You are not showing what your PSUs look like. If you have proper PSU with enough A to power your strip and ESP connect that, not 4.6V but full 5V or even 5.1V.
Then use recommended level shifter and if LEDs still flicker disconnect all peripherals from the board and use only ESP, level shifter and LEDs. If it still flickers it may be faulty ESP or faulty LED strip. There are plenty of both.
dear @blazoncek thanks for your reply.
Ill try to answer as well as I can to all your questions:
I have 2 PCB with 2 different PSU:
DevKit is connected to my USB 3.0 PC port
custom PCB has a 4,6V 5A DC/DC converter
Yes, I’m sure that both of ther can power up 3 WS2813 LEDs.
When I power up all the 45 LEDs, the works well, except the first that is flickering.
The issue is the same with 5,0V supply and 4,6V supply. Both board have ESP32 powered at 3,3V.
WS2813 works from 3,7V to 5,5V so a 4,6V level for power supply is not critical (and also there is the same issue with 5,0V supply from USB)
SN74LVC2T45 level shifter is one suggested by WLED faq (and also its signal is clear, by the way I checked it with my scope, its a clear plot).
already done: with 3 LEDs both works, with 45 LEDs the first LED is flickering
I think that it’s rare that 2 different ESP32 could be broken in the same way.
About the LED strip: 3 and 45 came from the same reel. I cutted the 45 removing the 1st LED, now it has 44 and has the same behaviour.
Thanks in advance for your reply, I hope to find the solution!
I also attach a picture of my power supply: from 4,6V up to 5,1V same issue
If LEDs after the first display ok then it is not a WLED issue but the LED strip issue.
If the whole strip flashes (or parts of it) then the cause is in ESP and/or WLED.
Fist LED on WS2813 &WS2815 can (and will) use BI as an input if it decides that DI is not good. It is entirely up to LED IC to do that. What will it display then I do not know.
If you want to check the output of ESP & your board, connect WS2812 strip (which uses a single wire for data but the same protocol as WS2813) and if the flickering on the 1st LED is gone then you have located where the error occurs - WS2813 LED strip.
Try NOT using a PC as the USB PS, perhaps a separate 2A USB charger.
Or a separate set of wires to regulated supply at 5V
You want at least a clean 1A 5v supply for the MCU, the shifter won’t load that by any appreciable amount
In general I would power the level shifter with the same power as the MCU.
You might even take the shifter out for now.
Keep the number of variables down to the minimum.
Dear @blazoncek your are right: I’m frustrated and I’m sorry for that. It’s been 3 weeks of testing and still not working .
I would like to cooperate because I think that WLED is far away better than SP107E and I would like to use it.
At this point I don’t know what other tests I can do ti find the issue. Please could you suggest me some test that I haven’t already do?
Thanks in advance for support