• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 99 subscribers
  • Views 533 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Question about LCD Display

Yang Luo
Prodigy 230 points


Dear all,

I'm running 6.15.00 WINCE BSP on my custom board. The board was working fine with a 7 inch LCD.

Currently I'm working to make the board work with a 3 inch 240x400 LCD panel. The LCD panel supports both MCU and RGB  interface. And it needs to be initialized from SPI port before being used.  With help from the FAE I'm now able to make it display correctly in EBOOT, as shown in below display_in_eboot.jpg.

However display in NK is incorrect as shown in display_in_nk.jpg.

I verified the LCD panel is not initialized again after booting into the NK( LCD power /reset/SPI show no activity during NK startup). I did clean sysgen and everything is the same.

Do you have any clew about the issue?

 

Thanks

Luo Yang

 

  • 0
    Prodigy 100 points

    Hi， Luo Yang

    You had better reinitialize the LCD Panel throught SPI to make it work well.

     

  • 0 in reply to David Shen69377
    Prodigy 230 points

    Thanks David,

    I noticed there's some change in the BSP display code between 6.09 & 6.15. I did include the LCD SPI initialization into the driver code but it's not called during NK loading.

     

    Regards

    Luo Yang

  • 0 in reply to Yang Luo
    Prodigy 230 points

    I also doubt since the LCD panel is already initialized in EBOOT, and it's not powered off , reset  during NK load. I don't see the reason to initialize it again. But anyway I tried to reinitialize it again. I put the LCD re-initialization in the keypad driver so that I can push a button to trigger the LCD to re-init. However the LCD display becomes blank after I re-initialize it. It seems that I can't do a proper init while the interface is in use.

    I'm now trying to port the display code of BSP 6.09 back to do a LCD re-init in the LCD driver initialization, see if it works.

    Regards

    Luo Yang

  • 0 in reply to Yang Luo
    Prodigy 230 points

    I've solved the problem by chance. I put my solution here for your reference.

    I was trying to tap the signals with Oscilloscope probe. When it comes to the vsync, the LCD panel suddenly start showing correct WINCE desktop. I then tested ground vsync with resistor, or make the vsync wire shorter(the LCD panel is connected to board through wires), but none of them work. 

    Finallly I series a small resistor to the vsync signal and now it works well.

    I believe the vsync signal level is too high(5v peak-to-peak), which causes the LCD ic to reject the signal. Adding a resistor reduces the signal level. But I still don't understand why the signal is accepted by LCD in EBOOT, but got rejected in NK.

     

    Regards

    Luo Yang