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Nextion display issues — Parallax Forums

Nextion display issues

Out of courtesy for @JonnyMac I’ve moved this discussion into a separate thread so I dont plug-up Jon’s teaching efforts.

My original post:
I seem to have bricked my Nextion display. The display came pre-loaded with a neat, interactive "fake factory" demo, but when I tried to load a basic UI (just a "hello world"), the display tried to update its firmware from the SD card, rebooted a couple of times, and now it says "System Data ERROR!". It does respond on the serial channel however, and I've sent it a reset command which it executes... and then it displays the same error. So I'm sorta stuck.

I'd like to copy a known good boot image to the SD and see if this fixes it, but I have no such thing. In an effort to ungork my display, could you post a complete UI in a "ready to run" format? I don't care what it is or how bad it looks... I just need something that I know runs to try to get out of this hole.

ADDIT: it responds just fine to commands over the 9600 baud serial channel. I can draw boxes, circles and clear the screen under P2 control. It just wont load pages from SD.


  • JonnyMacJonnyMac Posts: 7,823
    edited 2021-11-21 17:23

    If you connect the Nextion to a USB-Serial converter you can download a new TFT file. Make a very simple project without graphics to keep things light. That said, I have tried the serial download all the way up to 921600 and it worked. Once you get an app into your display, I would suggest trying another uSD card for loading a project. Make sure the card is empty except for the TFT file.

    When loading from uSD:
    -- power down
    -- install uSD with TFT file (and nothing else)
    -- power up; allow file to load
    -- power down, remove uSD card; power back up

    I'll make a simple TFT for you but I need to know your display type (basic, enhanced, intelligent) and the screen dimensions as that information is compiled into the TFT.

  • Thank you, Jon!. It is the 3.5 inch / “basic” display that you recommended in your “shopping list” for your upcoming workshops.

    I also just ordered a USB->TTL converter as well, as it seems most of the developers are using this method.

    Again, many thanks!

  • JonnyMacJonnyMac Posts: 7,823

    Since I know you have a Prop-Plug, you can use that (the Nextion IO is 3.3V but 5V tolerant). Connect the PP ground to ground of the 5V supply for the display, PP.TX to Nextion.RX, and PP.RX to Nextion.TX (I haven't tested this yet, but am confident it will work).

    I've attached a TFT file with a couple widgets (progress bar and slider) that don't require a font file. In Nextion debug it looks like this.

    I have downloaded it over the serial link and it works on my basic display that is 3.5" with a resolution of 480x320. I had to ZIP the file for forum upload.

  • JonnyMacJonnyMac Posts: 7,823
    edited 2021-11-21 20:08

    I just verified that you can in fact upload to the Nextion with a Prop-Plug.

  • JRoarkJRoark Posts: 936
    edited 2021-11-21 21:20

    @JonnyMac No joy. Erased the SD card, put the .TFT file on it (only thing there, except for the hidden windows system file), and I get:

    Baud: 9600
    SD Card Update ......
    After 2 seconds beginning update

    The above cycles in an endless loop. Various combinations of power-off timing with and w/o card produce the same error:

    System Data ERROR!

    So we'll try the Prop plug.. right after I find it. lol
    THANK YOU for taking the time to generate and post that file for me.

  • SUCCESS! And via SD card no less.
    It seems the Nextion display works fine on 3.3vdc as long as you don't try to access the SD card. This post in the other thread was my undoing, and it's my own danged fault:

    Thierry (Keymaster); 
    "The Basic, Discovery, and Enhanced series use 3.3v logic but are 5V logic tolerant and should work with any MCU without need of level conversion".  

    I took this to mean that the on-board logic of the Nextion display was all 3.3v and would likely be powered by LDO's from a 5v rail. So if you feed it anything from 3.3v to 5v in, it should work. And on the serial channel it did. But the board seems to need 5v for the SD card. As soon as I gave the board 5V at the header, it popped right up and downloaded the TFT file from the SD card and away we went.

  • JonnyMacJonnyMac Posts: 7,823
    edited 2021-11-21 21:23

    There are several warnings sprinkled around the Nextion site about possible damage with low power. I'm glad you got things working.

  • @JonnyMac Oh, now there you go with actual FACTS!

    I never said I was the brightest bulb in the string. :):)

  • JonnyMacJonnyMac Posts: 7,823


  • I got Nextion screen working, resized the keypad in inkscape for the 4.3 screen. I tried to zip my .HMI but when you unzip, it doesn't work on the editor. So here is a picture, Note I used the hotspot button for the number keys, then in the event you have to assign print "7" for the button 7 etc. Then it will show the number on any serial terminal when pressed, like Tera term, putty, phython program etc.

    1200 x 1600 - 400K
    768 x 1024 - 220K
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