i2c.c File Reference

Contains C source for the I2C functionality. More...

#include "i2c.h"

Go to the source code of this file.

Functions
errStatus	gpioI2cSetup (void)
	Initial setup of I2C functionality. More...
errStatus	gpioI2cCleanup (void)
	Disables the I2C controller and unmaps the memory used for the i2c functionality. This function should be called when finished with the I2C module. More...
errStatus	gpioI2cSet7BitSlave (uint8_t slaveAddress)
	Sets the 7-bit slave address to communicate with. More...
errStatus	gpioI2cWriteData (const uint8_t *data, uint16_t dataLength)
	Writes data to the address previously specified by gpioI2cSet7BitSlave(). More...
errStatus	gpioI2cReadData (uint8_t *buffer, uint16_t bytesToRead)
	Read a number of bytes from I2C. The slave address should have been previously set with gpioI2cSet7BitSlave(). More...
errStatus	gpioI2cSetClock (int frequency)
	Sets the I2C Clock Frequency. More...

Variables
static volatile uint32_t *	gI2cMap = NULL
	Pointer which will be mmap'd to the I2C memory in /dev/mem.
static int	i2cByteTxTime_ns
	The time it takes ideally transmit 1 byte with current I2C clock.

Detailed Description

Contains C source for the I2C functionality.

This is is part of https://github.com/alanbarr/RaspberryPi-GPIO a C library for basic control of the Raspberry Pi's GPIO pins. Copyright (C) Alan Barr 2012

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file i2c.c.

Function Documentation

gpioI2cCleanup()

errStatus gpioI2cCleanup

(

void

)

Disables the I2C controller and unmaps the memory used for the i2c functionality. This function should be called when finished with the I2C module.

Returns

An error from errStatus.

Examples:

i2c_example_bitexpander.c, i2c_example_eeprom.c, and i2c_example_temp_sensor.c.

Definition at line 156 of file i2c.c.

gpioI2cReadData()

errStatus gpioI2cReadData	(	uint8_t *	buffer,
		uint16_t	bytesToRead
	)

Read a number of bytes from I2C. The slave address should have been previously set with gpioI2cSet7BitSlave().

Parameters

[out]	buffer	A pointer to a user defined buffer which will store the bytes.
	bytesToRead	The number of bytes to read.

Returns

An error from errStatus.

Examples:

i2c_example_eeprom.c, and i2c_example_temp_sensor.c.

Definition at line 348 of file i2c.c.

gpioI2cSet7BitSlave()

errStatus gpioI2cSet7BitSlave

(

uint8_t

slaveAddress

)

Sets the 7-bit slave address to communicate with.

This value can be set once and left if communicating with the same device.

Parameters

slaveAddress

7-bit slave address.

Returns

An error from errStatus.

Examples:

i2c_example_bitexpander.c, i2c_example_eeprom.c, and i2c_example_temp_sensor.c.

Definition at line 217 of file i2c.c.

gpioI2cSetClock()

errStatus gpioI2cSetClock

(

int

frequency

)

Sets the I2C Clock Frequency.

Note

The desired frequency should be in the range: I2C_CLOCK_FREQ_MIN <= frequency <= I2C_CLOCK_FREQ_MAX.

Parameters

frequency

Desired frequency in Hertz.

Returns

An error from errStatus

Examples:

i2c_example_eeprom.c.

Definition at line 465 of file i2c.c.

gpioI2cSetup()

errStatus gpioI2cSetup

(

void

)

Initial setup of I2C functionality.

gpioSetup() should be called prior to this.

Returns

An error from errStatus.

Examples:

i2c_example_bitexpander.c, i2c_example_eeprom.c, and i2c_example_temp_sensor.c.

Definition at line 36 of file i2c.c.

gpioI2cWriteData()

errStatus gpioI2cWriteData	(	const uint8_t *	data,
		uint16_t	dataLength
	)

Writes data to the address previously specified by gpioI2cSet7BitSlave().

Parameters

[in]	data	Pointer to the start of data to transmit.
	dataLength	The length of data.

Returns

errStatus An error from errStatus

Examples:

i2c_example_bitexpander.c, i2c_example_eeprom.c, and i2c_example_temp_sensor.c.

Definition at line 243 of file i2c.c.