added DCF77 function (experimental, not fully working yet)

include/cyclic.h

@@ -11,11 +11,14 @@
 #include "bme680mems.h"
 #endif
 
-// Needed for RTC time sync if RTC present on board
 #ifdef HAS_RTC
 #include "rtctime.h"
 #endif
 
+#ifdef HAS_DCF77
+#include "dcf77.h"
+#endif
+
 void doHousekeeping(void);
 uint64_t uptime(void);
 void reset_counters(void);

include/dcf77.h

@@ -0,0 +1,16 @@
+#ifndef _DCF77_H
+#define _DCF77_H
+
+#include "globals.h"
+
+extern TaskHandle_t DCF77Task;
+extern hw_timer_t *dcfCycle;
+
+enum dcf_pulses { dcf_off, dcf_zero, dcf_one };
+
+int dcf77_init(void);
+void dcf77_loop(void *pvParameters);
+void IRAM_ATTR DCF77IRQ(void);
+void sendDCF77(void);
+
+#endif

include/if482.h

@@ -2,7 +2,6 @@
 #define _IF482_H
 
 #include "globals.h"
-#include "irqhandler.h"
 
 extern TaskHandle_t IF482Task;
 

src/cyclic.cpp

@@ -60,6 +60,10 @@ void doHousekeeping() {
   ESP_LOGD(TAG, "Bmeloop %d bytes left | Taskstate = %d",
            uxTaskGetStackHighWaterMark(BmeTask), eTaskGetState(BmeTask));
 #endif
+#ifdef HAS_DCF77
+  ESP_LOGD(TAG, "DCF77loop %d bytes left | Taskstate = %d",
+           uxTaskGetStackHighWaterMark(DCF77Task), eTaskGetState(DCF77Task));
+#endif
 
 #if (HAS_LED != NOT_A_PIN) || defined(HAS_RGB_LED)
   ESP_LOGD(TAG, "LEDloop %d bytes left | Taskstate = %d",
@@ -79,6 +83,11 @@ void doHousekeeping() {
            bme_status.temperature, bme_status.iaq, bme_status.iaq_accuracy);
 #endif
 
+// generate DCF77 timeframes
+#ifdef HAS_DCF77
+  sendDCF77();
+#endif
+
   // check free heap memory
   if (ESP.getMinFreeHeap() <= MEM_LOW) {
     ESP_LOGI(TAG,

