Search found 988 matches

by siggi
Mon Mar 11, 2024 8:50 am
Forum: Development
Topic: werewolf for the zx81 16k
Replies: 11
Views: 685

Re: werewolf for the zx81 16k

Moggy wrote: Sun Mar 10, 2024 10:35 am Yes it does.

Example.

." some text "

This is the standard way to print text in Forth.
I would have expected that:

. "txet emos "

:mrgreen:
by siggi
Mon Feb 26, 2024 9:17 am
Forum: Hardware
Topic: 16k Sinclair issue 1 pack
Replies: 33
Views: 1256

Re: 16k Sinclair issue 1 pack

You should use Schottky diodes to pull TTL signals to low!

The diodes and the resistor can be soldered directly to the pins of the connector:

https://forum.tlienhard.com/phpBB3/down ... hp?id=8612

(Perfectly viewable on a 22" monitor) ;)
by siggi
Sun Feb 25, 2024 11:46 pm
Forum: Software
Topic: Frontend for ZXpand+ with pictures on the right side?
Replies: 7
Views: 509

Re: Frontend for ZXpand+ with pictures on the right side?

Wilf Rigter has written programs, which use hires display in the upper screen area and text mode in the lower area.
So everything is possible, when using a ZX81, but somebody needs to do it :mrgreen:
by siggi
Sat Feb 24, 2024 4:00 pm
Forum: Hardware
Topic: I've borked it
Replies: 123
Views: 5070

Re: I've borked it

Hopefully you have plugged in the CPU and ULA the right direction, NOT as shown in the ZX81 manual chapter 25:

https://www.manualslib.com/manual/12017 ... =71#manual

;)
by siggi
Fri Feb 23, 2024 11:23 pm
Forum: Hardware
Topic: ZX81 toZX80 conversion.
Replies: 22
Views: 1639

Re: ZX81 toZX80 conversion.

Moggy wrote: Fri Feb 23, 2024 11:53 am I have just the tool for the job!! :lol:
No, that tool makes longer slots on the outside and shorter on the inside.
I think, that is a better tool (also for other problems) ...

Image

:mrgreen:
by siggi
Fri Feb 23, 2024 11:13 pm
Forum: ZX BASIC
Topic: New Screen Saver :-) Enjoy!
Replies: 3
Views: 447

Re: New Screen Saver :-) Enjoy!

A much shorter screen saver solution, and also space saving.

Code: Select all

10 SAVE "SCREEN"
20 RUN
But be careful: works only on real original Zeddies (not on machines, using a non-compatible ROM like ZxPand, Mefisdos, ZxNU, ZxMore, ZxBlast, ZxDeluxe, ...)

:mrgreen:
by siggi
Fri Feb 23, 2024 11:45 am
Forum: Development
Topic: Yet another graphics demo in WRX mode
Replies: 3
Views: 4341

Re: Yet another graphics demo in WRX mode

Here it is (incl. 50 Hz screen flicker)
IMG_1373.JPG
by siggi
Fri Feb 23, 2024 10:55 am
Forum: Hardware
Topic: ZX81 toZX80 conversion.
Replies: 22
Views: 1639

Re: ZX81 toZX80 conversion.

You should replace the black stripes by real slots (for better cooling) ..

:mrgreen:
by siggi
Wed Feb 21, 2024 11:17 am
Forum: Hardware
Topic: I've borked it
Replies: 123
Views: 5070

Re: I've borked it

As I have already written in the other thread: bend the ram's pin /OE up and connect it to the Z80 /RD signal (e. g. at the edge connector).
That solves the timing problem during WRITE cycles ....

Siggi
by siggi
Wed Feb 21, 2024 9:02 am
Forum: Hardware
Topic: I've borked it
Replies: 123
Views: 5070

Re: I've borked it

I've compared the Hitachi chip against the half K chip read cycles and it looks like /OE is doing nothing. Looks like the whole thing is driven by the /CE and I should instead tie /OE to ground? Or do I have that wrong? This diagram shows a "Read Cycle (1) (/CE controlled )" Maybe it has also a dif...