Date   : Wed, 01 Jul 2009 21:44:37 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: mystery ROMs

Rick Murray wrote:
>    [EPROM 27C256] InterWORD [1]
>
> 1 - I will remove the label and rip Interword directly from EPROM, but
> it may fail in an emulator as it is mounted on some sort of carrier
> board which looks like it is somehow fiddling with the addressing, for
> it's a bigger EPROM than normal.
 
Interword has two 16K images that sit in the same ROM slot.
Interword selects between each half itself by accessing certain
locations. I beleive it reads from certain ROM locations to select
which half appears.
 
>    [EPROM   [2] ] ARM ADT
> 
> 2 - This may or may not be for the BBC. It's an Intel EPROM marked:
> i 3407-0391
>   S70058
>   U732054ZS
 
Even if it's not for the BBC, any contents might be interesting.
Wonder if it contains ARM code?
 
> I also have a bunch of 'blank' EPROMs which may or may not contain
> stuff. If there is a "(C)" in the start of the EPROM (around +8 or
> somesuch? that's the BBC ROM ID isn't it?) I'll save out these as well...
 
The (C) string can be anywhere in the first 256 bytes. Byte 7 is
the offset from the start of the ROM to the (C) string, eg:
 
=>*mdump -80 F18000+80
F18000 00 00 00 4C CE 9A 82 17 53 41 63 6F 72 6E 20 41 ...LN...SAcorn A
                            |
                            V
F18010 44 46 53 00 31 35 33 00 28 43 29 31 39 38 34 00 DFS.153.(C)1984.
F18020 A0 04 24 CD 10 13 B1 B0 99 26 C2 88 D0 F8 A9 40  .$M..10.&B.Px)@
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
There are three food groups: brown, green and ice cream.