Using GPIO pins
I'm trying to use the GPIO pin on pin 7 of port J7 of the VOXL Flight. (BLSP6_GPIO_26_AUX2_3P3) Should this pin be accessible from the voxl-gpio utility? Attempting to read (voxl-gpio read 26) or write to it (voxl-gpio write 26 1) seems to have no effect.
Also, the docs claim that most pins can also be used as GPIO pins. Is this true, and if so is there a reference somewhere for the GPIO pin numbers corresponding to pins normally mapped to I2C / UARTs?