A Website dedicated to the Acorn System Computers

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Wed Oct 09, 2019 10:26 pm

My Dutch isn't up to the job - any idea what to search for?

D

bprosman
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Re: A Website dedicated to the Acorn System Computers

Post by bprosman » Wed Oct 09, 2019 10:32 pm

https://www.marktplaats.nl/q/19+inch+rack/
I have some 19" cases but shipping to the UK might be costly.

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Wed Oct 09, 2019 11:07 pm

Ah, I think they're all "racks". What I'm looking for is a "sub-rack" for eurocards (100x160mm pcbs) like the Acorn System 5 case Verotec still make all the parts but I don't seem to be able to find prices anywhere: http://www.verotec.co.uk/documents/broc ... uction.pdf

What I've have found made by Schroff are eye-wateringly expensive. I'm sure there are loads of these chucked in skips every day but I don't seem to be able to find any! Or I'm looking for the wrong thing...

D

Prime
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Re: A Website dedicated to the Acorn System Computers

Post by Prime » Thu Oct 10, 2019 8:14 am

dominicbeesley wrote:
Wed Oct 09, 2019 11:07 pm
What I've have found made by Schroff are eye-wateringly expensive. I'm sure there are loads of these chucked in skips every day but I don't seem to be able to find any! Or I'm looking for the wrong thing...
The one I built my system clone in I bought from a (ametur) Raido rally, for a pretty reasonable price, so that may be worht a look.

Cheers.

Phill.

eXne
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Re: A Website dedicated to the Acorn System Computers

Post by eXne » Sat Oct 12, 2019 3:34 pm

I wasn’t aware that Acorn was into 19” rack cards. Looks very nice.
It takes me back to my VME 19” boards time :D
Acorn BBC + 6502 and Z80 2nd proc and CoPro, Master 128, 512 + 80186. Atom Prophet

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Mon Oct 14, 2019 12:08 am

Thanks everyone,

bprosman has found a rack for me, plus somebody on another Forum has promised me a whole bunch of bits so I should be good to go. I've also scored some parts of ebay so hopefully I should be good to go quite soon. I've started collecting information on dimensions for front plates etc.

I'll get my z80 machine housed first to hone my skills at front panel making and then start on the Acorn. I'm not sure how I'll proceed, whether to make near as possible replica boards or my own take. I'll probably have a go at laying out some replicas of the cpu and cassette/input board, though with the INS8154 being near as dammit unobtainable maybe I shouldn't bother? Any Ideas? I've seen mention of mods for running with 6522's instead were they extensive mods? (I'm a complete System noob)

D

Kazzie
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Re: A Website dedicated to the Acorn System Computers

Post by Kazzie » Mon Oct 14, 2019 8:55 am

dominicbeesley wrote:
Mon Oct 14, 2019 12:08 am
Thanks everyone,

bprosman has found a rack for me, plus somebody on another Forum has promised me a whole bunch of bits so I should be good to go. I've also scored some parts of ebay so hopefully I should be good to go quite soon. I've started collecting information on dimensions for front plates etc.

I'll get my z80 machine housed first to hone my skills at front panel making and then start on the Acorn. I'm not sure how I'll proceed, whether to make near as possible replica boards or my own take. I'll probably have a go at laying out some replicas of the cpu and cassette/input board, though with the INS8154 being near as dammit unobtainable maybe I shouldn't bother? Any Ideas? I've seen mention of mods for running with 6522's instead were they extensive mods? (I'm a complete System noob)

D
I started playing around with trying to replace the INS8154 with a 6522, by wiring up a 6522 to the appropriate signals from my System 1 board. The main take-away from the experiment was that it works, but the NMOS version of the 6522 doesn't source enough current to light a (calculator-style) LED display very brightly. A CMOS version (65C22) may work better, or if you're going to use it in a System 2+ then it probably won't be of any concern to you.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Mon Oct 14, 2019 10:18 am

Aha, thanks I found your thread, very useful. I take from it that you didn't need to make any changes to the monitor code either which is nice!

D

Prime
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Re: A Website dedicated to the Acorn System Computers

Post by Prime » Mon Oct 14, 2019 1:32 pm

Kazzie wrote:
Mon Oct 14, 2019 8:55 am
I started playing around with trying to replace the INS8154 with a 6522, by wiring up a 6522 to the appropriate signals from my System 1 board. The main take-away from the experiment was that it works, but the NMOS version of the 6522 doesn't source enough current to light a (calculator-style) LED display very brightly. A CMOS version (65C22) may work better, or if you're going to use it in a System 2+ then it probably won't be of any concern to you.
Can't remember if the outputs are just used as outputs e.g. one port configured as outputs the other as inputs. But if they are only uni-directional then I guess putting a buffer chip in might be an easyish solution.

Cheers.

Phill.

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Mon Oct 14, 2019 2:24 pm

Or maybe just specify the WD part which has beefier output buffers built in...

I've got to give this some thought. I'm not sure whether there would be demand for a System CPU "clone" card. Or whether it would be possible, easily, to make something that would cover all these points:
- have sockets for both INS8154 and 6522
- cover the later 2MHz (or faster) cards
- work in all System 1-5 setups

This would no doubt need configuration but it might be nice to get a single board laid out to do all of the above or is this a stupid idea.

Anyway this won't be any time soon, I've got plenty of other stuff to get on with!

D

Kazzie
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Re: A Website dedicated to the Acorn System Computers

Post by Kazzie » Tue Oct 15, 2019 5:03 am

Making a hybrid System 1 / System 5 (2MHz 6502A) card on one eurocard feels like a bit of a stretch, as the latter is markedly different. A universal System 1-4 8154/6522 card would definitely be feasible.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Tue Oct 15, 2019 8:56 am

I've not found out much about the later card. Has there a food source of info anywhere? Did the while bus run at the faster speed or did it cycle stretch like the beeb?

dominicbeesley
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Re: A Website dedicated to the Acorn System Computers

Post by dominicbeesley » Tue Oct 15, 2019 10:54 am

To answer my own question - I have now! The System 5 handbook has all I need for now.

You're right the "5" cpu card is quite different to the "1" card...I'll give it some thought...

D

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