[Coco] (very very slightly OT) 6800 emulator

[coco at yourdvd.net]

yes, i was just going by what i remembered from the byte magazine
articles, but memoy can be an evil little thing...r

> -------- Original Message --------
> Subject: Re: [Coco] (very very slightly OT) 6800 emulator
> From: jdaggett at gate.net
> Date: Mon, April 30, 2007 9:42 am
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> 
> Again I reitterate that the emulation board was a functional
> equivalent of the 6809 
> that was built around the 6800.  Also to do a beadboard where you
> implement the 
> 6809 hardware in logic would be emensely complex and time consuming to
> get 
> running. 
> 
> Chances are the instruction set and register movement were not at the
> full 2 MHz 
> speed rated for the final silicon. Also when you go from evalu
> ation/breadboard to 
> actual silicon timings do change. Back in the 70's it was not uncommon
> to do 
> multiple passes on the silicon. In fact if the first silicon worked at
> any speed 
> above 10KHz that was a blessing. Usually by the third pass you had
> pretty much 
> production ready ICs.  Only a minor tweak in the fourth pass would
> meet the final 
> design goals. 
> 
> Today an IC as complex as the 6809 can be done is one or two passes of
> silicon. 
> Six to nine months as compared to two years. 
> 
> 
> james 
> 
> 
> On 30 Apr 2007 at 0:17, Joel Ewy wrote:
> 
> > It does if you want to emulate it at full speed or better.  But
> > Motorola's purpose in emulating the 6809 on the 6800 wasn't to play
> > cool CoCo games from the past, er, from the future.  It was to test
> > the instruction set, and maybe to begin writing 6809 software (maybe
> > assemblers and such) before there were actual 6809 chips available.
> > Yes, it would have been slower than the 6809, but it could have been
> > made to work just the 6809 would have.
> 
> 
> 
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