src/dcf77.cpp

@@ -0,0 +1,219 @@
+//
+// source:
+// https://www.elektormagazine.com/labs/dcf77-emulator-with-esp8266-elektor-labs-version-150713
+//
+/*
+ Simulate a DCF77 radio receiver
+ Emit a complete three minute pulses train from the GPIO output
+ the train is preceded by a single pulse and the lacking 59th pulse to allow
+ some clock model syncronization of the beginning frame. After the three pulses
+ train one more single pulse is sent to safely close the frame
+*/
+
+#if defined HAS_DCF77
+
+#include "dcf77.h"
+
+// Local logging tag
+static const char TAG[] = "main";
+
+TaskHandle_t DCF77Task;
+QueueHandle_t DCFSendQueue;
+hw_timer_t *dcfCycle = NULL;
+
+#define DCF77_FRAME_SIZE 60
+#define DCF_FRAME_QUEUE_SIZE (HOMECYCLE / 60 + 1)
+
+// array of dcf pulses for three minutes
+uint8_t DCFtimeframe[DCF77_FRAME_SIZE];
+
+// initialize and configure DCF77 output
+int dcf77_init(void) {
+
+  DCFSendQueue = xQueueCreate(DCF_FRAME_QUEUE_SIZE,
+                              sizeof(DCFtimeframe) / sizeof(DCFtimeframe[0]));
+  if (!DCFSendQueue) {
+    ESP_LOGE(TAG, "Could not create DCF77 send queue. Aborting.");
+    return 0; // failure
+  }
+  ESP_LOGI(TAG, "DCF77 send queue created, size %d Bytes",
+           DCF_FRAME_QUEUE_SIZE * sizeof(DCFtimeframe) /
+               sizeof(DCFtimeframe[0]));
+
+  pinMode(HAS_DCF77, OUTPUT);
+  digitalWrite(HAS_DCF77, LOW);
+
+  return 1; // success
+
+} // ifdcf77_init
+
+// called every 100msec for DCF77 output
+void DCF_Ticker() {
+
+  static uint8_t DCF_Frame[DCF77_FRAME_SIZE];
+  static uint8_t bit = 0;
+  static uint8_t pulse = 0;
+  static bool BitsPending = false;
+
+  while (BitsPending) {
+    switch (pulse++) {
+
+    case 0: // start of second -> start of timeframe for logic signal
+      if (DCF_Frame[bit] != dcf_off)
+        digitalWrite(HAS_DCF77, LOW);
+      return;
+
+    case 1: // 100ms after start of second -> end of timeframe for logic 0
+      if (DCF_Frame[bit] == dcf_zero)
+        digitalWrite(HAS_DCF77, HIGH);
+      return;
+
+    case 2: // 200ms after start of second -> end of timeframe for logic signal
+      digitalWrite(HAS_DCF77, HIGH);
+      return;
+
+    case 9: // last pulse before next second starts
+      pulse = 0;
+      if (bit++ != DCF77_FRAME_SIZE)
+        return;
+      else { // last pulse of DCF77 frame (59th second)
+        bit = 0;
+        BitsPending = false;
+      };
+      break;
+
+    }; // switch
+  };   // while
+
+  // get next frame to send from queue
+  if (xQueueReceive(DCFSendQueue, &DCF_Frame, (TickType_t)0) == pdTRUE)
+    BitsPending = true;
+
+} // DCF_Ticker()
+
+void dcf77_loop(void *pvParameters) {
+
+  configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
+
+  // task remains in blocked state until it is notified by isr
+  for (;;) {
+    xTaskNotifyWait(
+        0x00,      // don't clear any bits on entry
+        ULONG_MAX, // clear all bits on exit
+        NULL,
+        portMAX_DELAY); // wait forever (missing error handling here...)
+
+    DCF_Ticker();
+  }
+  vTaskDelete(DCF77Task); // shoud never be reached
+} // dcf77_loop()
+
+uint8_t dec2bcd(uint8_t dec, uint8_t startpos, uint8_t endpos,
+                uint8_t pArray[]) {
+
+  uint8_t data = (dec < 10) ? dec : ((dec / 10) << 4) + (dec % 10);
+  uint8_t parity = 0;
+
+  for (uint8_t n = startpos; n <= endpos; n++) {
+    pArray[n] = (data & 1) ? dcf_one : dcf_zero;
+    parity += (data & 1);
+    data >>= 1;
+  }
+
+  return parity;
+}
+
+void enqueueTimeframe(time_t t) {
+
+  uint8_t ParityCount;
+
+  // ENCODE HEAD
+  // bits 0..19 initialized with zeros
+  for (int n = 0; n <= 19; n++)
+    DCFtimeframe[n] = dcf_zero;
+  // bits 17..18: adjust for DayLightSaving
+  DCFtimeframe[18 - (myTZ.locIsDST(t) ? 1 : 0)] = dcf_one;
+  // bit 20: must be 1 to indicate time active
+  DCFtimeframe[20] = dcf_one;
+
+  // ENCODE MINUTE (bits 21..28)
+  ParityCount = dec2bcd(minute(t), 21, 27, DCFtimeframe);
+  DCFtimeframe[28] = (ParityCount & 1) ? dcf_one : dcf_zero;
+
+  // ENCODE HOUR (bits 29..35)
+  ParityCount = dec2bcd(hour(t), 29, 34, DCFtimeframe);
+  DCFtimeframe[35] = (ParityCount & 1) ? dcf_one : dcf_zero;
+
+  // ENCODE DATE (bits 36..58)
+  ParityCount = dec2bcd(day(t), 36, 41, DCFtimeframe);
+  ParityCount +=
+      dec2bcd((weekday(t) - 1) ? (weekday(t) - 1) : 7, 42, 44, DCFtimeframe);
+  ParityCount += dec2bcd(month(t), 45, 49, DCFtimeframe);
+  ParityCount +=
+      dec2bcd(year(t) - 2000, 50, 57,
+              DCFtimeframe); // yes, we have a millenium 3000 bug here ;-)
+  DCFtimeframe[58] = (ParityCount & 1) ? dcf_one : dcf_zero;
+
+  // ENCODE TAIL (bit 59)
+  DCFtimeframe[59] = dcf_off;
+  // --> missing code here for switching second!
+  /*
+  In unregelmäßigen Zeitabständen muss eine Schaltsekunde eingefügt werden. Dies
+  ist dadurch bedingt, dass sich die Erde nicht genau in 24 Stunden um sich
+  selbst dreht. Auf die koordinierte Weltzeitskala UTC bezogen, wird diese
+  Korrektur zum Ende der letzten Stunde des 31. Dezember oder 30. Juni
+  vorgenommen. In Mitteleuropa muss die Schaltsekunde daher am 1. Januar um 1.00
+  Uhr MEZ oder am 1.Juli um 2.00 MESZ eingeschoben werden. Zu den genannten
+  Zeiten werden daher 61 Sekunden gesendet.
+  */
+
+  // post generated DCFtimeframe data to DCF SendQueue
+  if (xQueueSendToBack(DCFSendQueue, (void *)&DCFtimeframe[0], (TickType_t)0) !=
+      pdPASS)
+    ESP_LOGE(TAG, "Failed to send DCF data");
+
+  // for debug: print the DCF77 frame buffer
+  char out[DCF77_FRAME_SIZE + 1];
+  uint8_t i;
+  for (i = 0; i < DCF77_FRAME_SIZE; i++) {
+    out[i] = DCFtimeframe[i] + '0'; // convert int digit to printable ascii
+  }
+  out[DCF77_FRAME_SIZE] = '\0'; // string termination char
+  ESP_LOGD(TAG, "DCF=%s", out);
+}
+
+void sendDCF77() {
+
+  time_t t = now();
+
+  /*
+    if (second(t) > 56) {
+      delay(30000);
+      return;
+    }
+  */
+
+  // enqueue DCF timeframes for each i minute
+  for (uint8_t i = 0; i < DCF_FRAME_QUEUE_SIZE; i++)
+    enqueueTimeframe(t + i * 60);
+
+  /*
+    // how many to the minute end ?
+    // don't forget that we begin transmission at second 58
+    delay((58 - second(t)) * 1000);
+
+    // three minutes are needed to transmit all the packet
+    // then wait more 30 secs to locate safely at the half of minute
+    // NB 150+60=210sec, 60secs are lost from main routine
+    delay(150000);
+  */
+
+} // Ende ReadAndDecodeTime()
+
+// interrupt service routine triggered each 100ms by ESP32 hardware timer
+void IRAM_ATTR DCF77IRQ() {
+  xTaskNotifyFromISR(DCF77Task, xTaskGetTickCountFromISR(), eSetBits, NULL);
+  portYIELD_FROM_ISR();
+}
+
+#endif // HAS_DCF77

