Re: Transwarp GAL chips

[Rubywand <rubywand@swbell.net>]

Ecitnerppa writes ...
>
> ....
> Personally, I've been desperately trying to get my cache up to 32K. I only own
> one Transwarp, but I've got two 8K cache cards, both REV A, both version 1.5 of
> the firmware ROM. There are several questions raised by this:
> 
> Are there later revisions of the cache card?


     According to a reprint (from WDC) of John Link's 1991 cache upgrade
article the standard 8k-to-32k cache upgrade kit from AE came with a new
"piggyback board" 
with a 1.7w32S ROM installed. Swapping in the new board plus cutting a
couple bowtie traces appears to be all that was required.

     In a post a couple years ago, Charles A. Plater notes:

>>

I downloaded something from GEnie this last weekend about a _new_ 32k 
cache upgrade for a TWGS.  The only problem is that you have to have the 
1.7 or greater ROM version to use it.  All of the original 8k cache
cards 
have the 1.5 ROM version.  SHH Systeme cannot supply the ROMS as they
are 
copyrighted. ....

<< 


> I've put 32K SRAM chips in one card, cutting some "bowtie" connections and > soldering others in order to impliment the additional address pins. ....
>

     Someone with TWGS experience or knowledge of alternative cache
upgrade methods is going to have to come to the rescue here. Just
guessing: It is conceivable that, however correct your hardware mods,
the 65C816 will not send the required address signals to your new 32k
memory IC's without the v1.7 ROM.

     By the way, John Link mentions that a speed upgrade can be done to
boards having the v1.5 ROM. The 1991 series of articles ends with a
fairly involved upgrade to 10MHz. This, was, evidently, before the
better 65C816's arrived.

     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.

     The catch here is that he had earlier installed the AE 32k cache
upgrade which happened to include 35ns RAM. The original 8k RAM was
rated at 45ns. Also, there seems to be no mention of ROM speed
differences, if any.


Rubywand