RMT based NeoPixels (WS2812B) flickers when WiFi is used

Posts: 4
Joined: Sun Feb 03, 2019 6:47 am

Re: RMT based NeoPixels (WS2812B) flickers when WiFi is used

Postby Andreas_Mainz » Mon Dec 23, 2019 9:25 pm


my experience is following:

1.) level shifter is NOT needed
2.) If i use Esp8266 every thing works fine
3.) If i use Esp32 flickering starts -> Timing issue
4.) It does not depend on Wifi and BT off -> still flickering
5.) Most important ist the strip.show() function, i removed it from the code and moved it in a timer interrupt routine

Code: Select all

  timer = timerBegin(0, 80, true);
  /* Attach onTimer function to our timer */
   timerAttachInterrupt(timer, &ISR_Task_10ms, true);
   timerAlarmWrite(timer, [b]9000[/b], true); // alle 10 ms
and in the timer interrupt:

Code: Select all

void IRAM_ATTR ISR_Task_10ms()
  strip.show(); // Initialize all pixels to 'off'
So flickering is nearly but not completly disappered. The timerinterval is critical, if it still flickers change "9000" value to different
values. See attached the logic analyser tape.
ws2812_esp32.JPG (45.52 KiB) Viewed 535 times

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