I decided to create a simple C library for USART and AVR microcontrollers for the purpose of studying the USART serial interface.
This library is likely to be often updated. Open source code on my github:
https://github.com/xdth/AVR_dthUSART
Below is an example application. It will echo back strings received via serial at 9600 bit rate (defined in dthUSART.h), using the internal oscillator at 1 Mhz.
Read more “dthUSART – C library for AVR microcontrollers (beta) and example code”
We will use an attiny2313 AVR microcontroller to display strings on an HD44780 LCD (4-bit mode).
482 bytes of flash written. Using internal oscillator.
## Connections
+-----------------------------------+----------------+ | HD44780 LCD | attiny2313 MCU | +-----------------------------------+----------------+ | PIN 1 (GND) | | | PIN 2 (+5V) | | | PIN 3 (contrast/GND) | | | PIN 4 (reg select) | PIN 2 (PD0) | | PIN 5 (R/W) | PIN 3 (PD1) | | PIN 6 (Enable) | PIN 6 (PD2) | | PIN 7 | | | PIN 8 | | | PIN 9 | | | PIN 10 | | | PIN 11 | PIN 12 (PB0) | | PIN 12 | PIN 13 (PB1) | | PIN 13 | PIN 14 (PB2) | | PIN 14 | PIN 15 (PB3) | | PIN 15 (220 Omhs resistor to +5V) | | | PIN 16 (GND) | | +-----------------------------------+----------------+
I prefer to develop in pure C instead of using the Arduino framework, for both learning and code size purposes. I use the Arduino board solely as an AVR programmer, using my script qAVR to flash the microcontroller.
## material
– breadboard
– jumper wires
– 10µF capacitor
– 220 ohms resistor
– LED
– Arduino
– Target microcontroller (in our example, attiny2313)
## install dev env
pacman -S avr-gcc avr-libc avrdude
wget https://raw.githubusercontent.com/xdth/qavr/master/qavr (place it in your .bin folder)
This shell script will compile a C program, generate an hex file and flash it to an AVR microcontroller.
For updates, check my github repository: https://github.com/xdth/qavr
