Search found 133 matches

by poglad
Thu May 15, 2014 10:57 am
Forum: ZX BASIC
Topic: Prime Numbers
Replies: 8
Views: 3094

Re: Prime Numbers

Oh I see - so with fewer families, it gets less efficient more quickly, and with more families it would stay efficient for a larger range. The guy who wrote the original article seemed to think that 24 families was some kind of naturally-occurring constant. I suppose for the candidates he chose, it ...
by poglad
Thu May 15, 2014 10:53 am
Forum: ZX BASIC
Topic: GOTO abuse
Replies: 5
Views: 2174

Re: GOTO abuse

Absolutely! :D
by poglad
Thu May 15, 2014 7:36 am
Forum: ZX BASIC
Topic: GOTO abuse
Replies: 5
Views: 2174

Re: GOTO abuse

Which is "better" depends on your aims. Personally I'd do it the first way - in structured programming this is a "case", and the ZX81 doesn't offer that directly so you have to use GOTO to do it - a perfectly good use of GOTO. The first way retains the appearance of the list of operations based on a...
by poglad
Thu May 15, 2014 12:15 am
Forum: ZX BASIC
Topic: Prime Numbers
Replies: 8
Views: 3094

Re: Prime Numbers

And why are there 24 families, rather than more? Come to that, what does it have to do with chromosomes?
by poglad
Thu May 15, 2014 12:11 am
Forum: Development
Topic: ZX80 Core - new ZX80 motherboards
Replies: 259
Views: 77263

Re: ZX80 Core - new ZX80 motherboards

Thanks, it certainly helped with the SMD capacitors! ;) Measuring the values with a multimeter, the video-related signals are nothing much like the ones in the guide - but I suppose that's because of the random video output I'm getting. I measured CLK on the Z80, and get 2.1V (not 1.8V) and on IC20 ...
by poglad
Wed May 14, 2014 3:59 pm
Forum: Development
Topic: ZX80 Core - new ZX80 motherboards
Replies: 259
Views: 77263

Re: ZX80 Core - new ZX80 motherboards

Thanks Karl. I don't have an oscilloscope, but I measured the impedance and voltage etc. at an earlier stage and got the expected figures. I'll work through the troubleshooting chapter this evening and see what I can find. R100 I found, but I also found an additional SMD capacitor that didn't seem t...
by poglad
Wed May 14, 2014 2:19 pm
Forum: ZX BASIC
Topic: Prime Numbers
Replies: 8
Views: 3094

Re: Prime Numbers

That's a fascinating web page you've got there Tim! As for the algorithm, I can see why a mathematician would consider it bunkum. After all, postulating a mathematical correspondence between chromosome families and prime numbers isn't far removed from deriving your algorithm from the dimensions of t...
by poglad
Wed May 14, 2014 10:43 am
Forum: Development
Topic: ZX80 Core - new ZX80 motherboards
Replies: 259
Views: 77263

Re: ZX80 Core - new ZX80 motherboards

Well I finished building it - looks great, but - ahem - doesn't actually work. The chances of me getting it right first time were very slim, of course! :lol: So I may be asking for some advice here later after I've spent some more time poking around with my multimeter! :geek: Basically, without the ...
by poglad
Tue May 13, 2014 6:00 pm
Forum: Development
Topic: Transparent case for ZX80CORE
Replies: 28
Views: 8617

Re: Transparent case for ZX80CORE

Dying to see the first photos of this, by the way! :D
by poglad
Mon May 12, 2014 11:21 pm
Forum: Development
Topic: ZX80 Core - new ZX80 motherboards
Replies: 259
Views: 77263

Re: ZX80 Core - new ZX80 motherboards

I've created a Flickr album to show my progress...

https://www.flickr.com/photos/51900952@ ... 628673844/