main/iotbalkon.c

/**
 * @file iotbalkon.c
 * @brief iotbalkon project.
 */

#include "config.h"

static const char *TAG = "iotbalkon";

/*
 * Main State table.
 */
typedef enum {
    State_Init = 0,
    State_Connect_Wifi,
    State_Connect_MQTT,
    State_Working,
    State_WorkDone,
    State_Disconnect_MQTT,
    State_Disconnect_Wifi,
    State_Wait,
    State_Measure,
    State_GoSleep
} Main_State;


static TaskHandle_t			xTaskBMP280 = NULL;
static TaskHandle_t			xTaskINA219 = NULL;
static TaskHandle_t			xTaskAPDS9930 = NULL;
static TaskHandle_t			xTaskMQTT = NULL;
static TaskHandle_t			xTaskWifi = NULL;
static TaskHandle_t			xTaskOUT = NULL;

#define	MAX_LOOPS			32
#define SUB_TIME			1000

float					temperature;
float					pressure;
float					solarVolts, solarCurrent, solarPower;
float					batteryVolts, batteryCurrent, batteryPower;
int					batteryState;
float					s_Volts[MAX_LOOPS + 1];
float					s_Current[MAX_LOOPS + 1];
float					b_Volts[MAX_LOOPS + 1];
float					b_Current[MAX_LOOPS + 1];
bool					m_Valid[MAX_LOOPS + 1];
uint64_t				m_Time[MAX_LOOPS + 1];
uint64_t				gLastTime;
uint64_t				gTimeNext;

uint8_t					loopno = 0;
uint8_t					loops = 0;
uint8_t					ST_LOOPS = 6;

int					DisCounter = 0;

extern BMP280_State			*bmp280_state;			///< I2C state
extern SemaphoreHandle_t		xSemaphoreBMP280;		///< I2C lock semaphore
extern bmp280_params_t			bmp280_params;
extern bmp280_t				bmp280_dev;
extern SemaphoreHandle_t		xSemaphoreINA219;
extern ina219_t				ina219_b_dev;
extern ina219_t				ina219_s_dev;
extern INA219_State			*ina219_state;
extern SemaphoreHandle_t		xSemaphoreAPDS9930;
extern apds9930_t			apds9930_dev;
extern APDS9930_State			*apds9930_state;
extern SemaphoreHandle_t		xSemaphoreWiFi;
extern WIFI_State			*wifi_state;			///< WiFi state

uint32_t				Alarm = 0;

/*
 * Alarm bits
 */
#define AL_ACCULOW			0x01
#define AL_NOWIFI			0x02


#define ST_INTERVAL			10000
#define MAX_LOOPS			32

/*
 * Variables in NVS namespace "balkon"
 */
uint8_t					Relay1;
uint8_t					Relay2;
uint8_t					Dimmer3;
uint8_t					Dimmer4;


//                              0%    10%    20%    30%    40%    50%    60%    70%    80%    90%   100%
float Charge_C_5[11]     = { 12.40, 12.60, 12.75, 12.95, 13.20, 13.35, 13.55, 13.67, 14.00, 15.25, 15.94 };
float Charge_C_10[11]    = { 12.20, 12.38, 12.60, 12.80, 13.05, 13.20, 13.28, 13.39, 13.60, 14.20, 15.25 };
float Charge_C_20[11]    = { 12.00, 12.07, 12.42, 12.70, 12.85, 13.02, 13.11, 13.15, 13.25, 13.60, 14.15 };
float Charge_C_40[11]    = { 11.55, 11.80, 12.25, 12.57, 12.70, 12.80, 12.90, 12.95, 13.00, 13.20, 13.50 };
float Rest[11]           = { 11.50, 11.70, 11.88, 12.10, 12.22, 12.30, 12.40, 12.50, 12.57, 12.64, 12.72 };
float Load_C_20[11]      = { 11.45, 11.70, 11.80, 12.05, 12.20, 12.28, 12.37, 12.48, 12.55, 12.57, 12.60 };
float Load_C_10[11]      = { 10.98, 11.27, 11.50, 11.65, 11.85, 12.00, 12.10, 12.20, 12.30, 12.40, 12.50 };
float Load_C_5[11]       = { 10.20, 10.65, 10.90, 11.15, 11.35, 11.55, 11.63, 11.75, 11.90, 12.00, 12.08 };


