hal-avr0-uart - AVR0 UART Hardware Abstraction

The hal-avr0-uart is a lightweight uart hardware abstraction library for AVR0 microcontrollers. It provides a clean interface for uart initialization and communication while hiding direct register-level interaction from higher software layers. The library is intended for projects that want to separate low-level device startup code from application logic and establish a small, reusable system layer for AVR0 targets.

Features

• UART configuration for AVR0 devices.
• UART communication for AVR0 devices.
• Encapsulation of low-level register access.
• Compact and reusable API for embedded projects.
• Foundation for layered HAL architectures.

The hal-avr0-uart library reduces coupling by providing a focused interface for essential uart system services. This improves portability inside a project, keeps startup code organized, and makes higher-level modules easier to maintain.

File Structure

hal/
├── common/
|   └── enums/
|       └── UART_enums.h
└── avr0/
    └── uart/
        ├── uart.c
        └── uart.h

Downloads

The library can be downloaded (zip or tar), cloned or used as submodule in a project.

Type	File	Description
Library	zip / tar	AVR0 uart library

Using with git clone

mkdir -p ./hal/
git clone https://github.com/0x007E/hal-common.git ./hal
mv ./hal/hal-common ./hal/common

mkdir -p ./hal/avr0
git clone https://github.com/0x007E/hal-avr0-uart.git ./hal/avr0
mv ./hal/avr0/hal-avr0-uart ./hal/avr0/uart

Using as git submodule

git submodule add https://github.com/0x007E/hal-common.git   ./hal/common
git submodule add https://github.com/0x007E/hal-avr0-uart.git ./hal/avr0/uart

Programming

Additional parameters like uart baudrate, handshake, pin definitions and many more can be setup in the header file. A user friendly description can be found here.

#include "../hal/avr0/uart/uart.h"

int main(void)
{
	uart_init();

    uart_putchar('T');
    uart_putchar('E');
    uart_putchar('S');
    uart_putchar('T');
    uart_putchar('\n');
    uart_putchar('\r');

    UART_Data status = UART_Empty;

    while (1)
    {
        printf("\n\rEnter character: ");
        unsigned char data = uart_getchar(&status);

        printf("\n\rCharacter: %c", data);
        
        // Non-blocking
        if(uart_scanchar(&data) == UART_Received)
        {
            printf("\n\rCharacter received: %c", data);
        }

        printf("\n\rEnter a number: ");

        unsigned int value = 0;

        if(scanf("%u", &value) == 1)
        {
            printf("\n\rNumber: %u", value);
        }
        else
        {
            uart_clear();
            printf("\n\rError->NaN!");
        }
    }
}

To use floating point with printf/scanf on the avr0 platform, a guide howto configure Microcip Studio can be found in this blog entry.

Additional Information

Type	Link	Description
AVR0-Series	pdf	megaAVR® 0-series family datasheet

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