Re: Upgrading TWGS; Need GALs

[supertimer@aol.com (Supertimer)]

ToasterKing <ToasterKing @ mindless.com> wrote:

>Does anyone know where the high-speed GAL chip set can be found for
>upgrading the TransWarp GS accelerator?  Any info would be appreciated. 
>Thanks a lot!

There was a long discussion here about this subject a week or so ago.
Basically, any 65C816 chip manufactured by WDC since 1992 does not
require the so called high-speed GAL chip set (they actually slow down
the TWGS because pre-1992 chips were inferior, it turns out).

Rubywand posted that the chips since 1992 don't need swapped GALs:

Rubywand <rubywand@swbell.net> wrote:

>     In 1992, John Link welcomes WDC's new, improved 65C816's with
>another speed-up article involving much less bother. He says that he
>obtained reliable operation at 12.5MHz without increasing Voltage and,
>as noted by Scott G, without swapping out GALs.

Scott G wrote a HyperCard GS stack that graphically illustrates the
upgrade process and talks about why the GALs are not needed:

Scott G wrote:

>Point your web browser to:
>
>http://ground.isca.uiowa.edu/apple2/apple16/Hypermedia/Hypercard/
>and download TWGSupgrade.SHK or TWGSupgrade.BSQ from the list of
>files.  This is a stack that will tell you, among other things,
>where to get the source of the ROM upgrade.  If you don't have
>HyperCard IIGS, the runtime player is available from this list as
>HCGSPLAYER.SHK (it lets you run, but not create, stacks).

Todd Whitesel discusses which instructions the GALs slowed down
that don't need to be anymore with the new 65C816 chips:

toddpw@ugcs.caltech.edu (Todd P. Whitesel) wrote:

>>It says that the GALs were needed to slow the processor down for certain
>>operations, because the chips weren't very good.
>
>I think that was because the REP and SEP instructions turned out to require
>a really hideous signal wire stretching across most of the chip (on WDC's
>layout, anyway) -- as you overclocked the 65816 more and more, REP & SEP
>would croak first, and then later on all sorts of stuff would fail (i.e.
>hang city).
>
>Probably if it hadn't been for REP and SEP, WDC would have gotten faster
>chips working a heck of a lot sooner, quite possibly changing history.
>
>If the modern 65816's are a new layout, then I'd expect the REP/SEP problem
>to be a non-issue for them -- and unless there were other features in the
>GALs, it would seem to be sufficient grounds to update the FAQ.

Good luck upgrading your TWGS!