/*
 * Calculate the load state of the battery.
 */
void BatteryState(float Voltage, float Current) {
  int i;

  batteryState = 0;
  ESP_LOGI(TAG, "Batt %.4fV %.4fmA", Voltage, Current);

  if (Current < -750) {
    // Load current > C/5, 1A
    for (i = 0; i < 10; i++) {
      if (Load_C_5[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Load C/5   %d%%", batteryState);

  } else if (Current < -375) {
    // Load current > C/10, 500mA
    for (i = 0; i < 10; i++) {
      if (Load_C_10[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Load C/10  %d%%", batteryState);

  } else if (Current < -125) {
    // Load current > C/20, 250mA
    for (i = 0; i < 10; i++) {
      if (Load_C_20[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Load C/20  %d%%", batteryState);

  } else if (Current > 750) {
    // Charge > C/5, 1A
    for (i = 0; i < 10; i++) {
      if (Charge_C_5[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Charge C/5  %d%%", batteryState);

  } else if (Current > 375) {
    // Charge > C/10, 500mA
    for (i = 0; i < 10; i++) {
      if (Charge_C_10[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Charge C/10 %d%%", batteryState);

  } else if (Current > 187.5) {
    // Charge > C/20, 250 mA
    for (i = 0; i < 10; i++) {
      if (Charge_C_20[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Charge C/20 %d%%", batteryState);

  } else if (Current > 62.5) {
    // Charge > C/40, 125 mA
    for (i = 0; i < 10; i++) {
      if (Charge_C_40[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Charge C/40 %d%%", batteryState);

  } else {
    // Rest
    for (i = 0; i < 10; i++) {
      if (Rest[i + 1] >= Voltage) {
        break;
      }
    }
    batteryState = i * 10;
    ESP_LOGI(TAG, "Rest   %d%%", batteryState);
  }
}


uint64_t millis(void) {
    return esp_timer_get_time() / 1000;
}


/*
 * Read the temperature and pressure from the BMP280.
 */
void getTempBaro() {
    temperature = 20;
    pressure = 1000;

    request_bmp280();

    while (! ready_bmp280()) {
	vTaskDelay(10 / portTICK_PERIOD_MS);
    }

    if (xSemaphoreTake(xSemaphoreBMP280, 25) == pdTRUE) {
	temperature = bmp280_state->temperature;
	pressure = bmp280_state->pressure / 100.0;
	ESP_LOGI(TAG, "Temperature: %.2f Pressure: %.1f hPa", temperature, pressure);
	xSemaphoreGive(xSemaphoreBMP280);
    } else {
	ESP_LOGE(TAG, "Can't lock xSemaphoreBMP280");
    }
}


/*
 * Read voltage and current from both INA219 boards. The results
 * are stored in an array so that we later can average the results.
 */
void getVoltsCurrent() {

    request_ina219();

    while (! ready_ina219()) {
        vTaskDelay(10 / portTICK_PERIOD_MS);
    }

    if (xSemaphoreTake(xSemaphoreINA219, 25) == pdTRUE) {

	s_Volts[loopno] = ina219_state->Solar.volts + ina219_state->Solar.shunt;
	s_Current[loopno] = ina219_state->Solar.current;
	b_Volts[loopno] = ina219_state->Battery.volts + ina219_state->Battery.shunt;
        b_Current[loopno] = ina219_state->Battery.current;
	m_Valid[loopno] = ina219_state->valid;
	xSemaphoreGive(xSemaphoreINA219);

	/*
	 * Check for crazy values
	 */
	if ((b_Volts[loopno] < 10) || (b_Volts[loopno] > 15.0)) {
	    m_Valid[loopno] = false;
	}
	if ((b_Current[loopno] < 0) || (b_Current[loopno] > 2000)) {
	    m_Valid[loopno] = false;
	}
	if (s_Volts[loopno] < 0) {
	    s_Volts[loopno] = 0.0;
	}
	if (s_Volts[loopno] > 24) {
	    m_Valid[loopno] = false;
	}
	if (s_Current[loopno] < 0) {
	    s_Current[loopno] = 0.0;
	}
	if (s_Current[loopno] > 2000) {
	    m_Valid[loopno] = false;
	}
    }

    uint64_t  ms = millis();
    m_Time[loopno] = ms - gLastTime;
    gLastTime = ms;

