Re: 65816

[waynes@intergate.ca (Wayne Stewart)]

Mark Cummings wrote
> Welcome to the fast lane Wayne >>>>>>>

Wouldn't call it all that fast, my fastest ZipGS gets 15mhz with a 64k cache
 
> I'm pretty certain, being a Transwarper myself, that the early ones were
> only 6MHz and not marked. Later ones, like the one I had prior to upgrading
> was a 7MHz type marked with a "-7" on the CPU. This is not to say that
> either wouldn't run faster. I think that some users were successfull at
> getting 8 or 9 MHz from an unmodified card, except the crystal of course.
> 
> The crystal is part of the clue if you knew it was original. just divide it
> by 4 and you have the processor rating. If the card has an upgraded crystal,
> that may make determining the original setup impossible as it is easily
> swapped. Perhaps the GALS or the ROM version will give a better clue as to
> the original setup. The early models only used REV A GALS. My 7MHz model
> unmodified had GAL 2B & 3C and all the rest were #A's. Also my original
> EPROM was REV 1.5 8S.

As I recieved it, it had Rev A GALs and a Rev 1.5 EPROM running at 7mhz
though flakily at the time. Unfortunately with an 8k cache. All the chip 
dates(88 & 89) seem to indicate a fairly early production.

> Of couse I upgraded to 32K cache & ROM 1.8 via Joachim & got the faster
> 14MHz processor through Ryan and crystals through Mouser Electronics (www
> site). I had a lot of problems with it crashing initially at 10 & 12.5 MHz
> and have never been able to run it at 16 MHz. In fact performance was so
> unreliable before and after the mod I wasn't actually using it for over 6
> months. I recently found that part of the cause of my problems is the CPU
> cable, and the associated connector on the TWGS. A few days ago I cleaned
> those connectors using a product called CO-Contact cleaner, which is an
> electrical connector cleaner. This has improved the TWGS performance
> dramatically. I no longer have crashes every 10 mins, and have run it for
> many hours on end at 10MHz. Ultimately I would like to replace the TWGS
> connector with a newer gold plated one as mine is rather dull grey colour
> and I think that's a weak point on my card. Also replacing the ribbon cable
> may help too.

I gave a friend all my half size oscillators last year but I have a slew of 
full size ones from my ZipGS upgrade days so I whipped up an adaptor for the 
full size and have been running it for the last 4 hours at 14mhz. Unfortunetly
with a faster oscillator I get an error message. Likely I'm at the limit of 
that 45ns cache.
I imagine like with the ZipGS going from an 8k to a 32k cache would be about 
equivelent to a 3mhz speed increase?
Wasn't planning on any further upgrades, now I'll have to admit I'm awfully 
tempted.

	Wayne