81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
/*
|
|
* Copyright 2018 Google Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "mgos.h"
|
|
#include "mgos_i2c.h"
|
|
|
|
#define MGOS_SI7021_READ_DELAY (2)
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
struct mgos_si7021;
|
|
|
|
/*
|
|
* Initialize a Si7021 on the I2C bus `i2c` at address specified in `i2caddr`
|
|
* parameter (default Si7021 is on address 0x40). The sensor will be polled for
|
|
* validity, upon success a new `struct mgos_si7021` is allocated and
|
|
* returned. If the device could not be found, NULL is returned.
|
|
*/
|
|
struct mgos_si7021 *mgos_si7021_create(struct mgos_i2c *i2c, uint8_t i2caddr);
|
|
|
|
/*
|
|
* Destroy the data structure associated with a Si7021 device. The reference
|
|
* to the pointer of the `struct mgos_si7021` has to be provided, and upon
|
|
* successful destruction, its associated memory will be freed and the pointer
|
|
* set to NULL.
|
|
*/
|
|
void mgos_si7021_destroy(struct mgos_si7021 **sensor);
|
|
|
|
/*
|
|
* The sensor will be polled for its temperature and humidity data. If the poll
|
|
* has occured in the last `MGOS_SI7021_READ_DELAY` seconds, the cached data is
|
|
* used (so as not to repeatedly poll the bus upon subsequent calls).
|
|
*/
|
|
bool mgos_si7021_read(struct mgos_si7021 *sensor);
|
|
|
|
/*
|
|
* The sensor will be polled for its temperature and humidity data. If the poll
|
|
* has occured in the last `MGOS_SI7021_READ_DELAY` seconds, the cached data is
|
|
* used (so as not to repeatedly poll the bus upon subsequent calls).
|
|
*
|
|
* The return value is the temperature of the sensor in Celsius, or NAN if no
|
|
* data was found.
|
|
*/
|
|
float mgos_si7021_getTemperature(struct mgos_si7021 *sensor);
|
|
|
|
/*
|
|
* The sensor will be polled for its temperature and humidity data. If the poll
|
|
* has occured in the last `MGOS_SI7021_READ_DELAY` seconds, the cached data is
|
|
* used (so as not to repeatedly poll the bus upon subsequent calls).
|
|
*
|
|
* The return value is the humidity of the sensor in percent relative humidity,
|
|
* or NAN if no data was found.
|
|
*/
|
|
float mgos_si7021_getHumidity(struct mgos_si7021 *sensor);
|
|
|
|
/*
|
|
* Initialization function for MGOS -- currently a noop.
|
|
*/
|
|
bool mgos_si7021_i2c_init(void);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|