timeserver (experimental)

include/globals.h

@@ -5,7 +5,7 @@
 #include <Arduino.h>
 
 // Time functions
-#include <Time.h>
+#include "microTime.h"
 #include <Timezone.h>
 #include <RtcDateTime.h>
 #include <Ticker.h>

include/timesync.h

@@ -1,24 +1,21 @@
 #ifndef _TIME_SYNC_TIMESERVER_H
 #define _TIME_SYNC_TIMESERVER_H
 
+#include <ctime>
+#include <chrono>
 #include "globals.h"
 #include "timesync.h"
 #include "timekeeper.h"
 
 #define TIME_SYNC_SAMPLES 3   // number of time requests for averaging
-#define TIME_SYNC_CYCLE 30     // seconds between two time requests
+#define TIME_SYNC_CYCLE 20    // seconds between two time requests
 #define TIME_SYNC_TIMEOUT 120 // timeout seconds waiting for timeserver answer
-#define TIME_SYNC_TRIGGER 1.0f // time deviation threshold triggering time sync
+#define TIME_SYNC_TRIGGER 1   // time deviation threshold triggering time sync
 #define TIME_SYNC_FRAME_LENGTH 0x06 // timeserver answer frame length
 
-typedef struct {
+void send_timesync_req(void);
-  uint32_t seconds;
+void recv_timesync_ans(uint8_t buf[], uint8_t buf_len);
-  uint8_t fractions; // 1/250ths second = 4 milliseconds resolution
+void process_timesync_req(void *taskparameter);
-} time_sync_message_t;
-
-void send_Servertime_req(void);
-void recv_Servertime_ans(uint8_t buf[], uint8_t buf_len);
-void process_Servertime_sync_req(void *taskparameter);
 void store_time_sync_req(time_t secs, uint32_t micros);
 
 #endif

src/lorawan.cpp

@@ -175,7 +175,7 @@ void showLoraKeys(void) {
 
 void onEvent(ev_t ev) {
   char buff[24] = "";
-  uint32_t now_micros;
+  uint32_t now_micros = 0;
 
   switch (ev) {
 
@@ -238,21 +238,27 @@ void onEvent(ev_t ev) {
                                                : PSTR("TX_COMPLETE"));
     sprintf(display_line6, " "); // clear previous lmic status
 
-    if (LMIC.dataLen) {
+    if (LMIC.dataLen) { // did we receive data -> display info
       ESP_LOGI(TAG, "Received %d bytes of payload, RSSI -%d SNR %d",
                LMIC.dataLen, LMIC.rssi, LMIC.snr / 4);
       sprintf(display_line6, "RSSI -%d SNR %d", LMIC.rssi, LMIC.snr / 4);
 
-      // check if this is a timesync answer, then call timesync processor
+      if (LMIC.txrxFlags & TXRX_PORT) { // FPort -> use to switch
+        switch (LMIC.frame[LMIC.dataBeg - 1]) {
 #if (TIME_SYNC_TIMESERVER)
-      if ((LMIC.txrxFlags & TXRX_PORT) &&
+        case TIMEPORT: // timesync answer -> call timesync processor
-          (LMIC.frame[LMIC.dataBeg - 1] == TIMEPORT))
+          recv_timesync_ans(LMIC.frame + LMIC.dataBeg, LMIC.dataLen);
-        recv_Servertime_ans(LMIC.frame + LMIC.dataBeg, LMIC.dataLen);
+          break;
 #endif
-      // check if this an opcode, then call rcommand interpreter
+        case RCMDPORT: // opcode -> call rcommand interpreter
-      if ((LMIC.txrxFlags & TXRX_PORT) &&
-          (LMIC.frame[LMIC.dataBeg - 1] == RCMDPORT))
           rcommand(LMIC.frame + LMIC.dataBeg, LMIC.dataLen);
+          break;
+        default: // unknown port -> display info
+          ESP_LOGI(TAG, "Received data on unsupported port #%d",
+                   LMIC.frame[LMIC.dataBeg - 1]);
+          break;
+        }
+      }
     }
     break;
 

