[Coco]: Tandy's biggest mistakes thread

[jdaggett at gate.net]

Kevin

The current available parts on the market now,  5 to 7 Mhz is about max. Most will 
do 3 MHz. Some might be pushed up to 7MHz. at above 2 to 3 MHz the chip needs 
heat sinking or it will not last long. 

If one were to take the time and redo the MPU on newer processes, 66 MHz would 
not be a proble at all. Flint Weller in his doctorail thesis did a 6809E on Kawasaki 
cmos_cba process and achieved speeds of 25 Mhz. That probably is 0.25 micron. If 
one took care on some of the critical circuits that would affect propogation delay 
that could easily be pushed to 66MHz. 

I  have Flint Weller's VHDL code as well as John Kent's VHDL code and have 
studied it a bit. John Kent's VHDL code in FPGA will run about 10 Mhz. There are 
open cores for the Z80 that will run 35 MHz in a FPGA and at 100 MHz in 0.18 
micron CMOS ASIC. Ideally one could get a MC6809/HD6309 core to run similar. 

Also one must consider that a MPU like the 609 will run slower in a FPGA than is 
actual dedicated silicon. J ust the nature of the designs. 

james


On 20 Apr 2005 at 12:50, Kevin Diggs wrote:

Date sent:      	Wed, 20 Apr 2005 12:50:07 -0700
From:           	Kevin Diggs <kevdig at hypersurf.com>
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Subject:        	Re: [Coco]:  Tandy's biggest mistakes thread
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> JDag,
> 
>  How fast could we get a 6809-like core to run? Think we could get in
> the 66 MHz range?
> 
>      kevin