Sinclair ZX80 / ZX81 / Z88 Forums

Hi there seems to be 26 pins at the connector. I don't know that interface, but I think it is designed to behave like a PC's 25 pin printer port. Thus the interface connector can be connected 1:1 (ribbon cable) to a 25 pin "centronics type" D-SUB connector (one wire not connected). The 25 pole conne...

Try
LET A = NOT PI

24V 1,2 A.
see

https://k1.spdns.de/Vintage/Sinclair/82 ... 20Printer/

See also:
https://forum.tlienhard.com/phpBB3/view ... f=2&t=3293

HTH Siggi

I recommend to use the following shutdown program:
Then you can pull the plug ...


Siggi

I still have a lot of punched cards, when I learned PASCAL programming. I will check, whether I also have some old Cobol programs I once wrote ...

Siggi

Do you know Wilf's NOVA? It supports "BASIC line number trace". Maybe that could be used to implement Single Stepping at Basic level... http://www.user.dccnet.com/wrigter/index_files/nova2005.htm And Single Stepping in Z88DK compiled C programs would also be nice to have :mrgreen: https://www.z88dk....

Is there a schema of the board?
32KB is enough ram for a lot of ZX81 applications. But having 40KB ram, it would be possible to use more ZeddyNet applications, which run above 32K and are 16K in size. So I would need to add more ram ....

Siggi

I have a board of the same (probably German) company (for an enhanced character set). To use 64K ram, some kind of paging-logic is needed to switch different ram block to the same address area "seen" by the Z80 (e. g. 2 16kB pages at address 32K-48K). Thus an output latch (typically 8 bit) is needed...

I don't see any pics.

Is it that board on the left side of the picture?

https://forum.tlienhard.com/phpBB3/view ... 866#p32866

That is a 64K ram pack, having also an 8 bit output port, e. g. for remote control of a cassette recorder and for paging of ram banks

Siggi

Years ago I played around with that program. But it ran faster than the music. Is it designed for a 50 Hz or a 60 Hz Zeddy? Maybe the speed was not OK, because I had used a patched rom (for faster BASIC FOR/NEXT) in my Zeddy. Maybe nowadays, when using a ZX81x2 rom, the turntable must run at 45 rpm,...