exxos's Atari, Amiga & retro forum

A decoder board which can solder on top of the CPU. So it should fit more problematic layout motherboards. This should decode 104 & 206 space. It should handle bus errors (like when trying to write to ROM space etc).

Prototypes will be available in store in the near future :)

Looks very nice! Did you mean to put the year as 2026? Maybe it's the long wait times from China :D

viking272 wrote: 17 Apr 2025 21:49 Did you mean to put the year as 2026? Maybe it's the long wait times from China :D

Yeah.. it's part of my "system" not to mix stuff up.. "next year" means "future" as in new stuff not made yet... So if I have a 2025 or less date stamp, it's likely a older design or something. Better than just version numbering stuff as I've no way to easily tell if version x of something has been made yet or not...Well it makes sense to me anyway :lol:

Plus a year will probably be how long it normally takes me to test stuff.... :lol:

Very nice and clean!

Would this be adaptable to 4x TOS, and maybe in place programmable EEPROMs?

We will see how my other forum post goes... I very well may be one of the first in line to buy when they are in stock. :lol:

Selecting TOS is done by switches or jumpers to the address lines. It doesn't have much to do with a decoder. A decoder selects the ROM on 2 different address spaces so you can use TOS104 / 206 or whatever.

Prototypes come :) Now to find some time to actually test one...

exxos wrote: 07 May 2025 19:44 Prototypes come :) Now to find some time to actually test one...

Maybe call on some willing alpha testers in your forum @exxos (hint hint)? :D

There are bound to be a few willing victims to help with this (and not just me...I'm sure there was recently a post from another forum member wanting to use TOS 2.06 in a Mega ST, so one where the clearance prevents your existing product from physically fitting)?

I've a couple of Mega STs as well as (too many) STF/M models of many different layouts if you want any help...

It may actually fit on the bottom of the CPU for the mega :shrug:

I plan to try it on a H4 as it should fit right into a 68k socket...

The one upgrade missing from the MegaST I always wanted was 256k Tos. Short fly leads should do the job and a little inginu.. ing... smarts.
This is indeed a good day. I'm going to need more desk space.

Success! :D

I cheated and installed it in a H5 CPU socket. Of course ordinarily this would be soldered on top of the CPU with wires or headers.


Spent 10 minutes puzzling why it kept crashing, spot the "obvious" mistake! :lol: :roll:


TOS104 & TOS206 booting :)


Now in stock

https://www.exxosforum.co.uk/atari/store2/#0311


Once they have sold, I will open pre-orders to get some more made.