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Forum Index : Microcontroller and PC projects : COM port CLOSE question....

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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9748

Posted: 05:22pm 03 Jul 2017

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Hi folks.

QUESTION: When you CLOSE a com port, exactly what state does the MM leave the pin in?

Can I assume inactive high-impedance?

Smoke makes things work. When the smoke gets out, it stops!

Zonker

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Joined: 18/08/2012
Location: United States
Posts: 772

Posted: 06:32pm 03 Jul 2017

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Back to "NUL" not defined... So it's like you never assigned it...

So, for the TX out pin you would need a pull-up resistor if you are going to release the pin by closing the port... (or assign it a DOUT HI state)

Edited by Zonker 2017-07-05

Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9748

Posted: 07:15pm 03 Jul 2017

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OK then. I think this is where my HC-12 com port problem is(other thread), you see.

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