ardupilot/libraries/AP_TemperatureSensor/AP_TemperatureSensor_config.h

#pragma once

#include <AP_HAL/AP_HAL_Boards.h>

// Enabled 0 is compiled out (disabled)
// Enabled 1 is always enabled on all vehicles
// Enabled 2 is enabled with dummy methods for all vehicles except Sub and SITL

#ifndef AP_TEMPERATURE_SENSOR_ENABLED
#if BOARD_FLASH_SIZE <= 1024
    #define AP_TEMPERATURE_SENSOR_ENABLED 0
#elif (CONFIG_HAL_BOARD == HAL_BOARD_SITL)
    #define AP_TEMPERATURE_SENSOR_ENABLED 1
#else
    #define AP_TEMPERATURE_SENSOR_ENABLED 2
#endif
#endif

#ifndef AP_TEMPERATURE_SENSOR_BACKEND_DEFAULT_ENABLED
#define AP_TEMPERATURE_SENSOR_BACKEND_DEFAULT_ENABLED AP_TEMPERATURE_SENSOR_ENABLED
#endif

#ifndef AP_TEMPERATURE_SENSOR_MAX31865_ENABLED
    #define AP_TEMPERATURE_SENSOR_MAX31865_ENABLED AP_TEMPERATURE_SENSOR_BACKEND_DEFAULT_ENABLED
#endif

#ifndef AP_TEMPERATURE_SENSOR_ANALOG_ENABLED
    #define AP_TEMPERATURE_SENSOR_ANALOG_ENABLED AP_TEMPERATURE_SENSOR_BACKEND_DEFAULT_ENABLED
#endif

#ifndef AP_TEMPERATURE_SENSOR_DRONECAN_ENABLED
    #define AP_TEMPERATURE_SENSOR_DRONECAN_ENABLED AP_TEMPERATURE_SENSOR_BACKEND_DEFAULT_ENABLED && HAL_ENABLE_DRONECAN_DRIVERS
#endif
#if AP_TEMPERATURE_SENSOR_DRONECAN_ENABLED && !HAL_ENABLE_DRONECAN_DRIVERS
    #error AP_TEMPERATURE_SENSOR_DRONECAN_ENABLED requires HAL_ENABLE_DRONECAN_DRIVERS
#endif

#ifndef AP_TEMPERATURE_SENSOR_MLX90614_ENABLED
    #define AP_TEMPERATURE_SENSOR_MLX90614_ENABLED AP_TEMPERATURE_SENSOR_ENABLED
#endif

// maximum number of Temperature Sensors
#ifndef AP_TEMPERATURE_SENSOR_MAX_INSTANCES
#define AP_TEMPERATURE_SENSOR_MAX_INSTANCES             3
#endif

// first sensor is always the primary sensor
#ifndef AP_TEMPERATURE_SENSOR_PRIMARY_INSTANCE
#define AP_TEMPERATURE_SENSOR_PRIMARY_INSTANCE          0
#endif