usart.c File Reference

Function defines for the USART driver. More...

#include "usart.h"

Functions
void	usart_start (const usart_peripheral_t usart, const uint32_t baudrate, const usart_mode_t mode)
	Initiates the USART peripheral with specified options.
void	usart_set_dma (const usart_peripheral_t usart, const _Bool forTX, const _Bool forRX)
	Configures the USART DMA functionality.
void	usart_set_interrupts (const usart_peripheral_t usart, const struct USARTISR config)
	Enables the specified USART interrupts.
void	usart_set_databits (const usart_peripheral_t usart, const usart_stopbits_t stopbits, const usart_databits_t databits)
	Sets the USART databits to the specified values.
void	usart_set_parity (const usart_peripheral_t usart, const usart_parity_t parity)
	Sets the USART parity to the specified mode.
void	usart_tx_message (const usart_peripheral_t usart, const char *message)
	Writes specified message to USART buffer.
uint16_t	usart_rx_byte (const usart_peripheral_t usart)
	Reads the received data from the USART buffer.
void	usart_stop (const usart_peripheral_t usart)
	Disable the USART interface.

Detailed Description

Function defines for the USART driver.

This file contains all of the function definitions declared in usart.h.

Author

Vasileios Ch. (BillisC)

Bug

None, yet.

Function Documentation

usart_rx_byte()

uint16_t usart_rx_byte

(

const usart_peripheral_t

usart

)

Reads the received data from the USART buffer.

In receive/transceive mode the data will be read from the DR register and the RXNE flag will be cleared. Beware that this method is very slow and may cause overrun errors if not used in conjuction with interrupts.

Parameters

usart

The selected USART

Returns

The received data

usart_set_databits()

void usart_set_databits	(	const usart_peripheral_t	usart,
		const usart_stopbits_t	stopbits,
		const usart_databits_t	databits )

Sets the USART databits to the specified values.

The available number of stopbits and databits for the USART are specified in usart_stopbits_t and usart_databits_t enums respectively. Any other value will be ignored.

Parameters

usart	The selected USART
stopbits	The number of stop bits
databits	The word length

Returns

None

usart_set_dma()

void usart_set_dma	(	const usart_peripheral_t	usart,
		const _Bool	forTX,
		const _Bool	forRX )

Configures the USART DMA functionality.

Parameters

usart	The selected USART
forTX	Enable / Disable DMA for TX
forTX	Enable / Disable DMA for RX

Returns

None

usart_set_interrupts()

void usart_set_interrupts	(	const usart_peripheral_t	usart,
		const struct USARTISR	config )

Enables the specified USART interrupts.

The available interrupts are located in the usart_isr struct.

Parameters

usart	The selected USART
config	The ISR configuration

Returns

None

usart_set_parity()

void usart_set_parity	(	const usart_peripheral_t	usart,
		const usart_parity_t	parity )

Sets the USART parity to the specified mode.

The available parity modes for the USART are specified in usart_parity_t. Any other value will be ignored. Please note that setting the parity modes will automatically set the PCE (parity control) bit. If the mode is "off" it will be cleared.

Parameters

usart	The selected USART
parity	The selected parity

Returns

None

usart_start()

void usart_start	(	const usart_peripheral_t	usart,
		const uint32_t	baudrate,
		const usart_mode_t	mode )

Initiates the USART peripheral with specified options.

The available modes for the USART peripheral are specified in the usart_mode_t enum. Any other value will be ignored.

Parameters

usart	The selected USART
baudrate	The desired communication bitrate
mode	The desired communication mode
x8_oversample	Use x8 oversampling instead of x16

Returns

None

usart_stop()

void usart_stop

(

const usart_peripheral_t

usart

)

Disable the USART interface.

The function will wait until all transmissions are complete and turn off the specified USART peripheral.

Parameters

usart

The selected USART

Returns

None

usart_tx_message()

void usart_tx_message	(	const usart_peripheral_t	usart,
		const char *	message )

Writes specified message to USART buffer.

In transmit/transceive mode the data will be written to the DR register and be shifted out of the TX pin when ready. Using it without DMA is not recommended for multibyte messages.

Parameters

usart	The selected USART
character	Pointer to the message

Returns

None