Getting the 3.5" Display to work with moode audio and the Rasberry Pi OS 12 Bookworm

[f-o-n]

The current script did not work with the latest Moode Raspberry Pi Bookworm release and my Raspberry Pi 4B with an MPI3501 display. Here are the manual steps I took to get it working together with Moode Audio:

1. Install missing (and legacy) packages:

sudo apt install xserver-xorg-input-evdev xserver-xorg-video-fbdev xserver-xorg-video-fbturbo lightdm evtest git

2. Switch from Wayland to X11:

Run:

sudo raspi-config

Navigate to: 6 Advanced Options → A6 Wayland → W1 X11

3. Get files from repo:

git clone https://github.com/goodtft/LCD-show
cd LCD-show
sudo mkdir -p /etc/X11/xorg.conf.d
sudo cp ./usr/tft35a-overlay.dtb /boot/overlays/tft35a.dtbo
sudo cp ./usr/99-calibration.conf-35-90 /etc/X11/xorg.conf.d/99-calibration.conf
sudo cp ./usr/99-fbturbo.conf /usr/share/X11/xorg.conf.d/99-fbturbo.conf

4. Edit /usr/share/X11/xorg.conf.d/99-fbturbo.conf:

Section "Device"
    Identifier      "Allwinner A10/A13/A20 FBDEV"
    Driver          "fbturbo"
    # Switch to /dev/fb0 for default output (usually hdmi) with evdev
    Option          "fbdev" "/dev/fb1"
    Option          "SwapbuffersWait" "true"
    Option          "DRI" "false"
    Option          "ShadowFB" "off"
EndSection

5. Edit /etc/X11/xorg.conf.d/99-calibration.conf:

Section "InputClass"
    Identifier      "calibration"
    MatchProduct    "ADS7846 Touchscreen"

    # Using libinput (better touch support, matrix-based calibration)
    Driver "libinput"
    # Option "TransformationMatrix" "-1 0 1 0 -1 1 0 0 1"

    # Or use evdev (worse touch support in chrome but supports direct calibration)
    # Driver "evdev"
    # Option "Calibration" "3936 227 268 3880"
    # Option "SwapAxes" "0"
    # Option "TransformationMatrix" "1 0 0 0 -1 1 0 0 1"
    # Option "EmulateThirdButton" "1"
    # Option "EmulateThirdButtonTimeout" "750"
    # Option "EmulateThirdButtonMoveThreshold" "30"
EndSection

6. Touchscreen calibration (only if using evdev):

sudo apt install xinput-calibrator
DISPLAY=:0 xinput_calibrator

Results can then be persisted in 99-calibration.conf

7. Add or modify following Values in /boot/firmware/config.txt:

dtparam=spi=on
enable_uart=1
dtoverlay=tft35a:rotate=0

hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 320 480 60 6 0 0 0
hdmi_drive=2

# Important: keep this line present but commented to pass screen size to Chromium with moode
#dtoverlay=vc4-kms-v3d

8. Enable autologin with LightDM:

Edit /etc/lightdm/lightdm.conf:

[Seat:*]
autologin-user=admin  # or your username
autologin-user-timeout=0

Notes:

• Moode's UI scales better in portrait mode; hence the resolution is set to 320x480 and rotation to 0.
• If you rotate the screen, you must also set the corresponding transformation matrix for the touchscreen. This tool is helpful: https://codepen.io/GottZ/full/pWpNgK
• When running display config commands over SSH, prepend them with DISPLAY=:0.

Debugging Tools:

cat /var/log/Xorg.0.log | grep EE
cat /var/log/Xorg.0.log | grep fb
ls /dev/fb*
fbset -fb /dev/fb0
sudo evtest

Moode Settings:

In Moode UI: Go to Configure → Peripherals → General settings and enable Display. This ensures the display manager is started and .xinitrc is executed, which launches Chromium in kiosk mode with the Moode UI.

References:

• https://michael-peeters.blogspot.com/2018/03/
• https://github.com/jwa-7/goodtft-kiosk

[jasperkuipers]

Hi!

This look promising! Do you think this workflow will work for the MHS35 as well? Are there any mutation needed?

Like to hear from you!

Thanks in advance

Jasper

[f-o-n]

Probably, haven't tested it but you can try changing following:

Copy the right overlay for your display: sudo cp ./usr/mis35-overlay.dtb /boot/overlays/mis35.dtbo and in /boot/firmware/config.txt the overlay and the right resolution needs to be selected:

dtoverlay=mis35:rotate=90
hdmi_cvt 480 320 60 6 0 0 0"

/etc/X11/xorg.conf.d/99-calibration.conf also needs the correct calibration matrix if evdev is used.

[jasperkuipers]

@f-o-n , thanks you for your reply!

I will test it out and let you know if it worked.

Do you also know how I can set this touchscreen as a single display? Currently it forces me to connect a HDMI monitor as well.

Kind resgards,

Jasper

[nolith]

@f-o-n that you very much for putting this instructions together. It helped me a lot.

I have the WebUI working, but it's cropped, I can only see a tiny fraction of it.

From Moode web config it detects a resolution of 1920x1080 that matches my onboard HDMI connected to the AVR

fbset -fb /dev/fb0

mode "1920x1080"
    geometry 1920 1080 1920 1080 16
    timings 0 0 0 0 0 0 0
    rgba 5/11,6/5,5/0,0/0
endmode

But my LCD screen has a different resolution

fbset -fb /dev/fb1

mode "320x480"
    geometry 320 480 320 480 16
    timings 0 0 0 0 0 0 0
    nonstd 1
    rgba 5/11,6/5,5/0,0/0
endmode

I also noticed that if I have my AVR attached, I cannot see the boot sequence on the LCD (it's likely sent to my headless AVR) but if I boot without the HDMI cable, I can see it on screen. Is there a way I can make that reliably showing on the LCD?