Touch Screen not funcitoning

[ojtramp]

Hi everyone

I am not getting any response from the resistive touch screen and am not sure what is wrong. I have installed the drivers as I have described in my previous issue regarding being unable display anything on the screen here, and then installed the screen via the automated script.

I am successfully using fbcp to mirror my HDMI output on Raspberry Pi OS 32-bit 2020-12-02.

The touchscreen is registered by the system but when I launch evtest it is not registering any input when I touch the screen.

pi@raspberrypi:~ $ evtest
No device specified, trying to scan all of /dev/input/event*
Not running as root, no devices may be available.
Available devices:
/dev/input/event0: Microsoft Microsoft® 2.4GHz Transceiver v5.0 Consumer Control
/dev/input/event1: Microsoft Microsoft® 2.4GHz Transceiver v5.0 Mouse
/dev/input/event2: Apple Inc. Apple Keyboard
/dev/input/event3: Apple Inc. Apple Keyboard
/dev/input/event4: ADS7846 Touchscreen
Select the device event number [0-4]: 4
Input driver version is 1.0.1
Input device ID: bus 0x0 vendor 0x0 product 0x0 version 0x0
Input device name: "ADS7846 Touchscreen"
Supported events:
Event type 0 (EV_SYN)
Event type 1 (EV_KEY)
Event code 330 (BTN_TOUCH)
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 0
Min 0
Max 4095
Event code 1 (ABS_Y)
Value 0
Min 0
Max 4095
Event code 24 (ABS_PRESSURE)
Value 0
Min 0
Max 255
Properties:
Testing ... (interrupt to exit)

I am also not getting any output using the following command sudo cat /dev/input/event4, but am on my other inputs.

Any help in getting this to work would be great!

Thanks

Ollie

[shawaj]

@ojtramp can you try adding dtoverlay=media-center,speed=32000000,rotate=0 to the /boot/config.txt

[ojtramp]

Thanks shawaj but unfortunately it already has the line below:
dtoverlay=media-center,speed=32000000,rotate=270

[shawaj]

Ah ok, can you try adding dtoverlay= right at the top of the file.

This will stop the overlay on the eeprom from loading.

Also is your RasPi fully updated?

[ojtramp]

Doesn't seem to change anything unfortunately, still no output on evtest.

I've copied the whole of my config.txt, I've tried commenting out the line doverlay=vc4-fkms-v3dbut that doesn't allow input from the touchscreen.

The RasPi is fully updated (sudo apt-get update and sudo apt-get upgrade).

> dtoverlay=media-center,speed=32000000,rotate=270
> 
> # For more options and information see
> # http://rpf.io/configtxt
> # Some settings may impact device functionality. See link above for details
> 
> # uncomment if you get no picture on HDMI for a default "safe" mode
> #hdmi_safe=1
> 
> # uncomment this if your display has a black border of unused pixels visible
> # and your display can output without overscan
> disable_overscan=1
> 
> # uncomment the following to adjust overscan. Use positive numbers if console
> # goes off screen, and negative if there is too much border
> #overscan_left=16
> #overscan_right=16
> #overscan_top=16
> #overscan_bottom=16
> 
> # uncomment to force a console size. By default it will be display's size minus
> # overscan.
> #framebuffer_width=1280
> #framebuffer_height=720
> 
> # uncomment if hdmi display is not detected and composite is being output
> #hdmi_force_hotplug=1
> 
> # uncomment to force a specific HDMI mode (this will force VGA)
> #hdmi_group=1
> #hdmi_mode=1
> 
> # uncomment to force a HDMI mode rather than DVI. This can make audio work in
> # DMT (computer monitor) modes
> #hdmi_drive=2
> 
> # uncomment to increase signal to HDMI, if you have interference, blanking, or
> # no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18
# Additional overlays and parameters are documented /boot/overlays/README
# Enable audio (loads snd_bcm2835)
dtparam=audio=on
[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2
[all]
#dtoverlay=vc4-fkms-v3d
#dtoverlay=ads7846,cs=1,penirq=25,penirq_pull=2,speed=50000,keep_vref_on=0,pmax=255,xohms=150,rotate=270

[shawaj]

@ojtramp sorry I think I didn't make myself clear.

At the top of the file you should put dtoverlay= just that text by itself.

At the bottom you should have dtoverlay=media-center,speed=32000000,rotate=270

[ojtramp]

Oops! Sorry I misunderstood. I've made the corrections but unfortunately still nothing with evtest.
Now I am not seeing anything on the screen (just HDMI), although the backlight is on.

[shawaj]

@ojtramp could you just try a config.txt with:

dtoverlay=
disable_overscan=1
dtparam=audio=on
dtparam=spi=on
dtparam=i2c_arm=on
dtoverlay=vc4-fkms-v3d
max_framebuffers=2
dtoverlay=media-center,speed=32000000,rotate=270

First you should back up the old one and then create a new one:

mv /boot/config.txt /boot.config.old
nano /boot/config.txt

Then ctrl x, y and enter to save

[ojtramp]

So the screen is now mirroring my HDMI again but still no touch input registered by evtest

[shawaj]

I missed dtparam=i2c_arm=on from the above. Have edited.

[ojtramp]

No problem, updated and rebooted. Can still see the screen but still no touch input registered by evtest.

[shawaj]

Hmm, maybe try reseating the screen FPC cable in its connector?

Otherwise I'm out of ideas and inclined to say maybe it's a faulty display or touch controller.

Maybe @tvoverbeek or @ryanteck might have some other ideas?

[ojtramp]

Happy to reseat the FPC cable but might wait until there are any other ideas (I've got no idea what I'm doing so dont want to cause any damage until its the last resort).

Thanks for your help though! Appreciate it

[shawaj]

@ojtramp it shouldn't be too difficult to do. You just pull the two black bits shown in the below image, gently, away from the white part (in opposite direction to blue arrows)

And then pull out the gold/brown cable, then line it up as straight as you can and then push the black clips back in.

Could you share a photo of the top and bottom of the device as close up and high res as you can?

[ojtramp]

You're right, that wasn't too bad. Unfortunately still no luck.

Here are some images, happy to retake if you need them to be more in focus.

[ojtramp]

Any other ideas or shall I contact PiSupply for a replacement device?