I suggest you try listening to the sound track from "The Sound Of Music"

You would do well to heed that advice, instead of repeatedly asking the same questions over and over again and paying no attention to the answers.

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If anyone on here Wants a Z80 chip, I have one.

I have no use for it and I will Mail it to that person for FREE.

However, I am just leaving to go on a Holiday to Chile, so DON'T email me till after March 3, 2008.

Take care.....Gary

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Chile?, that sounds a bit random?

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PIC programmer software, and PIC Tutorials at:
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Chile is mainstream. Now Tristan da Cunha, Peter I, or Pitcairn Island those would be outliers.

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One Week at the Very bottom of Chile, (To See Penguins and there offspring) One week up on the Main land of Chile, (Sightseeing and visit with a guy I met on the Internet) Than off to Hawaii to warm up Before returning home.

Your Just Jealous!

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I No Longer accept Private Messages on here.
All Emails to me Must Contain the Word \"Electronic\" in the \"Subject Line\"
or they go Directly to my Junk Mail Folder.
Email me at: chemelec@hotmail.com
Website: http://www3.telus.net/chemelec

 

Am not!

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PIC programmer software, and PIC Tutorials at:
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What is a "Counter Timer Circuit" and what does it do?

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A Z80 CTC (Counter Timer Chip) has a number of counters. When you connect a syncronous clock to the input of a counter we call it a timer because all the clock pulses are the same distance apart.

If we connect an asyncronous clock to the input we call it a counter because it "counts" events like people going through a turnstyle, but gives no information about the interval between the people.

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We never have time to do it right; but we always have time to do it over.

 

Ok. Thanks Papabravo.

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Hey Marks256, here's a ZX81 clone schematic (yes Z80 with video)
http://www.user.dccnet.com/wrigter/i...s/ZX97lite.htm
http://oldcomputers.net/

__________________
Bill
Smart Kits build Smart People
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I was under the impression that you had already started.

At any rate, I would prefer you learn the simple and common things, before learning the complex and rare things.

The "devices insert instructions during interrupts" is an 8080/Z80 weirdness that AFAIK no other line of processors use. There were many competitors to Intel and Zilog, and if anyone else used that weird protocol, I'm not aware of it.

Most, if not all, other processors handle interrupts pretty much the same way the PIC does. The IBM mainframe, the Pentium, Motorola microprocessors and microcontrollers, and many others. The processor (not the device!) performs the equivalent of a subroutine call.

 

Ok. Scratch the question on how keyboards handle multiple inputs. I think i figured it out on my own. Instead of the keyboard just being a bunch of buttons hooked up to high, some sort of scan system goes through (demux?) each individual line looking for keys that are on or off. that way, if two keys are pressed in one row, and one in another, the device won't get confused. this way, only ONE "row" has it's data being read. not the whole keyboard at a single given time... right?


Thanks for the link to the clone! and to oldcomputers.net

To me, this is simple. This is how I learn. Just because YOU may learn by starting out simple, and getting more and more complex, doesn't mean EVERY body learns that way. Call me weird, call me crazy, whatever. I learn more by failing then i do succeeding.

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There is no "I" in "team", unless Apple makes it... Then it would be iTeam.

 

OK, you're weird and crazy.

twenty five years ago, the available home computer technology was a major encouragement and opportunity for people to learn and progress in electronics and programming. the current trend is to make the user more and more remote from the technology they're using. the fun is leaking away.

 

I think that's why Marks256 wants to play with the z80. Not very practical, but much more "fun" for him than a PIC. People build tube amps. Why not vintage computers? It's a hobby for most of the people here.
That's pretty much how most keyboards work; a scanned matrix of keys.

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Thank you! I couldn't have said it better (not the song, either... )

Ok. Thanks.




Another question. How does an 8 bit processor handle numbers larger then 255?

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