Date   : Thu, 04 Aug 2005 22:21:29 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Acorn Econet Bridge

On Thu, 2005-08-04 at 21:56 +0200, Johan Heuseveldt wrote:
> I did some quick looks on the disassembly, and it was easy to figure out
> that the ADLC'c are at addresses &C800 and &D800. But also addresses &C000
> and &D000 are used. Could be some memory logic?

Ok, just did a quick check with a meter on the board...

&C000 jumper block 1
&C800 ADLC 1
&D000 jumper block 2
&D800 ADLC 2

&E000 - &FFFF is ROM.
&0000 - &1FFF and &8000 - &9FFF both map to RAM.

> The ROM is split in two address areas: &E000 and &F000. I just wonder
> if that has something to do with hardware as well, as the difference
> is the A12 address line.

I can't see any particular reason for that; both locations are within
the ROM address range.

cheers

Jules