main.cc

/*
 * Copyright 2020 Daniel Friesel
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "config.h"
#ifdef CONFIG_driver_bme680_bsec_save_state
#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
#define BSEC_STATE_PATH TOSTRING(CONFIG_driver_bme680_bsec_state_path)
#include <stdio.h>
#endif

#include "arch.h"
#include "driver/gpio.h"
#include "driver/stdout.h"
#include "driver/uptime.h"

#if defined(CONFIG_meta_driver_hardware_i2c)
#include "driver/i2c.h"
#elif defined(CONFIG_driver_softi2c)
#include "driver/soft_i2c.h"
#endif

#include "driver/bme680.h"
#include "driver/bme680_util.h"
#include "driver/bme680-bsec-armv6/bsec_interface.h"

const char* accuracy[] = {"(unreliable)", "(calibration required)", "(auto-trim in progress)", ""};

#ifdef CONFIG_driver_bme680_bsec_save_state
// For (de)serialization of library state across application restarts
uint8_t serialized_state[BSEC_MAX_STATE_BLOB_SIZE];
uint8_t work_buffer[BSEC_MAX_STATE_BLOB_SIZE];
#endif

void loop(void)
{
	static bsec_bme_settings_t sensor_settings;

	static uint16_t iteration = 0;

	struct bme680_field_data data;
	bsec_input_t bsec_inputs[BSEC_MAX_PHYSICAL_SENSOR];
	bsec_output_t bsec_outputs[BSEC_NUMBER_OUTPUTS];

	uint8_t num_bsec_inputs = 0;
	uint8_t num_bsec_outputs = BSEC_NUMBER_OUTPUTS;

	int64_t now = uptime.get_us() * 1000;
	uint32_t now_s = uptime.get_s();

	/*
	 * BSEC expects the application to observe precise timing constraints.
	 * After each call to bsec_sensor_control, sensor_settings.next_call is set
	 * to the nanosecond timestamp of the next call. Significant violations
	 * cause bsec_sensor_control to return a BSEC_W_SC_CALL_TIMING_VIOLATION
	 * warning.
	 */

	if (now < sensor_settings.next_call) {
		if (sensor_settings.next_call - now < 1000000000) {
			// less than one second -> sleep
			arch.delay_us((sensor_settings.next_call - now) / 1000);
			now = uptime.get_us() * 1000;
		} else {
			// more than one second -> next loop() call is sufficient
			return;
		}
	}

	/*
	 * Retrieve sensor configuration from BSEC. In our case, it's fairly simple:
	 * all virtual sensors are set to the same sample rate, so we expect
	 * physical sensor readings to be the same for each BSEC call. However,
	 * if we disable virtual sensors, or change their sample rate, this is
	 * no longer the case.
	 * Also, bsec_sensor_control controls sensor_settings.next_call, so we
	 * need to call it anyways.
	 */
	bsec_library_return_t status = bsec_sensor_control(now, &sensor_settings);

	if (status < 0) {
		kout << "bsec_sensor_control error: " << status << endl;
		return;
	}
	if (status > 0) {
		kout << "bsec_sensor_control warning: " << status << endl;
	}

	/*
	 * bsec_sensor_control tells us whether it needs new sensor data or
	 * not. If so: configure the sensor as indicated and perform a measurement.
	 */
	if (sensor_settings.trigger_measurement) {
		bme680.tph_sett.os_hum = sensor_settings.humidity_oversampling;
		bme680.tph_sett.os_pres = sensor_settings.pressure_oversampling;
		bme680.tph_sett.os_temp = sensor_settings.temperature_oversampling;
		bme680.gas_sett.run_gas = sensor_settings.run_gas;
		bme680.gas_sett.heatr_temp = sensor_settings.heater_temperature;
		bme680.gas_sett.heatr_dur = sensor_settings.heating_duration;

		bme680.power_mode = BME680_FORCED_MODE;
		bme680.setSensorSettings(BME680_OST_SEL | BME680_OSP_SEL | BME680_OSH_SEL | BME680_GAS_SENSOR_SEL);

		bme680.setSensorMode();

