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

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