Re: TWGS without fast GALs (was Re: ORCA/C v2.0)

[fmlin@terapin.com (Frank M. Lin)]

>How fast can a TWGS be without the fast GALs but with that 14-MHz
>65816 CPU ? Has anybody gone beyond 10 MHz ?

This is a direct quote from this article you'll get by sending SASE to Wester
Design Center.  They won't sell you an engineering sample unless you have a
copy of the article.  So please, if you're interested in up grading your
twgs/zip at all, send 'em a SASE!!

Their address:

The Western Design Center, Inc.
2166 East Brown Road
Mesa, Arizona 85213
phone: 602-962-4545
fax  : 602-835-6442

Now on with the quote...

[..]
Use new GALs: As indicated in the sidebar "10 Megahertz Barriers",
some operations are unreliable when you drive a 65c816 processor
faster than 4 MHz.  GAL chips on the TWGS intercept these instructions
and add additional cycles when they excute to provide reliable
operation at faster speed.

You need a revision E ( or later ) #3 GAL to operate the TWGS at 10
MHz; Applied programmed that chip to compensate for certain 16-bit
instructions that do not excute properly at 10 MHz. [..]

[.. goes on and states extra voltage will be nice ..]

You can order the TWGS 3E GAL directly from Applied as a single
item, but I suggest that you get the set of four high performance
GALs ( #2, #3, #4, and #5 ) if you are going to the trouble and expense of
ordering.  Those high performance parts increase the likelihood of
the success with your 10 MHz upgrade.
[..]

end of quoting...

frank m. lin
fmlin@terapin.com