I created a sample application for the WP8548 on my mangOH rev 8 board with firmware 16.10.3.
I try to control some LEDs (via an external pullup resistor) using the GPIO1-4 pins on the IOT0 connector.
Apparently there is no support for the open drain, tri state and high z functionality.
I already created an issue on the legato github (see github.com/legatoproject/legato-af/issues/16),
but, I would like to understand if there would be a reason on hardware or system level for this issue.
Does the WP8548 controller have any constraint on its GPIO output?