81 lines
2.6 KiB
C
81 lines
2.6 KiB
C
/*
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* Copyright 2018 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include "mgos.h"
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#include "mgos_i2c.h"
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#define MGOS_HTU21DF_READ_DELAY (2)
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct mgos_htu21df;
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/*
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* Initialize a HTU21DF on the I2C bus `i2c` at address specified in `i2caddr`
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* parameter (default HTU21DF is on address 0x40). The sensor will be polled for
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* validity, upon success a new `struct mgos_htu21df` is allocated and
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* returned. If the device could not be found, NULL is returned.
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*/
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struct mgos_htu21df *mgos_htu21df_create(struct mgos_i2c *i2c, uint8_t i2caddr);
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/*
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* Destroy the data structure associated with a HTU21DF device. The reference
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* to the pointer of the `struct mgos_htu21df` has to be provided, and upon
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* successful destruction, its associated memory will be freed and the pointer
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* set to NULL.
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*/
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void mgos_htu21df_destroy(struct mgos_htu21df **sensor);
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/*
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* The sensor will be polled for its temperature and humidity data. If the poll
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* has occured in the last `MGOS_HTU21DF_READ_DELAY` seconds, the cached data is
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* used (so as not to repeatedly poll the bus upon subsequent calls).
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*/
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bool mgos_htu21df_read(struct mgos_htu21df *sensor);
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/*
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* The sensor will be polled for its temperature and humidity data. If the poll
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* has occured in the last `MGOS_HTU21DF_READ_DELAY` seconds, the cached data is
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* used (so as not to repeatedly poll the bus upon subsequent calls).
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*
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* The return value is the temperature of the sensor in Celsius, or NAN if no
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* data was found.
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*/
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float mgos_htu21df_getTemperature(struct mgos_htu21df *sensor);
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/*
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* The sensor will be polled for its temperature and humidity data. If the poll
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* has occured in the last `MGOS_HTU21DF_READ_DELAY` seconds, the cached data is
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* used (so as not to repeatedly poll the bus upon subsequent calls).
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*
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* The return value is the humidity of the sensor in percent relative humidity,
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* or NAN if no data was found.
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*/
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float mgos_htu21df_getHumidity(struct mgos_htu21df *sensor);
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/*
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* Initialization function for MGOS -- currently a noop.
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*/
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bool mgos_htu21df_i2c_init(void);
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#ifdef __cplusplus
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}
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#endif
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