LEDs¶

NMHW21 provides four LEDs that can be controlled by user application or via command line.

The LEDs are described as follows:

Indicator onboard (ind)
Status onboard (status)
Indicator user-interface (ind ui)
Status user-interface (status ui)

Standard LED behavior¶

On startup (during bootloader/system-boot) the LEDs follow a specific pattern. During the startup the LEDs on the user-interface and the onboard LEDs are synced.

‘ind’ = ‘ind ui’

‘status’ = ‘status ui’

start of the bootloader (hard coded into u-boot)

ind - red

status - red

start of kernel (defined in the device tree)

ind - off

status - orange

Hard reset¶

On a hard reset the onboard status LED starts orange.

Mainboard Indicator¶

Green

$ echo 1 > /sys/class/leds/ind\:green/brightness
$ echo 0 > /sys/class/leds/ind\:red/brightness

Orange

$ echo 1 > /sys/class/leds/ind\:green/brightness
$ echo 1 > /sys/class/leds/ind\:red/brightness

Red

$ echo 0 > /sys/class/leds/ind\:green/brightness
$ echo 1 > /sys/class/leds/ind\:red/brightness

Off

$ echo 0 > /sys/class/leds/ind\:green/brightness
$ echo 0 > /sys/class/leds/ind\:red/brightness

Mainboard Status¶

Green

$ echo 1 > /sys/class/leds/status\:green/brightness
$ echo 0 > /sys/class/leds/status\:red/brightness

Orange

$ echo 1 > /sys/class/leds/status\:green/brightness
$ echo 1 > /sys/class/leds/status\:red/brightness

Red

$ echo 0 > /sys/class/leds/status\:green/brightness
$ echo 1 > /sys/class/leds/status\:red/brightness

Off

$ echo 0 > /sys/class/leds/status\:green/brightness
$ echo 0 > /sys/class/leds/status\:red/brightness

User Interface Indicator¶

Green

$ echo 1 > /sys/class/leds/ui\:ind\:green/brightness
$ echo 0 > /sys/class/leds/ui\:ind\:red/brightness

Orange

$ echo 1 > /sys/class/leds/ui\:ind\:green/brightness
$ echo 1 > /sys/class/leds/ui\:ind\:red/brightness

Red

# echo 0 > /sys/class/leds/ui\:ind\:green/brightness
$ echo 1 > /sys/class/leds/ui\:ind\:red/brightness

Off

# echo 0 > /sys/class/leds/ui\:ind\:green/brightness
$ echo 0 > /sys/class/leds/ui\:ind\:red/brightness

User Interface Status¶

Green

$ echo 1 > /sys/class/leds/ui\:status\:green/brightness
$ echo 0 > /sys/class/leds/ui\:status\:red/brightness

Orange

$ echo 1 > /sys/class/leds/ui\:status\:green/brightness
$ echo 1 > /sys/class/leds/ui\:status\:red/brightness

Red

$ echo 0 > /sys/class/leds/ui\:status\:green/brightness
$ echo 1 > /sys/class/leds/ui\:status\:red/brightness

Off

$ echo 0 > /sys/class/leds/ui\:status\:green/brightness
$ echo 0 > /sys/class/leds/ui\:status\:red/brightness