BBC Master Ethernet and Processor Adaptor

discuss both original and modern hardware for the bbc micro/electron
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mgarmett
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BBC Master Ethernet and Processor Adaptor

Post by mgarmett »

Hi All,

Does anyone know if there are any open source projects for adding Ethernet to a BBC Master, I am aware of the Ethernet board by Sprow, but that looks to be out of production.

Also, given the very high prices commanded by external universal processor adaptors these days, does a schematic exist anywhere for one of these devices so that a modern reproduction could be made? I know we can easily connect a raspberry pi based coprocessor, but I am looking to create an alternative that will allow us to connect original coprocessor hardware externally to a master. I am not really sure what sort of logic these devices contain, are they just a glorified power supply and external connector? From the pictures I’ve seen they all seem to have some logic chips etc., but it’s not really clear to me what else they do. I’ve tried to use photographs to create something, but having never seen one in real life, I don’t want to risk destroying anything.

Cheers and thanks

Mark
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danielj
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Re: BBC Master Ethernet and Processor Adaptor

Post by danielj »

The universal adaptors are just a power supply and then, by the looks of it, a couple of buffers: http://chrisacorns.computinghistory.org ... 2ProcF.jpg

I'm not aware of any open source ethernet projects, but there are an awful lot of econet projects that seem to be nearing the brink of completion that would allow connection back to a PC that way (which is arguably rather more suitable for a RAM limited 8bit machine than ethernet! :D)

d.
mgarmett
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Re: BBC Master Ethernet and Processor Adaptor

Post by mgarmett »

Thanks Daniel

Cheers

Mark
wiggy
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Re: BBC Master Ethernet and Processor Adaptor

Post by wiggy »

Here are some closeups of the "useful" half of the board. The transistor is a BC239.

The other half of the board is just a 5V linear PSU.

Hope that helps.
Attachments
Universal 2nd Proc - Track Side
Universal 2nd Proc - Track Side
Universal 2nd Proc - Top Side
Universal 2nd Proc - Top Side
johnkenyon
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Re: BBC Master Ethernet and Processor Adaptor

Post by johnkenyon »

I assume the TIC116, resistor and yellow diode are for a crowbar circuit...
wiggy
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Re: BBC Master Ethernet and Processor Adaptor

Post by wiggy »

Looks like it - most of Acorn's linear PSUs have one. Interestingly, though, the place where the 3.15A fuse should go just has a wire link on mine, so as with most crowbars, we'll just have to hope we never need it...

For reference, the yellow diode is a BZXxx 5V1 (the xx being whatever's underneath so I can't read it!)
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