Date   : Thu, 19 Jul 2007 22:13:20 +0100
From   : info@... (Sprow)
Subject: modern BBC remake

In article <469F2B25.2030904@...>,
   Jules Richardson <julesrichardsonuk@...> wrote:
> > > [...] Under the project name "TurboB"
> > 
> > Here goes with my thought processes:
> > 
> > Hardware:

In article <009001c7c9eb$9608b8c0$0a01a8c0@...>,
   Mark Usher <mu.list@...> wrote:
> Oh, and the output from a modern BBC remake should be VGA sync speed
> compatible.

I think that's implied by my 1280x1024 video mode, which wouldn't work on a
TV anyway.

[snip]

> >  * Upgrades
> >    Space for GoMMC upgrade.
> >    Space for Econet/Ethernet networking (probably in place of cassette 
> >    port).

> See above about casing - by all means provide a header on the board 
> somewhere, but I wouldn't bust a 
> gut over making them a core part of the design

The GoMMC upgrade path is of course just a ROM socket, which I'd already
proposed having 4 of, so it'd mainly be a case of watching for mechanical
gotchas.

The Econet/Ethernet thing wouldn't take much space on the PCB, it'd just
have its output sockets lined up with the old holes in the case. You can get
serial to Ethernet converters ("TCP/IP modules") so I'd not be proposing a
whole network stack running on the poor 6502. Infact just incorporating the
Econet <> Ethernet bridge would suffice.

> >  * System/user VIA
> >    Possibly no printer port, replaced by a USB PIC and/or PS/2 keyboard 
> >    port.

> Can't a module be made which makes a PS/2 keyboard look like a BBC 
> keyboard as 
> far as the hardware's concerned, and it'd just plug in via the normal beeb 
> keyboard socket? Why waste the printer port on this?

The loss of the printer port was to make some space to have other connectors
(rather than wanting people to print through it). I take your point though

> > Software:
> >  * Based on patched B+ OS
>
> Agreed. Minor patching might be required I suppose, but if you can't 
> essentially drop an original MOS in there and be away then it doesn't bode 
> well for compatibility!

Patched in the same way the ADFS ROM is patched for IDE drives, so 95%
original code, just a few NOPs and JMPs inserted where needed.

> >  * It'd take about 2 years to complete
>
> Your call - I can happily futz around with LS logic

I'll probably think about it again, then slap myself back to reality and
shelve it again.

> Are we talking acres of surface mount stuff here, or a more traditional 
> DIL design within the realms of the home constructor? 

0.5mm pitch surface mount is in the realms of the home constructor isn't it?
Or is that just me?

It'd be a mix I suspect. DIL for things like ROM sockets TMS5220 and 1770,
surface mount for pretty much everything else: allows a whole lot more to be
crammed onto the board while leaving room for new stuff like internal
coprocessor sockets,
Sprow.