stm32f4_uart.c File Reference

Provides serial communication over UART1 and UART2. More...

#include "uart.h"
#include "stm32f4_uart1.h"
#include "stm32f4_uart2.h"

Include dependency graph for stm32f4_uart.c:

Functions
int	__io_putchar (int ch)
	syscall declaration for putchar so that printf may be used. More...
hal_status_t	hal_uart_init (hal_uart_t uart)
	Initialize the UART channel associated with the parameter uart. Must be called prior to using the channel. More...
hal_status_t	hal_uart_deinit (hal_uart_t uart)
	Deinitialize the UART channel associated with the parameter uart. More...
hal_status_t	hal_uart_read (hal_uart_t uart, uint8_t *data, size_t len, size_t *bytes_read)
	Read an incoming byte stream. More...
hal_status_t	hal_uart_write (hal_uart_t uart, const uint8_t *data, size_t len, size_t *bytes_written)
	Write an outgoing byte stream. More...

Detailed Description

Provides serial communication over UART1 and UART2.

Copyright (c) 2025 Cory McKiel. Licensed under the MIT License. See LICENSE file in the project root.

Function Documentation

__io_putchar()

int __io_putchar

(

int

ch

)

syscall declaration for putchar so that printf may be used.

Parameters

ch	The character to print.

Returns

ch, the value that was passed in as parameter.

hal_uart_deinit()

hal_status_t hal_uart_deinit

(

hal_uart_t

uart

)

Deinitialize the UART channel associated with the parameter uart.

Only a channel that has been initialized can be successfully deinitialized.

Parameters

uart	The UART channel to deinitialize.

Returns

HAL_STATUS_OK on successful deinitialization, HAL_STATUS_ERROR otherwise.

Note

Brings down the peripheral, but not the gpio port that was initialized. This is because gpio ports are shared and unexpected deinits could disrupt other drivers without coordination.

hal_uart_init()

hal_status_t hal_uart_init

(

hal_uart_t

uart

)

Initialize the UART channel associated with the parameter uart. Must be called prior to using the channel.

Parameters

uart	The UART channel to initialize.

Returns

HAL_STATUS_OK on successful initialization, HAL_STATUS_ERROR otherwise.

hal_uart_read()

hal_status_t hal_uart_read	(	hal_uart_t	uart,
		uint8_t *	data,
		size_t	len,
		size_t *	bytes_read
	)

Read an incoming byte stream.

Data is placed into the buffer in the same order it was received on the UART channel. There is no way to partition it using this API. Any processing (i.e. parsing for the start of a command) needs to happen at a higher level.

Parameters

uart	The UART channel to read from.
data	A buffer to return read data to client.
len	The max number of bytes to read into buffer. Should not exceed buffer size.
bytes_read	Return the actual number of bytes that were successfully read.

Returns

HAL_STATUS_OK on success, HAL_STATUS_ERROR otherwise.

hal_uart_write()

hal_status_t hal_uart_write	(	hal_uart_t	uart,
		const uint8_t *	data,
		size_t	len,
		size_t *	bytes_written
	)

Write an outgoing byte stream.

Parameters

uart	The UART channel to write to.
data	A buffer filled with data to send.
len	The number of bytes to send. Should not exceed buffer size.
bytes_written	Return the actual number of bytes that were successfully written.

Returns

HAL_STATUS_OK on success, HAL_STATUS_ERROR otherwise.