Re: CBM-II Colour mod

From: Steve Gray <sjgray_at_rogers.com>
Date: Tue, 7 Nov 2017 19:19:44 +0000 (UTC)
Message-ID: <598654193.4110878.1510082384786@mail.yahoo.com>
Nope, that's about it. You could probably wire it up in an hour. Me, it takes years ;-)Basically, the circuit that handles the current monochrome 80 columns is duplicated for colour. Due to the 1Mhz clock commodore had to split the ram into two, read them at the same time, latch them and shift them out one after the other. So for an 80-column colour screen you'd effectively have a 32-bit wide video buss.
The article mentions a 160x100 pixel "graphics" mode, which I assume is just done with standard petscii block characters.
Steve

      From: Jim Brain <brain@jbrain.com>
 To: cbm-hackers@musoftware.de 
 Sent: Tuesday, November 7, 2017 2:08 PM
 Subject: Re: CBM-II Colour mod
   
On 11/7/2017 12:46 PM, smf wrote:
>
> I doubt commodore needed to use their fab to create the colour 8032 
> either. They probably just doubled up on the logic fetching characters 
> from two banks and buffering to create 80 columns, then selected which 
> nybble to output to the monitor based on the monochrome output.
>
I was wondering the same.  Steve, is there much more of an issue to just 
adding more memory as a second set of buffers for color and allowing 80 
columns?

Jim

-- 
Jim Brain
brain@jbrain.com
www.jbrain.com


      Message was sent through the cbm-hackers mailing list


   

       Message was sent through the cbm-hackers mailing list
Received on 2017-11-07 20:01:58

Archive generated by hypermail 2.2.0.