src/display.cpp

@@ -145,12 +145,14 @@ void refreshtheDisplay() {
 
     uint8_t msgWaiting;
     char buff[16]; // 16 chars line buffer
+#if defined HAS_RTC || defined HAS_GPS
     const char timeNosyncSymbol = '?';
-#ifdef HAS_IF482
+#if defined HAS_IF482 || defined HAS_DCF77
     const char timesyncSymbol = '+';
 #else
     const char timesyncSymbol = '*';
 #endif
+#endif // HAS_RTC
 
     // update counter (lines 0-1)
     snprintf(
@@ -214,17 +216,16 @@ void refreshtheDisplay() {
     u8x8.printf("%4dKB", getFreeRAM() / 1024);
 
 #ifdef HAS_LORA
-
     u8x8.setCursor(0, 6);
-#ifndef HAS_RTC
+#if (!defined HAS_RTC) && (!defined HAS_GPS)
     // update LoRa status display (line 6)
     u8x8.printf("%-16s", display_line6);
-#else
+#else          // HAS_RTC or HAS_GPS
     // update time/date display (line 6)
     time_t t = myTZ.toLocal(now());
     char timeState =
         timeStatus() == timeSet ? timesyncSymbol : timeNosyncSymbol;
-#ifdef RTC_INT // make timestatus symbol blinking
+#ifdef RTC_INT // make timestatus symbol blinking if pps line
     if (second(t) % 2)
       timeState = ' ';
 #endif         // RTC_INT

src/gpsread.cpp

@@ -73,7 +73,7 @@ time_t get_gpstime(void) {
   if ((gps.time.age() < 1500) && (gps.time.isValid())) {
     t = tmConvert_t(gps.date.year(), gps.date.month(), gps.date.day(),
                     gps.time.hour(), gps.time.minute(), gps.time.second());
-    ESP_LOGD(TAG, "GPS time: %d/%d/%d %d:%d:%d", year(t), month(t), day(t),
+    ESP_LOGD(TAG, "GPS time: %4d/%02d/%02d %02d:%02d:%02d", year(t), month(t), day(t),
              hour(t), minute(t), second(t));
   } else {
     ESP_LOGW(TAG, "GPS has no confident time");

src/hal/generic.h

@@ -55,6 +55,9 @@
 // Settings for IF482 interface
 #define HAS_IF482 9600, SERIAL_7E1, GPIO_NUM_12, GPIO_NUM_14 // IF482 serial port parameters
 
