Date   : Sun, 13 Jun 2004 15:34:29 +0200
From   : John Kortink <kortink@...>
Subject: Re: Solid state storage for the beeb

On 13 Jun 2004 11:53:18 +0100, jgh@... (Jonathan Graham
Harston)u wrote:

>> Message-ID: <tdlmc0tm222f7gdq3451d6decmn9enbs70@...>
> 
>John Kortink <kortink@...> wrote:
>> On Sat, 12 Jun 2004 19:12:51 +0100, Sprow <info@...> wrote:
>> >   John Kortink <kortink@...> wrote:
>> >> Currently I'm tapping 4 bits of port A of the user VIA,
>> >> but I'm moving everything to a ROM socket.
> 
>Good idea. I have a mouse plugged into my user port.

That's port B, of course. Although the point is moot.

>> Well, I'd rather assume all ports are in use (floppy needed
>> as a source for files, the user port for 65Link, 1 MHz bus for
>> whatever, Tube for 2nd processor). Except perhaps the printer
> 
>All my external connectors usually have something plugged in. Of course,
>you can daisy-chain the 1MHz bus.
> 
>I'd've prefered access via FRED (the 1MHz bus)

It's a place to consider as an alternative. But part of
the appeal of solid state storage is having it inside
the case. Nothing to dig up and connect, just get out
your beeb and play. But I'll consider doing an external
version as well. I agree the 1MHz bus would be the best
place.

>, but using a ROM socket for
>access looks ok. The only problem that ROM-based code has to jump down
to
>low memory to look around the side of the current ROM to the page with
the
>memory card in it.

GoMMC itself doesn't need to. The software is on the
interface as well. Access to the top locations of the
ROM space go into the CPLD.

Other ROMs wanting read/write access to the MM card
could get that via, e.g., an 'unknown' OS_Word call.

>Can you publish the hardware API, then it will be simple for people like
>Sprow and me to integrate a driver into our software.

I will. Once it's finished.


John Kortink