Tiny SMD switches or tact switches for silly emulator project?

[Matthias Melcher]

Matthias Melcher wrote:
I can upload the ZX Spectrum ROM myself. Will it have

It's a worthless project to me if it is not plug-n-play though.

Yes, good point. Their Sinclair ROM's including documented assembler
have been out there for soo long now that I am surprised that they
bother. But as soon as lawyers get involved... ;-)

I'm not sure how to handle the video on the Spectrum.

You'd need a second processor that uses the Z80 instruction cycles to
read RAM and generate the image. Kind of interleaving Z80 vs. video
processor access. That's why all those early homecomputers up to the
Amiga had so funny clocks like 3.6MHz or 7.16MHz .... .

 

[Joseph2k]

http://www3.alps.co.jp/WebObjects/catalog.woa/PDF/E/Switch/Tact/SKRK/SKRK.PDF

Nice. I'll see if I can make this fit. Should just squeeze in.


I wanted to do this for a business card ZX Spectrum or ZX-81 emulator.
Unfortunately, "due to other licensing arrangements" (cellphone ports
of 8-bit games, I believe), Amstrad cannot license their firmware for
this use.

How about a PDA like [transparent] sensor over your card?

 

[Joseph2k]

Yes, good point. Their Sinclair ROM's including documented assembler
have been out there for soo long now that I am surprised that they
bother. But as soon as lawyers get involved... ;-)


You'd need a second processor that uses the Z80 instruction cycles to
read RAM and generate the image. Kind of interleaving Z80 vs. video
processor access. That's why all those early homecomputers up to the
Amiga had so funny clocks like 3.6MHz or 7.16MHz .... .

Actually interleaving CPU accesses with video accesses started with the
Apple II [Ca 1972] and most any related patent is expired.

 

[William P.N. Smith]

I'm trying to build a PDP-1 emulator on a 90x55mm business card.

My kids are reaching the age where they are ready to start learning
about the fiddly little bits inside a computer, and some recent talk
of the switches-and-lights computers has me interested in getting such
a thing.

Does anyone make a commercially-available (real or emulated) processor
with switches and lights like we all learned on in The Good Old Days?
8*)

I've found http://www.imsai.net/ but it's not clear what I'd need or
if they are still "in production"...

Thanks!