DCF77 code performance improvement

include/dcf77.h

@@ -6,14 +6,18 @@
 #define DCF77_FRAME_SIZE (60)
 #define DCF77_PULSE_LENGTH (100)
 
-extern uint8_t DCFpulse[];
+#ifdef DCF77_ACTIVE_LOW
+enum dcf_pinstate { dcf_high, dcf_low };
+#else
+enum dcf_pinstate { dcf_low, dcf_high };
+#endif
 
 enum dcf_pulses { dcf_off, dcf_zero, dcf_one };
-enum dcf_pinstate { dcf_low, dcf_high };
 
 void DCF_Pulse(time_t t);
-void IRAM_ATTR DCF77_Frame(time_t t);
+uint8_t IRAM_ATTR DCF77_Frame(time_t t);
-void set_DCF77_pin(dcf_pinstate state);
+uint8_t IRAM_ATTR dec2bcd(uint8_t dec, uint8_t startpos, uint8_t endpos,
-uint8_t dec2bcd(uint8_t dec, uint8_t startpos, uint8_t endpos, uint8_t pArray[]);
+                          uint8_t pArray[]);
+uint8_t IRAM_ATTR setParityBit(uint8_t p);
 
 #endif

src/dcf77.cpp

@@ -16,15 +16,20 @@ https://github.com/udoklein/dcf77
 // Local logging tag
 static const char TAG[] = "main";
 
-// array of dcf pulses for one minute
+// array of dcf pulses for one minute, secs 0..16 and 20 are never touched, so
-uint8_t DCFpulse[DCF77_FRAME_SIZE + 1];
+// we initialize them statically to avoid dumb recalculation every minute
+static uint8_t DCFpulse[DCF77_FRAME_SIZE] = {
+    dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero,
+    dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero,
+    dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_zero, dcf_one};
 
 // triggered by 1 second timepulse to ticker out DCF signal
 void DCF_Pulse(time_t t) {
 
+  TickType_t startTime = xTaskGetTickCount();
   uint8_t sec = second(t);
 
-  TickType_t startTime = xTaskGetTickCount();
+  ESP_LOGD(TAG, "DCF77 sec %d", sec);
 
   // induce 10 pulses
   for (uint8_t pulse = 0; pulse <= 9; pulse++) {
@@ -33,18 +38,18 @@ void DCF_Pulse(time_t t) {
 
     case 0: // start of second -> start of timeframe for logic signal
       if (DCFpulse[sec] != dcf_off)
-        set_DCF77_pin(dcf_low);
+        digitalWrite(HAS_DCF77, dcf_low);
       else // 59th second reached, nothing more to do
         return;
       break;
 
     case 1: // 100ms after start of second -> end of timeframe for logic 0
       if (DCFpulse[sec] == dcf_zero)
-        set_DCF77_pin(dcf_high);
+        digitalWrite(HAS_DCF77, dcf_high);
       break;
 
     case 2: // 200ms after start of second -> end of timeframe for logic 1
-      set_DCF77_pin(dcf_high);
+      digitalWrite(HAS_DCF77, dcf_high);
       break;
 
     case 9: // 900ms after start -> last pulse
@@ -52,32 +57,31 @@ void DCF_Pulse(time_t t) {
 
     } // switch
 
+    // impulse period pause
     vTaskDelayUntil(&startTime, pdMS_TO_TICKS(DCF77_PULSE_LENGTH));
 
   } // for
 } // DCF_Pulse()
 
-void IRAM_ATTR DCF77_Frame(time_t tt) {
+uint8_t IRAM_ATTR DCF77_Frame(time_t tt) {
 
   uint8_t Parity;
   time_t t = myTZ.toLocal(tt); // convert to local time
 
-  // ENCODE HEAD
+  // ENCODE DST CHANGE ANNOUNCEMENT (Sec 16)
-  // secs 0..19 initialized with zeros
+  DCFpulse[16] = dcf_zero; // not yet implemented
-  for (int n = 0; n <= 19; n++)
+
-    DCFpulse[n] = dcf_zero;
+  // ENCODE DAYLIGHTSAVING (secs 17..18)
-  // secs 17..18: adjust for DayLightSaving
+  DCFpulse[17] = myTZ.locIsDST(t) ? dcf_one : dcf_zero;
-  DCFpulse[18 - (myTZ.locIsDST(t) ? 1 : 0)] = dcf_one;
+  DCFpulse[18] = myTZ.locIsDST(t) ? dcf_zero : dcf_one;
-  // sec 20: must be 1 to indicate time active
-  DCFpulse[20] = dcf_one;
 
   // ENCODE MINUTE (secs 21..28)
   Parity = dec2bcd(minute(t), 21, 27, DCFpulse);
-  DCFpulse[28] = (Parity & 1) ? dcf_one : dcf_zero;
+  DCFpulse[28] = setParityBit(Parity);
 
   // ENCODE HOUR (secs 29..35)
   Parity = dec2bcd(hour(t), 29, 34, DCFpulse);
-  DCFpulse[35] = (Parity & 1) ? dcf_one : dcf_zero;
+  DCFpulse[35] = setParityBit(Parity);
 
