GEN4-4DPI-70CT-CLB touchscreen doesn't work on raspberry 4 (Buster)

[newager]

I am working on a project and trying to make this screen work. Everything is successful except the touchscreen, during calibration is doesn't respond to any touches.

The kernel is:

Linux zynthian 4.19.97-v7l+ #2 SMP Sun Mar 29 06:27:59 BST 2020 armv7l GNU/Linux

And I am using your driver set for this kernel, the latest I could find on the net.

dmesg | grep spi - says

[ 0.188720] spi-bcm2835 fe204000.spi: could not get clk: -517
[ 0.278322] 4d-hats spi0.0: 4d-hat registered, product code = b4

I have enabled 4dpi_touch in /etc/modules as was suggested in some post - no result.

There are a couple things connected to RPi except the screen - MCP23017 and a soundcard (the screen interface is the first in the line) but removing them gives absolutely the same result.

Please advise, how to proceed further - I have no more ideas.

Thanks !

[frsantiago]

Hi,

Good Day.

Welcome to the forum.

Calibration only works with resistive touch and not on the capacitive touch.

I hope this helps.

Best Regards,
Ferdinand

[newager]

Hi,

In that case could you help with the instructions how to make capacitive touch interface work under raspbian buster ?

The common instruction manual doesn't help. Does it requires specific driver ?

Please help. it's a pity to get such a nice screen and not to use all it's features.

[newager]

Hi,

Good Day.

Welcome to the forum.

Calibration only works with resistive touch and not on the capacitive touch.

I hope this helps.

Best Regards,
Ferdinand

Hello again !

I continue trying to make capacitive touch work on my GEN4-4DPI-70CT-CLB on different raspberry pies (3B rev.1.2, 4B rev.1.1 4GB) on different kernels, compiling drivers from 4d systems git library - no success too. Screen itself works fine, but no touch.

My question is, what chipset is used for capacity touch in this screen model, is it Focaltech FT5446 ? Please help me with some instruction at least - I am a bit lost with all these blind attempts...

Maybe you can at least lead me to some drivers that might work on some linux distribution ?

Please help me out if possible !

Thank you !

Andrei

[frsantiago]

Dear Andrei,

Good Day.

If you installed the latest Raspbian OS then use the current display kernel, the touch should work fine with gen4-4DPi-70CT-CLB with Raspberry Pi 4. Please check the connection of the touch flex to the connector at the back of the display module.

For the touch driver IC, yes we are using FT5446 and the driver was already installed. You can also try to uncomment

#dtoverlay=4dpi-70ct from config.txt and try if the touch will now work.

Thank you.

Best Regards,
Ferdinand