Sinclair ZX80 / ZX81 / Z88 Forums

David G wrote: ↑Thu Dec 12, 2024 11:07 pm Since none of these boards are available any longer, what is the current go-to for a hobbyist slot extender board?

Check the David Stephenson's ZX81 Bus Extender.

In EO you can associate any key on the ZX81 to the PC arrows keys, see the "Options/Keyboard" menu (or F7).

Just one oddity is the SHIFT and J to exit the configuration program and LOAD a tape does not work. It literally ignores that input. You're right, the response to the SHIFT+J combination was not good. If you press SHIFT first and then J, it will have no effect. Both keys need to be pressed at the e...

I understand, I tested with the emulator just to make sure if the program was changing the I register, which was not confirmed. As far as I know, EO perfectly emulates the behavior of reg. I, so I infer that the problem you are experiencing is not caused directly by these chess programs.

Changes between FAST/SLOW don't alter the I register. I did a simple test on EightyOne with Psion Chess and ZX Chess and both kept the UDG characters, so I believe the problem is not in the programs. I just loaded an alternative UDG font and manually changed the I register (Click on the figure to se...

Issues identified with zxpand+v72x2c ROM have been fixed, faulty file replaced in https://sinclairzxworld.com/viewtopic.php?p=56168#p56168 . The basic functions have been tested and work satisfactorily, but I have not tested the ZXPAND command, if anyone who uses it can test and report, I will be gr...

Fred and Paul, you are right, there is a problem with the zxpand+v72x2 ROM boot. And CAT also crashes the system when it fills the screen (seen the video below). Until I have a definitive solution, hold the SHIFT key during boot to force the MENU.P (ZXpand Commander) to load and use it to navigate a...

What version of EO are you using? The v66x2 ROM is intended for the classic ZXpand, which EO emulates up to version 1.5. From version 1.6 onwards, EO emulates the ZXpand+, so you should use the v72x2 ROM.

I assume also that the new spand ROM references the character table in the main onboard ROM? Ah so burn the image to a 2764 EPROM of which I have many ( as found on the classic ZXpand) then replace the one on the spand and off we go? Yes I did try the ROM in Eighty One and just got a screenful of g...

What do they have over the older X2 ROM? This is the old X2 ROM with the ZXpand routines added. The intention is to rewrite the ZXpand EPROM and thus have access to the Big Bang features without having to change the ZX81's internal ROM. Personally, I prefer this configuration; when I need to run so...