2.10.1. Blinking an LED#
LEDs can be accessed and controlled through the sysfs LED interface.
For example, the AM62x Starter Kit EVM has the following LEDs available in sysfs:
# ls /sys/class/leds
am62-sk:green:heartbeat mmc0:: mmc1:: out0 out1 out2 out3 out4 out5 out6 out7
The following commands can be used to turn an LED on or off:
# echo 1 > /sys/class/leds/<led_name>/brightness
# echo 0 > /sys/class/leds/<led_name>/brightness
Where <led_name> can be any one of the LEDs listed under /sys/class/leds.
Something similar to the following can be put to a shell script to blink an LED (i.e., periodically turn the LED on/off):
for i in {1..10}
do
echo 1 > /sys/class/leds/<led_name>/brightness
sleep 0.5
echo 0 > /sys/class/leds/<led_name>/brightness
sleep 0.5
done
The following commands can be used to start or stop heartbeat blinking for an LED:
# echo heartbeat > /sys/class/leds/<led_name>/trigger
# echo none > /sys/class/leds/<led_name>/trigger