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Re: ZX80 3K Ram Pack memory

Posted: Fri Apr 13, 2018 8:48 pm
by 1024MAK
Mike, can you clarify, are you trying to test your 3k RAM pack on a ZX80 or a TS1000?

Mark

Re: ZX80 3K Ram Pack memory

Posted: Fri Apr 13, 2018 9:12 pm
by mhudson52
Mark, trying to test on a TS1000. Don't have any other machines available.

Mike

Re: ZX80 3K Ram Pack memory

Posted: Fri Apr 13, 2018 11:59 pm
by sirmorris
Oh.
:oops:

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 1:24 am
by 1024MAK
mhudson52 wrote:
Fri Apr 13, 2018 9:12 pm
Mark, trying to test on a TS1000. Don't have any other machines available.

Mike
Apart from the different TV timing (and reduction in slow mode processing speed), it should be same as a ZX81. So the same program should work. It's too late here for my brain to spot the problem :roll:

Mark

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 1:44 am
by 1024MAK
Using this program:
IMG_6765.JPG
RAMTOP Program
I get these results on a standard ZX81:
IMG_6766.JPG
Results on a 1k ZX81
Mark

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 2:31 am
by mhudson52
Thanks, Mark, I'll give it a go a report back the results.

BTW, Charlie, that was a most impressive solution! :D

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 1:20 pm
by sirmorris
Thanks Mike. I have now run the ZX80 mem approximator on a real ZX80 with the pack and I get ... (drum roll please)

20468!

20468 - 16384 = 4084

Which is very nearly 4k.

1K internal + 3K?

So I think it's working.

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 1:27 pm
by 1024MAK
Yes, the "3k" RAM pack actually contains 3k bytes of RAM. The decoding circuit also maps the internal 1k bytes of RAM so with a ZX80 or ZX81 you should get a total of 4K bytes.

Mark

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 2:34 pm
by mhudson52
I wasn't aware that it would piggy-back itself to the existing memory and yield 4K total memory. Not having either a ZX80 or 81 to test on is a handicap for me.

I may just have to purchase the Bulgarian ZX80 clone kit and stick it in my 3D printed case with decals to have a new addition to my shelf. My vacuum molded case isn't quite ready for prime time.

Awesome work, guys, and thanks!

Mike

Re: ZX80 3K Ram Pack memory

Posted: Sat Apr 14, 2018 3:02 pm
by sirmorris
You're most welcome. I'm happy to expend energy in favour of those who themselves contribute.