i2c.h File Reference

Include dependency graph for i2c.h:

API Description

This file defines the i2c/Iic interface for libmraa. A context represents a bus and that bus may contain multiple addresses or i2c slaves. It is considered best practice to make sure the address is correct before doing any calls on i2c, in case another application or even thread changed the addres on that bus. Multiple instances of the same bus can exist.

    mraa_i2c_context i2c;
    i2c = mraa_i2c_init(0);

    mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
    rx_tx_buf[0] = HMC5883L_CONF_REG_B;
    rx_tx_buf[1] = GA_1_3_REG;
    mraa_i2c_write(i2c, rx_tx_buf, 2);

Go to the source code of this file.

Functions
mraa_i2c_context	mraa_i2c_init (int bus)
mraa_i2c_context	mraa_i2c_init_raw (unsigned int bus)
mraa_result_t	mraa_i2c_frequency (mraa_i2c_context dev, int hz)
int	mraa_i2c_read (mraa_i2c_context dev, uint8_t *data, int length)
uint8_t	mraa_i2c_read_byte (mraa_i2c_context dev)
mraa_result_t	mraa_i2c_write (mraa_i2c_context dev, const uint8_t *data, int length)
mraa_result_t	mraa_i2c_write_byte (mraa_i2c_context dev, const uint8_t data)
mraa_result_t	mraa_i2c_address (mraa_i2c_context dev, int address)
mraa_result_t	mraa_i2c_stop (mraa_i2c_context dev)

Typedefs
typedef struct _i2c *	mraa_i2c_context

Function Documentation

mraa_i2c_context mraa_i2c_init

(

int

bus

)

Initialise i2c context, using board defintions

Parameters

bus	i2c bus to use

Returns

i2c context or NULL

Here is the caller graph for this function:

mraa_i2c_context mraa_i2c_init_raw

(

unsigned int

bus

)

Initialise i2c context, passing in spi bus to use.

Parameters

bus	The i2c bus to use i.e. /dev/i2c-2 would be "2"

Returns

i2c context or NULL

Here is the caller graph for this function:

mraa_result_t mraa_i2c_frequency	(	mraa_i2c_context	dev,
		int	hz
	)

Sets the frequency of the i2c context

Parameters

dev	The i2c context
hz	The bus frequency in hertz

Returns

Result of operation

Here is the caller graph for this function:

int mraa_i2c_read	(	mraa_i2c_context	dev,
		uint8_t *	data,
		int	length
	)

Read from an i2c context

Parameters

dev	The i2c context
data	pointer to the byte array to read data in to
length	max number of bytes to read

Returns

length of the read in bytes or 0

Here is the caller graph for this function:

uint8_t mraa_i2c_read_byte

(

mraa_i2c_context

dev

)

Read a single byte from the i2c context

Parameters

dev	The i2c context

Returns

The result of the read or -1 if failed

Here is the caller graph for this function:

mraa_result_t mraa_i2c_write	(	mraa_i2c_context	dev,
		const uint8_t *	data,
		int	length
	)

Write to an i2c context

Parameters

dev	The i2c context
data	pointer to the byte array to be written
length	the number of bytes to transmit

Returns

Result of operation

Here is the caller graph for this function:

mraa_result_t mraa_i2c_write_byte	(	mraa_i2c_context	dev,
		const uint8_t	data
	)

Write a single byte to an i2c context

Parameters

dev	The i2c context
data	The byte to write

Returns

Result of operation

Here is the caller graph for this function:

mraa_result_t mraa_i2c_address	(	mraa_i2c_context	dev,
		int	address
	)

Sets the i2c context address.

Parameters

dev	The i2c context
address	The address to set for the slave (ignoring the least signifcant bit). If set to 0, the slave will only respond to the general call address.

Returns

Result of operation

Here is the caller graph for this function:

mraa_result_t mraa_i2c_stop

(

mraa_i2c_context

dev

)

De-inits an mraa_i2c_context device

Parameters

dev	The i2c context

Returns

Result of operation

Here is the caller graph for this function:

Typedef Documentation

typedef struct _i2c* mraa_i2c_context

Opaque pointer definition to the internal struct _i2c