Sinclair ZX80 / ZX81 / Z88 Forums

Welcome Kai,

it is an honor to see you among us. i have at times studied the schematics for the LCD interface and often wondered about building a similar unit alas it never came about.

regards
Andy

nollkolltroll wrote: ↑Tue Jan 15, 2019 11:27 am A tip for viewing interlaced pictures, both standard and 3-lace: lower the contrast and brightness and the flickering will be reduced A LOT.

+1 thats how i took a picture

Should be

IN A,($FE)

very cool indeed, seems to work well with my 15" Sanyo b+w cctv monitor. Flickry as ever but hey oh...


more pixels than you can imagine.

regards Andy

Brilliant stuff indeed, Shame the humble zeddy doesn't have sprites... Imagine some awesome scrolling action games...

Thanks for sharing this with us.

Andy

interesting bit of kit, NO zx81 included in that auction.. think i'll pass

Andy

Welcome Pete, hope you enjoy learning about the quirks and tricks the little black door stopper has.

Mostly we don't bite, so any questions feel free to ask away.

Regards Andy

what i wanna know is what the heck is the ~IORQ line doing after the nmi stops... what in the world would cause so many io instructions ? how many lines has your logic analyser got ? i'm thinking about probing the entire data bus and ~m1 in addition to the other lines then you can decode the exact i...

McKlaud wrote: ↑Sat Nov 10, 2018 8:51 pm well, this is not the case in my ULA, because I've got pull-ups and pull-downs there.

When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

Sir Arthur Conan Doyle, stated by Sherlock Holmes.

strike that one then soon we will nail it down

Gents, correct me if i am wrong, but there is no NMI generation at all when the ZX80_81 is pulled down. The quoted numer of 55 or 31 indicates how many scanlines should be generated and this value is read from ROM and held under the system variable called MARGIN. The MARGIN value is driven by the o...