[Coco] Hitachi HD63C09 Question

[Gene Heskett]

On Wednesday 20 June 2007, George's Coco Address wrote:
>Since you've asked this before and no one has replied, I would assume that
>no one has tried it, or won't admit to it.
>It is an interesting query.
>
I have a 6309 in my coco3, but have not tried it at lower voltages.  The gime 
in particular would seem to need a full 5 volts, and may even be happier on 
more than that given it propensity to show you how well the interrupts are 
working with its video flickering as it is, the interrupt line is so badly 
overpulled that when an IRQ is asserted, the 5 volt line is pulled down 
several millivolts which in turn causes a video flicker.

As for the 6309 itself, I would assume, from the rise and fall times observed 
on any output pin, that it would be capable of 3.3 volt operation  at normal 
bus speeds, if not at an octave plus above them.  I have, on my 100 mhz dual 
trace scope, observed 10ns rise and fall times while running on its normal 5 
volts, actually about 4.88 from my psu since one elderly AT psu is running my 
whole system.  If this sort of performance is achieved internally, I have no 
doubt my 3mhz rated 63C09 could run at 20mhz.  But to test that we'd have to 
build a test system using some other video as the gime simply cannot keep up, 
its output drivers are far too puny, and incapable of a rail to rail swing in 
anything less than microsecond time frames.  A WP-RS, running on its own 
internal clock, would make a suitable test beds video I believe as it could 
be fed data at a much faster rate than the stock coco3 can manage.  That's 
text only of course but a character written to it once per pass through the 
test loop would serve as a watchdog I'd think.  It would make an interesting 
experiment.

>----- Original Message -----
>From: <jdaggett at gate.net>
>To: "coCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
>Sent: Wednesday, June 20, 2007 8:41 PM
>Subject: [Coco] Hitachi HD63C09 Question
>
>>I know the Coco Community has used the Hitachi 6309 chip for a while. Most
>> operation has centered around speeding up the 63C09E be yond 3MHz. I was
>> wondering if anyone has experimented running the MPU at or below 2MHz and
>> at
>> 3.3VDC instead of 5VDC? IF the 63C09 was designed in the mid 80's then it
>> is
>> possible that at normal speeds the 63C09E just might run at 3.3VDC.
>>
>> Has anyone attempted or does anyone know of any tests done with lower VDC?
>>
>> james
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco
>
>--
>Coco mailing list
>Coco at maltedmedia.com
>http://five.pairlist.net/mailman/listinfo/coco



-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
When your memory goes, forget it!