Volumio with 3.5" TFT Touch Screen (GPIO) RPi 3B+

Hi I have a question: I got everything running, thanks to the many tips here. The longest task was the touch screen mirrored on the x axis which I corrected the
99-calibration.conf file:

Section “InputClass”
Identifier “calibration”
MatchProduct “ADS7846 Touchscreen”
Option “Calibration” “268 3880 227 3936”
Option “SwapAxes” “0”
Option “InvertX” “1”
Driver “evdev”
EndSection

The only problem I have and I do not find the config file. I would also like to control the “Browse library” by the touchscreen but I can’t. I can control everything through the browser but when I am in “Stand alone” mode, I would like also to be able to choose the music… How can I do this ???
Do I need to buy a bigger tft ?

Thanks and best regards

What config file do you mean? The files named “config.txt” and “userconfig.txt” both reside in “/boot”.

The local display should show the same UI like in a browser on another device. It could be that the mobile version of th UI is shown if you are using your touch screen in portait mode but you should be able to reach “Browse library” nonetheless.

If you should be using the “contemporary” UI theme you could try the “classic” theme which might fit a small screen better.

Hi. Thanks a lot for the quick answer. In fact it was by clicking the “classic” theme which resolved the issue.

With the contemporary theme I am not able to browse on the 3.5" tft…

Best regards
Christoph

Good it’s solved. :smiley:

I tried to follow this tutorial, but as soon as I do the LCD-Show for setup, the raspberry reboots and comes back with a kernel panic.

Is this just me or one of the latest updates?

Don’t use that script.

It modifies /boot/cmdline.txt and renders Volumio unbootable. It is possible to “repair” that but typically it is faster / easier to just start with a fresh Volumio system. Then don’t run LCD-Show but do the necessary steps manually. What is necessary depends on your screen.

What is the brand and exact model name of your screen?

I got mine from amazon and I guess I’ll debug in the kernel crash as I suspect that model isn’t what it pretends to be.

Maybe I misread your previous post: How far does the boot process go until it crashes?

I caught the crash pretty early on boot still on the HDMI. The crash stack implies that I’m missing some register here which leads me to the conclusion that this is some weird controller sitting on the GPIO.

As far as I can see I may do it in 2 ways:

  1. the annoying trial and error:
    Flash volumio, test driver, see what it does

  2. find some clue about the controller and debug into it, maybe write my own driver.

depending on how far me this bottle of wine gets today, I may end up with the 2nd option.

IMHO there is no need to write a new driver. If you could identify your screen most probably you can get along without that. Is it touchscreen or just an HDMI connected display?

I suspect it’s a touch due to its surface, sitting on some print without any text - connects through GPIO

Do you have a link to the Amazon product page?

doesn’t show up anymore - bought it long time ago and had it collecting dust

Ok, any writings on the PCB?

No, no writings visible but decoding the 26 GPIO pins got me as far as this,

  • 1 and 17 check out as 3.3V +
  • 2 and 4 should be around 5V +
  • 6, 9, 14, 20 and 25 seem to be ground
  • 23 looks like a clock to me
  • 21 seems to act up on touch
  • 19 looks like some SPI bus stuff to me

at least that’s what I could find out so far.

yet unknown:

  • 3, 5, 7, 8, 10, 11, 12, 13, 15, 16, 18, 21, 24, 26

the SPI bus - if that is it what I am looking for clocks around 100-130 MHz (rough guess due to my meter being crap)

counting pixels suggest we’re at a (native) resolution of 320*480

Is there any hint on the touch controller like “XPT2046”?

I’ll see if I can hack something together to access the touch. I mean, it should spit out something on that when addressed correctly.

You may have a look here and try out if it works for your display, too.

I figured it could be a MHS-3.5inch display due to the XPT2046 touch controller hailing.

Seems to be similar to the Quimat display the instructions I linked to are referring to.