src/timekeeper.cpp

@@ -45,7 +45,7 @@ time_t timeProvider(void) {
 
 // kick off asychronous Lora timeserver timesync if we have
 #if (TIME_SYNC_TIMESERVER)
-  send_Servertime_req();
+  send_timesync_req();
 // kick off asychronous lora network sync if we have
 #elif (TIME_SYNC_LORAWAN)
   LMIC_requestNetworkTime(user_request_network_time_callback, &userUTCTime);
@@ -116,7 +116,7 @@ void timepulse_start(void) {
 void IRAM_ATTR CLOCKIRQ(void) {
 
   BaseType_t xHigherPriorityTaskWoken;
-  SyncToPPS(); // calibrates UTC systime, see Time.h
+  SyncToPPS(); // calibrates UTC systime, see microTime.h
   xHigherPriorityTaskWoken = pdFALSE;
 
   if (ClockTask != NULL)
@@ -149,7 +149,7 @@ time_t compiledUTC(void) {
 time_t tmConvert(uint16_t YYYY, uint8_t MM, uint8_t DD, uint8_t hh, uint8_t mm,
                  uint8_t ss) {
   tmElements_t tm;
-  tm.Year = CalendarYrToTm(YYYY); // year offset from 1970 in time.h
+  tm.Year = CalendarYrToTm(YYYY); // year offset from 1970 in microTime.h
   tm.Month = MM;
   tm.Day = DD;
   tm.Hour = hh;

src/timesync.cpp

@@ -17,32 +17,38 @@ algorithm in applications without granted license by the patent holder.
 static const char TAG[] = __FILE__;
 
 TaskHandle_t timeSyncReqTask;
-time_sync_message_t time_sync_messages[TIME_SYNC_SAMPLES] = {0},
+
-                    time_sync_answers[TIME_SYNC_SAMPLES] = {0};
 static uint8_t time_sync_seqNo = 0;
-static bool time_sync_pending = false;
+static bool lora_time_sync_pending = false;
+
+typedef std::chrono::system_clock myClock;
+typedef myClock::time_point myClock_timepoint;
+typedef std::chrono::duration<long long int, std::ratio<1, 1000>>
+    myClock_msecTick;
+// 32bit millisec resolution from epoch until year 2038
+myClock_timepoint time_sync_tx[TIME_SYNC_SAMPLES];
+myClock_timepoint time_sync_rx[TIME_SYNC_SAMPLES];
 
 // send time request message
-void send_Servertime_req() {
+void send_timesync_req() {
 
   // if a timesync handshake is pending then exit
-  if (time_sync_pending) {
+  if (lora_time_sync_pending) {
     ESP_LOGI(TAG, "Timeserver sync request already pending");
     return;
   } else {
     ESP_LOGI(TAG, "Timeserver sync request started");
 
-    time_sync_pending = true;
+    lora_time_sync_pending = true;
 
     // clear timestamp array
-    for (uint8_t i = 0; i <= TIME_SYNC_SAMPLES + 1; i++) {
+    for (uint8_t i = 0; i < TIME_SYNC_SAMPLES; i++) {
-      time_sync_messages[i].seconds = time_sync_answers[i].seconds =
+      time_sync_tx[i] = time_sync_rx[i] = myClock_timepoint(); // set to epoch
-          time_sync_messages[i].fractions = time_sync_answers[i].fractions = 0;
     }
 
     // kick off temporary task for timeserver handshake processing
     if (!timeSyncReqTask)
-      xTaskCreatePinnedToCore(process_Servertime_sync_req, // task function
+      xTaskCreatePinnedToCore(process_timesync_req, // task function
                               "timesync_req",       // name of task
                               2048,                 // stack size of task
                               (void *)1,            // task parameter
@@ -52,25 +58,26 @@ void send_Servertime_req() {
   }
 }
 
-// process timeserver timestamp response, called from rcommand.cpp
+// process timeserver timestamp answer, called from lorawan.cpp
-void recv_Servertime_ans(uint8_t buf[], uint8_t buf_len) {
+void recv_timesync_ans(uint8_t buf[], uint8_t buf_len) {
 
