Schematics for C64 Plus with 80 Columns
Schematics for C64 Plus with 80 Columns

More schematics from 30 years ago.  This is for a computer known internally as the C64+ or C64 Plus and has built in 80 column support.  Unfortunately there is a page missing.

Click on the schematic to see a larger image.

 

c64_plus_1_of_6thumb.pngc64_plus_2_of_6thumb.pngc64_plus_3_of_6thumb.pngc64_plus_4_of_6thumb.pngc64_plus_6_of_6thumb.png


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bilherd's picture

Well done Bil.
Here's an idea for a new article or video.
More info about the C64+, perhaps just some stories, meetings etc.
 
 

There is a small amount of information on how this worked at the following URL:
http://6502.org/users/andre/hwinfo/crtc/uses.html#c64_80col
 
Apparently, the 6545 ic (on image/page 6) takes over when in 80 Col mode. There is a pass-through for the VIC chip output. (Just like 80-Col addon cartridges for the C64).
 
The Wiki page for the C128's 8565 80-Col controller says: "The 8568 embodied many of the features of the older 6545E monochrome CRT controller plus RGBI color."
http://en.m.wikipedia.org/wiki/MOS_Technology_8568
..So I guess some of the work on the C64plus may have been carried forward into the design of the C128.

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