ZX80 development - some questions

ZX80, ZX 81, ZX Spectrum, TS2068 and other clones
alvin
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Posts: 1872
Joined: Mon Jul 16, 2007 7:39 pm

Post by alvin »

ShaunB wrote:I think that all ZX81 memory expansions work on the ZX80, and you are able to emulate the ZX80 with 32K RAM expansion. I'm therefore wondering if it's possible to access the 2nd 16K page with z88dk somehow? Is this possible? Or is this a question for ZX80 experts?
If there is more memory you can use it. If the zx80 is similar to the zx81 then some expanded ram may not be available for programs (you can't execute code there). By default z88dk is just going to let your program grow so if there are special memory regions like this you may want to create a section for it and deliberately put stuff there so that stuff that can go there is separated from stuff that can't. Then the stuff that can't go there has more space too.

I don't know enough about the zx80 to know the situation. Maybe stefano knows more or you can find some more info from a zx80 group.
siggi
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Posts: 344
Joined: Thu Jul 26, 2007 9:06 am

Post by siggi »

ShaunB wrote:Hi Alvin,

I think that all ZX81 memory expansions work on the ZX80, and you are able to emulate the ZX80 with 32K RAM expansion. I'm therefore wondering if it's possible to access the 2nd 16K page with z88dk somehow? Is this possible? Or is this a question for ZX80 experts?

Thanks,

Shaun
No, the real ZX80 does not have the /ROMCS signal at its edge connector (used by ZX81 ram expansions to disable ROM mirrors above 32K). Thus the ZX80 can only work with 16KB ram.

Siggi
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