RE: 6545 40/80 col register values

From: Baltissen, GJPAA (Ruud) <>
Date: Wed, 25 Apr 2012 07:56:30 +0200
Message-ID: <>
Hallo André,

> the width is ingrained into the hardware


> (80 cols require double the bandwith a 1 mhz 8 bit system can deliver)

This sounds to me that a 1 MHz system isn't fast enough. ???

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. 

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