Date   : Thu, 03 Aug 2006 11:42:28 +0100 (BST)
From   : gARetH baBB <hick.bbc@...>
Subject: Re: Electron cartridge interface

On Thu, 3 Aug 2006, Steve O'Leary wrote:

> It's been a long time since I've looked at this and most of the 
> connections are obvious but some could benefit from a description. For 
> example the ROM_OE which I would hazard a guess is the ROM Output Enable 
> and this would go hi when the electron is wanting to page in a sideways 
> ROM/RAM. But this is only a guess ?

It goes high on a memory access to either valid ROM socket (0,1 or 2,3) 
for the slot.

(ROM)QA provides the low bit of the ROM socket accessed.

There is also a select line for ROM socket 13, it's probably A19 
"reserved".