Re: Using a Arduino Mage2560 as IEEE disk

From: Hans Liss <Hans_at_Liss.pp.se>
Date: Fri, 10 Jan 2020 14:52:30 +0100
Message-ID: <562692f8-743e-4c09-12ae-134078fe6a37_at_Liss.pp.se>
On 2020-01-10 13:54, Baltissen, GJPAA (Ruud) wrote:
>> Do you know if someone has designed a shield for it already?
> No idea at all. In fact I had no idea what you meant with “shield”. Now I know that a shield is a daughterboard that fits on the original Arduinoe (or Pi).

Yes, it makes it far more tidy than building it on a separate breadboard 
or similar. I've just designed a shield for the mega for testing CDP1802 
processors and it turned out very nice.

>> I'm thinking it should include ...
> Not knowing how the schematic looked like, I had to download and install Kicad first. I created a PNG of the schematic and if interested, ask me.

Oh, nice! I only read about the pin assignments in the source code, and 
that sounded easy enough. I can design and test the shield; I just need 
to know what to include beyond the basics.

> First I haven't any knowledge of the Mega2560 at all so I have no idea how the various pins behave: totem pole, OC or something else? What they can drive? Can at least one be used as interrupt input? So that are things I have to learn first. And that will cost time which I don't have very much ☹
If it will help to add drivers or something like that, that can 
certainly be done. I don't know anything at all about the IEEE bus.
> I would certainly include an ATN trap. And why not adding an IEC bus? If possible parallel to the IEEE one. A small LCD screen + some buttons?

A lot of that will depend on what the software can (be made to) do as 
well, of course. But since it's a Mega 2560 there are certainly lots of 
pins to play with. I'll look for a hardware interrupt pin - that's 
something I haven't played with on Arduinos before.

As for the IEC bus, I'm not sure how to implement that in parallell to 
the IEEE bus. Can that be done with external logic or will the Arduino 
have to implement both? TBH, for now I think I would leave the IEC out 
of it and just get the basic parallel working the way the author intended.


/Hans
Received on 2020-05-30 00:14:34

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