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/*
MCP9808 for ChibiOS/RT - Copyright (C) 2016 Stephane D'Alu
*/
#ifndef _SENSOR_MCP9808_H_
#define _SENSOR_MCP9808_H_
#include <math.h>
#include "i2c_helpers.h"
#include "sensor.h"
/*===========================================================================*/
/* Driver constants. */
/*===========================================================================*/
#define MCP9808_CONTINUOUS_ACQUISITION_SUPPORTED TRUE
#define MCP9808_I2CADDR_FIXED 0x18
/**
* @brief Time necessary for the sensor to boot
*/
#define MCP9808_BOOTUP_TIME 0
/**
* @brief Time necessary for the sensor to start
*/
#define MCP9808_STARTUP_TIME 0
/*===========================================================================*/
/* Driver pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
#define MCP9808_I2CADDR_DEFAULT MCP9808_I2CADDR_FIXED
/*===========================================================================*/
/* Driver data structures and types. */
/*===========================================================================*/
/**
* @brief Different possible resolution
*/
typedef enum {
RES_2 = 0x00, /**< @brief Resolution of 1/2 = 0.5 */
RES_4 = 0x01, /**< @brief Resolution of 1/4 = 0.25 */
RES_8 = 0x10, /**< @brief Resolution of 1/8 = 0.125 */
RES_16 = 0x11, /**< @brief Resolution of 1/16 = 0.0625 */
} MCP9808_resolution_t;
/**
* @brief MCP9808 configuration structure.
*/
typedef struct {
I2CHelper i2c; /* keep it first */
} MCP9808_config;
/**
* @brief MCP9808 configuration structure.
*/
typedef struct {
MCP9808_config *config;
sensor_state_t state;
MCP9808_resolution_t resolution;
uint16_t cfg;
} MCP9808_drv;
/**
* @brief MCP9808 measure reading
*/
typedef struct {
float temperature;
} MCP9808_measure;
/*===========================================================================*/
/* Driver macros. */
/*===========================================================================*/
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
/**
* @brief Initialize the sensor driver
*/
void
MCP9808_init(MCP9808_drv *drv,
MCP9808_config *config);
/**
* @brief Check that the sensor is really present
*/
msg_t
MCP9808_check(MCP9808_drv *drv);
/**
* @brief Start the sensor
*/
msg_t
MCP9808_start(MCP9808_drv *drv);
/**
* @brief Stop the sensor
*
* @details If the sensor support it, it will be put in low energy mode.
*/
msg_t
MCP9808_stop(MCP9808_drv *drv);
/**
* @brief Control the MCP9809 resolution.
*/
msg_t
MCP9808_setResolution(MCP9808_drv *drv,
MCP9808_resolution_t res);
/**
* @brief Time in milli-seconds necessary for acquiring a naw measure
*
* @returns
* unsigned int time in millis-seconds
*/
unsigned int
MCP9808_getAcquisitionTime(MCP9808_drv *drv);
/**
* @brief Trigger a mesure acquisition
*/
static inline msg_t
MCP9808_startMeasure(MCP9808_drv *drv) {
(void)drv;
return MSG_OK;
}
/**
* @brief Read the newly acquiered measure
*
* @note According the the sensor design the measure read
* can be any value acquired after the acquisition time
* and the call to readMeasure.
*/
msg_t
MCP9808_readMeasure(MCP9808_drv *drv,
float *temperature);
/**
* @brief Read temperature and humidity
*
* @details According to the sensor specification/configuration
* (see #MCP9808_CONTINUOUS_ACQUISITION_SUPPORTED),
* if the sensor is doing continuous measurement
* it's value will be requested and returned immediately.
* Otherwise a measure is started, the necessary amount of
* time for acquiring the value is spend sleeping (not spinning),
* and finally the measure is read.
*
* @note In continuous measurement mode, if you just started
* the sensor, you will need to wait getAcquisitionTime()
* in addition to the usual getStartupTime()
* @note If using several sensors, it is better to start all the
* measure together, wait for the sensor having the longuest
* aquisition time, and finally read all the values
*/
msg_t
MCP9808_readTemperature(MCP9808_drv *drv,
float *temperature);
/**
* @brief Return the temperature value in °C.
*
* @note Prefere readTemperature(), if you need better error handling.
*
* @return The temperature in °C
* @retval float humidity percent
* @retval NAN on failure
*/
static inline float
MCP9808_getTemperature(MCP9808_drv *drv) {
float temperature = NAN;
MCP9808_readTemperature(drv, &temperature);
return temperature;
}
#endif
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