ZX81 Clone Tynemouth Minstrel 3

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: ZX81 Clone Tynemouth Minstrel 3

Post by 1024MAK »

See this thread.

Mark

Mustermann
Posts: 34
Joined: Sun Dec 22, 2019 12:09 pm
Location: Augsburg, Germany

Re: ZX81 Clone Tynemouth Minstrel 3

Post by Mustermann »

tynemouthsoftware wrote:
Mon Jan 20, 2020 12:22 pm
Looks interesting. A couple of questions. What extra software can you now run with the 56K RAM that couldn't run before, and are there any programs which did run with 16/32K but will not work with the extra RAM? I have not found much software which needs more that the standard 16K, so trying to judge if it is worth adding this to a future Minstrel.

Also, what is the test program you are using, my googling ability has failed me?

Thanks,

Dave
I used sysinfo.p as test program. The program can be found here:
http://www.8bit-wiki.de/8bitdb.html?&no ... b4c83c75c1

Extra things that will work with 56k:

POKE 16389,255
NEW
DIM A(9000)

Will not work without additional RAM(tested).

I found that "The Crystal Frog" need RAM between 16k and 48k(tested)

This can be fixed by changing RAM configuration from 8k-40k to 16k-48k but there are other programs that need 8k-16k.

If I am right, hero.81 need 48k RAM and beamride.81 need 32k between 16k and 48k(not tested yet).

Ok. these are only a very few programs, but I am also planning to build a ROM overlay to run alternative ROMs.

For the ROM overlay I need to solve at least one additional issue:

RAM is connected to CPU in refresh cycle, not to character generator as ROM is.
If I will write an ROM image to RAM and then swith 0k-8k to RAM, Characters can't be read from RAM.

Have a nice weekend,

Max
ZX81 issue 1 near to original state
ZX81 issue 1 56k internal ram with battery backup, UDG, CHR$128 and WRX enabled
Minstrel 3 ZX81 clone 64k with battery backup, UDG, CHR$128 and WRX enabled

Mustermann
Posts: 34
Joined: Sun Dec 22, 2019 12:09 pm
Location: Augsburg, Germany

Re: ZX81 Clone Tynemouth Minstrel 3

Post by Mustermann »

Hero(hero.p) tested as working with Minstrel 3 + 56k.

I had some issues with my TFT monitor running Minstrel in PAL mode when Hero was loaded.
This could be solved by switching to NTSC mode(even if I am in Europe).

Max
Attachments
Hero.jpg
ZX81 issue 1 near to original state
ZX81 issue 1 56k internal ram with battery backup, UDG, CHR$128 and WRX enabled
Minstrel 3 ZX81 clone 64k with battery backup, UDG, CHR$128 and WRX enabled

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