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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 4th Oct 2019, 10:30 pm   #1
dominicbeesley
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Default Acorn System 1 clone

I've recently had a few spare hours and decided to have a look at the original Acorn System 1. As these are quite rare I decided the best way to find out about this was to make one. Armed with the datasheet for the INS8154 chip and the circuit diagrams and manuals for the system 1 I've made an FPGA clone...and it seems to work

It works well with all 128 bytes of RAM and 512k bytes of ROM!

There's a video of it here: https://youtu.be/5R9nzFvlU3A in shake-o-vision running the game program "duck shoot" that is near the end of the user manual. I've added a "faux" cassette interface - which is actually just a 300 baud serial interface so I can save and load to my PC!

I'm now planning to make a real (i.e. with real IC's not an fpga) clone my first stumbling block is where/how to get a case. The eurocard rack systems do seem to still be made but are eye-wateringly expensive does anyone know where to look for suitable junk. I'd like to make a System 4 or 5 which had the System 1 at its heart but with additional cards holding ram and disk controllers etc.

System 5

D
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Old 9th Nov 2019, 5:29 pm   #2
Karen O
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Default Re: Acorn System 1 clone

Hi Dom,
You can get prototype boards in Eurocard size (160x100). Not sure if the holes are in the right place for the DIN connector though. You can also get card guides with fixing at one end (bolts to the backplane). There's always a way!
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Old 10th Nov 2019, 7:27 pm   #3
dominicbeesley
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Default Re: Acorn System 1 clone

Thanks Karen,

Thanks to EdDinning of this parish and BProssman on Stardot I know am quite well provisioned and have two card frames and various rails and fixings. I'll still need to do a bit of metal bashing but it will probably not be until after Christmas as we've finally got a moving date.

I have got some old prototyping and wirewrap cards which are great for the z80 project I never quite finished years ago but don't have the right a+b holes for an Acorn style back-plane but I should be able to get hold of some from somewhere...

D
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