Configuring Kuman 3.5 SC6AC TFT touchscreen

Hardware
1

Dear All,

I am trying to build a custom Zynthian with a Raspberry 3B V1.2.
I have a Kuman 3.5 TFT resistive touchscreen that woks ok with the generic HDMI configuration.

I’d like to make it work with its drivers in order to use the resistive touchscreen and keep the HDMI plug available.

I tried to use the waveshare 35a configuration as suggested here by @wolfpaw98 but it was not working. It returned a black screen asking for zynthian login.

I also tried to compile the driver according to these instructions but then i get a messed up and blurred image.

Did anyone had success with this screen and would kindly share some tips on how to make it work?

Thank you very much!

2

Hi,
it looks that the display is working with an hdmi connection for image and the touch is done trough GPIO’s. You can’t unplug the hdmi imho.

3

I don’t know,
one guy (Pasquale C. pictures with red background) on the amazon reviews claims that by installing the drivers you should be able to connect just with GPIO.

I will try by installing the standard raspbdian distro that hase the drivers pre installed and see what happens when booting without HDMI.

4

:+1:

5

Using the precompiled image the touchscreen works nicely, but requires the hdmi.
So yes apparently the hdmi is necessary. Here there is the mapping of the gpio and if I understand it correctly the gpio is used for power and for the touch panel only.

The nice thing now would be to use a Zynthian image and make the touchscreen work.
So here there is the repo of the drivers with some installation/configuration scripts.

I guess I have to tweak the one corresponding to my device, and use only the code lines responsible for driver installation and configuration, correct?

6

Ok, I partly fixed my issues and I hope this will help.

So basically I haven’t figured out that i needed to add dtoverlay=ads7846 in the display config box.

My current working configuration is the following:

display= Generic hdmi display

config:

disable_overscan=1
display_hdmi_rotate=2
dtoverlay=ads7846,penirq=25,speed=10000,penirq_pull=2,swapxy=1,xohms=150

everything else as default.

I also found helpful to install and configure the touchscreen as described here, as the solution provided in this post was not working for me.

One step further.

External usb Audio and midi next.

1 Like
7

Was there a file /usr/share/X11/xorg.conf.d/01-input.conf. Already there?

8

No, there was no such file. Why?

9

I’m trying to work uot a catch all solution for configuring touchscreens