   // ENCODE DATE (secs 36..58)
   Parity = dec2bcd(day(t), 36, 41, DCFpulse);
@@ -85,30 +89,24 @@ void IRAM_ATTR DCF77_Frame(time_t tt) {
   Parity += dec2bcd(month(t), 45, 49, DCFpulse);
   Parity += dec2bcd(year(t) - 2000, 50, 57,
                     DCFpulse); // yes, we have a millenium 3000 bug here ;-)
-  DCFpulse[58] = (Parity & 1) ? dcf_one : dcf_zero;
+  DCFpulse[58] = setParityBit(Parity);
 
-  // ENCODE TAIL (sec 59)
+  // ENCODE MARK (sec 59)
-  DCFpulse[59] = dcf_off;
+  DCFpulse[59] = dcf_off; // !! missing code here for leap second !!
-  // !! missing code here for leap second !!
 
-  // timestamp the frame with minute pointer
+  // return the minute for which this frame is generated
-  DCFpulse[60] = minute(t);
+  return minute(t);
 
-  /*
+} // DCF77_Frame()
-    // for debug: print the DCF77 frame buffer
+
-    char out[DCF77_FRAME_SIZE + 1];
+// helper function to encode parity
-    uint8_t i;
+uint8_t IRAM_ATTR setParityBit(uint8_t p) {
-    for (i = 0; i < DCF77_FRAME_SIZE; i++) {
+  return ((p & 1) ? dcf_one : dcf_zero);
-      out[i] = DCFpulse[i] + '0'; // convert int digit to printable ascii
-    }
-    out[DCF77_FRAME_SIZE] = '\0'; // string termination char
-    ESP_LOGD(TAG, "DCF minute %d = %s", DCFpulse[DCF77_FRAME_SIZE], out);
-  */
 }
 
 // helper function to convert decimal to bcd digit
 uint8_t IRAM_ATTR dec2bcd(uint8_t dec, uint8_t startpos, uint8_t endpos,
-                uint8_t pArray[]) {
+                          uint8_t pArray[]) {
 
   uint8_t data = (dec < 10) ? dec : ((dec / 10) << 4) + (dec % 10);
   uint8_t parity = 0;
@@ -122,24 +120,4 @@ uint8_t IRAM_ATTR dec2bcd(uint8_t dec, uint8_t startpos, uint8_t endpos,
   return parity;
 }
 
-// helper function to switch GPIO line with DCF77 signal
-void set_DCF77_pin(dcf_pinstate state) {
-  switch (state) {
-  case dcf_low:
-#ifdef DCF77_ACTIVE_LOW
-    digitalWrite(HAS_DCF77, HIGH);
-#else
-    digitalWrite(HAS_DCF77, LOW);
-#endif
-    break;
-  case dcf_high:
-#ifdef DCF77_ACTIVE_LOW
-    digitalWrite(HAS_DCF77, LOW);
-#else
-    digitalWrite(HAS_DCF77, HIGH);
-#endif
-    break;
-  } // switch
-} // DCF77_pulse
-
 #endif // HAS_DCF77

src/timemanager.cpp

@@ -62,7 +62,7 @@ int syncTime(uint32_t t) { // t is UTC time in seconds epoch
 // helper function to sync moment on timepulse
 int wait_for_pulse(void) {
   // sync on top of next second with 1pps timepulse
-  if (xSemaphoreTake(TimePulse, pdMS_TO_TICKS(1000)) == pdTRUE)
+  if (xSemaphoreTake(TimePulse, pdMS_TO_TICKS(1010)) == pdTRUE)
     return 1; // success
   ESP_LOGD(TAG, "Missing timepulse");
   return 0; // failure
@@ -190,13 +190,14 @@ void clock_loop(void *pvParameters) { // ClockTask
 
   TickType_t wakeTime;
   time_t t;
+  uint8_t current_frame;
 
 #define t1(t) (t + DCF77_FRAME_SIZE + 1) // future time for next DCF77 frame
 #define t2(t) (t + 1) // future time for sync with 1pps trigger
 
 // preload first DCF frame before start
 #ifdef HAS_DCF77
-  DCF77_Frame(t1(now()));
+  current_frame = DCF77_Frame(t1(now()));
 #endif
 
   // output time telegram for second following sec beginning with timepulse
@@ -216,9 +217,9 @@ void clock_loop(void *pvParameters) { // ClockTask
 #elif defined HAS_DCF77
 
     if (second(t) == DCF77_FRAME_SIZE - 1) // is it time to load new frame?
-      DCF77_Frame(t1(t));                  // generate next frame
+      current_frame = DCF77_Frame(t1(t));  // generate next frame
 
-    if (DCFpulse[DCF77_FRAME_SIZE] ==
+    if (current_frame ==
         minute(t1(t)))  // have recent frame? (pulses could be missed!)
       DCF_Pulse(t2(t)); // then output next second of this frame