    ESP_LOGI(TAG, "Measure: %d  Valid: %s  Battery: %.3fV %.1fmA  Solar: %.3fV %.1fmA  time %llu",
		  loopno, (m_Valid[loopno]) ? "true":"false", b_Volts[loopno], b_Current[loopno], s_Volts[loopno], s_Current[loopno], m_Time[loopno]);

    if (loopno < (MAX_LOOPS - 1))
	loopno++;
}


void getLightValues() {

    request_apds9930();

    while (! ready_apds9930()) {
        vTaskDelay(10 / portTICK_PERIOD_MS);
    }
}


void app_main(void)
{
    uint64_t	totalTime, gTimeInMillis;
    nvs_handle_t	my_handle;

#ifdef CONFIG_CODE_PRODUCTION
    ESP_LOGI(TAG, "Starting production");
#endif
#ifdef CONFIG_CODE_TESTING
    ESP_LOGI(TAG, "Starting testing");
#endif

    /*
     * Initialize NVS
     */
    esp_err_t err = nvs_flash_init();
    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
      ESP_ERROR_CHECK(nvs_flash_erase());
      err = nvs_flash_init();
    }
    ESP_ERROR_CHECK(err);

    err = nvs_open("balkon", NVS_READWRITE, &my_handle);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Error (%s) opening NVS handle 'balkon'", esp_err_to_name(err));
    } else {
        err = nvs_get_u8(my_handle, (char *)"out1", &Relay1);
	if (err == ESP_ERR_NVS_NOT_FOUND) {
	    err = nvs_set_u8(my_handle, (char *)"out1", 0);
	    Relay1 = 0;
	}
	if (err != ESP_OK) {
	    ESP_LOGE(TAG, "Error (%s) opening NVS handle 'balkon', key 'out1'", esp_err_to_name(err));
	}

	err = nvs_get_u8(my_handle, (char *)"out2", &Relay2);
        if (err == ESP_ERR_NVS_NOT_FOUND) {
            err = nvs_set_u8(my_handle, (char *)"out2", 0);
            Relay2 = 0;
        }
	if (err != ESP_OK) {
            ESP_LOGE(TAG, "Error (%s) opening NVS handle 'balkon', key 'out2'", esp_err_to_name(err));
        }

	err = nvs_get_u8(my_handle, (char *)"out3", &Dimmer3);
        if (err == ESP_ERR_NVS_NOT_FOUND) {
            err = nvs_set_u8(my_handle, (char *)"out3", 0);
            Dimmer3 = 0;
        }
	if (err != ESP_OK) {
            ESP_LOGE(TAG, "Error (%s) opening NVS handle 'balkon', key 'out3'", esp_err_to_name(err));
        }

	err = nvs_get_u8(my_handle, (char *)"out4", &Dimmer4);
        if (err == ESP_ERR_NVS_NOT_FOUND) {
            err = nvs_set_u8(my_handle, (char *)"out4", 0);
            Dimmer4 = 0;
        }
	if (err != ESP_OK) {
            ESP_LOGE(TAG, "Error (%s) opening NVS handle 'balkon', key 'out4'", esp_err_to_name(err));
        }

	nvs_commit(my_handle);
	nvs_close(my_handle);
    }

    gLastTime = millis();
    ESP_ERROR_CHECK(i2cdev_init());

    bmp280_init_default_params(&bmp280_params);
    memset(&bmp280_dev, 0, sizeof(bmp280_t));
    memset(&ina219_b_dev, 0, sizeof(ina219_t));
    memset(&ina219_s_dev, 0, sizeof(ina219_t));
    memset(&apds9930_dev, 0, sizeof(apds9930_t));

