The original coco had an MC6809E processor (a slight variation of the
MC6809 processor), a MC6883 Synchronous Address Multiplexer and a MC6847
Graphics Chip.
The 6883 SAM was the "glue" that provided all of the timing and address
decoding for the entire system. To reduce flicker the 6847 and 6809E
memory accesses were alternate cycled. This means that they used
opposite edges of the Phase 1 clock to access memory. However, this
meant running the system at .8949 MHz. The SAM had the ability to run
the CPU at twice that speed but this resulted in the video being disabled.
The 6883 SAM could address up to 96K of memory but to populate that much
memory required after market modifications.
There are many programs and peripherals available for the Color
Computer. The floppy disk system used 5 1/4" diskettes and could run
operating systems like Flex, Star DOS and OS/9 Level 1. I don't recall
if OS/9 Level II was ported to the Color Computer.
I believe there was even some kind of hard disk drive interface
available, though not from Tandy IIRC.
The audio cassette interface used 1200Hz/2400Hz tones to represent ones
and zeros.
There are many Color Computer enthusiast groups all over the country and
people still make add-ons and software for it.
Please just google Tandy Color Computer.
On 1/23/2023 11:22 AM, Chris via cctalk wrote:
I don't even remember signing up for the RetroAbout64K mailing list. I haven't
seen any actual dicussion in my remembrance. But I do get once or twice a week
an email about COCO Nation or some such. Sounds like a hot chocolate
enthusiasts group seeking world domination. Anyway I've had COCOs going back.
Or 1 that I scarfed from a friend for 20$ (back in 89 I think). I realize it
has a 6809 and all, the successor to the venerable 6800. But what can you do
with the things? Is there even a color output, despite the name. I can't
remember. I only remember playing Dungeons of Daggorath or whatever. The guy I
bought it from claimed he programmed a complex naval similation. Yeah whatever.
