(world / NSEC_PER_SEC),
107 (int)(world % NSEC_PER_SEC));
110 /*********************
111 * Signal generation *
112 *********************/
114 #define EMIT_CLOCKS(nsec) ((uint16_t)((nsec) * 24 / 1000))
115 #define EMIT_NSEC(clocks) ((uint16_t)((clocks) * 1000 / 24))
117 static uint32_t *emit_pcr = 0; // transmit pin name
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)
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
126 void emit_init(int alt, PinName pin, PinMode mode)
129 emit_pcr = (uint32_t*)(PORTA_BASE + pin);
132 SIM->SCGC6 |= SIM_SCGC6_TPM1_MASK;
133 SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1);
136 emit_pcr[0] = PORT_PCR_ISF_MASK
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);
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; // ..
150 TPM1->STATUS = TPM_STATUS_CH0F_MASK
151 | TPM_STATUS_TOF_MASK;
153 TPM1->CONF = TPM_CONF_CSOO_MASK;
156 void emit_enable(uint64_t start, uint64_t period)
158 const int slack_clocks = 0x8000; // tune based on emit_worst
161 emit_period = period;
162 emit_due = start + period;
164 // TODO - tune slack time
165 // TODO - check clock power
166 // TODO - TPM clock source
167 emit_slack = EMIT_NSEC(slack_clocks);
169 time_printf("emit scheduled", emit_due);
172 void emit_schedule(uint64_t when)
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
179 TPM1->SC = TPM_SC_TOF_MASK;
182 TPM1->CONTROLS[0].CnV = EMIT_CLOCKS(start);
183 TPM1->MOD = TPM_MOD_MOD(EMIT_CLOCKS(stop));
186 TPM1->SC = TPM_SC_TOF_MASK
191 //sirq_printf("emitting event\r\n");
194 void emit_transmit(uint64_t local, uint64_t world)
196 static uint64_t prev = 0;
198 // Record how how much time we have to reschedule
199 if (prev && (local-prev) > emit_worst)
200 emit_worst = (local-prev);
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;
211 /************************
212 * Serial I/O functions *
213 ************************/
221 static uint32_t serial_device_id = 0;
223 const uint64_t serial_sync_delay = NSEC_PER_SEC / 100; // 1hz
224 static uint64_t serial_sync_due = 0;
226 static tdma_t *serial_tdma_rcv = NULL;
227 static tdma_t *serial_tdma_xmt = NULL;
229 static uint64_t serial_prev_local = 0;
230 static uint64_t serial_prev_seq = 0;
232 static uint64_t serial_xmt_local = 0;
233 static uint64_t serial_xmt_seq = 0;
236 * Convert world to local time
238 uint64_t serial_read_time(ntime_t time)
240 return ((uint64_t)time.seconds) * NSEC_PER_SEC
241 + ((uint64_t)time.nanosec);
244 ntime_t serial_write_time(uint64_t time)
247 buf.seconds = time / NSEC_PER_SEC;
248 buf.nanosec = time % NSEC_PER_SEC;
253 * Output initialization message init message
255 void serial_send_init(uint16_t device, uint64_t local)
260 * Output time sync message
262 void serial_send_sync(sirq_t *port, uint64_t now)
264 if (serial_sync_due == 0 || now < serial_sync_due)
267 //sirq_printf("sending sync\r\n");
269 // Calculate world time
271 uint64_t world = time_to_world(serial_xmt_local);
277 // Transmit sync message
278 head.header = MSG_HEADER;
279 head.msgid = MSG_ID_SYNC;
280 head.length = sizeof(body);