    i2c_dev_t dev = { 0 };
    dev.cfg.sda_io_num = CONFIG_I2C_MASTER_SDA;
    dev.cfg.scl_io_num = CONFIG_I2C_MASTER_SCL;
    dev.cfg.master.clk_speed = 400000;

    dev.addr = 0x39;
    if (i2c_dev_probe(&dev, I2C_DEV_WRITE) == 0) {
	ESP_ERROR_CHECK(apds9930_init_desc(&apds9930_dev, 0x39, 0, CONFIG_I2C_MASTER_SDA, CONFIG_I2C_MASTER_SCL));
	ESP_ERROR_CHECK(apds9930_init(&apds9930_dev));
	ESP_LOGI(TAG, "Found APDS-9930 id: 0x%02x", apds9930_dev.id);
    }
    dev.addr = 0x40;
    if (i2c_dev_probe(&dev, I2C_DEV_WRITE) == 0) {
	ESP_ERROR_CHECK(ina219_init_desc(&ina219_b_dev, 0x40, 0, CONFIG_I2C_MASTER_SDA, CONFIG_I2C_MASTER_SCL));
	ESP_ERROR_CHECK(ina219_init(&ina219_b_dev));
	ESP_LOGI(TAG, "Found INA219 @0x40 Battery");
    }
    dev.addr = 0x41;
    if (i2c_dev_probe(&dev, I2C_DEV_WRITE) == 0) {
	ESP_ERROR_CHECK(ina219_init_desc(&ina219_s_dev, 0x41, 0, CONFIG_I2C_MASTER_SDA, CONFIG_I2C_MASTER_SCL));
	ESP_ERROR_CHECK(ina219_init(&ina219_s_dev));
        ESP_LOGI(TAG, "Found INA219 @0x41 Solar");
    }
    dev.addr = 0x76;
    if (i2c_dev_probe(&dev, I2C_DEV_WRITE) == 0) {
	ESP_ERROR_CHECK(bmp280_init_desc(&bmp280_dev, BMP280_I2C_ADDRESS_0, 0, CONFIG_I2C_MASTER_SDA, CONFIG_I2C_MASTER_SCL));
	ESP_ERROR_CHECK(bmp280_init(&bmp280_dev, &bmp280_params));
	ESP_LOGI(TAG, "Found BMP280 @ 0x76 id: 0x%02x", bmp280_dev.id);
    } else {
    	dev.addr = 0x77;
    	if (i2c_dev_probe(&dev, I2C_DEV_WRITE) == 0) {
	    ESP_ERROR_CHECK(bmp280_init_desc(&bmp280_dev, BMP280_I2C_ADDRESS_1, 0, CONFIG_I2C_MASTER_SDA, CONFIG_I2C_MASTER_SCL));
	    ESP_ERROR_CHECK(bmp280_init(&bmp280_dev, &bmp280_params));
            ESP_LOGI(TAG, "Found BMP280 @ 0x77 id: 0x%02x", bmp280_dev.id);
    	}
    }

    /*
     * Create FreeRTOS tasks
     */
    xSemaphoreBMP280 = xSemaphoreCreateMutex();
    xSemaphoreINA219 = xSemaphoreCreateMutex();
    xSemaphoreAPDS9930 = xSemaphoreCreateMutex();


    xTaskCreate(&task_bmp280,   "task_bmp280",      2560, NULL, 8, &xTaskBMP280);
    xTaskCreate(&task_ina219,   "task_ina219",      2560, NULL, 8, &xTaskINA219);
    xTaskCreate(&task_apds9930, "task_apds9930",    2560, NULL, 8, &xTaskAPDS9930);
    xTaskCreate(&task_out,      "task_out",         2560, NULL, 9, &xTaskOUT);
    // esp_log_level_set("MQTT_CLIENT", ESP_LOG_ERROR);
    xTaskCreate(&task_mqtt,     "task_mqtt",        4096, NULL, 5, &xTaskMQTT);
    // esp_log_level_set("wifi", ESP_LOG_ERROR);
    xTaskCreate(&task_wifi,     "task_wifi",        4096, NULL, 3, &xTaskWifi);

    vTaskDelay(10 / portTICK_PERIOD_MS);

