[Coco] GIME Chip

[jdaggett at gate.net]

Robert

The rise and fall times of the E and Q clocks could also alter 
performance. Since the GIME generates these signals and the 
presence of the caps tends to lead me to believe that the E and Q 
clock rise and fall times were very quick. Also  the RAS and CAS 
lines have RC filters. These are used to reduce harmonics 
generation that cause EMI. This is the ringing seen  on the square 
wave. 

Also the specs on the duty cycle and difference in phase between 
the E and Q clock signals are somewhat wide. 

james


On 5 Mar 2005 at 10:08, Robert Gault wrote:

Date sent:      	Sat, 05 Mar 2005 10:08:43 -0500
From:           	Robert Gault <robert.gault at worldnet.att.net>
To:             	CoCoList for Color Computer Enthusiasts 
<coco at maltedmedia.com>
Subject:        	Re: [Coco] GIME Chip
Send reply to:  	CoCoList for Color Computer Enthusiasts 
<coco at maltedmedia.com>
	<mailto:coco-
request at maltedmedia.com?subject=unsubscribe>
	<mailto:coco-
request at maltedmedia.com?subject=subscribe>

> Very interesting analysis. We might learn something by examining the
> E, Q, RAS, and CAS lines with a good scope for both '86 and '87 GIMEs
> on the same Coco.
> 
> I also vaguely remember some articles where the caps C10 and C11 on
> the E and Q lines were altered or at least checked. Also some
> proposals for circuit change around IC9 74LS138.
> 
> -- 
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco