Expansion Board (Hardkernel) GPIO,SPI,ADC,Sensors,LED & Key

Compatible with XU / XU3 / XU4 Series

• 4 x buttons (GPIO)
• 1 x button  (Power On)
• 5 x LEDs (GPIO)
• 1 x SPI Flash 2Mbit (Upto 20Mhz SPI clocking)
• 1 x I2C Temperature/Pressure sensor BMP180
• 1 x I2C Ambient Light sensor BH1780GLI
• 1 x Trimpot(variable resistor) for ADC access
• 1 x IDC cable is included

Schematics
http://dn.odroid.com/ODROID-XU/Expansion_Board/ExpansionBoard.pdf

Software 
Driver source code
https://github.com/hardkernel/linux/tree/odroidxu-3.4.y/drivers/hardkernel

Android Example source code
http://dn.odroid.com/ODROID-XU/Expansion_Board/


Driver access

SPI
Misc device driver
Device node : /dev/ioboard-spi-misc
Refer device/hardkernel/ioboard-spi.h source to read/write/erase the SPI Flash memory.

LED & KEY
/sys/device/platform/ioboard-keyled/
board_test : Default value is 1 and test mode. If this is 0, change to normal mode to read/write.
led1 ~ led5: write only. Chnage the LED state (1 : on, 0 : off)
sw1 ~ sw4: read only. Read the state of switch. (1 : pressed, 0 : released)
To read the Switch state, must use the polling method. (interrupt feature is not implemented)

ADC
/sys/device/platform/ioboard-adc/
enable : on/off (read/write)
value : ADC raw value (0~4095)
voltage : 0V ~ 1800mV 

Ambient Light senor (Software driven bit-bang I2C)
/sys/device/platform/i2c-gpio.10/i2c-10/10-0029
enable : on/off (read/write)
lux : sensor value in Luix (0 ~ 65535 lux)

Pressure sensor/temperature sensor (Software driven bit-bang I2C)
/sys/device/platform/i2c-gpio.10/i2c-10/10-0077
enable : on/off (read/write)
pressure : atomospheric pressure, pa unit. (ex)101614(pa) = 1016.14hpa
temperature : 10 times.... (ex) 195 = 19.5C