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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.
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
Mark
Re: ZX80 3K Ram Pack memory
Posted: Sat Apr 14, 2018 1:44 am
by 1024MAK
Using this program:
- RAMTOP Program
I get these results on a standard ZX81:
- 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!
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.