Device driver interface for the AT24CXXX EEPROM units. More...

Detailed Description

Device driver interface for the AT24CXXX EEPROM units.

Overview

Various manufacturers such as Atmel/Microchip or ST offer small I2C EEPROMs which usually come in 8-pin packages and are used for persistent data storage of settings, counters, etc. This driver adds support for these devices with direct read and write functions.

The high level wrapper for RIOTs MTD interface to utilize the I2C EEPROMs as MTD storage is described in drivers_mtd_at24cxxx.

A list of supported devices can be found in the at24cxxx_defines.h file.

Usage

The preconfigured devices in the at24cxxx_defines.h file devices are easily accessible as pseudomodules and can be added to the Makefile of your project:

 USEMODULE += at24c02

When using one of the pseudomodules, the configuration of the device is already predefined in the AT24CXXX_PARAMS macro and can be used for the initialization:

 at24cxxx_t eeprom_dev;
 at24cxxx_params_t eeprom_params = AT24CXXX_PARAMS;

 at24cxxx_init(&eeprom_dev, &eeprom_params);

For other devices that are not yet part of the library, the generic module has to be added:

 USEMODULE += at24cxxx

The predefined macro can not be used in this case, so the parameters of the device have to be added to the at24cxxx_params_t structure manually with the values from the corresponding datasheet:

 at24cxxx_t eeprom_dev;
 at24cxxx_params_t eeprom_params = {
     .i2c = I2C_DEV(0), \
     ...
 };

 at24cxxx_init(&eeprom_dev, &eeprom_params);

Files
file	at24cxxx_defines.h
	Constants for various I2C EEPROM devices.

file	at24cxxx_params.h
	Default configuration for the AT24CXXX driver.

file	at24cxxx.h
	Device driver interface for AT24CXXX EEPROM units.

Data Structures
struct	at24cxxx_params
	Struct that holds initialization parameters. More...

struct	at24cxxx_t
	Struct that represents an AT24CXXX device. More...

Typedefs
typedef struct at24cxxx_params	at24cxxx_params_t
	Struct that holds initialization parameters.

Enumerations
enum	{ AT24CXXX_OK , AT24CXXX_I2C_ERROR }
	Return values. More...

Functions
int	at24cxxx_init (at24cxxx_t dev, const at24cxxx_params_t params)
	Initialize an AT24CXXX device handle with AT24CXXX parameters.

int	at24cxxx_read_byte (const at24cxxx_t dev, uint32_t pos, void dest)
	Read a byte at a given position `pos`.

int	at24cxxx_read (const at24cxxx_t dev, uint32_t pos, void data, size_t len)
	Sequentially read `len` bytes from a given position `pos`.

int	at24cxxx_write_byte (const at24cxxx_t *dev, uint32_t pos, uint8_t data)
	Write a byte at a given position `pos`.

int	at24cxxx_write (const at24cxxx_t dev, uint32_t pos, const void data, size_t len)
	Sequentially write `len` bytes from a given position `pos`.

int	at24cxxx_set (const at24cxxx_t *dev, uint32_t pos, uint8_t val, size_t len)
	Set `len` bytes from a given position `pos` to the value `val`.

int	at24cxxx_clear (const at24cxxx_t *dev, uint32_t pos, size_t len)
	Set `len` bytes from position `pos` to AT24CXXX_CLEAR_BYTE.

int	at24cxxx_erase (const at24cxxx_t *dev)
	Set the entire EEPROM memory to AT24CXXX_CLEAR_BYTE.

int	at24cxxx_enable_write_protect (const at24cxxx_t *dev)
	Enable write protection.

int	at24cxxx_disable_write_protect (const at24cxxx_t *dev)
	Disable write protection.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Return values.

Definition at line 83 of file at24cxxx.h.

Function Documentation

◆ at24cxxx_clear()

int at24cxxx_clear	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		size_t	len
	)

Set len bytes from position pos to AT24CXXX_CLEAR_BYTE.

