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/*
* Copyright (C) 2014-2015 Freie Universitรคt Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_periph_i2c I2C
* @ingroup drivers_periph
* @brief Low-level I2C peripheral driver
*
* @{
* @file
* @brief Low-level I2C peripheral driver interface definition
*
* The I2C signal lines SDA/SCL need external pull-up resistors which connect
* the lines to the positive voltage supply Vcc. The I2C driver implementation
* should enable the pin's internal pull-up resistors. There are however some
* use cases for which the internal pull resistors are not strong enough and the
* I2C bus will show faulty behavior. This can for example happen when
* connecting a logic analyzer which will raise the capacitance of the bus. In
* this case you should make sure you connect external pull-up resistors to both
* I2C bus lines.
*
* The minimum and maximum resistances are computed by:
* \f{eqnarray*}{
* R_{min} &=& \frac{V_{DD} - V_{OL(max)}} {I_{OL}}\\
* R_{max} &=& \frac{t_r} {(0.8473 \cdot C_b)}
* \f}<br>
* where:<br>
* \f$ V_{DD} =\f$ Supply voltage,
* \f$ V_{OL(max)} =\f$ Low level voltage,
* \f$ I_{OL} =\f$ Low level output current,
* \f$ t_r =\f$ Signal rise time,
* \f$ C_b =\f$ Bus capacitance <br>
* <br>The pull-up resistors depend on the bus speed.
* Some typical values are:<br>
* Normal mode: 10kΩ<br>
* Fast mode: 2kΩ<br>
* Fast plus mode: 2kΩ
*
* For more details refer to section 7.1 in:<br>
* http://www.nxp.com/documents/user_manual/UM10204.pdf
*
* @note The current version of this interface only supports the
7-bit addressing mode.
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
*/
#ifndef I2C_H
#define I2C_H
#include <stdint.h>
#include <limits.h>
#include "periph_cpu.h"
/**
* @todo Remove dev_enums.h include once all platforms are ported to the
* updated periph interface
*/
#include "periph/dev_enums.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Flag signaling a write operation on the bus
*/
#define I2C_FLAG_WRITE 0
/**
* @brief Flag signaling a read operation on the bus
*/
#define I2C_FLAG_READ 1
/**
* @brief Default I2C device access macro
* @{
*/
#ifndef I2C_DEV
#define I2C_DEV(x) (x)
#endif
/** @} */
/**
* @brief Default I2C undefined value
* @{
*/
#ifndef I2C_UNDEF
#define I2C_UNDEF (UINT_MAX)
#endif
/** @} */
/**
* @brief Default i2c_t type definition
* @{
*/
#ifndef HAVE_I2C_T
typedef unsigned int i2c_t;
#endif
/** @} */
/**
* @brief Default mapping of I2C bus speed values
* @{
*/
#ifndef HAVE_I2C_SPEED_T
typedef enum {
I2C_SPEED_LOW = 0, /**< low speed mode: ~10kbit/s */
I2C_SPEED_NORMAL, /**< normal mode: ~100kbit/s */
I2C_SPEED_FAST, /**< fast mode: ~400kbit/sj */
I2C_SPEED_FAST_PLUS, /**< fast plus mode: ~1Mbit/s */
I2C_SPEED_HIGH, /**< high speed mode: ~3.4Mbit/s */
} i2c_speed_t;
#endif
/** @} */
/**
* @brief Initialize an I2C device to run as bus master
*
* @param[in] dev the device to initialize
* @param[in] speed the selected bus speed
*
* @return 0 on successful initialization
* @return -1 on undefined device given
* @return -2 on unsupported speed value
*/
int i2c_init_master(i2c_t dev, i2c_speed_t speed);
/**
* @brief Get mutually exclusive access to the given I2C bus
*
* In case the I2C device is busy, this function will block until the bus is
* free again.
*
* @param[in] dev I2C device to access
*
* @return 0 on success
* @return -1 on error
*/
int i2c_acquire(i2c_t dev);
/**
* @brief Release the given I2C device to be used by others
*
* @param[in] dev I2C device to release
*
* @return 0 on success
* @return -1 on error
*/
int i2c_release(i2c_t dev);
/**
* @brief Read one byte from an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[out] data the result that was read
*
* @return the number of bytes that were read
* @return -1 on undefined device given
* @return -2 on invalid address
*/
int i2c_read_byte(i2c_t dev, uint8_t address, void *data);
/**
* @brief Read multiple bytes from an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[out] data array holding the received bytes
* @param[in] length the number of bytes to read into `data`
*
* @return the number of bytes that were read
* @return -1 on undefined device given
*/
int i2c_read_bytes(i2c_t dev, uint8_t address, void *data, int length);
/**
* @brief Read one byte from a register at the I2C slave with the given
* address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[out] data the result that was read
*
* @return the number of bytes that were read
* @return -1 on undefined device given
*/
int i2c_read_reg(i2c_t dev, uint8_t address, uint8_t reg, void *data);
/**
* @brief Read multiple bytes from a register at the I2C slave with the given
* address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[out] data array holding the received bytes
* @param[in] length the number of bytes to read into `data`
*
* @return the number of bytes that were read
* @return -1 on undefined device given
*/
int i2c_read_regs(i2c_t dev, uint8_t address, uint8_t reg,
void *data, int length);
/**
* @brief Write one byte to an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] data byte to write to the device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_byte(i2c_t dev, uint8_t address, uint8_t data);
/**
* @brief Write multiple bytes to an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] data array with bytes to write to the target device
* @param[in] length number of bytes to write to the target device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_bytes(i2c_t dev, uint8_t address, const void *data, int length);
/**
* @brief Write one byte to a register at the I2C slave with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[in] data byte to write to the device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_reg(i2c_t dev, uint8_t address, uint8_t reg, uint8_t data);
/**
* @brief Write multiple bytes to a register at the I2C slave with the given
* address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[in] data array with bytes to write to the target device
* @param[in] length number of bytes to write to the target device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_regs(i2c_t dev, uint8_t address, uint8_t reg,
const void *data, int length);
/**
* @brief Power on the given I2C peripheral
*
* @param[in] dev the I2C device to power on
*/
void i2c_poweron(i2c_t dev);
/**
* @brief Power off the given I2C peripheral
*
* @param[in] dev the I2C device to power off
*/
void i2c_poweroff(i2c_t dev);
#ifdef __cplusplus
}
#endif
#endif /* I2C_H */
/** @} */
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