topic Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display in i.MX Processors

SOM i.MX 8M Plus and a 1920x720 dual LVDS display

Clean_design — Tue, 03 May 2022 14:38:59 GMT

Hello everyone,

I am planning to use an i.MX 8M Plus SOM to display images on a 1920x720 display with 2 LVDS displays:

My question is do I need to use both of the SOM LVDS interfaces (in split mode) ? if that's the case do I need to use one LVDS port for odd pixels/pins and the other for the even pixels/pins ?

Also any bsp or design example is more than welcome.

Thank you!

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

marcelziswiler — Tue, 17 May 2022 13:43:06 GMT

This looks like a regular dual-channel LVDS display which should be supported. However, a more interesting aspect of such displays is their pixel mapping which should also be mentioned in the Datasheet (BTW: What exact display make/model is it?). That said there are more or less only two possibilities called JEIDA or VESA and both should be supported.

On this topic, I have an additional question: Table 13-33. Pixel Mapper Modes of the i.MX 8M Plus Applications Processor Reference Manual, Rev. 1, 06/2021 mentions both Dual and Split mode but does not further explain anything about it. What exactly are those?

My understanding is, that the i.MX 8M Plus only supports one single LVDS display. Is that a correct assumption or can two (albeit single-channel only) displays be connected concurrently?

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

marcelziswiler — Tue, 17 May 2022 15:27:12 GMT

BTW: Here you may find a dual-channel example albeit using a bridge rather than a display.

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mp-evk-it6263-lvds-dual-channel.dts?h=lf-5.15.y

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mp-evk.dts?h=lf-5.15.y#n675

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

marcelziswiler — Wed, 06 Jul 2022 09:03:45 GMT

Dear NXP, we are still waiting on an answer here. Thanks!

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

eric_lee1 — Fri, 26 Aug 2022 14:20:54 GMT

Hi NXP,

We are also facing the same question on i.mx8mp. It is no problems to support one single channel or one dual-channel lvds display. Could the lvds interface support two single channel lvds display and how?

-Eric

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

joanxie — Wed, 02 Nov 2022 08:19:25 GMT

i.mx8mp can support two single LVDS up to 720p, what issue do you have?

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

eric_lee1 — Wed, 02 Nov 2022 08:56:10 GMT

I don't think it is true. i.MX8M Plus can only supports one single-channel or one dual-channel LVDS interface because there is only one lcdif2 controllers. Unlike i.MX6, there are two IPU controllers that can support two separate LVDS displays. If i.MX8M Plus can support two single separate LVDS displays, how do you make device tree to work?

-Eric

Re: SOM i.MX 8M Plus and a 1920x720 dual LVDS display

joanxie — Mon, 07 Nov 2022 05:50:53 GMT

yes you are right, I was told that imx8mp can support this, but I tested it that imx8mp failed with this, so imx8mp only can support one display with dual channel