This was a quick project built simply to make use of a spare Atmel 8051 compatible microcontroller I bought to experiment with. I have used the Arduino / AVR chips and have had some experience with 8051 chips in the past and I wanted to see what I could do. I found that as a hobbyist the 8051 was not really a suitable micro hence I didn’t do too much with it. Anyway this is a basic 12 hour alarm clock with simple power outage backup and uses the main CPU clock to keep time so no RTC required which saves on parts. It’s based off someone else’s code and design but I added my own modifications.