BME680 support (experimental); LoRa Time sync (experimental)

src/bme680read.cpp

@@ -0,0 +1,65 @@
+#ifdef HAS_BME
+
+#include "globals.h"
+
+// Local logging tag
+static const char TAG[] = "main";
+
+#include <Wire.h>
+#include <SPI.h>
+#include <Adafruit_Sensor.h>
+#include "Adafruit_BME680.h"
+
+#define SEALEVELPRESSURE_HPA (1013.25)
+
+// I2C Bus interface
+Adafruit_BME680 bme;
+
+bmeStatus_t bme_status;
+TaskHandle_t BmeTask;
+
+// BME680 read loop Task
+void bme_loop(void *pvParameters) {
+
+  configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
+
+  // initialize BME680 sensor
+  if (!bme.begin()) {
+    ESP_LOGE(TAG, "BME680 chip not found on i2c bus, bus error %d. "
+                  "Stopping BME task.");
+    vTaskDelete(BmeTask);
+  } else {
+    ESP_LOGI(TAG, "BME680 chip found.");
+  }
+
+  // Set up oversampling and filter initialization
+  bme.setTemperatureOversampling(BME680_OS_8X);
+  bme.setHumidityOversampling(BME680_OS_2X);
+  bme.setPressureOversampling(BME680_OS_4X);
+  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
+  bme.setGasHeater(320, 150); // 320*C for 150 ms
+
+  // read loop
+  while (1) {
+
+    vTaskDelay(10000 / portTICK_PERIOD_MS);
+
+    if (!bme.performReading()) {
+      ESP_LOGE(TAG, "BME680 read error");
+      continue;
+    }
+
+    // read BME data and cast to global struct
+    bme_status.temperature = (uint16_t)bme.temperature;
+    bme_status.pressure = (uint16_t)(bme.pressure / 100.0);
+    bme_status.humidity = (uint16_t)bme.humidity;
+    bme_status.gas_resistance = (uint16_t)(bme.gas_resistance / 1000.0);
+    bme_status.altitude = (uint16_t)bme.readAltitude(SEALEVELPRESSURE_HPA);
+
+  } // end of infinite loop
+
+  vTaskDelete(NULL); // shoud never be reached
+
+} // bme_loop()
+
+#endif // HAS_BME

src/cyclic.cpp

@@ -3,12 +3,12 @@
 
 // Basic config
 #include "cyclic.h"
-#include "rcommand.h"
-#include "spislave.h"
 
 // Local logging tag
 static const char TAG[] = "main";
 
+uint32_t userUTCTime; // Seconds since the UTC epoch
+
 // do all housekeeping
 void doHousekeeping() {
 
@@ -19,7 +19,10 @@ void doHousekeeping() {
   if (cfg.runmode == 1)
     do_reset();
 
-// task storage debugging //
+  spi_housekeeping();
+  do_timesync();
+
+  // task storage debugging //
   ESP_LOGD(TAG, "Wifiloop %d bytes left",
            uxTaskGetStackHighWaterMark(wifiSwitchTask));
   ESP_LOGD(TAG, "IRQhandler %d bytes left",
@@ -28,10 +31,9 @@ void doHousekeeping() {
   ESP_LOGD(TAG, "Gpsloop %d bytes left", uxTaskGetStackHighWaterMark(GpsTask));
 #endif
 
-  spi_housekeeping();
-
 #if (HAS_LED != NOT_A_PIN) || defined(HAS_RGB_LED)
-  ESP_LOGD(TAG, "LEDloop %d bytes left", uxTaskGetStackHighWaterMark(ledLoopTask));
+  ESP_LOGD(TAG, "LEDloop %d bytes left",
+           uxTaskGetStackHighWaterMark(ledLoopTask));
 #endif
 
 // read battery voltage into global variable
@@ -40,17 +42,6 @@ void doHousekeeping() {
   ESP_LOGI(TAG, "Measured Voltage: %dmV", batt_voltage);
 #endif
 
