refactor + documentation

thermo_sensor/main/thermo_sensor.c

@@ -19,22 +19,33 @@ bmp280_t dev_bmp_280;
 
 void main_loop(void *pvParameters) {
     while (1) {
-        vTaskDelay(pdMS_TO_TICKS(10000));
         ygg_bmp280_read_sensor(&dev_bmp_280); 
         ygg_send_sensor_readouts(SENSOR_NAME,
                                  CURR_READOUT);
+        vTaskDelay(pdMS_TO_TICKS(10000));
     }
 }
 
 void app_main()
 {
+    // NVS -  Non-Volatile Storage, this memory stays untouched
+    // after power off. It is key value memory stored
+    // in separate partition of flash. It takes about 20kB.
+    // Here it is not used directly. It is required by WiFi
+    // driver to store SSID and password.
+    // NVS is organized into pages. Single page is one flash
+    // sector - typically 4096B
     esp_err_t ret = nvs_flash_init();
+
     if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        // ESP_ERR_NVS_NEW_VERSION_FOUND - NVS header page is
+        // stored in newer version (newer IDF) than version
+        // it is used by this application
         ESP_ERROR_CHECK(nvs_flash_erase());
-        ret = nvs_flash_init();
+        ESP_ERROR_CHECK(nvs_flash_init());
     }
-    ESP_ERROR_CHECK(ret);
-    wifi_init_sta();
+
+    ygg_wifi_init_sta();
 
     httpd_handle_t server = ygg_start_webserver();
     httpd_register_uri_handler(server, &ygg_temp_uri);