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Enables an alternate function on a GPIO button. This method applies to the onboard GPIO connector and is currently supported on the XTx44, XTx43, XDx34, XDx33, HDx24, HDx23, and HO523 models.
The first argument specifies the GPIO button number (between 0 and 7). The second argument specifies the alternate function setting; the following table outlines the possible alternate setting for each pin:
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