ZX Spectrum internals (Was: ZX81 kits)

From: Iggy Drougge <optimus_at_canit.se>
Date: Sun Sep 30 20:39:50 2001

Tony Duell skrev:

>As I've said a couple of times before, I can make a video circuit with
>somewhat better capabilities than the ZX81's built-in video (40*25 text,
>block grapghics, colour) in 2 or 3 chips. Add another chip or so to
>encode the outputs to PAL (although I'd probably prefer to feed the RGB
>signals into a TV's SCART socket these days...)

What chips would you use? I assume that the Speccy uses one chip for its
entire video generation, but where would you split the functions?

----
(update a few minutes later, aren't off-line readers a wonderful thing?)
I went and opened up my own seemingly-dead Spectrum... Wait, that's no ZX81.
I've been thinking about SZ Spectrums all the time.
Oh well, I might just ask anyway, since I've opened it up...
What is that chip next to the Z80? It's labelled PCF1306P.
And why is there a switch glued on top of the Z80 with wires going to the
character ROM? Since it's a localised character ROM piggybacked on top of the
one soldered to the motherboard, could it be for switching charsets?
--
En ligne avec Thor 2.6a.
Allt ?r under kontroll, och caps lock ?r bredvid.

Received on Sun Sep 30 2001 - 20:39:50 BST