    /*
     * Main application loop.
     */
    int State = State_Init;
    int OldState = State_Init + 1;


    while (1) {
//	request_ina219();
	request_apds9930();
	vTaskDelay(5000 / portTICK_PERIOD_MS);
    }

    while (1) {
	if (OldState != State) {
	    ESP_LOGI(TAG, "Switch to state %d", State);
	    OldState = State;
	}

	gTimeInMillis = millis();

	switch (State) {
	    case State_Init:		getTempBaro();
					getLightValues();
					getVoltsCurrent();
					State = State_Connect_Wifi;
					DisCounter = 0;
					request_WiFi(true);
		    			break;

	    case State_Connect_Wifi:	if (ready_WiFi()) {
					    State = State_Connect_MQTT;
					    /*
					     * Give the network stack a bit more time to setup
					     */
					    vTaskDelay(250 / portTICK_PERIOD_MS);
					    request_mqtt(true);
					    Alarm &= ~AL_NOWIFI;
					    ESP_LOGI(TAG, "Connected counter WiFi %d", DisCounter);
					    DisCounter = 0;
					} else {
					    /*
					     * 30 seconds connection try.
					     */
					    DisCounter++;
					    vTaskDelay(1000 / portTICK_PERIOD_MS);
					    ESP_LOGI(TAG, "* Counter WiFi %d", DisCounter);
					    if (DisCounter > 30) {
						Alarm |= AL_NOWIFI;
						request_WiFi(false);
						State = State_Init;
						vTaskDelay(4000 / portTICK_PERIOD_MS);
					    }
					}
					break;

	    case State_Connect_MQTT:	if (ready_mqtt()) {
					    State = State_Working;
					    ESP_LOGI(TAG, "Connected counter MQTT %d", DisCounter);
                                            DisCounter = 0;
					} else {
					    DisCounter++;
					    if (DisCounter > 60) {
						request_mqtt(false);
						request_WiFi(false);
						State = State_Init;
						vTaskDelay(2000 / portTICK_PERIOD_MS);
					    }
					    vTaskDelay(1000 / portTICK_PERIOD_MS);
					}
					break;

	    case State_Working:		/*
					 * The final measure power usage.
					 * This one should include the WiFi usage current.
					 */
					getVoltsCurrent();
					solarVolts = solarCurrent = solarPower = batteryVolts = batteryCurrent = batteryPower = 0;
					loops = 0;
      					totalTime = 0;
					for (int i = 0; i < loopno; i++) {
	      				    /*
    					     * If there are only 2 loops, and the flag that we came from deep-sleep is set
    					     * then assume the following:
   					     *   1. No current (or very low for the dc converter) during DS_TIME seconds.
    					     *   2. Low power during 0.5 second (no WiFi yet).
    					     *   3. 5 seconds power usage for the last measurement.
    					     * Calculate the average battery current from this.
    					     *
    					     * If there are more loops and we came from continues running do the following:
    					     *   1. Take the current use from all exept the last one, weight loops * 10 seconds.
    					     *   2. Take the last one, and weight for 5 seconds.
    					     * Calculate the average battery current from this.
    					     */
					    if (m_Valid[i]) {
						solarVolts += s_Volts[i];
						solarCurrent += s_Current[i];
						batteryVolts += b_Volts[i];
						if (i == (loopno - 1)) {
						    // Add the extra time
						    m_Time[i] += SUB_TIME;
						}
						batteryCurrent += b_Current[i] * m_Time[i];
						totalTime += m_Time[i];
						loops++;
					    }
					}

      					// if (EEPROM.read(EM_DS_Active)) {
        				//    totalTime += EEPROM.read(EM_DS_Time) * 1000;
        				//    batteryCurrent += DS_CURRENT * EEPROM.read(EM_DS_Time) * 1000;
					//    //        Serial.printf("Added %d totalTime %d\n", EEPROM.read(EM_DS_Time) * 1000, totalTime);
      					// }

