NHD-2.4-240320CF-BSXV-F Flickering/white screen

toasty gear

Hey,

I'm using the NHD-2.4-240320CF-BSXV-F with an ESP32s3 communicating over 4 wire SPI

I had some success displaying things on the screen using SPI libraries which support the 7789 driver(Adafruit_ST7789.h and TFT_eSPI.h).

I'm able to display minimal elements such as a single line of text. The problem arises with any bigger operation, like trying to set background color or displaying an image, the display starts to flicker and eventually turns blank, same behavior with both of the mentioned libraries.

Schematic:

PCB section with ribbon cable screen connection

SPI traces are relatively short, so signal integrity shouldn't be a problem. I have tried different speeds for SPI 10-27MHz.

My questions are:

  • Could you verify the electrical connections for any obvious mistakes?
  • What could this behavior of briefly working and then fading out suggest ?
  • Is there any initial "flashing" of the ST7789VI necessary?  (I'm not able to run the Arduino example code on my ESP32)
  • Is it fine to have VDDIO permanently tied to 3.3V and the IM0 = 0V and IM1 = 3.3V ?

 

The display has a great quality so we would love to figure this out and use it in our product !

Thank you for any insight.

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Comments

3 comments

Date Votes
  • Engineering Support
    Community moderator

    Hello,

    I have verified the electrical connections and they are connected correctly. The connection VDDIO = 3.3V, IM0 = 0V and IM1 = 3.3V are correct as well to achieve 4 wire SPI communication.

    I have performed a test with your setup using the example in Adafruit_ST7789.h library and I do not see any fading or flickering in the display.

    I would suggest you to check for power issues. You can also swap the display if you have another to see if the display itself is causing the issue.

    Here's the example that I have used - https://github.com/adafruit/Adafruit-ST7735-Library/blob/master/examples/graphicstest_st7789/graphicstest_st7789.ino

    We recommend you to try the above suggestions and let us know if it helps.

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  • toasty gear

    Hello,

    Thank you for your response!

    For power we are using a TLV758P which can output up to 500m-A. The screens datasheets suggests a typical consumption of 110m-A and the esp32 of 200, so it should be fine in terms of power.

    I ran the same example code of the graphicstest_st7789.ino you can see the result in this video. When freshly turned on the display has the most crisp image which quickly fades away over a couple of seconds, and there are the other glitches which you can see in the video.

    I'll order another sample of the screen to check if maybe that unit is faulty.

     

     

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  • Engineering Support
    Community moderator

    Hi,


    While you wait for a new display, I recommend running our sample code using an Arduino, if you have one, to help narrow down the root cause. I will also suggest checking that the display connection is securely fastened.

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