Getting Started, Documentation, and Tutorials
GPIO access via Python with Linux OS
Adafruit tutorial for digital and I2C
Notes:
The Android operating system needs an HDMI monitor plugged in on power up, otherwise it just goes to sleep. An adapter to a VGA monitor did not work for me.
The Dragonboard comes with Android Lollipop installed.
Plug in the keyboard, mouse, and monitor, then plug in the power. The Dragonboard will then boot up.
The tutorials describe how to use other operating systems like Linux and how to program the GPIO.