Why is my STM32h747i-DISCO board display shows horizontal lines / noisy image after approx. 10 sec of usage? is it a hardware issue?

[SKuma.49]

I recently bought a STM32h747i-DISCO board from DIGIKEY. After uploading a standard demo program from touch GFX the display was working fine for approximately 10 seconds, then it shows distorted or horizontal lines and it gets worse after some time. Every time when I unplug and connect it to my laptop the display works fine for 10 sec and afterwards the same problem occurs. Why is this happening?

I have attached the images of the display. Any suggestions?

[MM..1]

Maybe dont stable power

[S.Ma]

Read the user manual and check which version of the board you have (there is a sticker on the board with 2 data, the order code and the version code).

Then if the board is the first version, download the out of the box demo binary, program it and check if the display is ok for a minute. If yes, then it's a SW issue. If no, check the connectors of the display. Seems like the VCOM of the display is not working properly and causes sticky pictures.

[Osman SOYKURT]

Hello SKuma.49,

I can see on the image you shared, you are using revision AT2 with a MB1166-A09 LCD daughterboard.

I tested on my side with a revision AT1 with a MB1166-A03 LCD daughterboard and I didn't face the issue you're mentioning.

From what I can see on the user manual of the STM32H747i-disco, the display changed between these 2 revisions (LCD FRIDA FRD397B25009-D-CTK is replaced by FRIDA FRD400B25025-A-CTK)

 

I think that could be the issue, but more investigation is needed.

/Osman

[Thierry GUILHOT]

Hello SKuma.49,

As reported by S.Ma and explained into the corresponding user manual, a boards product is identified using two stickers: the product identification one and a board reference one for each board composing the product.

According to the shared pictures, your product identification is DK32H747I$AT2. This product (DK32H747I$AT2) is based on a new LCD display FRIDA FRD400B25025-A-CTK which is not compatible with the released Demo firmware. This explains why this product is not delivered with the Demo firmware already flashed.

If you are using the released demo firmware, it won't work properly with this product. For this product, it is required to use the updated LCD display driver available on GitHub and to recompile the demo firmware.

Thierry,

[SKuma.49]

Thankyou all.

Hi, Thierry GUILHOT: As per S.Ma i downloaded the demo binaries provided in the ST Webpage see link: https://www.st.com/en/evaluation-tools/stm32h747i-disco.html#tools-software and upload it to my stm32h747i-disco board but again i see horizontal lines / distorted display same as the one i attached previously.

can you please send me the GitHub link having the updated LCD display driver for my board? I will try to update the LCD driver and then try to recompile the demo firmware as per your suggestion

[Thierry GUILHOT]

Hi  SKuma.49,

The binary of the demo available on the ST web page (https://www.st.com/en/evaluation-tools/stm32h747i-disco.html#tools-software) is not up-to-date and does not support the new LCD mounted on the product DK32H747I$AT2 that you've got.

The updated driver is available on GitHub at this link: https://github.com/STMicroelectronics/STM32CubeH7/commit/1c84713102f8509deb79ae14db8dbb104c17c45e#diff-8a5b12f7040dfb560c495dc0a1213725ba939bf19d531dd1e97067b6a1a79ec0.

Please note that you'll need to enable the right LCD component through the stm32h747i_discovery_conf.h file.

Thierry,