Question about interfacing


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Hi- I have a Papilio one on the way, hope to see it in a day or two, really excited about it.

Anyway, I've got a pretty easy question about interfacing the papilio to other hardware.  Basically, what I'd like to do is connect the papilio to the bus on my Apple IIe, and also to my macbook via usb at the same time.

I'm pretty sure that this should be possible, but what I'm wondering is do I need to do anything to electrically isolate the macbook from the papilio or the papilio from the apple II?  I'm pretty sure I need to level shift the logic signals on the apple II, as it's 5v.  Do I have to do anything else?

The reason I'm wondering is I remember when RS232 ports used optoisolators to prevent problems, and I'm not sure if this is the same sort of thing.


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Generally, Macbooks are already isolated as most of the laptops. Because of electrical laws, you don't have any current way between the primary (AC line) and the secondary (DC line to the laptop) of your computer.

However, if you prefer to use a opto-isolated communication, I saw USB isolating devices from OLIMEX, I guess other manufacturers sell this king of devices too.

Apple II is an old kind of device, it probably works with 5V so using the level shifter is important.

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The 16 bit I/O Wing is what you would be looking for to provide 5V tolerance. Opto-isolation is probably more then you need to do, unless there is some kind of freak accident you just need to worry about protecting the 3.3V I/O of the Papilio from the 5V I/O of the Apple IIe.

Unfortunately we are out of stock of the 16 bit I/O Wings, but LinkSprite is doing a run of these boards and they should hopefully be ready very soon.


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