Datasheet

On / Off Using STMPE GPIO

Another option is to just turn it on and off using the extra GPIO created by the touchscreen driver

Thanks to the raspberry Pi overlay system, this GPIO is already set up for you in a file called

/sys/class/backlight/soc:backlight/brightness

To turn the backlight off run

sudo sh -c 'echo "0" > /sys/class/backlight/soc\:backlight/brightness'

To turn it back on, run

sudo sh -c 'echo "1" > /sys/class/backlight/soc\:backlight/brightness'

For older versions of PiTFT Kernel

On older versions of the PiTFT kernel/overlay, the GPIO was not tied to the backlight device. Start by getting access to

the GPIO by making a device link

sudo sh -c "echo 508 > /sys/class/gpio/export"

ls -l /sys/class/gpio

For some

really

old versions, the GPIO pin was #252 not #508 so substitute that if you're running something from 2014

or earlier

Once you verify that you see GPIO #508, then you can set it to an output, this will turn off the display since it will output

0 by default

sudo sh -c "echo 'out' > /sys/class/gpio/gpio508/direction"

Then turn the display back on with

sudo sh -c "echo '1' > /sys/class/gpio/gpio508/value"

or back off

sudo sh -c "echo '0' > /sys/class/gpio/gpio508/value"

https://learn.adafruit.com/adafruit-pitft-28-inch-resistive-touchscreen-display-raspberry-

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