NEOPIXELS ESP8266-01 GPIO2 first one flashes blue

All ESP8266 boards running MicroPython.
Official boards are the Adafruit Huzzah and Feather boards.
Target audience: MicroPython users with an ESP8266 board.
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mflmartin
Posts: 43
Joined: Sat Jul 23, 2016 7:30 pm

NEOPIXELS ESP8266-01 GPIO2 first one flashes blue

Post by mflmartin » Fri Apr 02, 2021 5:12 pm

Hi!

So I am playing with neopixels, and they are the regular RGB ones (no need for bpp=4), and they appear to work ok. Nevertheless, everytime I reset the module, the first one flashes blue. I connected the array of leds to GPIO2 for the input signal.

After that, if I change the colors or turn all of them off, it is ok. But I don't like that behaviour. If I don't do anything, no code at all, the first one stays light blue as well. So it has nothing to do with the code itself.

I don't know if this is because of GPIO2 is connected to something else, internally... or it is because of another reason.

Neopixels are powered by 5V, and Esp8266 with 3.3V, as I read that the input line of neopixels is 3.3V tolerant.

Also, as a side note, there is flickering sometimes. I looked for information in the forum but I didn't find anything conclusive. Is there a way to use esp8266 and avoid flickering? Or it is not possible at all?
Nevertheless, I doubt that is the issue, because once the color is set, If I disconnect the Input line for the neopixels, they flicker as well slightly from time tome, and by that time, they are just connected to 5V and Ground, and that's it. So this can't be a timing issue with the esp8266, right?

Thanks!

ammonyte
Posts: 1
Joined: Sat Apr 03, 2021 3:35 am

Re: NEOPIXELS ESP8266-01 GPIO2 first one flashes blue

Post by ammonyte » Sat Apr 03, 2021 3:49 am

everytime I reset the module, the first one flashes blue.
I connected the array of leds to GPIO2 for the input signal.
Based on these two lines, the first issue of the lights being powered on startup seems to be caused by the GPIO2 pin being pulled high at boot. If you have tried to pull it low, you may have noticed that it fails to boot.

Here's an incredible resource for many things related to the ESP8266: https://randomnerdtutorials.com/esp8266 ... nce-gpios/
If you scroll down a little, you will find a nice table with information about the module's pinout.


I can't speak much about the issue you are having with your flickering, but I did find a link that seems similar to the project you may be working on: https://randomnerdtutorials.com/esp32-e ... eb-server/.f

Hopefully, that helps you debug a little easier. Good luck!

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