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sensirion_i2c_hal.h
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sensirion_i2c_hal.h
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/*
* Copyright (c) 2018, Sensirion AG
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of Sensirion AG nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SENSIRION_I2C_HAL_H
#define SENSIRION_I2C_HAL_H
#include "sensirion_config.h"
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/**
* Select the current i2c bus by index.
* All following i2c operations will be directed at that bus.
*
* THE IMPLEMENTATION IS OPTIONAL ON SINGLE-BUS SETUPS (all sensors on the same
* bus)
*
* @param bus_idx Bus index to select
* @returns 0 on success, an error code otherwise
*/
int16_t sensirion_i2c_hal_select_bus(uint8_t bus_idx);
/**
* Initialize all hard- and software components that are needed for the I2C
* communication.
*/
void sensirion_i2c_hal_init(void);
/**
* Release all resources initialized by sensirion_i2c_hal_init().
*/
void sensirion_i2c_hal_free(void);
/**
* Execute one read transaction on the I2C bus, reading a given number of bytes.
* If the device does not acknowledge the read command, an error shall be
* returned.
*
* @param address 7-bit I2C address to read from
* @param data pointer to the buffer where the data is to be stored
* @param count number of bytes to read from I2C and store in the buffer
* @returns 0 on success, error code otherwise
*/
int8_t sensirion_i2c_hal_read(uint8_t address, uint8_t* data, uint16_t count);
/**
* Execute one write transaction on the I2C bus, sending a given number of
* bytes. The bytes in the supplied buffer must be sent to the given address. If
* the slave device does not acknowledge any of the bytes, an error shall be
* returned.
*
* @param address 7-bit I2C address to write to
* @param data pointer to the buffer containing the data to write
* @param count number of bytes to read from the buffer and send over I2C
* @returns 0 on success, error code otherwise
*/
int8_t sensirion_i2c_hal_write(uint8_t address, const uint8_t* data,
uint16_t count);
/**
* Sleep for a given number of microseconds. The function should delay the
* execution approximately, but no less than, the given time.
*
* When using hardware i2c:
* Despite the unit, a <10 millisecond precision is sufficient.
*
* When using software i2c:
* The precision needed depends on the desired i2c frequency, i.e. should be
* exact to about half a clock cycle (defined in
* `SENSIRION_I2C_CLOCK_PERIOD_USEC` in `sensirion_sw_i2c_gpio.h`).
*
* Example with 400kHz requires a precision of 1 / (2 * 400kHz) == 1.25usec.
*
* @param useconds the sleep time in microseconds
*/
void sensirion_i2c_hal_sleep_usec(uint32_t useconds);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* SENSIRION_I2C_HAL_H */