This is a wrapper around

See also: at24cxxx_set.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[in]	len	Requested length to be written

Returns

See also: at24cxxx_set

◆ at24cxxx_disable_write_protect()

int at24cxxx_disable_write_protect ( const at24cxxx_t * dev )

Disable write protection.

Parameters

[in] dev AT24CXXX device handle

Returns: AT24CXXX_OK on success; -ENOTSUP if pin_wp was initialized with GPIO_UNDEF

◆ at24cxxx_enable_write_protect()

int at24cxxx_enable_write_protect ( const at24cxxx_t * dev )

Enable write protection.

Parameters

[in] dev AT24CXXX device handle

Returns: AT24CXXX_OK on success; -ENOTSUP if pin_wp was initialized with GPIO_UNDEF

◆ at24cxxx_erase()

int at24cxxx_erase ( const at24cxxx_t * dev )

Set the entire EEPROM memory to AT24CXXX_CLEAR_BYTE.

This is a wrapper around

See also: at24cxxx_clear.

Parameters

[in] dev AT24CXXX device handle

Returns

See also: at24cxxx_set

◆ at24cxxx_init()

int at24cxxx_init	(	at24cxxx_t *	dev,
		const at24cxxx_params_t *	params
	)

Initialize an AT24CXXX device handle with AT24CXXX parameters.

Parameters

[in,out]	dev	AT24CXXX device handle
[in]	params	AT24CXXX parameters

Returns: AT24CXXX_OK on success; -AT24CXXX_I2C_ERROR if i2c could not be acquired; -EINVAL if input parameters are NULL

◆ at24cxxx_read()

int at24cxxx_read	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		void *	data,
		size_t	len
	)

Sequentially read len bytes from a given position pos.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[out]	data	Read buffer
[in]	len	Requested length to be read

Returns: AT24CXXX_OK on success; -ERANGE if pos + len is out of bounds

See also: i2c_read_regs

◆ at24cxxx_read_byte()

int at24cxxx_read_byte	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		void *	dest
	)

Read a byte at a given position pos.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[out]	dest	Read byte

Returns: AT24CXXX_OK on success; -ERANGE if pos is out of bounds

See also: i2c_read_regs

◆ at24cxxx_set()

int at24cxxx_set	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		uint8_t	val,
		size_t	len
	)

Set len bytes from a given position pos to the value val.

Writing is performed in chunks of size AT24CXXX_SET_BUFFER_SIZE.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[in]	val	Value to be set
[in]	len	Requested length to be written

Returns: AT24CXXX_OK on success; -ERANGE if pos + len is out of bounds

See also: i2c_write_byte

◆ at24cxxx_write()

int at24cxxx_write	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		const void *	data,
		size_t	len
	)

Sequentially write len bytes from a given position pos.

Writing is performed in chunks of size AT24CXXX_PAGE_SIZE.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[in]	data	Write buffer
[in]	len	Requested length to be written

Returns: AT24CXXX_OK on success; -ERANGE if pos + len is out of bounds

See also: i2c_write_regs

◆ at24cxxx_write_byte()

int at24cxxx_write_byte	(	const at24cxxx_t *	dev,
		uint32_t	pos,
		uint8_t	data
	)

Write a byte at a given position pos.

Parameters

[in]	dev	AT24CXXX device handle
[in]	pos	Position in EEPROM memory
[in]	data	Value to be written

Returns: AT24CXXX_OK on success; -ERANGE if pos is out of bounds

See also: i2c_write_regs

Detailed Description

Overview

Usage

Files

Data Structures

Typedefs

Enumerations

Functions

Enumeration Type Documentation

◆ anonymous enum

Function Documentation

◆ at24cxxx_clear()

◆ at24cxxx_disable_write_protect()

◆ at24cxxx_enable_write_protect()

◆ at24cxxx_erase()

◆ at24cxxx_init()

◆ at24cxxx_read()

◆ at24cxxx_read_byte()

◆ at24cxxx_set()

◆ at24cxxx_write()

◆ at24cxxx_write_byte()