Search found 988 matches

by siggi
Mon Dec 14, 2009 9:53 pm
Forum: Hardware
Topic: 32k 62256 mem mod help
Replies: 24
Views: 37958

Re: 32k 62256 mem mod help

Hi Mike, you could use the ram-test routine of the rom itself: when you switch on the Zeddy the rom tests the ram from 16K to 32K and sets RAMTOP above the last ram adress (normally 32K). But it does not test above 32K, so even if you have 32K ram installed, only 16K is tested after power-on. It you...
by siggi
Sun Dec 13, 2009 6:29 pm
Forum: Development
Topic: BIN2P + other utils for compiling - Where?
Replies: 4
Views: 5254

Re: BIN2P + other utils for compiling - Where?

Here it is (coming with z88dk)

HTH Siggi
by siggi
Sun Dec 13, 2009 11:07 am
Forum: Development
Topic: BIN2P + other utils for compiling - Where?
Replies: 4
Views: 5254

Re: BIN2P + other utils for compiling - Where?

I recommend to use a C-compiler like z88dk to make programs for a Zeddy. This compiler uses libraries adapted for the ZX81 and knows about the ZX81's special hardware/interrupt features (e. g. that the IX and IY register are used by the NMI-routine are not saved on stack, so they may not be used by ...
by siggi
Sun Dec 13, 2009 10:23 am
Forum: ZX BASIC
Topic: Basic RAM limites.
Replies: 4
Views: 7346

Re: Basic RAM limites.

The D-File can be above 32K, if you don't have a /M1-circuit (to execute m/c above 32K) installed or have it disabled. But it cannot go above 48K, because the memory logic would (during display and /M1 active) redirect access from the D-File to the 16K range and then the Zeddy would crash, because t...
by siggi
Mon Dec 07, 2009 4:52 pm
Forum: Hardware
Topic: Back to memories.
Replies: 3
Views: 6692

Re: Back to memories.

Hi! I plan to install the RomCs decoder. But, there's something wrong. There is a RomCs on the zx81's edge connector. Where is it located? After the R28 resistor (Rom side) or before (ULA) ? After the resistor (Rom side) This resistor seem to be used to pull down the ROMCS to 0v on the edge conecto...
by siggi
Mon Nov 23, 2009 9:13 am
Forum: Emulators
Topic: EightyOne - time to bring it up to date?
Replies: 17
Views: 24654

Re: EightyOne - time to bring it up to date?

In the last millenium I wrote a game to simulate a nuclear power plant (Harrisburg :mrgreen: ). To control the reactor, you have to press 2 keys simultaneously . E. g. to open the valve for the steam, you have to press "D" and "K" (for '+') or "D" and "L" (for '-') to close it. I PEEKed some BASIC ...
by siggi
Fri Nov 20, 2009 9:49 am
Forum: Emulators
Topic: EightyOne - time to bring it up to date?
Replies: 17
Views: 24654

Re: EightyOne - time to bring it up to date?

Hi Dominique at least using BASIC it is possible to check multi-keypresses with EO (despite of the limited capabilities of a PC compared to a ZX81 :lol: ). In the last millenium I wrote a game to simulate a nuclear power plant (Harrisburg :mrgreen: ). To control the reactor, you have to press 2 keys...
by siggi
Wed Nov 18, 2009 10:35 pm
Forum: Software
Topic: SYNCWARS16 (By FRED. NACHBAUR)
Replies: 3
Views: 9434

Re: SYNCWARS16 (By FRED. NACHBAUR)

Yes.
And here are some of them ...

http://www.pictureviewerpro.com/hosting/zx81/fredn.htm

Siggi
by siggi
Tue Nov 10, 2009 2:03 pm
Forum: Hardware
Topic: SAVING sound?????
Replies: 5
Views: 5231

Re: SAVING sound?????

Are they? MIC = audio OUT (for SAVE programs) EAR = audio IN (for LOAD programs) Yes. For details about "mic" and "line" input levels: see http://harada-sound.com/sound/handbook/input.html So your tape deck should have a "mic" level input, otherwise you would need an additional preamplifier. Siggi
by siggi
Thu Nov 05, 2009 4:20 pm
Forum: Development
Topic: CODING COMPO: make a ZX81 1K demo!! :)
Replies: 20
Views: 15879

Re: CODING COMPO: make a ZX81 1K demo!! :)

Doesn't work on emul (I'm at wotk, at the moment). I will check it out in the evening. AKAIK: works with some emuls Does it require any hardware midifications? No Anyway it's not i BASIC, so cannot "compete". ;) This time at least. ;) The main work (drawing circles) is done by a BASIC program. Only...