i2c.c File Reference

HAL I2C driver implementation for STM32F4 series. More...

#include "core/cortex-m4/i2c.h"
#include "core/cortex-m4/clock.h"
#include "core/cortex-m4/i2c_reg.h"
#include "core/cortex-m4/rcc_reg.h"
#include <stdbool.h>
#include <stdint.h>

Include dependency graph for i2c.c:

Macros
#define	TIMEOUT   1000000
	Maximum wait cycles for flag checks.
#define	I2C1_EN   1
	Init status mask for I2C1.
#define	I2C2_EN   2
	Init status mask for I2C2.
#define	I2C3_EN   4
	Init status mask for I2C3.

Functions
uint8_t	hal_i2c_get_init_status (void)
	Get initialization status of I2C buses.
hal_i2c_status_t	hal_i2c_init (hal_i2c_bus_t bus, hal_i2c_config_t *config)
	Initialize I2C peripheral in master mode.
hal_i2c_status_t	hal_i2c_write (uint8_t bus, uint8_t dev_addr, const uint8_t *data, uint16_t len)
	Write data to I2C device.
hal_i2c_status_t	hal_i2c_read (uint8_t bus, uint8_t dev_addr, uint8_t *data, uint16_t len)
	Read data from I2C device.
hal_i2c_status_t	hal_i2c_write_read (uint8_t bus, uint8_t dev_addr, const uint8_t *tx_data, uint16_t tx_len, uint8_t *rx_data, uint16_t rx_len)
	Combined write-read operation.

Detailed Description

HAL I2C driver implementation for STM32F4 series.

This file provides a complete hardware abstraction layer for I2C communication on STM32F4 microcontrollers. It supports:

• Master mode operation (7-bit addressing)
• Standard mode (100 kHz) and Fast mode (400 kHz)
• Combined write/read operations
• Timeout handling for robust operation
• Automatic clock configuration

The implementation handles all low-level register operations and provides high-level functions for common I2C transactions.

Note

Slave mode is not currently implemented (marked as TODO)

Copyright

© NAVROBOTEC PVT. LTD.

Macro Definition Documentation

I2C1_EN

#define I2C1_EN   1

Init status mask for I2C1.

I2C2_EN

#define I2C2_EN   2

Init status mask for I2C2.

I2C3_EN

#define I2C3_EN   4

Init status mask for I2C3.

TIMEOUT

#define TIMEOUT   1000000

Maximum wait cycles for flag checks.

Function Documentation

hal_i2c_get_init_status()

uint8_t hal_i2c_get_init_status

(

void

)

Get initialization status of I2C buses.

Get the initialization status of the I²C peripheral.

Returns

Bitmask indicating which I2C buses are initialized

Return values

Bit	0: I2C1 status
Bit	1: I2C2 status
Bit	2: I2C3 status

hal_i2c_init()

hal_i2c_status_t hal_i2c_init	(	hal_i2c_bus_t	bus,
		hal_i2c_config_t *	config )

Initialize I2C peripheral in master mode.

Initialize the I²C peripheral.

Parameters

[in]	bus	I2C bus identifier (I2C1, I2C2, I2C3)
[in]	config	Pointer to configuration structure

Returns

Status of initialization

Return values

HAL_I2C_OK	Initialization successful
HAL_I2C_ERR_REINIT	Bus already initialized
HAL_I2C_ERR_BUS	Unsupported mode (slave not implemented)

Configures the specified I2C bus with:

• Clock speed (standard/fast mode)
• APB1 clock prescaler
• Rise time calculation
• Peripheral enable

Note

Automatically enables the required RCC clock for the I2C peripheral

< I²C base address

hal_i2c_read()

hal_i2c_status_t hal_i2c_read	(	uint8_t	bus,
		uint8_t	dev_addr,
		uint8_t *	data,
		uint16_t	len )

Read data from I2C device.

Read data from an I²C device.

Parameters

[in]	bus	I2C bus identifier
[in]	dev_addr	7-bit device address
[out]	data	Pointer to receive buffer
[in]	len	Number of bytes to receive

Returns

Status of operation

Return values

HAL_I2C_OK	Reception successful
HAL_I2C_ERR_TIMEOUT	Bus timeout occurred
HAL_I2C_ERR_BUS	Invalid parameters

Performs complete I2C read transaction:

1. START condition
2. Address + Read bit
3. Data bytes with proper ACK/NACK
4. STOP condition

< I²C base address

hal_i2c_write()

hal_i2c_status_t hal_i2c_write	(	uint8_t	bus,
		uint8_t	dev_addr,
		const uint8_t *	data,
		uint16_t	len )

Write data to I2C device.

Write data to an I²C device.

Parameters

[in]	bus	I2C bus identifier
[in]	dev_addr	7-bit device address
[in]	data	Pointer to transmit buffer
[in]	len	Number of bytes to transmit

Returns

Status of operation

Return values

HAL_I2C_OK	Transmission successful
HAL_I2C_ERR_TIMEOUT	Bus timeout occurred

Performs complete I2C write transaction:

1. START condition
2. Address + Write bit
3. Data bytes
4. STOP condition

hal_i2c_write_read()

hal_i2c_status_t hal_i2c_write_read	(	uint8_t	bus,
		uint8_t	dev_addr,
		const uint8_t *	tx_data,
		uint16_t	tx_len,
		uint8_t *	rx_data,
		uint16_t	rx_len )

Combined write-read operation.

Write to a device register and read back data.

Parameters

[in]	bus	I2C bus identifier
[in]	dev_addr	7-bit device address
[in]	tx_data	Pointer to transmit buffer
[in]	tx_len	Number of bytes to transmit
[out]	rx_data	Pointer to receive buffer
[in]	rx_len	Number of bytes to receive

Returns

Status of operation

Return values

HAL_I2C_OK	Operation successful
HAL_I2C_ERR_TIMEOUT	Bus timeout occurred
HAL_I2C_ERR_BUS	Invalid parameters

Performs combined I2C transaction:

1. Write phase (registers/commands)
2. Repeated START
3. Read phase (data) Handles all ACK/NACK and STOP conditions automatically

< I²C base address