MC9SO8QE32 - using pull-downs on general-purpose inputs?

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MC9SO8QE32 - using pull-downs on general-purpose inputs?

Contributor I

Referencing the MC9SO8QE32 Rev7 09/2011 here, I can't determine if a GPIO pin configuration I'm seeking help with has a solution. I am using this platform integrated through a Digi International XBee radio product, the S3B programmable, to control an embedded system. I have some existing discrete inputs fed to this controller that are sourcing 3v3/high when active, 0/low normal. I want to use a pull-down for the input, as opposed to a more traditional pull-up. 

Digi's configuration utility grants changing this via AT commands to an Ember radio controller used by default on the majority of their other trims of this product, which will easily configure select GPIO inputs with the built-in pullup/pulldown. But it does not seem to be documented very clearly for the programmable model utilizing the SO8 architecture in their SDK/API specification in regards to configuring this, which will bypass the Digi utility. There are a lot of examples configuring the pull-up, but not as a pull-down. There are even XML utilities within the SDK that allow some configuration through drop-down menus, but pull-down isn't specified like it is in the Digi utility. Additionally, there is also mention through other documentation that it is not advisable to adjust the basic GPIO configuration during runtime since their configuration macros handle it all at a particular time during execution. 

I thought I'd ask here just to determine if it was possible at the core and go from there. I'm sure I'm overcomplicating this having typed this much already, but I'm really just trying to figure out if these channels have pull-downs. 

On a MC9SO8QE32CFT, I am particularly talking about these two pins:

Pin 45 (PTC5/TPM3CH5/ACPM2O)


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NXP TechSupport
NXP TechSupport

The pins as GPIO is no possible to enable the internal pull down, the only way to set the internal up down is using the KBI function on the pin, please check the section

7.3.3KBI Interrupt Edge Select Register (KBIxES)

on the reference manual

Maybe this can work for your application