Running Code and Talking to the Outside World

I’m still having a ton of fun with the rosco_m68k single board computer, and regularly writing project logs on Hackaday. If you’re interested, be sure to follow the project there as that’s where the regular updates happen, but here’s an in-brief update on what’s been happening.

Firstly, the board now has a lot more wires:

The ROM and RAM are both now hooked up to the buses, along with a MC68901 Multi-Function Peripheral that handles IO.

The system is successfully running code from the ROMs, and the RAM is working fine. I have code that does a full write/read test of the on-board RAM, and other code that just uses it and both are fine.

There’s some new glue logic to support the MC68901 (the top board in the picture) which has upped the chip-count a bit, and I’ve completely redone power distribution which was starting to get a bit shaky due to the way the project has grown.

Everything is connected together via the buses in the center of the picture, and the control bus has grown to accomodate all the CPU control lines and the address decoder outputs.

I’ve had a bit of a nightmare this weekend trying to get the MFP working properly (See this and this on Hackaday if you fancy a laugh) but it’s finally working, and I’m almost at the point of sending “Hello, World” to a serial terminal. After that, I’ll be off to the races with this project – debugging is so much easier when you can actually output stuff rather than just run logic traces.

That’s all for now – as I say if you want to know more be sure to like and follow on Hackaday!

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