Re: 6545 40/80 col register values

----- Original Message ----- 
From: "Baltissen, GJPAA (Ruud)" <ruud.baltissen@apg.nl>
To: <cbm-hackers@musoftware.de>
Sent: Wednesday, April 25, 2012 1:56 AM
Subject: RE: 6545 40/80 col register values

> For those not familiar with the CBM hardware:
> - an 80-cols machine has 2 KB of RAM instead of 1 KB for the 40-cols one, 
> not a real problem
> - this RAM is wired in a different way for each machine. And that is a 
> problem!
> I used to have a board equiped with some added 74157 2-to-1 demultiplexers 
> replacing those wires plus a small board with extra ROMs. By flipping a 
> switch one could have either 40-cols or 80-cols mode after a reset.

---------------------
As a matter of fact Steve and I were just discussing that a few days ago; as
you say, the hardware to switch RAM & ROM etc. is pretty straightforward,
but we were speculating if it were feasible to switch modes (preferably in
software with a poke or printing a CHR$(x) ) *without* resetting the
computer...

Opinions?


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