[Coco] What would a CoCo successor have to have as a minimum?
alxevans at concentric.net
Tue Nov 23 09:34:11 EST 2010
--- On Mon, 11/22/10, Mark McDougall <msmcdoug at iinet.net.au> wrote:
> From: Mark McDougall <msmcdoug at iinet.net.au>
> Subject: Re: [Coco] What would a CoCo successor have to have as a minimum?
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Date: Monday, November 22, 2010, 6:26 PM
> On 23/11/2010 11:31 AM, Theodore
> (Alex) Evans wrote:
> > If one wants to get pedantic, 8ns giving you 125MHz is
> only 4x faster than
> > 25MHz, not 5x faster.
> Damn, my stupid calculator is broken, it _insists_ that
> 125/25=5, not 4! :(
Therefore 125 is five times 25 or four times more than 25. Stick it!
> > especially since there is nothing stopping you from
> giving the video side 32
> > bit access even with no changes to the CPU.
> ...except for the minor fact that you don't have 32-bit
You are making the assumption that the CoCo4 is on the DE1. Again stick it! We could design the bloody thing to have as wide a memory bus as we wanted, we just couldn't use the DE1 as our base.
> Surely that's just a matter of changing the port widths on
> John Kent's CPU09 core... right John? Maybe you should've
> used generics when you wrote it!?!
I was saying it would be nice. Hell, you aren;'t giving people crap about wanting to use 68k features (or even a 68k) in this proposed CoCo4. It is a question about what would be nice. The single biggest limitation on the 6809 is the size of the addresses. Memory paging techniques to access more than 64k are useful to an extent, but they are ackward. Heck, it is a pain in the ass to use the segemnents in an 8086 or 8088.
> Sorry to be sarcastic Alex, I couldn't help myself. But you
> do have a tendency to over-simplify everything.
Stick it! Great 512k of dual port ram can be had for $40. That is too damn expensive, so I am over simplifing.
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