My training project for ATmega88P.

This project demonstrates:

• using timer interrupt to execute action in regular intervals
• using PWM to dim LED (timer mentioned above changes brightness)
• using input interrupt to handle button press

• how to prevent button instability by ignoring button state changes for short time after a change

• using USART interrupt to read and send data

• integrate with libc stdio.h

• using software events to minimize ISR code

• interrupt sets flag
• main loop checks it, clears and performs action