Date : Wed, 07 Nov 2007 18:41:21 -0800 (PST)
From : cjl_craves@... (Peter Craven)
Subject: ROM / RAM boards...
How many ROMs could this hold at a time?? Was there any space available for SRAM?
Cheers
Pete
Dr Peter Craven (MBBS Uni. of Qld)
877 Wynnum Rd
Cannon Hill
QLD
Australia 4170
----- Original Message ----
From: Pete Turnbull <pete@...>
To: bbc-micro@...
Sent: Thursday, 8 November, 2007 6:34:26 AM
Subject: Re: [BBC-Micro] ROM / RAM boards...
On 07/11/2007 17:08, Rob wrote:
> On 07/11/2007, Jules Richardson <julesrichardsonuk@...> wrote:
>>
>> I just need the least painful route (which probably rules out the ROMEX board
>> as I really can't be bothered cutting wires and soldering to a new machine) so
>> adding some more expansion capability. I'm leaning toward the Sidewise boards
>> as one of those has all its pins bar one, unless someone thinks otherwise...
> I have no experience of the Aries offerings, but I've still got a
> sidewise board (bought new 25 years ago..) and it's definitely pretty
> simple.
> Socket 15 on the sidewise is split (optionally, set a link) into two
> 8K sockets into which you can put one or two 8K SRAM chips. Another
> link enables writes to that socket. ATPL chose to use the "any write
> access hits the RAM whatever the currently selected ROM" method, so
> you can just *LOAD romfile 8000 and it works. Can be iffy with some
> protection schemes though, so there's a link to disable writes. I
> (and most other serious users I imagine) took this out to a switch on
> the back, (along with, I think, the 8K/16k switch, because you could
> disable a corrupt ROM by swapping out the bottom 8K!)
I agree. The ATPL Sidewise was the Rolls Royce of sideways ROM boards.
I have two, and wired a switch -- actually a 3-position single-pole
double-throw with centre-off -- so that I can have the sideways RAM
write-protected, write-enabled, or disabled. Being able to disable it
is particularly useful because the RAM is normally mapped to the
highest-priority slot. However, on one of the boards, I just re-mapped
it to a lower slot number.
--
Pete Peter Turnbull
Network Manager
University of York
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