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