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TFP401A: HDMI to LVDS converter module based on TFP401A and SN75LVDS83B parts not working with Android

Part Number: TFP401A
Other Parts Discussed in Thread: SN75LVDS83B, , TFP401

Hi, our company is on process of developing a new product and we are using an HDMI to LVDS converter module based on TFP401A and SN75LVDS83B parts, for development we are using the Orange Pi Plus 2 with Android 4.4 (Linux kernel 3.4), for the video output we use the HDMI from the Orange Pi Plus 2 + the HDMI to LVDS module (mentioned above) + LG Display LCD Panel with LVDS input (15.6'' Size), the LCD Panel only supports a 1366x768@60Hz resolution and 70MHz of FCLK.

The configurations that we have made so far haven't made any change on the LCD video output, if we test the converter module with another OS (Ubuntu or Windows) it works (those tests have been made using the HDMI output from PC laptops and with an Orange Pi Plus 2E).

We would like to ask for some help because we don't know what else to modify on Android to make the HDMI to LVDS work, is there any specific configuration under Android to get some compatibility with the converter? we add some of the tests we have made:

1. Modify the HDMI resolution on the sys_config.fex file on lichee.

2. Modify the video timings on the following files of the kernel:

  • video/sunxi/disp2/hdmi/aw/hdmi_bsp_sun8iw7.c 
  • drivers/video/sunxi/disp2/hdmi/aw/hdmi_core.c      
  • drivers/video/sunxi/disp2/hdmi/aw/hdmi_edid.c      
  • drivers/video/sunxi/disp2/hdmi/drv_hdmi.c          
  • drivers/video/sunxi/disp2/hdmi/hdmi_hal.h          
  • include/video/sunxi_display2.h      

The modifications on those files were based on the following values:


{HDMI1360_768P, 0, 70000000, 0, 1360, 768, 1492, 42, 36, 48, 782, 6, 3, 5, 1, 1, 0, 0, 0},};

{HDMI1366_768P, 0, 70000000, 0, 1366, 768, 1492, 42, 36, 48, 782, 6, 3, 5, 1, 1, 0, 0, 0},};

 

3. The HDMI to LVDS converter is configured with a 1366x768 .bin edid file and it is working when is connected on the HDMI PC laptop port.

 

The main issue is under Android, we also tested the HDMI to LVDS converter with a Radxa Rock Pro board and it didn't work.

 

Please help.

 

Thanks.

 

Best Regards.

  • Hello,
    1. Can you connect your Orange Pi directly to a video sink with a HDMI cable? Does it work?
    The TFP401 is only a de-serializar, it will just decode any signal at its inputs whether it is valid video or just junk data.
    The TFP401 is not involved on the EDID exchange neither, there may be a negotiation problem between your video sink and the HDMI source, if the Source (your Orange Pi) can't meet the requirements of your sink then it won't send any video, can you take some scope captures of the HDMI differential signals?
    Have you tried with multiple resolutions?
    Does the HDMI contain embedded audio?

    Regards