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AM62P: TTL-RGB8888 LCD Interfacing

Jack
Mastermind 9145 points
Part Number: AM62P

Tool/software:

Hello AM62P Champ !

My customer is trying to interface the AM62P with their RGB8888 LCD module. They have built the latest version of the Android SDK, completed the custom board booting, and are now at the stage of trying to get the RGB LCD to work. They have disabled the HDMI output and tried using the attached device tree, but the display still isn't working.

k3-am62p5-sk-modify.zip

The default configuration for the SK-AM62P board has HDMI enabled, so it was configured to connect RGB to Port@2. PCLK, LCD Enable, and related power are all being supplied correctly, but the framebuffer is not being recognized. The LCD_PWM and LCD_enable pins have been forced to HIGH, and the LCD clock is outputting a stable 5.12MHz. It seems the framebuffer is not working correctly. What else should I check?

Assuming there are no errors in the DTS, please let me know what settings need to be configured on the Android side.

Regards, 

Jack

  • 0
    Mastermind 9145 points

    Hi.

    When the HDMI is not connected, the following log message appears: [ 10.965921][ T301] DEBUG: signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0000000000000008.

    It seems a fault error occurred.

    Of course, this message doesn't appear when the HDMI is connected.

    Regards, 

    Jack

  • 0 in reply to Jack
    TI__Prodigy 130 points

    Hi Jack,

    Can you confirm the android version, I assume it is android 15 if it is the latest.

    If there are no errors in the DTS, are the drivers present and loaded (Backlight pwm module as well as the panel driver).

    For the hwc crash above, can you confirm which commit (sha1) is currently used for the drm_hwcomposer ? (external/drm_hwcomposer from the root of the android tree).

    Thank you.

  • 0 in reply to Maxime Fournier
    Mastermind 9145 points

    Hi Maxime Fournier.

    Thanks for your reply.

    It's Android 15 based on SDK 10.01.01 (2025. 4. 2)

    Let me check the drivers present anad loading in addition to commit for drm_hwcomposer.

    Thanks.

    Regards, 

    Jack

  • 0 in reply to Jack
    Mastermind 9145 points

    Latest Commit Hash (SHA1) Used git log -1 --pretty=format:"%H"

    Latest commit hash (SHA1) used: 7979d2ae8c8c34d3cf0a5593c9788c5601e642f5

  • 0 in reply to Maxime Fournier
    Mastermind 9145 points

    Hi Maxime,

    Can you please suggest the changes required in DTS and panel-simple.c for RGB888 DPI support?

    I attached their current dts, panel-simple.c in addition to booting log.

    They also have tried to bring up DPI mode by following SPRADS3 AM62P DSS Overview. to convert to DPI mode. it's still failed to turn on RGB LCD.

    Please help us to bring up RGB888 DPI mode.


    0823 log_dts_simple-panel.zip

    Regards, 

    Jack

  • 0 in reply to Jack
    TI__Prodigy 130 points

    OK commit is not the issue. I will look at the logs and get back to you.

  • +1 in reply to Maxime Fournier
    Mastermind 9145 points

    Hi Maxim.

    They said the issue has been fixed as below.

    1. HDMI connection issue: patch applied

    2. In the DTS file: Switch DSS HDMI to DPI mode

    3. In panel-simple.c, add:

    }, {
    .compatible = "himax,hx8282a01",
    .data = &himax_hx8282a01,
    }, {

    Thanks.

    Regards, 

    Jack