-  // if no timesync handshake is pending or invalid buffer then exit
+  // if no timesync handshake is pending or spurious buffer then exit
-  if ((!time_sync_pending) || (buf_len != TIME_SYNC_FRAME_LENGTH))
+  if ((!lora_time_sync_pending) || (buf_len != TIME_SYNC_FRAME_LENGTH))
     return;
 
   uint8_t seq_no = buf[0], k = seq_no % TIME_SYNC_SAMPLES;
-  uint32_t timestamp_sec = 0;
+  uint16_t timestamp_msec = 4 * buf[5]; // convert 1/250th sec fractions to ms
+  uint32_t timestamp_sec = 0, tmp_sec = 0;
 
   for (uint8_t i = 1; i <= 4; i++) {
-    time_sync_answers[k].seconds = (timestamp_sec <<= 8) |= buf[i];
+    timestamp_sec = (tmp_sec <<= 8) |= buf[i];
   }
-  time_sync_answers[k].fractions = buf[5];
 
-  ESP_LOGD(TAG, "Timeserver answer:");
+  time_sync_rx[k] += std::chrono::seconds(timestamp_sec) +
+                     std::chrono::milliseconds(timestamp_msec);
 
-  ESP_LOGD(TAG, "ans.sec(%d)=%d / ans.ms(%d)=%d", k,
+  ESP_LOGD(TAG, "Timesync answer #%d rcvd at %d", seq_no,
-           time_sync_answers[k].seconds, k, time_sync_answers[k].fractions);
+           myClock::to_time_t(time_sync_rx[k]));
 
   // inform processing task
   if (timeSyncReqTask)
@@ -78,15 +85,15 @@ void recv_Servertime_ans(uint8_t buf[], uint8_t buf_len) {
 }
 
 // task for sending time sync requests
-void process_Servertime_sync_req(void *taskparameter) {
+void process_timesync_req(void *taskparameter) {
 
-  time_t t = 0, time_to_set = 0;
+  time_t time_to_set = 0;
-  uint32_t seq_no = 0, k = 0;
+  uint8_t k = 0, i = 0;
-  int time_diff_frac = 0, time_diff_ms = 0;
+  uint32_t seq_no = 0;
-  long time_diff_sec = 0, time_offset = 0;
+  auto time_offset = myClock_msecTick::zero();
 
   // enqueue timestamp samples in lora sendqueue
-  for (uint8_t i = 1; i <= TIME_SYNC_SAMPLES; i++) {
+  for (uint8_t i = 0; i < TIME_SYNC_SAMPLES; i++) {
 
     // wrap around seqNo 0 .. 254
     time_sync_seqNo = (time_sync_seqNo >= 255) ? 0 : time_sync_seqNo + 1;
@@ -96,55 +103,48 @@ void process_Servertime_sync_req(void *taskparameter) {
     payload.addByte(time_sync_seqNo);
     SendPayload(TIMEPORT, prio_high);
 
-    /* -> do we really need this? maybe for SF9 up?
-    // send dummy packet to trigger receive answer
-    payload.reset();
-    payload.addByte(0x99);           // flush
-    SendPayload(RCMDPORT, prio_low); // to open receive slot for answer
-    */
-
     // process answer
     if ((xTaskNotifyWait(0x00, ULONG_MAX, &seq_no,
-                         TIME_SYNC_TIMEOUT * 1000 / portTICK_PERIOD_MS) ==
+                         pdMS_TO_TICKS(TIME_SYNC_TIMEOUT * 1000)) == pdFALSE) ||
-         pdFALSE) ||
         (seq_no != time_sync_seqNo)) {
+
       ESP_LOGW(TAG, "Timeserver handshake failed");
       goto finish;
     } // no valid sequence received before timeout
 
-    else { // calculate time diff from set of collected timestamps
+    else { // calculate time diff from collected timestamps
-
       k = seq_no % TIME_SYNC_SAMPLES;
 
