Blinking Rainbow LED - What Does It Mean?

Official Hardware Nano Family Nano ESP32
1

So far I am not having much luck in getting my ILI9488 TFT to work with Nano ESP32.

Each time I compile and upload example display programs, Nano would go into a strange state, where the LED blinks slowly from Blue->Red->Green and the Comm Port (USB) becomes unresponsive and remains so even after power cycle by disconnecting the USB cable.

I have tried TFT_eSPI library, compiled and uploaded "Read_User_Setup.ino" example program. I also tried Adafruit_GFX library, ILI9488 Arduino Library, and "GraphicsTest.ino" sample program . Both combinations complied successful but go into the same unknown state after uploading. I am certain that the wirings are correctly assigned, both on software and hardware.

The only way way to get out of this state is by pressing the reset button quickly a few times, then the LED changes to slow blinking blue light. This seems to be one of the ways to unfreeze the Comm port. The other way is to short circuit the GND and B1 pins.

Question -
What does it mean and what triggers the board going into slow blinking rainbow light?

If ILI9488 won't work, my second option is to switch to L2C LCD display. Hopefully, I wouldn't have to that far.

Thank you for reading this.

RainBowNANO
RainBowNANO1920×1080 118 KB

2

The ILI9488 display libraries can be memory-intensive, particularly with large graphics libraries and complex screen updates. The ESP32 might be crashing if it's running out of memory or hitting a stack overflow.

4

Does the standard arduino Blink sketch upload and work?

5

Hi, @gchliu
Welcome to the forum.

Are the libraries compatible with ESP32 controller?

Have you Googled;

ILI9488 TFT Nano ESP32

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

6

Hello @aliarifat794, I think I have some suggestions for you - please try them and let me know if the situation improves:

  • Make sure you are using the Arduino ESP32 Boards package, not the "esp32" package, and update to the latest version.
  • Update the bootloader on the board by following this guide.
  • Make sure the Pin mapping is set to By GPIO Number by following this guide.

As a last resort, if you have a 3V3 USB-to-TTL serial cable you can attach it to the board's TX/RX pins and check the output there for some clues...

8

Thank you for the suggestion. I have already tried the example blinking program that came with the Arduino IDE. It worked fine as it should be without freezing the comm port and does not light up rainbow LED. The problem seems to be the TFT libraries that Nano ESP32 do not like. I have already tried 3 library packages - TFT_eSPI, TB_TFT_sSPI, and Adafruit. All compiled nicely but soon after uploading, they all froze the Comm port and turned on the rainbow led light.

9

Iburelli,

Thank for the suggestions. Unfortunately, it did not work. The COMM port becomes unresponsive and LED lights up with rainbow colours. Yes, I have assigned the wires correctly as per Nano's definitions, i.e. CIPO(MISO), COPI(MOSI) and SCK GPIO numbers (47, 38 and 48 respectively).

To eliminate the possible ILI9488 hardware conflict, I have completely disconnected it from the Nano ESP32 board and switched back on forth between the default(PIN) and legacy (GPIO) modes in IDE. All caused the COMM port unresponsive and turns on rainbow LED light, after uploading.

Not sure what to do next. I can change my game plan of either getting a knockoff ESP32 board or change the display.

The TFT_eSPI library by Bodmer appears to be the most common library for TFT integration. I am puzzled that I have so much trouble with this Nano ESP32 board.

George

10

Hi Tom,
According google search, no one seems to have good experience with the ESP32+ILI9488 combination. This includes myself.

George

11

I have assigned the wires correctly as per Nano's definitions, i.e. CIPO(MISO), COPI(MOSI) and SCK GPIO numbers (47, 38 and 48 respectively).

Please read the guides I linked to carefully.

  • ALWAYS use pin labels in your sketch (write D12, not 47!) with the Nano ESP32.
  • Also, ALWAYS set By GPIO Number since you use libraries.

Do not try other combinations as they will just result in more confusing situations.

Can you please post:

  • the sketch :slight_smile: or even better a minimal version that still crashes
  • the board package you are currently using and its version
  • the IDE log of a bootloader upgrade procedure

Thanks!

12

Iburelli,
Thanks for responding. The difficulties that I am having with Nano ESP32 board is finding a compatible library for ILI9488. So far, I have tried a handful of libraries and just couldn't upload any of the example sketchs each package comes with. The led to unresponsive state, eg. blinking rainbow LED.

If you like to experiment with TFT_eSPI library. It comes with an example sketch "TFT_eSPI\examples\Test and diagnostics\Read_User_Setup.ino" I am assuming you have access to a Nano ESP32 board. I would be interested to know if you were able to successfuly upload. You don't need an ILI9488 screen for this experiment.

FYI - as an experiment of my own, I was able to compile and upload the same example sketch to my UNO Wifi R2 board. There's definitely something that Nano ESP32 do not like with various TFT libraries.

Yes, it is confusing working with ESP32 GPIO and Arduino pin naming systems. Further confusing the situation, Nano ESP32 renamed MOSI and MISO to COPI and CIPO, respectively.

Thanks again for your time.

13

I am in the exact same situation.

Any sketch upload related with the TFT_eSPI, makes the Nano ESP32 go into the rgb led color circling mode, and the board dissapears from the board selector.
A double tap in the reset button allows to upload another functional sketch, and everything returns.

Nobody has had success with an ili9488 with an Arduino Nano ESP32?

Anybody knows where the problem can be? I suspect is something related about the VSPI and HSPI declarations.

14

Hi @dreamgame.

I believe all these reports are related:

If so, this is probably caused by a bug in either the "TFT_eSPI" library or version >2.0.14 of the "Arduino ESP32 Boards" / "esp32" boards platform: