RGB888 Configuration on STM32H750

[PushparajAdka]

Hi Team,

   We are running into a problem on TouchGFX (v4.25) on configuring our 480x272 display on the above discovery board I mentioned. 

1. We want to configure a text box and display this  color I attached below. We found that the RGB we have is RGB565 and we may need RGB888. But I do not see any difference even after the change in this configuration. 

1. We want to understand if it is really possible to achieve this color or is it a limitation of the board selected?
2. This information will help us to choose this controller for our further development or choose other products to achieve this. 

Looking forward for your response as soon as possible. Thank you so much.

Changed config: 

[PushparajAdka]

Looking forward for some response please.

[JohanAstrup]

Hello @PushparajAdka.

To ensure I fully understand, is your issue that the color displayed does not match the color you configured in TouchGFX Designer, or are you encountering problems during the conversion of your board setup from RGB565 to RGB888?

If it is the former, the display on the STM32H750B-DK unfortunately has quite poor color representation, so it is likely that this is the root cause of the issue. If you have access to other boards, you might want to try running the same GUI on models such as the STM32U5G9J-DK2, STM32H7S78-DK, or STM32N6570-DK, which feature displays with superior color representation.

If it is the latter, there should be no issues running RGB888 on the STM32H750B-DK. Could you please provide more details about the process you followed and the specific issues you are experiencing?

Best regards,
Johan

[PushparajAdka]

Hey Johan,

    Thanks for your response. Yes we are facing issue with the color representation.

In the above image I want color #22613C to be displayed in the display. But even after successful configuration of RGB888, still there is no change the color. I do not see the same color on the display. 

If it is the limitation then we can check with the displays that you have mentioned. If it is possible for you to show how #22613C looks in one of the displays you mentioned then we would like to order and go ahead with those displays.

Thanks

[JohanAstrup]

It is difficult to capture accurately in an image, but I have tried to compare the STM32H750B-DK with the STM32U5G9J-DK2 in the image below.

The color on the STM32U5G9J-DK2 doesn’t exactly match the color displayed on my computer monitor either (it appears slightly darker on my monitor). However, I cannot determine which one is more accurate.
Note: To my eye, the green on the STM32U5G9J-DK2 board appears a bit darker than it does in the image.

Best regards,
Johan

[PushparajAdka]

Thanks Johan, 

    This is actually going to help us. There are certain information and doubts about this display , which is my team discussing and we are not able to get some clarity.

1. Doubt : "We certainly need to investigate applying gamma correction or a LUT first. In photo/video applying a LUT can have a massive impact on color". Is this true? How is this done in our controller?

2. I am using argb888 for my ltdc display, the image which I get in board is approximately enhanced by rx4, bx2, gx4. so in order to get the desired image for one color i divided rgb by 4,2,4 respectively. Is it possible to achieve for all colors using L8 CLUT's, If yes please let know how.

Please help us in getting the clarity here. So we can go ahead decide the higher end display if required.