# Function of Pin 3 Port C on the Connectem

**URL:** <https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441>\
**Category:** NET+OS\
**Tags:** hardware, spi\
**Created:** [July 27, 2007, 5:23am UTC](https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441 "2007-07-27T05:23:37Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mentzer](https://avatars.discourse-cdn.com/v4/letter/m/94ad74/32.png) [@mentzer](https://forums.digi.com/u/mentzer)\
**Post date:** [July 27, 2007, 5:23am UTC](https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441/1 "2007-07-27T05:23:37Z")

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Good morning Digi world,

I has a question to the Port\_C pin 3. This pin has two functions, RX-Com\_B and interrupt. I need an interrupt, a RS232 and a SPI-interface in my application. Can I put the interrupt or the RX function of Pin3 on another pin? If this is possible, where must all the changes are made?

Thanks for your support.

Marcus

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**Author:** ![pevandenburie](https://avatars.discourse-cdn.com/v4/letter/p/7feea3/32.png) [@pevandenburie](https://forums.digi.com/u/pevandenburie)\
**Post date:** [July 27, 2007, 7:12am UTC](https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441/2 "2007-07-27T07:12:37Z")

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There is 2 serial ports on the Connect EM. The interrupt pin is on the RX second serial, so the first is free.  
I don’t think that you can transfert the interrupt pin on an other pin…

Paul

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**Author:** ![mentzer](https://avatars.discourse-cdn.com/v4/letter/m/94ad74/32.png) [@mentzer](https://forums.digi.com/u/mentzer)\
**Post date:** [July 30, 2007, 5:07am UTC](https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441/3 "2007-07-30T05:07:32Z")

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Hello Paul, thanks for your answer. That is true the EM-component has two serial ports. I need a SPI-port (Com A), (and) a RS232 (Com B) and an external interrupt in my application. Therefore my question, can I switch functions to another pin ?

Marcus

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**Author:** ![charliek](https://avatars.discourse-cdn.com/v4/letter/c/94ad74/32.png) [@charliek](https://forums.digi.com/u/charliek)\
**Post date:** [July 30, 2007, 9:47pm UTC](https://forums.digi.com/t/function-of-pin-3-port-c-on-the-connectem/3441/4 "2007-07-30T21:47:43Z")

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Check out the hardware reference guide for the NS7520 (processor in the EM)starting on page 84 of adobe. This, combined with the hardware reference for the Connect EM, gives you a list of what the various pins can be used for.