-// sync time & date if we have valid gps time
-#ifdef HAS_GPS
-  if (gps.time.isValid()) {
-    setTime(gps.time.hour(), gps.time.minute(), gps.time.second(),
-            gps.date.day(), gps.date.month(), gps.date.year());
-    ESP_LOGI(TAG, "Time synced to %02d:%02d:%02d", hour(), minute(), second());
-  } else {
-    ESP_LOGI(TAG, "No valid GPS time");
-  }
-#endif
-
   // check free memory
   if (esp_get_minimum_free_heap_size() <= MEM_LOW) {
     ESP_LOGI(TAG,
@@ -83,6 +74,24 @@ void reset_counters() {
   macs_ble = 0;
 }
 
+void do_timesync() {
+// sync time & date if we have valid gps time
+#ifdef HAS_GPS
+  if (gps.time.isValid()) {
+    setTime(gps.time.hour(), gps.time.minute(), gps.time.second(),
+            gps.date.day(), gps.date.month(), gps.date.year());
+    ESP_LOGI(TAG, "Time synced by GPS to %02d:%02d:%02d", hour(), minute(),
+             second());
+    return;
+  } else {
+    ESP_LOGW(TAG, "No valid GPS time");
+  }
+#endif
+  // Schedule a network time request at the next possible time
+  LMIC_requestNetworkTime(user_request_network_time_callback, &userUTCTime);
+  ESP_LOGI(TAG, "Network time request scheduled");
+}
+
 #ifndef VERBOSE
 int redirect_log(const char *fmt, va_list args) {
   // do nothing

src/hal/generic.h

@@ -13,6 +13,8 @@
 #define SPI_SCLK GPIO_NUM_18
 #define SPI_CS   GPIO_NUM_5
 
+#define HAS_BME 1  // BME680 sensor on I2C bus (SDA=4/SCL=15); comment out if not present
+
 #define CFG_sx1276_radio 1 // select LoRa chip
 //#define CFG_sx1272_radio 1 // select LoRa chip
 #define BOARD_HAS_PSRAM // use if board has external PSRAM

src/hal/heltec.h

@@ -3,6 +3,8 @@
 
 #include <stdint.h>
 
+#define HAS_BME 1  // BME680 sensor on I2C bus (SDA=4/SCL=15); comment out if not present
+
 // Hardware related definitions for Heltec LoRa-32 Board
 
 #define HAS_LORA 1       // comment out if device shall not send data via LoRa

src/lmic_config.h

@@ -21,6 +21,8 @@
 
 //#define LMIC_USE_INTERRUPTS
 
+#define LMIC_ENABLE_DeviceTimeReq 1
+
 // 16 μs per tick
 // LMIC requires ticks to be 15.5μs - 100 μs long
 #define US_PER_OSTICK_EXPONENT 4
@@ -38,7 +40,7 @@
 // enable more verbose output. Make sure that printf is actually
 // configured (e.g. on AVR it is not by default), otherwise using it can
 // cause crashing.
-//#define LMIC_DEBUG_LEVEL 1
+#define LMIC_DEBUG_LEVEL 2
 
 // Enable this to allow using printf() to print to the given serial port
 // (or any other Print object). This can be easy for debugging. The

