Search found 60 matches

by IanB
Thu Dec 10, 2020 1:00 pm
Forum: Hardware
Topic: 16K RAM pack Vs built-in 1K : how is internal RAM disabled?
Replies: 5
Views: 1651

Re: 16K RAM pack Vs built-in 1K : how is internal RAM disabled?

I wonder why Sinclair never made a 2K model for the UK? 1K is so tricky to do much with, increasing to 2K would have been a dramatic difference and it's easy to see why the Timex model had 2K as standard. Probably because they expected virtually everyone to upgrade to 16K. You buy the 1K machine, i...
by IanB
Mon Aug 31, 2015 12:10 am
Forum: Software
Topic: Calling in some help?
Replies: 5
Views: 12580

Re: Calling in some help?

I'm currently up to my neck in flowcharts, and that's just for my own code. :?

God help me with somebody else's!
by IanB
Sun Aug 30, 2015 8:20 pm
Forum: Development
Topic: Setting Slow And Fast Mode From Machine Code
Replies: 4
Views: 2450

Re: Setting Slow And Fast Mode From Machine Code

Yes I'm still working on 1k routines. :)

I just want this while I am testing my forthcoming routines to expand and contract the display file, and until they are optimised I don't want the ZX81 trying to display the screen before it is completed, and crashing :)
by IanB
Sun Aug 30, 2015 7:52 pm
Forum: Development
Topic: Setting Slow And Fast Mode From Machine Code
Replies: 4
Views: 2450

Re: Setting Slow And Fast Mode From Machine Code

Thanks Andy :)
by IanB
Sun Aug 30, 2015 7:28 pm
Forum: Software
Topic: Calling in some help?
Replies: 5
Views: 12580

Re: Calling in some help?

Have you considered learning to program? I'm not being facetious here; it's not hard once you get a start. You already understand computer organisation.
by IanB
Sun Aug 30, 2015 1:55 pm
Forum: Software
Topic: Calling in some help?
Replies: 5
Views: 12580

Re: Calling in some help?

I'm currently spending all my time in the bowels of the ZX81, and my Spectrum programming is rusty. As a general point though, reading your intentions, I seriously wonder whether it would be easier to reverse engineer the program code- which probably effects fairly simple rules, then rewrite the eng...
by IanB
Sun Aug 30, 2015 1:35 pm
Forum: Development
Topic: Setting Slow And Fast Mode From Machine Code
Replies: 4
Views: 2450

Setting Slow And Fast Mode From Machine Code

I'm probably being a bit dimwitted (not unusual for me) but I can't seem to work out the right way to call the ROM to set Fast or Slow (er, "Compute And Display" :) ) mode from a machine code routine. There is 0207h which the Disassembly calls "Slow/Fast" and 02E7h which it calls "Set Fast Mode", bu...
by IanB
Thu Aug 27, 2015 11:18 pm
Forum: Development
Topic: ZXmore or the ZX80CORE follow-up
Replies: 264
Views: 92149

Re: ZXmore or the ZX80CORE follow-up

Do you suggest me to connect the EAR output of the tape recorder to the MIC input of my sound card ?
Your sound card should have a line level input which will accomodate a line level signal.
by IanB
Wed Aug 26, 2015 5:07 pm
Forum: Hardware
Topic: Trying to restart a 33 years old ZX81 [SOLVED]
Replies: 54
Views: 19711

Re: Trying to restart a 33 years old ZX81 [SOLVED]

I think there was an unofficial law in the 1980s that any 78/79 series regulator had to be overloaded, inadequately heatsinked, and preferably so badly mounted that either the pins would snap or it would tear the tracks off the circuit board. They must have been the most abused component in history :)
by IanB
Wed Aug 26, 2015 4:25 pm
Forum: Hardware
Topic: Trying to restart a 33 years old ZX81 [SOLVED]
Replies: 54
Views: 19711

Re: Trying to restart a 33 years old ZX81 [SOLVED]

I wasn't. I was really not pleased at all. :)