A compatible LCD connector for general 40PIN LCD with PicoUltra or PicoUltraW

• PhoenixOwner

  Posts: 1

  Joined: 2024-09-26 14:59

  2024-09-26 16:31

  Due to I have a general 40PIN LCD panel, and I check the LCD pin interface of PicoUltra. I found that PicoUltra is RGB666, but general 40PIN LCD is rgb888. It cannot be completely compatible to PicoUltra. However, the lower 2-bit color signal could connect to GND as default value. This makes it possible to design an adapter to a user defined LCD.
  Expect hardware design, software is also important to meet new LCD. Through the checking of device-tree, 'display-timing' is defined in `sysdrv/source/kernel/arch/arm/boot/dts/rv1106-luckfox-pico-ultra-ipc.dtsi`. The directly method is to change display-timing in 'dts' file. But official SDK has the function of `luckfox-config`, user could set custom display-timing in cmd with the technology of `dynamic device tree`. This is pretty good to me for changing display-timing friendly.
  Just for funny, I make a PCB to change PicoUltra LCD connector to general 40PIN LCD, and the result shows that it works well.
  The following pictures show my test result:

  

  

  

  

  and the reference display-timing in `device-tree` is following:
  display-timings {
  native-mode = <&timing0>;
  
  timing0: timing0 {
  clock-frequency = <31000000>;
  hactive = <800>;
  vactive = <400>;
  hback-porch = <88>;
  hfront-porch = <40>;
  vback-porch = <32>;
  vfront-porch = <13>;
  hsync-len = <48>;
  vsync-len = <3>;
  hsync-active = <1>;
  vsync-active = <1>;
  de-active = <0>;
  pixelclk-active = <1>;
  };
  };
  
  I suggest changing display-timing through `luckfox-config` cmd rather than `device-tree` modification.
  
  TODO: Open source PCB.

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