[Color Computer] Re: [Coco] CoCo video?

jdaggett at gate.net jdaggett at gate.net
Mon Jan 30 13:07:18 EST 2006


I agree that there are many directions that one can go from the base of the Coco 3. My 
opinion is that the Multipack interface is a limiting item. To realy go forward the Coco 
expansion bus needs to be taken to 50 pins minimum. This can allow more decoded I/O 
than what is presently available. 


On 29 Jan 2006 at 22:00, Neil Morrison wrote:

To:             	"Coco on Yahoo" <colorcomputer at yahoogroups.com>
From:           	"Neil Morrison" <neilsmorr at hotpop.com>
Date sent:      	Sun, 29 Jan 2006 22:00:23 -0800
Subject:        	[Color Computer] Re: [Coco] CoCo video?
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> I know everyone has their own idea about 'expanding' the Coco. I still like 
> the idea of an expansion interface, like the old Model I, that sits under 
> the monitor. I see a fast processor with a meg of ram and all the I/O you 
> want, HD, FD, maybe even a USB. It would connect to the Coco via a cable and 
> a connector in the ROMPak slot and would use the Coco for keyboard, video, 
> and cassette say, but would do all the heavy processing. Good place to use a 
> DMA and maybe a meg of ROM for OS-9 or whatever.
> Neil
> ----- Original Message ----- 
> From: <jdaggett at gate.net>
> > Neil
> >
> > Yes there was. MC6844. This chip better interfaces with the MC6809 and
> > not the MC6809E. The MC6809 has an input labled DMABREQ. Asserting
> > this pin low will suspend the MC6809 execution for 16 cycles. Then the
> > MC6809 will execute one cycle. Thus there is an alternating of 16 to one
> > cycle ratio for DMA access.
> >
> > With some external logic this can be done with the MC6809E.
> >
> > james
> Brought to you by the 6809, the 6803 and their cousins! 
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