281 head.cksum = 0; // todo
283 body.seq = serial_xmt_seq;
284 body.time.seconds = world / NSEC_PER_SEC;
285 body.time.nanosec = world % NSEC_PER_SEC;
287 tdma_stop(serial_tdma_rcv);
289 tdma_start(serial_tdma_xmt);
290 sirq_write(port, &head, sizeof(head));
291 sirq_write(port, &body, sizeof(body));
292 tdma_stop(serial_tdma_xmt);
294 // save transmit time
295 int valid = tdma_stamp(serial_tdma_xmt, &local);
297 sirq_printf("sync transmit time -- missed\r\n");
299 //time_printf("sync transmit time ", local);
301 tdma_start(serial_tdma_rcv);
305 serial_xmt_local = local;
309 * Output external event received message
310 * event: id of the received event
311 * time: compensated timestamp of the event
313 void serial_send_event(sirq_t *port, uint16_t event, uint64_t local)
315 time_printf("event received", local);
318 uint64_t world = time_to_world(local);
319 ntime_t ltime = serial_write_time(local);
320 ntime_t wtime = serial_write_time(world);
324 event_msg_t body = {};
326 // Transmit sync message
327 head.header = MSG_HEADER;
328 head.msgid = MSG_ID_EVENT;
329 head.length = sizeof(body);
330 head.cksum = 0; // todo
332 body.device = serial_device_id;
337 // Transmit message to BBB
338 sirq_write(port, &head, sizeof(head));
339 sirq_write(port, &body, sizeof(body));
343 * Handle init message
345 void serial_handle_init(init_msg_t *msg)
347 sirq_printf("initialize: %s %s %s %s %s\r\n",
348 msg->valid & MSG_VALID_DEVICE ? "DEV" : "dev",
349 msg->valid & MSG_VALID_START ? "START" : "start",
350 msg->valid & MSG_VALID_PERIOD ? "PERIOD" : "period",
351 msg->valid & MSG_VALID_WORLD ? "WORLD" : "world",
352 msg->valid & MSG_VALID_SYNC ? "SYNC" : "sync");
353 sirq_printf(" dev -- %d\r\n", msg->device);
354 time_printf(" start ", serial_read_time(msg->start));
355 time_printf(" period", serial_read_time(msg->period));
356 time_printf(" world ", serial_read_time(msg->world));
358 if (msg->valid & MSG_VALID_DEVICE)
359 serial_device_id = msg->device;
361 if (msg->valid & MSG_VALID_START ||
362 msg->valid & MSG_VALID_PERIOD) {
363 uint64_t start = serial_read_time(msg->start);
364 uint64_t period = serial_read_time(msg->period);
365 emit_enable(start, period);
368 if (msg->valid & MSG_VALID_WORLD) {
369 uint64_t world = serial_read_time(msg->world);
370 uint64_t local = tdma_time();
371 time_ext_init(local, world);
374 if (msg->valid & MSG_VALID_SYNC)
375 serial_sync_due = tdma_time() + serial_sync_delay;
379 * Handle sync message
381 void serial_handle_sync(sync_msg_t *msg)
383 // Read receive timestamp for next time sync message
384 uint64_t current = 0;
385 int valid = tdma_stamp(serial_tdma_rcv, ¤t);
387 sirq_printf("sync receive time -- missing\r\n");
389 // time_printf("sync receive time ", current);
390 tdma_stop(serial_tdma_rcv);
393 uint64_t world = ((uint64_t)msg->time.seconds) * NSEC_PER_SEC
394 + ((uint64_t)msg->time.nanosec);
396 // Valid times timestamp
397 if (serial_prev_seq == (msg->seq-1)) {
398 uint64_t local = serial_prev_local;
399 time_ext_sync(local, world);
402 // Queue transmit to other board