src/lorawan.cpp

@@ -328,9 +328,9 @@ void lora_send(osjob_t *job) {
     // waiting for LoRa getting ready
   } else {
     if (xQueueReceive(LoraSendQueue, &SendBuffer, (TickType_t)0) == pdTRUE) {
-      // SendBuffer gets struct MessageBuffer with next payload from queue
+      // SendBuffer now filled with next payload from queue
       if (!LMIC_setTxData2(SendBuffer.MessagePort, SendBuffer.Message,
-                          SendBuffer.MessageSize, (cfg.countermode & 0x02))) {
+                           SendBuffer.MessageSize, (cfg.countermode & 0x02))) {
         ESP_LOGI(TAG, "%d byte(s) sent to LoRa", SendBuffer.MessageSize);
       } else {
         ESP_LOGE(TAG, "could not send %d byte(s) to LoRa",
@@ -384,7 +384,7 @@ esp_err_t lora_stack_init() {
   if (!LMIC_startJoining()) { // start joining
     ESP_LOGI(TAG, "Already joined");
   }
-  
+
   return ESP_OK; // continue main program
 #endif
 }
@@ -414,3 +414,48 @@ void lora_housekeeping(void) {
 // uxTaskGetStackHighWaterMark(LoraTask));
 #endif
 }
+
+void user_request_network_time_callback(void *pVoidUserUTCTime,
+                                        int flagSuccess) {
+  // Explicit conversion from void* to uint32_t* to avoid compiler errors
+  uint32_t *pUserUTCTime = (uint32_t *)pVoidUserUTCTime;
+
+  // A struct that will be populated by LMIC_getNetworkTimeReference.
+  // It contains the following fields:
+  //  - tLocal: the value returned by os_GetTime() when the time
+  //            request was sent to the gateway, and
+  //  - tNetwork: the seconds between the GPS epoch and the time
+  //              the gateway received the time request
+  lmic_time_reference_t lmicTimeReference;
+
+  if (flagSuccess != 1) {
+    ESP_LOGW(TAG, "Network time request callback error");
+    return;
+  }
+
+  // Populate "lmic_time_reference"
+  flagSuccess = LMIC_getNetworkTimeReference(&lmicTimeReference);
+  if (flagSuccess != 1) {
+    ESP_LOGW(TAG, "Network time request failed");
+    return;
+  }
+
+  // Update userUTCTime, considering the difference between the GPS and UTC
+  // epoch, and the leap seconds
+  *pUserUTCTime = lmicTimeReference.tNetwork + 315964800;
+
+  // Add the delay between the instant the time was transmitted and
+  // the current time
+
+  // Current time, in ticks
+  ostime_t ticksNow = os_getTime();
+  // Time when the request was sent, in ticks
+  ostime_t ticksRequestSent = lmicTimeReference.tLocal;
+  uint32_t requestDelaySec = osticks2ms(ticksNow - ticksRequestSent) / 1000;
+  *pUserUTCTime += requestDelaySec;
+
+  // Update the system time with the time read from the network
+  setTime(*pUserUTCTime);
+  ESP_LOGI(TAG, "Time synced by LoRa network to %02d:%02d:%02d", hour(),
+           minute(), second());
+}

src/main.cpp

@@ -35,6 +35,7 @@ IDLE          0     0     ESP32 arduino scheduler -> runs wifi sniffer
 looptask      1     1     arduino core -> runs the LMIC LoRa stack
 irqhandler    1     1     executes tasks triggered by irq
 gpsloop       1     2     reads data from GPS over serial or i2c
+bmeloop       1     2     reads data from BME680 over i2c
 IDLE          1     0     ESP32 arduino scheduler
 
 ESP32 hardware timers
@@ -157,6 +158,11 @@ void setup() {
   strcat_P(features, " GPS");
 #endif
 
+// initialize gps
+#ifdef HAS_BME
+  strcat_P(features, " BME");
+#endif
+
 // initialize LoRa
 #ifdef HAS_LORA
   strcat_P(features, " LORA");
@@ -275,6 +281,17 @@ void setup() {
                           1);        // CPU core
 #endif
 
+#ifdef HAS_BME
+  ESP_LOGI(TAG, "Starting BMEloop...");
+  xTaskCreatePinnedToCore(bme_loop,  // task function
+                          "bmeloop", // name of task
+                          2048,      // stack size of task
+                          (void *)1, // parameter of the task
+                          2,         // priority of the task
+                          &BmeTask,  // task handle
+                          1);        // CPU core
+#endif
+
   // start state machine
   ESP_LOGI(TAG, "Starting IRQ Handler...");
   xTaskCreatePinnedToCore(irqHandler,      // task function