PC7 is configured as a 1.8 volt output and wired to a red LED next to the
green LED on the FoxG20 main board. PC7 passes through a 100 ohm resistor
and the red LED is illuminated when PC7 is logical high.

The debian distribution configures PC7 as "user_led" in the "leds"
subsystem. This makes PC7 unavailable to the sysfs gpio subsystem. See the
/sys/class/leds/user_led directory. Reading "trigger" shows  the available
patterns:
  # cat trigger
none nand-disk mmc0 timer [heartbeat]

The entry in brackets is active. The "mmc0" entry will flash the red LED
when the microSD card is being accessed (read or written). The "timer" entry
flashes the red LED every second. And the "none" entry turns off the red LED.

Doug Gilbert
20110829