Date   : Mon, 09 May 2005 18:40:08 +0100
From   : Sprow <info@...>
Subject: Re: IDE Interface for BBC

In article <427EC106.1CFBAE39@...>,
   W.Scholten <whs@...> wrote:

[snip]

> > The IDE interface is just that - an IDE interface, a specification and
> > set of suggested complying interfaces. Anybody is welcome to use the
> > design in their own board. I set off to design a working IDE interface,
> > not to jump six or seven steps and try a design an integrated multiple
> > interface board without first getting the IDE interface itself working.
>
> Obviously that's why I suggest it now that it's working.
>
> It's a trivial design change to add the RAM but I've got no experience
> making PCBs, I've only used wire wrapping/experimenting boards etc. so
> it would take a while to get into it and it would 'compete'. 

I think Wouter you may have missed the design decision boat a little - I
suggested on 9th Jan 2004 that a block of SRAM could come in handy:
 <4c6dfad266info@...>
but due to space constraints on the IDE PCB conflicting with the desire to
use DIL parts there's no SRAM. 

I'd suggest a half way compromise which doesn't load the base cost for most
users would be to use a RAM disc for buffers.

<plug>
 http://www.sprow.co.uk/bbc/ramdisc.htm
</plug>

which handily plugs into the 1MHz bus anyway. If you don't have RAMFS loaded
then you can use the 8Mbytes of RAM for whatever you want, alternatively I
can add a call to allow you to "set aside" a pseudo file on the RAM disc to
use as IDE workspace.

Perfect,
Sprow.