The CoCo – The Tandy Color Computer

I think I can almost draw the circuit diagrams of this machine from memory! A 6809E processor, 6883 memory controller, a pair of 6821 PIAs to interface with the world, and a 6847 video chip. Tandy’s technical manual looked like a straight reprint of the Motorola “example layout” for a simple video game machine.

I can remember being a little disappointed back in 1981 when my dad came home with the Coco — we’d both been reading about the Hitachi Peach, which was a far more powerful machine, but I think it was out of our budget. The Coco was a hand-me-down from one of dad’s co-workers who had bought himself a Peach!

16k of RAM, a 1500bd cassette tape interface and a hideous keyboard made out of little plastic buttons. It was upgraded to 64k — at great expense — an old Cherry keyboard was laboriously hand-wired and plugged in, and I’ve still got an old shoe box of tapes — the floppy disk controller I intended to build never got past the plans and diagrams stage.

All things considered, I shouldn’t be too hard on the old beast, I think it was responsible for my first job, where my knowledge of 6809 assembler programming counted for more than my lack of completed degree.