		/*
		 * TODO recent versions of the bme680 open-source driver are able to
		 * calculate the required delay.
		 */
		arch.delay_ms(250);

		do {
			arch.delay_ms(5);
			bme680.getSensorMode();
		} while (bme680.power_mode == BME680_FORCED_MODE);

		if (sensor_settings.process_data) {
			bme680.getSensorData(&data);
			if (data.status & BME680_NEW_DATA_MSK) {
				if (sensor_settings.process_data & BSEC_PROCESS_TEMPERATURE) {
					bsec_inputs[num_bsec_inputs].sensor_id = BSEC_INPUT_TEMPERATURE;
					bsec_inputs[num_bsec_inputs].signal = data.temperature / 100.0f;
					bsec_inputs[num_bsec_inputs].time_stamp = now;
					num_bsec_inputs++;
				}
				if (sensor_settings.process_data & BSEC_PROCESS_HUMIDITY) {
					bsec_inputs[num_bsec_inputs].sensor_id = BSEC_INPUT_HUMIDITY;
					bsec_inputs[num_bsec_inputs].signal = data.humidity / 1000.0f;
					bsec_inputs[num_bsec_inputs].time_stamp = now;
					num_bsec_inputs++;
				}
				if (sensor_settings.process_data & BSEC_PROCESS_PRESSURE) {
					bsec_inputs[num_bsec_inputs].sensor_id = BSEC_INPUT_PRESSURE;
					bsec_inputs[num_bsec_inputs].signal = data.pressure;
					bsec_inputs[num_bsec_inputs].time_stamp = now;
					num_bsec_inputs++;
				}
				if (sensor_settings.process_data & BSEC_PROCESS_GAS) {
					bsec_inputs[num_bsec_inputs].sensor_id = BSEC_INPUT_GASRESISTOR;
					bsec_inputs[num_bsec_inputs].signal = data.gas_resistance;
					bsec_inputs[num_bsec_inputs].time_stamp = now;
					num_bsec_inputs++;
				}
			}
		}

		if (num_bsec_inputs > 0) {
			status = bsec_do_steps(bsec_inputs, num_bsec_inputs, bsec_outputs, &num_bsec_outputs);

			if (status < 0) {
				kout << "bsec_do_steps error: " << status << endl;
				return;
			}
			if (status > 0) {
				kout << "bsec_do_steps warning: " << status << endl;
			}

			for (uint8_t i = 0; i < num_bsec_outputs; i++) {
				switch (bsec_outputs[i].sensor_id) {
					case BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE:
						kout << now_s << " BME680 temperature " << bsec_outputs[i].signal << " °c" << endl;
						break;
					case BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY:
						kout << now_s << " BME680 humidity " << bsec_outputs[i].signal << " %" << endl;
						break;
					case BSEC_OUTPUT_RAW_PRESSURE:
						kout << now_s << " BME680 pressure " << bsec_outputs[i].signal / 100 << " hPa" << endl;
						break;
					case BSEC_OUTPUT_RAW_GAS:
						kout << now_s << " BME680 gas resistance " << bsec_outputs[i].signal << " Ω" << endl;
						break;
					case BSEC_OUTPUT_IAQ:
						if (bsec_outputs[i].accuracy > 0) {
							kout << now_s << " BME680 IAQ: " << bsec_outputs[i].signal << " " << accuracy[bsec_outputs[i].accuracy] << endl;
						}
						break;
					case BSEC_OUTPUT_STABILIZATION_STATUS:
						if (bsec_outputs[i].signal < 1) {
							kout << now_s << " BME680 IAQ initial stabilization in progress" << endl;
						}
						break;
					case BSEC_OUTPUT_RUN_IN_STATUS:
						if (bsec_outputs[i].signal < 1) {
							kout << now_s << " BME680 IAQ power-on stabilization in progress" << endl;
						}
						break;
					default:
						continue;
				}
			}
			kout << endl;
		}
	}

#ifdef CONFIG_driver_bme680_bsec_save_state
	if (++iteration == 600) {
		uint32_t  serialized_state_size;
		status = bsec_get_state(0, serialized_state, BSEC_MAX_STATE_BLOB_SIZE, work_buffer, BSEC_MAX_STATE_BLOB_SIZE, &serialized_state_size);
		if (status < 0) {
			kout << "bsec_get_state error: " << status << endl;
			return;
		}
		if (status > 0) {
			kout << "bsec_get_state warning: " << status << endl;
		}
		FILE *f = fopen(BSEC_STATE_PATH, "w");
		if (f == NULL) {
			perror("fopen");
			return;
		}
		if (fwrite(serialized_state, sizeof(uint8_t), serialized_state_size, f) < serialized_state_size) {
			perror("fwrite");
		}
		if (fclose(f) == EOF) {
			perror("fclose");
		}
		iteration = 0;
	}
#endif
}

int main(void)
{

	arch.setup();
	gpio.setup();
	kout.setup();

