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Bill Chennault
04-09-2007, 11:51 PM
All--

How do·I connect a dedicated Stamp output pin to a dedicated Stamp input pin on another Stamp?·I want to·experiment with some VERY rudimentary communication among Stamps. I want a Stamp to do some work, then tell another Stamp the results. The results may be as simple as setting a pin to indicate the work has been performed, or setting a pin to indicate the work has been done followed by a byte representing the work done. (I only need to communicate a few inches; say from one BOE to another as closely as I can place them.)

It sounds simple. Is it?

Thanks.

--Bill
ps I am fairly certain that I have seen this discussed. But, my SEARCH revealed little.

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Mike Green
04-10-2007, 12:31 AM
Theoretically, you could just connect the two pins together assuming that the two Stamps have a common ground connection. In practice, you should use a current limiting resistor to connect the pins, anywhere from 220 ohms to 10K in value, just in case you have a programming error and the two pins both get set to output mode at opposite levels (one low and one high) which would cause a short circuit and possibly burn out one or both I/O pins.

Bill Chennault
04-10-2007, 01:54 AM
Mike--

Does the current limiting resistor simply connect the two pins? (Forgive my ignorance.)

Thanks!

--Bill

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You are what you write.

allanlane5
04-10-2007, 02:15 AM
Yup, the 220 ohm current limiting resistor has one end connected to one BS2, and the other end connected to the pin on the other BS2.

Bill Chennault
04-10-2007, 02:18 AM
allanlane5 (http://forums.parallax.com/member.php?u=41268)--

Thank you so much!

--Bill



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You are what you write.

LSB
04-10-2007, 04:07 AM
Bill--

http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv16.pdf·is a primer on serial communications and seems like it may be of help.

Bill Chennault
04-10-2007, 04:16 AM
LSB--

Thank you! I saved it on my machine!

--Bill

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You are what you write.