LCD xpt2046 3.5" display settings

Hardware
1

For a new knobless Zynthian
my LCD xpt2046 3.5" display works using PiScreen 3.5 (V1) settings:

Config:
dtoverlay=piscreen,speed=16000000,rotate=90

but…

…the touch are inverted: left with right, up with down.

Are there any magical settings to write in config windows to fix it? :slightly_smiling_face:

How can I do the calibration without knobs and buttons?

2

I seem to remember doing it with a mouse, which sits nicely with the cursor bug, recently being fixed.

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3

Thanks Chris: with mouse I can arrive to calibration;
touch is strill inverted
I would like to understand if I can fix by Config.

There are settings like dtoverlay=ads7846,speed=2000000,cs=1,penirq=17,penirq_pull=2,swapxy=1,xohms=100,pmax=255
but I cannot understand the meaning

4

There is the screen calibration tool in the GUI admin section, Have you tried it…?

https://wiki.zynthian.org/index.php/Zynthian_UI_User_Guide_-_V1/V4#Touchscreen_Calibration

5

yes but still the same problem of inverted touch

6

Now that’s a pain…

That generally sorted out those sorts of problems before. Digging into the forum will show a fair bit of discussion on this issue.

Have you looked outside the zynthian community for settings ? It can get a bit, as you describe it, magical but that might flush something out…

All I can contribute is it used to be a right pain and if you did get it right it would reset when you powered off, but this is the first mention of it that wasn’t addressed by the tool.

7

In my reTerminal, I had the same problem. I fixed it editing the file /usr/share/X11/xorg.conf.d/40-libinput.conf. There, look for the section InputClass with the Identifier libinput touchscreen catchall, and in that section, add the following option: Option "InvertX" "1". The whole section would be as follows:

Section "InputClass"
        Identifier "libinput touchscreen catchall"
        MatchIsTouchscreen "on"
        MatchDevicePath "/dev/input/event*"
        Driver "libinput"
        Option "InvertX" "1"
EndSection

Hope it helps!

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8

thanks Oscaracena:
how could I use than in Zynthian?

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9

step 1 - get yourself to a Command Line on Zynthian - either “ssh” to Z or access terminal in webconf. If you don’t know how research or come back and ask.

step 2 - get into an editor on the file. vi is available along with many others. If you don’t know how you can find a VI tutorial on the web or in a book. Or ask if you get stuck here.

step 3 - add the section indicated by @oscaracena above.

step 4 - Try it!

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