In DP2 there is two ways to control GPIO:
1) with SDK using java (analyzed by Harry Fairhead here);
![enter image description here](https://i.stack.imgur.com/sw3zb.gif)
2) with NDK using C/C++ (analyzed by Harry Fairhead here).
![enter image description here](https://i.stack.imgur.com/dkcRK.gif)
With SDK using java the fastest pulses seen are around 0.23ms and there are lots of large (up to 8ms) interruptions (!!!) in the pulse train. And with NDK using C/C++ the pulse width is reduced from 0.23ms to just around 0.15ms.
Conclusion: Android Things DP2 Raspberry Pi GPIO max frequency is about 3 kHz, that is not fast enough to write drivers that interface to most not supported "from the box" protocols.
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