performance - What is Android Things Raspberry Pi GPIO max frequency?

Question

Where can be found the characteristics of the switching speed of GPIO port for the Raspberry Pi 3 under Android Things like that?

Answer 1

In DP2 there is two ways to control GPIO:

1) with SDK using java (analyzed by Harry Fairhead here);

2) with NDK using C/C++ (analyzed by Harry Fairhead here).

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.