Re: TransWarp IIgs GAL's - Upgrade now possible

["Henry" <apl2research@comcast.net>]

Hello Eric.

Cloning the TransWarp IIgs but in to a new FPGA would be the path we would 
take.  I may be wrong, but as stated earlier the "configuration code" for 
the XC2064 on the TransWarp IIgs is stored in ROM?  So, again I haven't even 
started any research on this, I would assume that if the code is readable 
then converting it in to something logical (i.e. - HDL or schematic) should 
just be a matter of time.

Am I missing something with my understanding of the XC2064?  Again, I 
haven't really looked in to this project yet.  Might be something later down 
the line for us.  I'm just glad to discuss it here and have something to 
reference later.


Henry S. Courbis
www.GSE-Reactive.com
Apple II Series Legacy Hardware - Come take a look at what we have to offer!

"Eric Smith" <eric@brouhaha.com> wrote in message 
qhr76ebup0.fsf@ruckus.brouhaha.com">news:qhr76ebup0.fsf@ruckus.brouhaha.com...
> Henry wrote:
>> I know my cards are 50 MHz speed FPGA.  Probably all that is needed to 
>> run
>> at 8 MHz reliably.  I do have all the tools for the surface mount 
>> operation,
>
> Mine has the -70 part, IIRC, and is running find at 12.5 MHz (configured
> that way when I bought it secondhand).  For reasons I stated earlier, it
> is unclear whether this depends on the FPGA actually having better
> performance than its specifications.
>
>> but finding just one or two of the FPGA might prove to be a head ache.
>
> Yes, very much so.  They also tend to be very expensive.
>
> A new Xilinx XC2S15 has much more logic capacity than the original part,
> and costs about $10 in small quantities.  Unfortunately it is not
> available in the same PLCC package.  Worse yet, without the source code
> (or schematics) for the original FPGA configuration, it is not possible
> to generate an equivalent FPGA configuration for the new part.
>
> This would be a fun reverse-engineering project, if only I had the time
> to spare.  But it is quite possible that designing a new IIgs accelerator
> from the ground up would take less time than reverse-engineering the
> TWGS FGPA configuration.