Date   : Tue, 12 Jun 2001 10:02:25 +0100
From   : Paras Sidapara <Paras.Sidapara@...>
Subject: Re: Differences between B and B+?

I toyed with the idea of a home made beeb but I don't have the patience for
such a long-term project!!! Oh well...

Anyway, main hardware differences are the implementation of shadow RAM and
sideways RAM on a B+.

Also I think the OS 2.00 & Basic 2 are in a single 32K ROM. I don't see why
you couldn't add the logic to make the thing behave *like* a B+. Although a
real B+ has these things incorporated from the ground up (so DIP switches
that reconfigured the hardware to really make it the same as a B+ would be
impossible), many model B add-on cards used to do a pretty good job of
making the hardware appear like a B+ (same registers, etc). Though I don't
recall any for which you could physically plug in a B+ OS ROM.

Why not compare schematics? Have a look at the excellent BBC Lives website
at http://bbc.nvg.org

Specifically the service manual:
http://bbc.nvg.org/doc/BPlusServiceManual.zip

Though I don't think that includes a schematic diagram, which can be found
at: http://bbc.nvg.org/doc/circuit/BBC-B+.zip

Have fun!

Paras

-----Original Message-----
From: Kris Adcock [mailto:krisa@...]
Sent: 11 June 2001 14:03
To: bbc-micro@...
Subject: [BBC-Micro] Differences between B and B+?


Afternoon all!

Does anyone know what the physical differences are between a model B and a
B+? I'm looking into (as a longish hobby-project) building my own Beeb, and
I'm currently using the model B schematic as a guide. I was just wondering
how the B+ differed, and if these differences could be incorporated,
selectable on DIP switches.

Also, is there anyone out there looking at alternatives to floppy drives? I
mean, anyone doing any projects to connect small hard-drives, SmartMedia
cards, PSX memory cards, etc as if they were a floppy drive?

A SmartMedia card containing all my favourite Beeb games, read on a
homemade, portable Beeb. Mmmmmm ...

Cheers,

Kris.


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