Trouble with HDMI Settings on NHD-7.0-HDMI-N-RSXN-CTU with Odroid

jon_makes_cars

Hi there,

I'm working on a car infotainment system based on an Odroid N2 and the NHD-7.0-HDMI-N-RSXN-CTU TFT display. Unfortunately the Odroid hdmi configuration is slightly different from the usual linux boot.ini and only natively supports a specific list of video settings, none of which seem to be compatible with this display. I've tested the display with a Raspberry Pi (android and raspian), and confirmed that it's working properly. Odroid provides the ability to directly set the details of the display in it's configuration files, but I'm not having any luck with this either:
https://wiki.odroid.com/odroid-c2/application_note/hdmi_autosetting

So what I'm trying to figure out, is how to give the Odroid the information it needs to display on your screen. I've looked at the data sheet, and tried using "xrandr --verbose" in Raspian to get the screen's information, but I can't seem to come up with a configuration that works. My concrete questions I guess are the following:

What are the start and end positions for the Sync area?
What is progress mode / which value should be used?
What are the polarities in Horizontal and Vertical directions?

The outputs from xrandr just say 800x480, without any information on the sync start / end and total pixels, and also doesn't provide information on the clock frequencies. All values other than the horizontal and vertical sizes are listed as zero.

I've tried calculating the sync start / end and total sizes based on the data sheet, with the back-porch either starting or ending with the sync area, both polarities, progress mode 0 and 1, and even setting everything except the H & V sizes to zero as per the xrandr result. I always get either a completely black screen or white with some black and colored vertical lines (always vertical, never horizontal).

It's late am I'm tired, but I'll list the values I've tried so far in my next post. Any help here would be very appreciated.

-Jon

0

Comments

3 comments

Date Votes
  • Sergio_M

    Hello Jon,

    Thank you for your interest in Newhaven Display!

    Please view the attached EDID Timing table, it should have what you are looking for in regard to the  start and end positions for the Sync area.
    You can also find this information in the module's user guide on page 9: https://www.newhavendisplay.com/userguides/NHD-7.0-HDMI-N_User_Guide.pdf

    The Horizontal and Vertical sync have a negative polarity.
    Please refer to the display driver datasheet on page 21.
    https://www.newhavendisplay.com/resources_dataFiles/datasheets/LCDs/HX8264-D02.pdf

    We are looking into the  module's progress mode and will have an answer for you as soon as possible.

    Thank you.

    0
  • jon_makes_cars

    Hi Sergio,

    The EDID table and datasheet are what I had been using, but somehow I can't figure out the correct values to make the screen run.

    The Odroid is looking for HDMI information in the following format:

    setenv modeline "horpixels, verpixels, pixel_clock, hor_freq, ver_freq, hdisp, hsyncstart, hsyncend, htotal, vdisp, vsyncstart, vsyncend, vtotal, hsync_polarity, vsync_polarity, progress_mode"

    As such, I entered the information for your display as follows (updated):

    Variable Values (1st try) Values (2nd try) Values (3rd try)
    horpixels: 800 800 800
    verpixels: 480 480 480
    pixel_clock (KHz): 32000 32000 32000
    hor_freq (Hz): 34480 34480 34480
    ver_freq (Hz): 65.68 65.68 65.68
    hdisp: 800 800 800
    hsyncstart: 840 (display 800 + front porch 40) 841 (display 800 + front porch 40 + 1st sync pixel) 840 (display 800 + front porch 40 + 1st sync pixel - 1 zero based index)
    hsyncend: 888 (sync start 840 + sync width 48) 888 (sync start 841 + sync width 48 - 1st pixel) 887 (sync start 840 + sync width 48 - 1st pixel)
    htotal: 928 (display 800 + blank 128) 928 928
    vdisp: 480 480 480
    vsyncstart: 493 (display 480 + front porch 13) 494 (display 480 + front porch 13 - 1st pixel) 493 (display 480 + front porch 13 - 1st pixel - zero based index)
    vsyncend: 496 (sync start 493 + sync width 3) 496 (sync start 494 + sync width 3 - 1st pixel) 495 (sync start 493 + sync width 3 - 1st pixel)
    vtotal: 525 (display 480 + blank 45) 525 525
    hsync_polarity: 0 (negative) 0 0
    vsync_polarity: 0 (negative) 0 0
    progress_mode: 0 (off) 0 (off) 0 (off)


    This didn't work, and I got a mostly white screen with some horizontal lines and flickering.

    Just for reference, I have tested the Odroid with another monitor and the Newhaven display with a raspberry pi to check that it's not a problem with the hardware. In both cases, everything was fine. It's only the combination of Newhaven display with the Odroid that seems to be a problem (both with the Odroid Linux distro and Android).

    0
  • Sergio_M

    Hello Jon,

    Have you tried what is suggested in this ODROID Wiki post?

    https://wiki.odroid.com/odroid-xu4/application_note/software/hdmi_custom_edid

    Here are the RGB timings we use for the EVE2 that may be be useful.

     /* Values specific to QVGA LCD display
    */ FT_DispWidth = 800;
        FT_DispHeight = 480;
        FT_DispHCycle =  928;
        FT_DispHOffset = 88;
        FT_DispHSync0 = 0;
        FT_DispHSync1 = 48;
        FT_DispVCycle = 525;
        FT_DispVOffset = 32;
        FT_DispVSync0 = 0;
        FT_DispVSync1 = 3;
        FT_DispPCLK = 2;
        FT_DispSwizzle = 0;
        FT_DispPCLKPol = 1;
        FT_DispCSpread = 0;
        FT_DispDither = 1;

    0

Please sign in to leave a comment.

Didn't find what you were looking for?

New post