#if defined(CONFIG_meta_driver_i2c)
	while (i2c.setup() != 0) {
		kout << "I2C setup FAILED" << endl;
		arch.delay_ms(1000);
	}
	kout << "I2C setup OK" << endl;
#endif

	// Set up (open-source) BME680 driver
	bme680.intf = BME680_I2C_INTF;
	bme680.read = bme680_i2c_read;
	bme680.write = bme680_i2c_write;
	bme680.delay_ms = bme680_delay_ms;

	int8_t bme680_status = bme680.init();
	while (bme680_status != 0) {
		kout << "BME680 init failed: " << (uint8_t)bme680_status << endl;
		arch.delay_ms(1000);
	}
	kout << "BME680 init OK" << endl;

	// Initialize proprietary BSEC library
	bsec_library_return_t bsec_status = bsec_init();
	while (bsec_status != BSEC_OK) {
		kout << "BSEC init failed: " << bsec_status << endl;
		arch.delay_ms(1000);
	}
	kout << "BSEC init OK" << endl;

#ifdef CONFIG_driver_bme680_bsec_save_state
	FILE *f = fopen(BSEC_STATE_PATH, "r");
	if (f != NULL) {
		size_t serialized_state_size = fread(serialized_state, BSEC_MAX_STATE_BLOB_SIZE, sizeof(uint8_t), f);
		if (serialized_state_size > 0) {
			bsec_status = bsec_set_state(serialized_state, BSEC_MAX_STATE_BLOB_SIZE, work_buffer, BSEC_MAX_STATE_BLOB_SIZE);
			if (bsec_status < 0) {
				kout << "bsec_set_state error: " << bsec_status << endl;
			}
			if (bsec_status > 0) {
				kout << "bsec_set_state warning: " << bsec_status << endl;
			}
		}
		if (fclose(f) == EOF) {
			perror("fclose");
		}
	} else {
		// file doesn't exist. that's harmless.
		perror("fopen");
	}
#endif

	/*
	 * Output configuration. The BME680 BSEC library supports several virtual
	 * sensors such as raw temperature, compensated temperature, or IAQ. Each
	 * virtual sensor is calculated based on past observations and the
	 * TPH+Gas readings obtained from the BME680 sinsor.
	 *
	 * Here, we are interested in seven different types of readings.
	 */
	bsec_sensor_configuration_t virtual_sensors[7];
	unsigned char n_virtual_sensors = 7;

	/*
	 * bsec_update_subscription writes required sensor settings to the
	 * sensor_configs array. We're not interested in them at the moment.
	 */
	bsec_sensor_configuration_t sensor_configs[BSEC_MAX_PHYSICAL_SENSOR];
	unsigned char n_sensor_settings = BSEC_MAX_PHYSICAL_SENSOR;

	/*
	 * Low Power mode -> 1/3 Hz (i.e., one sample every three seconds).
	 */
	float sample_rate = BSEC_SAMPLE_RATE_LP;

	/*
	 * We're interested in the following readings.
	 * See bsec_virtual_sensor_t definition in bsec_datatypes for a list of
	 * supported virtual sensor types ("sensor_ids").
	 */
	virtual_sensors[0].sensor_id = BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_TEMPERATURE;
	virtual_sensors[0].sample_rate = sample_rate;
	virtual_sensors[1].sensor_id = BSEC_OUTPUT_SENSOR_HEAT_COMPENSATED_HUMIDITY;
	virtual_sensors[1].sample_rate = sample_rate;
	virtual_sensors[2].sensor_id = BSEC_OUTPUT_RAW_PRESSURE;
	virtual_sensors[2].sample_rate = sample_rate;
	virtual_sensors[3].sensor_id = BSEC_OUTPUT_RAW_GAS;
	virtual_sensors[3].sample_rate = sample_rate;
	virtual_sensors[4].sensor_id = BSEC_OUTPUT_IAQ;
	virtual_sensors[4].sample_rate = sample_rate;
	virtual_sensors[5].sensor_id = BSEC_OUTPUT_STABILIZATION_STATUS;
	virtual_sensors[5].sample_rate = sample_rate;
	virtual_sensors[6].sensor_id = BSEC_OUTPUT_RUN_IN_STATUS;
	virtual_sensors[6].sample_rate = sample_rate;

	bsec_status = bsec_update_subscription(virtual_sensors, n_virtual_sensors, sensor_configs, &n_sensor_settings);

	while (bsec_status != BSEC_OK) {
		kout << "bsec_update_subscription error: " << bsec_status << endl;
		arch.delay_ms(1000);
	}
	kout << "bsec_update_subscription OK" << endl;

	arch.idle_loop();

	return 0;
}