# GPIO Serial Mux

**URL:** <https://forums.digi.com/t/gpio-serial-mux/4895>\
**Category:** NET+OS\
**Tags:** conenctcorewi9c\
**Created:** [April 3, 2007, 2:29pm UTC](https://forums.digi.com/t/gpio-serial-mux/4895 "2007-04-03T14:29:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![abettino](https://avatars.discourse-cdn.com/v4/letter/a/cdc98d/32.png) [@abettino](https://forums.digi.com/u/abettino)\
**Post date:** [April 3, 2007, 2:29pm UTC](https://forums.digi.com/t/gpio-serial-mux/4895/1 "2007-04-03T14:29:15Z")

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Hello,  
I am trying to select the GPIO function that is mux’ed with Serial port B on this ConnectCore Wi-9C board. I have changed in #define BSP\_GPIO\_MUX\_SERIAL\_B to BSP\_GPIO\_MUX\_INTERNAL\_USE only in the gpio.h file. I have also tried disabling the serial driver for serial port b in the bsp.h file. When I try toggling this port there is no effect. I have been successful doing this with GPIO pins that are not multiplexed. This is all with net os 7.0. Any help would be greatly appreciated.

Andy

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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:** [May 16, 2007, 8:10pm UTC](https://forums.digi.com/t/gpio-serial-mux/4895/2 "2007-05-16T20:10:29Z")

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Make sure you’re using the NAconfigureGPIOpin to configure the GPIO pin (checking the return value), and then use NAgetGPIOpin and NAsetGPIOpin to change the GPIO values.

If you really want to bypass the APIyou can go directly to the appropriate registers, see the 9360 hardware reference guide for details.