Retrochallenge 2024: Cat-644 Microcomputer

The Cat-644 is a computer I've been developing around an Atmega 644 microcontroller. It has been a long running side project that I get out every once in a while to work on. I've decided to work on it some more for this round of the retrochallenge.

Cat-644 Hardware 1.0

October 31

Enclosure

This has been a very long-running project. It has been in perpetual breadboard mode. Now that most of the focus is now on software rather than hardware, it is time to actually complete the hardware. There might be slight modifications in the future, but this is where I call it: This is the final 1.0 hardware design.

The enclosure is an ancient emptied out modem. I bought it WeirdStuff years ago when they were still in business. The front panel is a thin piece of wood, which eventually will be stained. On the front is just a power switch and reset button. I will probably add a power LED, and possibly an SD Card slot. I am unsure if I want it to be an internal only hard disk, or make it removable more like a floppy.

The circuit board takes up only about half the space. There is plenty of room for possible expansion. The thin wood works OK for the front panel, but for the back panel I want to reinforce it with something else.

Quick Demo

Here is a short video clip of the computer running:

I had a lot of fun getting this project going again for 2024. Once I realized that my focus was more on software, it really needed to be put in a box and turned into a computer that can just sit on my desk. When its on a breadboard, it takes up a lot of desk space, and is a very fragile. It is easy to disconnect something or short out a connection. The project feels complete in a way. Now it' is just another computer on my desk.