Date   : Fri, 14 Dec 2001 09:31:15 -0000
From   : "Rich Talbot-Watkins" <rich_tw@...>
Subject: Re: International fonts & mode 7

> > This is not quite true. As far as I remember SAA5050 has several
> > writable memory registers to program the additional symbols.
> > There are not many of them.
>
> So can you program these registers in software, like user-definable
> characters in other Modes with VDU23...? I always thought that you
> can't redefine characters in Mode 7, or were the memory registers in
> the SAA5050 preprogrammed before being fitted into BBC Micros going
> abroad?

Although the SAA5050 may have writable registers (and I don't know if it
does or not!), they weren't mapped to any memory location in the Beeb's I/O
space, so it wouldn't have been possible to access them.

The only way it was possible to change the Mode 7 character set was to
replace the 5050 with another version; effectively the characters were in
ROM.

Rich