403 serial_sync_due = tdma_time() + serial_sync_delay;
406 serial_prev_local = current;
407 serial_prev_seq = msg->seq;
411 * Handle event message
413 void serial_handle_event(event_msg_t *msg)
420 void serial_deliver(int msgid, void *body)
424 //sirq_printf("received init msg\r\n");
425 serial_handle_init((init_msg_t*)body);
428 //sirq_printf("received sync msg\r\n");
429 serial_handle_sync((sync_msg_t*)body);
432 //sirq_printf("received event msg\r\n");
433 serial_handle_event((event_msg_t*)body);
439 * Process serial receive messages
441 void serial_receive(parser_t *parser, int byte)
443 //sirq_printf("serial_receive - %02x\r\n", byte);
446 header_t *head = (header_t*)parser->buffer;
447 void *body = (void*)(head+1);
448 const int max_length = sizeof(parser->buffer)-sizeof(header_t);
450 // Process uart messages
451 parser->buffer[parser->index++] = byte;
452 switch (parser->state) {
454 if (parser->index == sizeof(uint16_t)) {
455 if (head->header == MSG_HEADER) {
458 parser->buffer[0] = parser->buffer[1];
464 if (parser->index == sizeof(header_t)) {
465 if (head->length <= max_length &&
466 head->msgid <= MSG_MAX_ID) {
475 if (parser->index == (int)sizeof(header_t)+head->length) {
476 serial_deliver(head->msgid, body);
484 /********************
486 ********************/
489 DigitalOut led1(LED1);
490 DigitalOut led2(LED2);
495 parser_t parser_mbed;
511 void task_serial(uint64_t local, uint64_t world)
513 while (sirq_ready(sirq_dbg)) {
514 //sirq_printf("serial recv - dbg\r\n");
515 serial_receive(&parser_dbg, sirq_getc(sirq_dbg));
518 while (sirq_ready(sirq_bbb)) {
519 //sirq_printf("serial recv - bbb\r\n");
520 serial_receive(&parser_bbb, sirq_getc(sirq_bbb));
523 while (sirq_ready(sirq_mbed)) {
524 //sirq_printf("serial recv - mbed\r\n");
525 serial_receive(&parser_mbed, sirq_getc(sirq_mbed));
529 void task_events(uint64_t local, uint64_t world)
534 if (tdma_stamp(tdma_evt, &event)) {
535 sirq_printf("event received - evt\r\n");
536 if (tdma_stamp(tdma_rcv, &event))
537 sirq_printf("event received - rcv\r\n");
538 if (tdma_stamp(tdma_xmt, &event))
539 sirq_printf("event received - xmt\r\n");
542 if (tdma_stamp(tdma_evt, &event))
543 serial_send_event(sirq_bbb, 0, event);
545 tdma_start(tdma_evt);
548 void task_sync(uint64_t local, uint64_t world)
550 serial_send_sync(sirq_mbed, local);
553 void task_leds(uint64_t local, uint64_t world)
555 static uint32_t which = 0;
561 void task_emit(uint64_t local, uint64_t world)
563 emit_transmit(local, world);
566 void task_debug(uint64_t local, uint64_t world)
568 //tdma_debug(tdma_rcv);
569 //tdma_debug(tdma_xmt);
571 //sirq_debug(sirq_mbed);
574 sirq_printf("background - %6u.%02u -> %u.%02u\r\n",
575 (uint32_t)(local / NSEC_PER_SEC),
576 (uint32_t)(local % NSEC_PER_SEC / 10000000),
577 (uint32_t)(world / NSEC_PER_SEC),
578 (uint32_t)(world % NSEC_PER_SEC / 10000000));
586 #define N_ELEM(x) (sizeof(x) / sizeof((x)[0]))
588 extern void test_main(void);
589 extern serial_t stdio_uart;
592 void (*task)(uint64_t, uint64_t);
596 { task_serial, 0 }, // always
597 { task_events, 0 }, // always -- testing
