[Resolved]PiScreen – No Picture / No Backlight

[bored]

Hi Folks,
Looking for a bit of support.

I put the piscreen together, however, there’s no picture or backlight.

I’ve installed the drivers, following the instructions at https://ozzmaker.com/piscreen-driver-install-instructions-2/

The touchscreen looks like it’s working though (I can see things happening when I cat /dev/input/event0)

Any help would be appreciated.

ls -l /dev/input/event*
crw-rw---T 1 root input 13, 64 Nov 3 21:50 /dev/input/event0

cat /proc/bus/input/devices

I: Bus=0000 Vendor=0000 Product=0000 Version=0000
N: Name="ADS7846 Touchscreen"
P: Phys=spi0.1/input0
S: Sysfs=/devices/platform/bcm2708_spi.0/spi_master/spi0/spi0.1/input/input0
U: Uniq=
H: Handlers=mouse0 event0
B: PROP=0
B: EV=b
B: KEY=400 0 0 0 0 0 0 0 0 0 0
B: ABS=1000003

[Mark Williams]

Hi
Can you please show us the output of

dmesg
and
cat /etc/modules

BTW: you checked that the backlight switch is in the on position?

Mark --OzzMaker.com --

[bored]

Hi Mark,

Thanks for the quick reply.

Yes, definitely checked the switch is in the “on” position! 🙂

dmesg output is here:
http://pastebin.com/6ZfKB1jb

/etc/modules is here:
http://pastebin.com/eYy2CkJq

[Mark Williams]

That all looks good, everything loaded properly.
The back light should come one even if nothing is being displayed.

the led:22 in the line below (from /etc/modules) will force the drivers to use GPIO22 to control the back light.
fbtft_device debug=3 rotate=90 name=flexfb speed=16000000 gpios=reset:25,dc:24,led:22

When you installed the drivers, was it from a clean image? We just need to work out if anything else is using that GPIO.

BTW: do you have the Kit or the Assembled PiSCreen

Mark --OzzMaker.com --

[bored]

Hi Mark,

I have the assembled PiScreen.
The drivers were installed to a clean image of 2014-09-09-wheezy-raspbian.

I can confirm that manually toggling GPIO22 (pin 15) on and off from a python console does toggle the backlight on and off.
However, the command:
echo 0 | sudo tee /sys/class/backlight/*/bl_power
both produce this error:

tee: /sys/class/backlight/*/bl_power: No such file or directory
0

and it’s the same for echo 1 as well.

After turning the backlight on manually, there’s still no image using fbi.

I should probably also mention that I’m doing all of this through an ssh console – there’s no monitor hooked up to the pi.

I will try a copy of your image tomorrow night, and post back.

Cheers,

Bored

[Mark Williams]

Mmmmm.
I just tried echo 0 | sudo tee /sys/class/backlight/*/bl_power and it worked fine for me, but I am running an earlier version of Raspbian, but it has been udpated.

I will have to test with the latest image file.

Mark --OzzMaker.com --

[bored]

hmmm… the image from your website works fine… so not a hardware issue.

Any other ideas?

Cheers

[Mark Williams]

I just tried with a vanilla install of 2014-09-09-wheezy-raspbian.
And it worked fine.

Here is the history of commands i used;

pi@raspberrypi ~ $ history
    1  sudo rpi-update
    2  sudo reboot
    3  sudo apt-get update
    4  sudo apt-get upgrade
    5  sudo REPO_URI=https://github.com/notro/rpi-firmware rpi-update
    6  sudo reboot
    7  sudo nano /etc/modprobe.d/raspi-blacklist.conf
    8  sudo nano /etc/modules
    9  sudo reboot
   10  sudo apt-get install fbi -y
   11  wget https://ozzmaker.com/Raspi_Logo.png
   12  sudo fbi -noverbose -T 1 -a -d /dev/fb1 Raspi_Logo.png
   13  echo 1 | sudo tee /sys/class/backlight/*/bl_power
   14  echo 0 | sudo tee /sys/class/backlight/*/bl_power

Mark --OzzMaker.com --

[bored]

Hi Mark,

Repeating those steps with a new, clean, image it worked fine.
I have absolutely no idea what went wrong on the previous image.

Thanks.

[Author]

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