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The AVR COG was my first real project with the AVR. It was an entry to the Circuit Cellar and Atmel 2004 AVR design contest. I didn't win a prize, but I did get a certificate. The design has some problems, the biggest being that it is very sensitive to the video signal level. I used a fixed bias into the internal comparator to detect sync. It works well if the signal is just right. Doesn't work at all if the signal isn't just right.

All the contest entries were still posted on the Circuit Cellar website until recently. A couple weeks ago I wanted to download it and show it to a coworker, but all the entries were gone. I decided to post it here. There are a few references on the Internet to this project where people have either duplicated it or based further work off it. It can be useful as is, but is especially useful as a basis for better designs and as an example of what can be done and how with minimal circuitry.

The available documents are:

• The writeup from the contest entry
• The schematic
• The main assembly listing
• The character set include file
• The character set description file
• The assembled hex file
• A readme file of notes
• The Bill of Materials

© 2012 William R Cooke