Sinclair ZX80 / ZX81 / Z88 Forums

Hello everyone!

Apologies for the clumsy English - is Google translator.

Never in my life did not concern the present Sinclair ZX81, but I recently did for him one old game.

Her descriptions and rules were published in 1990 in the Soviet journal http://en.wikipedia.org/wiki/Tekhnika_Molodezhi

Twenty-three years ago, many people have programmed it on many different computers.
I myself in 13 years (1993) started to write it for the Spectrum ... And then abandoned.

So I recently finished writing for the ZX81. In Basic. Rules (even if sometimes funny) tried to follow according to the journal article.

I know that the UDG to ZX81 is not so easy to do, but possible. Do not understand the intricacies of becoming I just sent them to the ROM for 7680 (1E00h). So the picture will be normal only in the emulator, with permission to write to the ROM.

The game became a little whole in the 16K. A bit assembler would help, but the last time I used it on the Spectrum in 1995.

So it's 100% pure BASIC!

P.S. Now do not clean basic. Changed attachment to the new version.

PPS: Small mistake in line 239.
Corrected. If you and I will continue to fix that - not before the autumn.

upd 9.03.14 - Remove two small bugs.

I'm sorry to have missed a little mistake.

Corrected file: see above.

Hi and welcome to the forum!

That's a lot of work you've done - you must be very dedicated

I will play this when I get the zx81 out again.

Thanks for sharing!

Thank you.

On a real ZX81 will be ugly - UDG not work.
No hardware revision pointer to a character set can not be moved to RAM. Big mistake engineers who made this computer.

After all, it could have been foreseen in advance, and there are simple solutions. For example, in ftp://ftp.worldofspectrum.org/pub/sincl ... SUMThe.pdf page 55, for example refinement UDG.

I can make a version without the UDG, if needed.

Cool !

Thanks for the link to the UDG circuit - I've been looking for this document for ages!

Thanks Buka !
The UDG can't work on the $1E00 ROM address (IR register), because of the direct wirrings beatween the ULA and the ROM.
We had to put a memory RAM, placed on the ROM plug (using Dx' data bus on the wirring diagram).
Have fun.

http://translate.google.fr/translate?sl ... 23reponses

DKTRONICS UDG Card:
http://translate.google.fr/translate?hl ... fr%2Fdk%2F

VTR card:
http://zx81.ordi5.free.fr/vtr/

XavSnap wrote:Thanks Buka !
The UDG can't work on the $1E00 ROM address (IR register)

I know that.

it seems so easy - LD A, addr; LD I, A ...
But addr is possible only from the ROM to take - getting garbage on the screen.

This game was written under an emulator, so ... If the real CHR board can send 512 bytes of the character set to the correct address and set the IR - tell me where?

Oops, as he wrote - there were references to hardware.

Sorry for beeing so unkind to correct you.
For UDG there is no need to change the data lines.
Only the lower address lines need to be A0'..A8' in order to get the ULA Adress lines instead of those from the Z80.
Kind regards
Paul

Test changes IR register.

On a real ZX81 100% should move in the limit h0-h2000.

In the limit of h2000-h4000 need to check with the real memory in this area...