Setting LVDS Display mode with WinIot

[aditya_h]

I am tying to connect 800x600 display to imx93 with WinIoT using LVDS mode.

Below Display Timing parameter is used 

/* 800x600@60 */
CONST IMX_DISPLAY_TIMING PreferredTiming_800x600_60 = {
.PixelClock = 40000000,
.HActive = 800,
.HBlank = 256,
.VActive = 600,
.VBlank = 28,
.HSync = 128,
.VSync = 4,
.HSyncOffset = 40,
.VSyncOffset = 1,
.HImageSize = 527,
.VImageSize = 296,
.HBorder = 0,
.VBorder = 0,
.EdidFlags = 0,
.Flags = 0,
.PixelRepetition = 0,
.Bpp = 24,
.PixelFormat = PIXEL_FORMAT_ARGB32,
};

The display is up but there are green patches on some areas with color gradient as shown in below image.

What could be the possible reason, And what should be the timing parameters value.

[michal_hromadka]

Hello @aditya_h ,

These parameters are set to some default values, but should be set according to the display datasheet. Do you have the datasheet of the display?

Regards,

Michal

[aditya_h]

Hi @michal_hromadka , Attaching the Display datasheet

[aditya_h]

@michal_hromadka Any inputs based on these data from the datasheet?

[michal_hromadka]

Hello @aditya_h ,

we are trying to reproduce this problem. What version of BSP are you using? 1.4.0?

Regards,

Michal

[aditya_h]

@michal_hromadka  Yes we are using 1.4.0.

And please note display we are using is RGB display(as referred in the datasheet), Does EVK93 support this? (We could see only ARGB/BGRA formats supported in EVK93).

If it is not supported what is the workaround? 

[michal_hromadka]

Hello @aditya_h ,

Your LCD panel does not seem to be compatible with the  LVDS Display Bridge. The panel supports RGB data via 3 of the 4 LVDS lines instead of the 4 lines supported by the i.MX93.

EDIT: The LCD is compatible if you omit the data3/RxIn3 line and switch the i.MX93 to JEIDA mode which maps the LSB RGB bits to this line (see below).

LCD panel input:

 i.MX93 LVDS output:

Regards,

Michal

 

[michal_hromadka]

Hello @aditya_h ,

We were able to simulate the color issue by switching the display to 6-bit mode. After switching from the default SPWD data mode to JEIDA, the colors were fixed.
Please try to make the changes in the file as shown below:

File: <BSP>\mu_platform_nxp\Silicon\ARM\NXP\iMX8Pkg\Library\iMX8LcdHwLib\iMX9xLvds.c

Please let us know if this changes helped you.

@Naveen_V_M, We have been able to fixed the issue by changes above.

Best regards,

Michal

 

Best re

[Naveen_V_M]

Hello @michal_hromadka ,

Thanks a lot, this fix works.

Your quick help is much appreciated.

regards

Naveen

[Naveen_V_M]

Hello @michal_hromadka ,

Is there a Driver or Hardware workaround to make the i.MX93 EVK compatible with the 3 line displays?

[michal_hromadka]

Hello @Naveen_V_M ,

I am currently discussing this with the developers to see if this is possible.

Regards,

Michal

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