Setting up the FullHD LCD Display on Colibri iMX7D (eMMC)


We are using a Colibri IMX7D (eMMC) with a 1920x1080@60Hz FullHD LCD display for my project. The display is connected to the Generic RGB Display connector on my Colibri Eval V3.2B.

Display we are using is G156HAN02302, and the settings are
Frame rate: 60Hz
Clock frequency 70.5Mhz
Horizontal Blanking (hsync+hfront porch+ hback porch) = 92
Vertical Blanking (vsync+vfront porch+ vback porch) =36

We modified the settings according to the datasheet in device-tree @display-Fullhd_overlay.dts and deployed it through torizon-core builder.


&{/panel-dpi} {
        status = "okay";
        width-mm = "344";
        height-mm = "194";
        panel-timing {
                clock-frequency = <141000000>;
                hactive = <1920>;
                vactive = <1080>;
                hback-porch = <102>;
                hfront-porch = <52>;
                vback-porch = <18>;
                vfront-porch = <2>;
                hsync-len = <26>;
                vsync-len = <4>;
                pixelclk-active = <0>;

Here LCD is displaying OK but has some flickering issues and not getting the exact clock frequency and Frame rate.

Please let me know how to set those parameters for Colibri IMX7D 1GB (eMMC).

Csn you see some descrepacy here?

Clock frequency: 70.5Mhz = 141/2 port LVDS
Horizontal Active Display (THD): 960 = 1920/2port

Because of Horizontal Display is in 2port, i think we need to consider 141Mhz in Device tree. Even we tried the clockfrq 70.5Mhz in device tree, but even though we are not getting the exact clock frequency & frame rate in output.
For 141Mhz the output is 88Mhz and for 70.5 Mhz the ouput is 54Mhz.

below is the settings provided in datasheet.

is there any default clock frequency dividing factor in Colibri iMX7d?


Above is the output image we are getting…

Could you try to set

clock-frequency = <75000000>;

We tried the clock frequency @ 75000000, but the output frequency is 55MHz only and the display output is same as above.

We tried on setting up the random clock frequency for checking, but the output is not even approximate to frequency mentioned in overlay.

Is there any settings need to add or modify in device tree overlay.

Unfortunately I can’t see anything wrong with picture you posted. For additional parameters please refer to this documents.


In the picture which i shared, words (“Torizon”, “Login”, “Unable to Login”) and image icons are not clear and covered with while line spaces.


As per the document shared, we modified and added some additional parameters in device tree overlay, but the display didn’t show any output and output clock frequency is 24Mhz. Overlay attached below for reference.

And is it mandatory to set frame buffer configuration for colibri-iMX7d(eMMC).


No, if you don’t need a display.

Could you please clarify -how exactly your display is connected ? Via RGB LCD or LVDS? could you post a picture of your connection and link to the display datasheet?

Our display is connected to the Generic RGB Display connector (X20) on Colibri Eval
Display we are using is G156HAN02302.

Datasheet and display connection attached below
G156HAN02302-specification-12051206.pdf (3.2 MB)
Display_Connection.pdf (666.7 KB)

According to provided display datasheet it’s an LVDS display. Apparently, issue you are observing related to your RGB LCD to LVDS converter implementation (Display Connection). Please contact Hardware Engineer to verify your converter schematic.