598 { task_sync, 0 }, // always
599 { task_emit, 0 }, // always
600 { task_leds, 100000000 }, // 10hz
601 { task_debug, 1000000000 }, // 1hz
604 void background(void)
607 uint64_t local = tdma_time();
608 uint64_t world = time_to_world(local);
611 for (unsigned i = 0; i < N_ELEM(tasks); i++) {
612 if (local >= tasks[i].due) {
613 tasks[i].task(local, world);
614 tasks[i].due += tasks[i].period;
619 int main(int argc, char **argv)
622 emit_init(3, PTE20, PullDown);
627 sirq_dbg = sirq_open(SIRQ_UART0, USBTX, USBRX, 115200); // to pc
628 sirq_bbb = sirq_open(SIRQ_UART1, PTE0, PTE1, 115200); // to bbb
629 sirq_mbed = sirq_open(SIRQ_UART2, PTD3, PTD2, 115200); // to mbed
632 tdma_evt = tdma_open(TDMA_CHAN0, 3, PTC9, PullDown); // async event
635 tdma_rcv = tdma_open(TDMA_CHAN2, 3, PTD2, PullUp); // time sync rcv
636 tdma_xmt = tdma_open(TDMA_CHAN3, 3, PTD3, PullUp); // time sync xmt
639 //tdma_rcv = tdma_open(TDMA_CHAN2, 2, USBRX, PullUp); // time sync rcv
640 //tdma_xmt = tdma_open(TDMA_CHAN3, 2, USBTX, PullUp); // time sync xmt
643 tdma_start(tdma_evt);
644 tdma_start(tdma_rcv);
645 tdma_start(tdma_xmt);
647 // Serial timestamping
648 serial_tdma_rcv = tdma_rcv;
649 serial_tdma_xmt = tdma_xmt;
652 //MCG->C1 = 0x05; // was 0x1A
653 //MCG->C2 = 0x2C; // was 0x24
654 //MCG->C3 = 0x91; // was 0x91
655 //MCG->C4 = 0x10; // was 0x10
656 //MCG->C5 = 0x01; // was 0x01
657 //MCG->C6 = 0x40; // was 0x40
658 //MCG->S = 0x6E; // was 0x6E
659 //MCG->SC = 0x02; // was 0x02
660 //MCG->ATCVH = 0x00; // was 0x00
661 //MCG->ATCVL = 0x00; // was 0x00
662 //MCG->C7 = 0x00; // was 0x00
663 //MCG->C8 = 0x80; // was 0x80
664 //MCG->C9 = 0x00; // was 0x00
665 //MCG->C10 = 0x00; // was 0x00
667 //sirq_printf("MGC - C1 %02hx\r\n", MCG->C1); // 1A
668 //sirq_printf("MGC - C2 %02hx\r\n", MCG->C2); // 24
669 //sirq_printf("MGC - C3 %02hx\r\n", MCG->C3); // 91
670 //sirq_printf("MGC - C4 %02hx\r\n", MCG->C4); // 10
671 //sirq_printf("MGC - C5 %02hx\r\n", MCG->C5); // 01
672 //sirq_printf("MGC - C6 %02hx\r\n", MCG->C6); // 40
673 //sirq_printf("MGC - S %02hx\r\n", MCG->S); // 6E
674 //sirq_printf("MGC - SC %02hx\r\n", MCG->SC); // 02
675 //sirq_printf("MGC - ATCVH %02hx\r\n", MCG->ATCVH); // 00
676 //sirq_printf("MGC - ATCVL %02hx\r\n", MCG->ATCVL); // 00
677 //sirq_printf("MGC - C7 %02hx\r\n", MCG->C7); // 00
678 //sirq_printf("MGC - C8 %02hx\r\n", MCG->C8); // 80
679 //sirq_printf("MGC - C9 %02hx\r\n", MCG->C9); // 00
680 //sirq_printf("MGC - C10 %02hx\r\n", MCG->C10); // 00
682 // Run background loop
686 // Performance testing
687 //uint64_t prev = 0, due = 0;
688 //uint64_t worst[10] = {};
691 // uint64_t local = tdma_time();
692 // if (prev && (local-prev) > worst[count])
693 // worst[count] = (local-prev);
695 // if (local > due) {
697 // static char str[] = "background background background\r\n";
698 // sirq_write(sirq_dbg, str, sizeof(str));
701 // sirq_printf("background\r\n");
702 // for (int i = 0; i < 10; i++) {
703 // sirq_printf(" worst[%d] = 0.%09u\r\n",
708 // due += NSEC_PER_SEC;
709 // count = (count + 1) % 10;