exxos's Atari, Amiga & retro forum

I'm very lucky to have got my hands on one of these:
It's basically a tiny device from Urban Jonsson, that lets you use a combination of power off/on, plus a press of the reset switch, to select which of the 2 versions of TOS in exxos' excellent fast ROM switcher for the STE that you wish to boot up in.

It means no cutting of the case for a switch to change your TOS. I'm all for that.

sweet! I've not even got one to mess with yet!

If exxos likes it, we may see it as an official feature of his future tos switcher revisions....

Apparently I have one of only 3 in existence!

The hardest part was finding R100 to take the reset signal from It's actually on the front left of the board, next to an axial capacitor, running north-south (Cartridge port is west, Floppy is east, back is north, front is south!). The pick off point was the north lead of R100.

It would be cool to add to future switcher revisions, as you can see, adding it to the GND and SEL headers on the SWITCHER board was straightforward. On Urban's advice, I removed the pull up resistor and added a 3rd pin from that hole up to VCC. It needed bending slightly in order align with the holes, which unlike GND & SEL, don't line up in a straight line.

Switching is easy. Power off, hold down reset, power on. Release reset, and you will switch ROM. Otherwise it will stay with whatever is currently selected.

exxos wrote: ↑Fri Jan 19, 2018 12:00 am sweet! I've not even got one to mess with yet!

You need one Chris

Made some new ones that won’t be such a tight fit. Thinking of making them with THT Attinies and in kit form; aka less work for ube.

That looks like a excellent idea I was moaning about wanting something like this before for some reason I cannot remember now

ube wrote: ↑Fri Jan 19, 2018 9:58 am

Made some new ones that won’t be such a tight fit. Thinking of making them with THT Attinies and in kit form; aka less work for ube.

Interesting redesign. My temptation after installing this, would be to mount it below the TOS switcher PCB, rather than above, as I've done, as it would clear the FDD better.

rubber_jonnie wrote: ↑Fri Jan 19, 2018 1:49 pm Interesting redesign. My temptation after installing this, would be to mount it below the TOS switcher PCB, rather than above, as I've done, as it would clear the FDD better.

Thats a good idea, I never thought of that!

Main problem with the first one is that the peg for mounting the floppy is right besides the header. And mounting it using a female header on the header-board, below the dualTOS, won’t work since it’ll hit the motherboard. At least I think came to that conclusion when I looked into it.