 The Color Computer (affectionately known as a Coco and formerly sold
by Tandy) has got to be the most underrated computer ever made. It was
based on the Motorola MC6809E. The circuit used for the original Coco
1 was, almost part for part, shown in the Motorola spec sheet for the
SN74LS783 - MC6883, a synchronous address multiplexer (called by
Cocoists a SAM.) The third major chip in the Coco was the MC6847 Color
Video Display Generator.
The Coco 1 was an 8/16 bit computer running at 0.89/1.78 MHz. The text
screen was 32 letters by 16 lines in uppercase. Graphics resolution
was 256x192x2 although owners quickly found that color artifacting
produced by the composite video output could increase the color count
by one or two orders of magnitude. Memory was limited to 32K ROM plus
64K RAM. With the Coco 3, the final version made by Tandy, the support
chips were enhanced to produce a base unit with 128K RAM, 80x25
character text, 640x192x4 or 320x192x16 graphics, and RGB video
output. The Coco1 did have one graphics capability that the Coco3
lacks, Semigraphics.
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