Backlight Control

Unlike the resistive 2.8" PiTFT, this little PiTFT does not have a resistive touch controller chip that we can take advantage of as an extra backlight control pin. Instead, you can set use GPIO #18 as an on/off or PWM control.

Note that if you are playing audio out the headphone jack, you can't use the PWM capabilities of GPIO #18 at the same time, the PWM function is reassigned to do audio. However,  you can use it as a simple on/off pin

There's python code available for controlling the PWM on #18 but you can also just use the kernel module and shell commands.

With these basic shell commands, you can set the GPIO #18 pin to PWM mode, set the output to 100 (out of 1023, so dim!), set the output to 1000 (out of 1023, nearly all the way on) and 0 (off)

Download: file
sudo apt-get install wiringpi
gpio -g mode 18 pwm
gpio -g pwm 18 100
gpio -g pwm 18 1000
gpio -g pwm 18 0

Try other numbers, from 0 (off) to 1023 (all the way on)!

This guide was first published on Dec 19, 2014. It was last updated on Dec 19, 2014. This page (Backlight Control) was last updated on Jun 21, 2019.