LCD Backlight

Most drivers use the fbtft backlight support to control backlight. This is enabled if there is a 'led' gpio present.

These drivers will have backlight power control exposed in the sysfs filesystem.

# Turn off backlight
echo 1 | sudo tee /sys/class/backlight/*/bl_power
# Turn on backlight
echo 0 | sudo tee /sys/class/backlight/*/bl_power

Brightness is currently not supported (need a kernel PWM driver).

Give all users backlight control permissions


SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power"

Backlight control outside of FBTFT

Wiring Pi can be used to dim the backlight.

sudo gpio mode 7 write
# Turn Off LCD backlight
sudo gpio write 7 0
# Turn On LCD backlight
sudo gpio write 7 1


  • accessory/add-on_boards/xu4_cloudshell/lcd_backlight.txt
  • Last modified: 2017/07/24 13:31
  • by luke.go