-      time_diff_sec +=
+      auto t_tx = std::chrono::time_point_cast<std::chrono::milliseconds>(
-          ((time_sync_messages[k].seconds - time_sync_answers[k].seconds) / TIME_SYNC_SAMPLES);
+          time_sync_tx[k]); // timepoint node after TX_completed
+      auto t_rx = std::chrono::time_point_cast<std::chrono::milliseconds>(
+          time_sync_rx[k]); // timepoint when message was seen on gateway
 
-      time_diff_frac +=
+      time_offset += t_rx - t_tx;
-          ((time_sync_messages[k].fractions - time_sync_answers[k].fractions) / TIME_SYNC_SAMPLES);
 
-      ESP_LOGD(TAG, "time_diff_sec=%d / time_diff_frac=%d", time_diff_sec,
+      if (i < TIME_SYNC_SAMPLES - 1)
-               time_diff_frac);
+        vTaskDelay(pdMS_TO_TICKS(TIME_SYNC_CYCLE * 1000));
     }
   } // for
 
-  // calculate time offset and set time if necessary
+  // calculate time offset from collected diffs and set time if necessary
-  time_diff_ms = 4 * time_diff_frac;
+  time_offset /= TIME_SYNC_SAMPLES;
-  time_offset = (time_diff_sec + (long) (time_diff_ms / 1000));
+  ESP_LOGD(TAG, "Avg time diff: %lldms", time_offset.count());
 
-  ESP_LOGD(TAG, "Timesync time offset=%d", time_offset);
+  if (abs(time_offset.count()) >= TIME_SYNC_TRIGGER) {
 
-  t = now();
+    /*
-
-  if (labs(time_offset) >= (t + TIME_SYNC_TRIGGER)) {
     // wait until top of second
-    if (time_diff_ms > 0) // clock is fast
+    if (time_offset_ms > 0) // clock is fast
       vTaskDelay(pdMS_TO_TICKS(time_diff_ms));
-    else if (time_diff_ms < 0) // clock is slow
+    else if (time_offset_ms < 0) // clock is slow
-      vTaskDelay(pdMS_TO_TICKS(1000 + time_diff_ms));
+      vTaskDelay(pdMS_TO_TICKS(1000 + time_offset_ms));
 
-    time_diff_sec++;
+    time_to_set = t - time_t(time_offset_sec + 1);
-    time_to_set = t - time_t(time_diff_sec);
+    */
-    ESP_LOGD(TAG, "Now()=%d, Time to set = %d", t, time_to_set);
+
+    time_t time_to_set = myClock::to_time_t(myClock::now() + time_offset);
+    ESP_LOGD(TAG, "New UTC epoch time: %d", time_to_set);
 
     // adjust system time
     if (timeIsValid(time_to_set)) {
@@ -161,20 +161,21 @@ void process_Servertime_sync_req(void *taskparameter) {
 
 finish:
 
-  time_sync_pending = false;
+  lora_time_sync_pending = false;
   timeSyncReqTask = NULL;
   vTaskDelete(NULL); // end task
 }
 
 // called from lorawan.cpp after time_sync_req was sent
-void store_time_sync_req(time_t secs, uint32_t micros) {
+void store_time_sync_req(time_t t_sec, uint32_t t_microsec) {
+
   uint8_t k = time_sync_seqNo % TIME_SYNC_SAMPLES;
 
-  time_sync_messages[k].seconds = (uint32_t) secs;
+  time_sync_tx[k] +=
-  time_sync_messages[k].fractions = (uint8_t) (micros / 4000); // 4ms resolution
+      std::chrono::seconds(t_sec) + std::chrono::microseconds(t_microsec);
 
-  ESP_LOGD(TAG, "Timeserver request #%d sent at %d.%03d", time_sync_seqNo,
+  ESP_LOGD(TAG, "Timesync request #%d sent at %d", time_sync_seqNo,
-           time_sync_messages[k].seconds, time_sync_messages[k].fractions);
+           myClock::to_time_t(time_sync_tx[k]));
 }
 
 #endif