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PiTFT - Unable to turn on and off the display #175

Closed aeromaxx closed 3 years ago

aeromaxx commented 3 years ago

I've just installed the "PiTFT 2.8" capacitive touch (240x320)" display using the latest 2.1.0 script, the screen is working. But before I was able to turn the display on and off, using the commands below but now I am unable to as these paths don't exist.

ON

sh -c '/bin/echo 0 > /sys/class/backlight/soc\:backlight/bl_power' sh -c 'echo "1" > /sys/class/backlight/soc\:backlight/brightness'

OFF

sh -c '/bin/echo 1 > /sys/class/backlight/soc\:backlight/bl_power' sh -c 'echo "0" > /sys/class/backlight/soc\:backlight/brightness'

https://github.com/adafruit/Raspberry-Pi-Installer-Scripts/blob/master/converted_shell_scripts/adafruit-pitft.sh

makermelissa commented 3 years ago

Hi, 2.1.0 is not the latest version of the script. We converted it to Python. Please try the 3.1.1 version. Here's how to run it: https://learn.adafruit.com/adafruit-pitft-28-inch-resistive-touchscreen-display-raspberry-pi/easy-install-2

Thanks.

aeromaxx commented 3 years ago

@makermelissa Thanks, but I have already tried that script and I don't get the option to turn the display on and off as and when I want, there is no mention of how to do that on the link you posted, I had to revert back to an older version of the script so I could turn the screen on and off when I want, the latest version doesn't have that functionality.

CrossVR commented 3 years ago

I'm not sure why, but the ability to control the backlight was removed in commit 8bc1771bb2b1e40202058f39cc136620ffecfb39. This change also seems to be preventing the display from turning on at startup.

makermelissa commented 3 years ago

Yeah, it could be related.

makermelissa commented 3 years ago

The ILI9341 driver is part of the Raspberry Pi OS and it looks like they took this out, so there's not much to do there. I was however able to control it using PWM and Python. Take a look at the Blinka on Raspberry Pi guide: https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/pwm-outputs-servos#pwm-leds-3067131-4. I just changed the Pin to D18 and it faded the backlight in and out perfectly.

makermelissa commented 3 years ago

Ok, I looked into this a bit more. /sys/class/backlight is only installed for the resistive touch screen because it is part of the STMPE driver. I have updated the guide page to include some alternative ways to control the backlight on the Capacitive screen.

aeromaxx commented 3 years ago

The ILI9341 driver is part of the Raspberry Pi OS and it looks like they took this out, so there's not much to do there. I was however able to control it using PWM and Python. Take a look at the Blinka on Raspberry Pi guide: https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/pwm-outputs-servos#pwm-leds-3067131-4. I just changed the Pin to D18 and it faded the backlight in and out perfectly.

@makermelissa Thanks for all your work on this, I am still able to successfully turn the display on and off using the 0.8.0 version of this script on the latest version of raspbian, so I am confused as to why it's not possible to do the same with later versions of the script, even ones that have been converter over to Python.

makermelissa commented 3 years ago

I'm not sure what you mean by the 0.8.0 version of the script. Could you point me to the one that works for you?

aeromaxx commented 3 years ago

@makermelissa This one is working for me, and lets me turn on/off the display as in the original post at the start of this thread.

https://github.com/adafruit/Adafruit-PiTFT-Helper/blob/master/adafruit-pitft-helper

makermelissa commented 3 years ago

Thanks, I didn't even know about that repo. I'll take a look. It's possible we diverged from there because it broke something else (perhaps a conflict with the resistive touch driver).