      					// If valid measurements
      					if (loops) {
					    solarVolts = solarVolts / loops;
					    solarCurrent = solarCurrent / loops;
					    solarPower = solarVolts * solarCurrent;
					    batteryVolts = batteryVolts / loops;
					    batteryCurrent = batteryCurrent / totalTime;
					    batteryPower = batteryVolts * batteryCurrent;
					    BatteryState(batteryVolts, (0 - batteryCurrent) + solarCurrent);

					    ESP_LOGI(TAG, "  Solar Volts: %.4fV Current %.4fmA Power %.4fmW", solarVolts, solarCurrent, solarPower);
					    ESP_LOGI(TAG, "Battery Volts: %.4fV Current %.4fmA Power %.4fmW", batteryVolts, batteryCurrent, batteryPower);

        				    /*   Check alarm conditions */
//					    if (batteryState <= 10) {
//					    	Alarm |= AL_ACCULOW;
//					    } else {
					    	Alarm &= ~AL_ACCULOW;
//					    }
      					}
					getTempBaro();
      					publish();
      					State = State_WorkDone;
      					gTimeNext = millis() + SUB_TIME;
					break;

	    case State_WorkDone:	vTaskDelay(20 / portTICK_PERIOD_MS);
					if (gTimeInMillis > gTimeNext) {
					    State = State_Disconnect_MQTT;
					    request_mqtt(false);
					}
					break;

	    case State_Disconnect_MQTT:	wait_mqtt(10000);
					State = State_Disconnect_Wifi;
					break;

	    case State_Disconnect_Wifi:	request_WiFi(false);
      					// // Reset values for average current measurement.
      					// HaveIP = false;
					loopno = 0;
					gLastTime = millis();
					//vTaskDelay(10 / portTICK_PERIOD_MS);

					/*
      					 *  If any output is on, use 6 10 seconds loops.
      					 *  If nothing on, do a deep sleep.
      					 */
					if (Relay1 || Relay2 || Dimmer3 || Dimmer4) {
        				//    if (EEPROM.read(EM_DS_Active)) {
          				//	EEPROM.write(EM_DS_Active, 0);
          				//	EEPROM.commit();
        				}

        				//    // Active mode, 60 seconds loop
					ST_LOOPS = 6;
					gTimeNext = millis() + ST_INTERVAL;
					ESP_LOGI(TAG, "Start sleeploops");
					State = State_Wait;
					//    #if Debug == true
        				//    Serial.println(F("Start sleeploops"));
					//    #endif
        				//    State = State_Wait;
      					// } else {
					//    ds_time = DS_TIME;
        				//    if (solarVolts < 6) {
          				//      // At night, increase the deep-sleep time.
          				//	ds_time *= 4;
        				//    }
        				//    if ((! EEPROM.read(EM_DS_Active)) || (EEPROM.read(EM_DS_Time) != ds_time)) {
          				//      EEPROM.write(EM_DS_Active, 1);
          				//      EEPROM.write(EM_DS_Time, ds_time);
          				//      EEPROM.commit();
          				//      Serial.println("wrote new deep-sleep settings");
        				//    }
        				//    State = State_GoSleep;
      					// }
					break;

	    case State_Wait:		if (gTimeInMillis > gTimeNext) {
					    State = State_Measure;
					}
					vTaskDelay(10 / portTICK_PERIOD_MS);
					break;

	    case State_Measure:		getVoltsCurrent();
					// if (isnan(Temperature)) {
      					//   getTempHumi();
      					// }
					gTimeNext = millis() + ST_INTERVAL;
					if (loopno >= ST_LOOPS) {
					    ESP_LOGI(TAG, "Enough loops, do connect");
        				    getLightValues();
					    State = State_Connect_Wifi;
					    DisCounter = 0;
					    request_WiFi(true);
					} else {
					    State = State_Wait;
					}
					break;

	    case State_GoSleep:		ESP_LOGE(TAG, "Entered GoSleep -- not supported");
					// ds_time = EEPROM.read(EM_DS_Time);
					// #if Debug == true
      					// Serial.printf("Going to deep-sleep for %d seconds\n", ds_time);
					// #endif
      					// ESP.deepSleep(ds_time * 1e6);
					break;
	}
        vTaskDelay(20 / portTICK_PERIOD_MS);
    }
    // Not reached.
}