On Sep 22, 2023, at 3:07 PM, Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 9/22/23 11:34, emanuel stiebler via cctalk wrote:
There are still some 84pin chips out there(Altera
& Xilinx). Sometimes
they are pulls, or some 5V tolerant xilinx xc95xxxxl
I still have a few 84 pin PLCC XC95108 5V CPLDs Originally, I did a
tape controller design with one before Xilinx discontinued them. I
figured that using a discontinued part was not the way forward, so I
dropped the project. Xilinx did/does have its ISE design suite, which
is fairly easy to use.
Eventually, it turned out that using a reasonably fast MCU with 5V
tolerant I/O worked just as well and avoided the "mystery in a chip" of
a CPLD.
I used an Arduino Feather that way, for my PS-2 to LK201 converter. And while not 5V
tolerant, a Raspberry Pico is a particularly powerful and cheap option; one of my projects
could run DDCMP at 10 Mb/s including the "integral modem" compatible signaling.
As I mentioned, 5V tolerant inputs can, at least for not too high speeds, be done simply
by resistive voltage dividers.
paul