Hardkernel has released guide book of Android platform development.
– Basic ( Android/Bootloader/Kernel Build and Installation )
– Intermediate ( Driver / HAL Development )
– Advanced (GPIO/UART/I2C/ADC access from Android application )
Kernel source code can be downloaded from this link.
< Kernel source code IO board >
There are also many useful Android application source code to access hardware in Android devices.
Sensor API < Source code >
Sensor e-Compass API < Source code >
Camera API (preview) < Source code >
Camera Application (Barcode & QR code reader) < Source code > taken from ZXing project.
Battery gauge API < Source code >
Audio API <Source code >
WiFi & Bluetooth API < Source code >
GPIO / IRQ access <Source code >
ADC access <Source code >
ADC access (Oscilloscope) < Source code >
UART access (GSP system) < Source code >
I2C access (Pressure & Barometer) < Source code >
I2C access (GPIO expansion) < Source code >