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Raspberry Pi 4B with HDMI touch Display

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Hi,

I used a Raspberry Pi 4B to drive a 4.3-inch HDMI capacitive touch screen(800 x 480). I modified the EW_DISPLAY_INTERFACE in the ewconfig file to EW_DISPLAY_INTERFACE_HDMI_0. I am very happy that everything went smoothly without any errors.
But when I input ./EmbeddedWizard-RasPi-4B, the Hello World program does not run, but suddenly the screen goes black, and then some parameters are displayed. The parameters shown are in the picture I gave.
I want to ask why this happens? Or does anyone want to use the Raspberry Pi 4B version to drive the unofficial HDMI display? You can share your experience with each other.

 

Thanks,

 

Jia

1 Answer

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by

Hello Jia,

it seems that EW_DISPLAY_INTERFACE_DSI_0 is still the selected display type. Can you make sure that the define EW_DISPLAY_INTERFACE is set to EW_DISPLAY_INTERFACE_HDMI_0 within the file ewconfig.h?

Just make sure that the file is saved and try to make a full rebuild by

make clean
make

Does it work?

Best regards,

Manfred.

by

Hello Manfred,

I made sure that the define EW_DISPLAY_INTERFACE is set to EW_DISPLAY_INTERFACE_HDMI_0 within the file ewconfig.h.

When I .enter /EmbeddedWizard-RasPi-4B, then there will be a screen like the picture above. Then the entire screen becomes black. After a few seconds, the screen shown in the figure below appears.

Does this mean that the screen is not working properly? Or if I want to make the screen work, what changes do I need to make?

Best regards,

Jia

 

by
Hi Jia,

this sounds really strange...

I just ordered the same display (Waveshare 4.3 inch HDMI LCD (B) 800x480) - it will be delivered on Monday...

Stay tuned...

Best regards,

Manfred.
by
Hello Manfred,

 

Thanks for your help. Then I am waiting for your good news.

 

Best regards,

 

Jia
by

Helli Jia,

here are the good news... 

I just received the mentioned display (Waveshare 4.3 inch HDMI LCD (B) 800x480) and did the following steps:

  • Disconnect the DSI display
  • Power the HDMI display via USB
  • Connect HDMI port of display to Mini-HDMI port 0 of RasPi-4B board
  • Connect Touch Mini-USB of display to an USB port of the RasPi-4B board
  • Power RasPi-4B - the display is detected automatically.
  • Build "HelloWorld" application according Getting Started documentation

And: it works... 

At the beginning, the display is a short moment black (I assume when the display mode changes), but then the GUI application appears as expected.

Can you try it once more?

Are you using the latest Raspberry Pi OS Lite (Bullseye)?

EDIT: Make sure to connect the touch!

Best regards,

Manfred.

by
Hello Manfred,

thanks for your help.

My mistake is, i don't connect Touch Mini-USB of display to an USB port of the RasPi-4B board.

Und jetzt Display funktioniert!

Vielen Dank für Ihre Hilfen.

Merry Christmas

Best regards,

Jia
by
So it doesn't work without touch? What if we connect Display LCD only with HDMI?
by

You can check with evtest if your touch input device is working:

sudo apt-get install evtest
evtest

Then you should get the touch events printed as soon as you touch the screen. Does this work?

Once the touch device is working, you can use it for the Embedded Wizard GUI application (ewconfig.h / ew_bsp_touch.c).

Best regards,

Manfred. 

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