Two BS1 hooked up in parallel (quick question)

ashor

Hello all:

I have a program that is too large to run in one Basic Stamp1. However, there are really two parts to the program and they don't have to be on the same Stamp. Question: can I have two Stamps hooked up to the same I/O cables, and same ground cable. Then just power up whichever Stamp is required for each program? I would only power up one at a time.

The real question is: if a Stamp is not powered up, are the I/O pins grounded? Would the Stamp that is not powered up mess up the other's I/O pins?

Thanks very much for your thoughts!

Andy

Mike Green

Yes, the unpowered Stamp will drag down the powered I/O pins

ashor

Thanks Mike, I guess I have to slim down my program.

Thanks for the help.

Andy

Beau Schwabe

ashor,

The Stamp without power will end up being powered through the ESD protection diodes inside the BS1. If you do this make sure that the BS1 program forces it's pins to be INPUTS

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.