Cubietruck GPIO Notes

Expansion Ports:

http://linux-sunxi.org/A20-Cubietruck#Expansion_Ports

We customized the fex file to add the following gpio declarations:

gpio_pin_3 = port:PC19<1><default><default><1>
gpio_pin_4 = port:PC21<0><default><default><0>

This means: gpio_pin_3 will be an output, initial state set to 1 (high?) and that is connected to pin 5 of connector 8 (the one closest to the Ethernet) gpio_pin_4 will be an input, no clue what the initial state parameter means in that case, and it is connected to pin 6 of the same connector 8.