exxos's Atari, Amiga & retro forum

Hi All,

Well I got bored of doing the adaptor the breadboard way, so fired up Eagle tonight and did the adaptor on there.

The idea is initially just to see if it will work. Why? I wanted to see if Icky and exxos's IDE adaptor will work when plugged into the Megabus since I know it works fine in the CPU socket.

Then once I've got that working, I'm looking at making Megabus to TOS rom switcher and various other ideas.

Of course the other thing that might be cool, is that on the Mongrel ST Remake, exxos has put 4 CPU sockets onto the schematic. I've essentially hijacked his Idea and given myself a one socket expansion port for my Mega.

Anyway, its all just for fun but what do you all think so far? All comments accepted and if it works out I'll probably make a couple of them for testing purposes.

Oops,helps if you put the circuit on the right side of the PCB. You can tell I don't use Eagle very often.

PhilC wrote: 08 May 2019 21:42 I've essentially hijacked his Idea and given myself a one socket expansion port for my Mega.

Dang it, knew I should have patented it!

PhilC wrote: 08 May 2019 21:42 Anyway, its all just for fun but what do you all think so far? All comments accepted and if it works out I'll probably make a couple of them for testing purposes.

One thing which should be mandatory when dealing with MHz stuff is a solid layer for a gnd and 5v. Normally routing is done on 2 layers like you seems to have, then a layer for power (4 total layers) Also put caps on the power rails.. Something like 1uF minimum 0805 or 1206 ceramic etc.

Cool, thanks.

The idea at first is to make one board the toner transfer method and then if it works to do as you've suggested but maybe including a couple of other things on it for my first order from JLC.

Thank you, very good piece of information. Will at least angle the corners when I start up Eagle later on,

Bit of an old necrobump, but @PhilC did you ever make any of these up?

mrbombermillzy wrote: 16 Aug 2025 21:14 Bit of an old necrobump, but @PhilC did you ever make any of these up?

I did make one but never got round to testing it. Let me see if I can find it.

Cool. Thanks.

The Mega ST Bus is not only a 1:1 mapping from the 68000 CPU Signals. However some Mega ST bus cards often use only 68k CPU signals but not all. The Mega ST Bus has no VCC connections.