USART.c File Reference

Implementation of USART serial communication functions. More...

#include "includes/CPU.h"
#include <avr/io.h>
#include "includes/USART.h"
#include <util/setbaud.h>

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Functions
void	initUSART (void)
	Initializes the USART peripheral.
void	transmitByte (uint8_t data)
	Transmits a single byte over USART.
uint8_t	receiveByte (void)
	Receives a single byte from USART.
void	printString (const char *String)
	Sends a null-terminated string over USART.

Detailed Description

Implementation of USART serial communication functions.

This file contains the implementation for initializing and using the USART peripheral on AVR microcontrollers. It provides functions for byte transmission/reception, string output, and formatted printing.

Author

Roybel Carbonell Camejo

Date

2026-04-29

Note

Uses setbaud.h header for automatic baud rate calculation

See also

USART.h For function interfaces

Definition in file USART.c.

Function Documentation

initUSART()

void initUSART

(

void

)

Initializes the USART peripheral.

Initializes the USART peripheral for serial communication.

Configures the USART with baud rate from setbaud.h calculations, enables transmitter and receiver, and sets frame format to 8 data bits, 1 stop bit, no parity.

Note

The setbaud.h header uses F_CPU and BAUD macros from CPU.h

Warning

Baud rate error checking should be performed at compile time

See also

CPU.h For F_CPU and BAUD definitions

<util/setbaud.h> For baud rate calculation macros

Definition at line 34 of file USART.c.

Referenced by main().

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printString()

void printString

(

const char *

String

)

Sends a null-terminated string over USART.

Iterates through each character in the string and transmits it one by one until the null terminator is reached.

Parameters

String

Pointer to the null-terminated string to transmit

Note

Blocking - each character waits for transmission to complete

Warning

String must be properly null-terminated

Definition at line 105 of file USART.c.

References transmitByte().

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receiveByte()

uint8_t receiveByte

(

void

)

Receives a single byte from USART.

Waits for a byte to be received (RXC flag set), then returns the received data from the UDR register.

Returns

uint8_t The received byte (0-255)

Note

Blocking function - waits indefinitely for incoming data

Warning

Ensure data is available before calling to avoid infinite loop

Definition at line 88 of file USART.c.

Referenced by main().

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transmitByte()

void transmitByte

(

uint8_t

data

)

Transmits a single byte over USART.

Waits for the transmit data register to be empty, then loads the data into the UDR register for transmission.

Parameters

data	The byte to transmit (0-255)

Note

Blocking function - waits until transmission buffer is ready

Warning

If called too frequently, may cause data loss

Definition at line 71 of file USART.c.

Referenced by main(), and printString().

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