uart.h File Reference

Header file for UART communication. More...

#include <avr/io.h>
#include <stdio.h>

Go to the source code of this file.

Macros
#define	UART_LBT   8
#define	BAUD_CALC(baud)   ((F_CPU / 4 / baud - 1) / 2)

Functions
void	uart_init (uint8_t brr_value)
	UART initialization function. More...
int	uart_transmit (char byte_data, FILE *stream)
	Function to transmit characters. More...
int	uart_receive (FILE *stream)
	Function to read characters. More...
int	uart_getline (char line[], int max)
	Function to read line. More...

Detailed Description

Header file for UART communication.

Author

Christoph Jurczyk

Date

October 21, 2018

License

This library is released under the GNU General Public License v3.0.

Macro Definition Documentation

BAUD_CALC

#define BAUD_CALC

(

baud

)

((F_CPU / 4 / baud - 1) / 2)

Calculation of LINBRR value for UART initialization.

UART_LBT

#define UART_LBT   8

Numbers of samples per bit.

Function Documentation

uart_getline()

int uart_getline	(	char	line[],
		int	max
	)

Function to read line.

Call this function to read a string until newline termination. Example call:

char read_buffer[256];
while(uart_getline(read_buffer, 256) != EOF)

Parameters

line	Is the buffer for the read line.
max	Maximum number of receiving characters.

Returns

Returns numbers of received characters or EOF flag.

uart_init()

void uart_init

(

uint8_t

brr_value

)

UART initialization function.

To initialize the UART connection call this function with the desired LINBRR value, which can be calculated wit the following command:

BAUD_CALC(9600)

Note

The baudrate can be change to your desired baudrate.

Call the initialization function as follow:

uart_init(BAUD_CALC(9600));

uart_receive()

int uart_receive

(

FILE *

stream

)

Function to read characters.

Call this function to read a character from the UART buffer. Example call:

char a = uart_receive();

Parameters

stream

Is an optional parameter for the FDEV_SETUP_STREAM.

Returns

Returns the character.

uart_transmit()

int uart_transmit	(	char	byte_data,
		FILE *	stream
	)

Function to transmit characters.

Call this function with a character or character array to transmit data via the UART connection. Example call:

uart_transmit('a');

Parameters

byte_data	Is the to transmitted data e.g. a character.
stream	Is an optional parameter for the FDEV_SETUP_STREAM.

Returns

Returns a 0 after successful transmission. This is necessary for the optional use in FDEV_SETUP_STREAM.