The rev D board has the following limitations in libmraa:
+- gpio 13 will not switch the LED as it's a different Gpio, use raw gpio '3' to do this
- gpio register access via /dev/uio is limited to pin2 and 3
- gpio interupts will only work on GPIO_EDGE_BOTH
- adc kernel module will return 12bit number. MRAA defaults shift this to 10bits