+// Settings for DCF77 interface
+#define HAS_DCF77 GPIO_NUM_13
+
 // Pins for LORA chip SPI interface, reset line and interrupt lines
 #define LORA_SCK  (5) 
 #define LORA_CS   (18)

src/main.cpp

@@ -28,7 +28,8 @@ Uused tasks and timers:
 Task          Core  Prio  Purpose
 ====================================================================================
 ledloop       0     3     blinks LEDs
-if482loop     1     3     serial feed of IF482 time telegrams
+if482loop     0     3     generates serial feed of IF482 time telegrams
+dcf77loop     0     3     generates DCF77 timeframe pulses
 spiloop       0     2     reads/writes data on spi interface
 IDLE          0     0     ESP32 arduino scheduler -> runs wifi sniffer
 
@@ -46,13 +47,13 @@ Tasks using i2c bus all must have same priority, because using mutex semaphore
 ESP32 hardware timers
 ================================
  0	triggers display refresh
- 1  unused (reserved for DCF77)
+ 1  triggers DCF77 clock signal
  2	triggers send payload cycle
  3	triggers housekeeping cycle
 
  RTC hardware timer (if present)
 ================================
- triggers IF482 clock generator
+ triggers IF482 clock signal
 
 */
 
@@ -64,8 +65,12 @@ char display_line6[16], display_line7[16]; // display buffers
 uint8_t volatile channel = 0;              // channel rotation counter
 uint16_t volatile macs_total = 0, macs_wifi = 0, macs_ble = 0,
                   batt_voltage = 0; // globals for display
-hw_timer_t *channelSwitch = NULL, *sendCycle = NULL, *homeCycle = NULL,
+
-           *displaytimer = NULL; // irq tasks
+hw_timer_t *sendCycle = NULL, *homeCycle = NULL;
+#ifdef HAS_DISPLAY
+hw_timer_t *displaytimer = NULL;
+#endif
+
 TaskHandle_t irqHandlerTask;
 SemaphoreHandle_t I2Caccess;
 
@@ -327,6 +332,16 @@ void setup() {
   setSyncInterval(TIME_SYNC_INTERVAL_RTC * 60);
 #endif // HAS_RTC
 
+#if defined HAS_DCF77
+  strcat_P(features, " DCF77");
+  assert(dcf77_init());
+#endif
+
+#if defined HAS_IF482 && defined RTC_INT
+  strcat_P(features, " IF482");
+  assert(if482_init());
+#endif
+
   // show compiled features
   ESP_LOGI(TAG, "Features:%s", features);
 
@@ -403,8 +418,6 @@ void setup() {
 #endif
 
 #if defined HAS_IF482 && defined RTC_INT
-  strcat_P(features, " IF482");
-  assert(if482_init());
   ESP_LOGI(TAG, "Starting IF482 Generator...");
   xTaskCreatePinnedToCore(if482_loop,  // task function
                           "if482loop", // name of task
@@ -419,6 +432,24 @@ void setup() {
   attachInterrupt(digitalPinToInterrupt(RTC_INT), IF482IRQ, FALLING);
 #endif
 
+#if defined HAS_DCF77
+  ESP_LOGI(TAG, "Starting DCF77 Generator...");
+  xTaskCreatePinnedToCore(dcf77_loop,  // task function
+                          "dcf77loop", // name of task
+                          2048,        // stack size of task
+                          (void *)1,   // parameter of the task
+                          3,           // priority of the task
+                          &DCF77Task,  // task handle
+                          0);          // CPU core
+
+  // setup 100ms clock signal for DCF77 generator using esp32 hardware timer 1
+  assert(DCF77Task != NULL); // has dcf77 task started?
+  dcfCycle = timerBegin(1, 8000, true);
+  timerAttachInterrupt(dcfCycle, &DCF77IRQ, true);
+  timerAlarmWrite(dcfCycle, 1000, true);
+  timerAlarmEnable(dcfCycle);
+#endif
+
 } // setup()
 
 void loop() {