New WS2813b

I think how they work is each Pixel compares the DI data stream with the BI data stream (with the leading 24 bits stropped from BI since they would be "consumed" by the preceeding Pixel) and, if they differ, it assumes the preceeding pixel is wonked and switches to looking at the BI data stream (ignoring the DI stream until power reset).


Also, I think a string (based on above) should be able to handle multiple pixel failures (assuming BI is propagated).


Dennis
 
dennismc said:
I think how they work is each Pixel compares the DI data stream with the BI data stream (with the leading 24 bits stropped from BI since they would be "consumed" by the preceeding Pixel) and, if they differ, it assumes the preceeding pixel is wonked and switches to looking at the BI data stream (ignoring the DI stream until power reset).


Also, I think a string (based on above) should be able to handle multiple pixel failures (assuming BI is propagated).


Dennis
Click to expand...

This is basically what the spec sheet says, but then I would speculate it should still work with just one signal because if it only saw the one signal then that should be considered a failure and the chip should switch if connected to the BI and should just run normal if connected to the DI. The chip shouldn't know if its data is coming from a controller or a previous pixel, it should behave the same. That is my taking of how it should work but then I may be completely wrong
 
Well just finished a heap of testing and the results are well odd lol.


WS2813 strip plugged into control board with DI data wire connected no lights running test pattern.
WS2813 strip plugged into control board with BI Data wire connected no lights running test pattern.
WS2813 strip plugged into control board with both DI and BI data wire connected no lights running test pattern.


I then tried this.


WS2813 strip plugged into control board with DI data wire connected.


Connected data wire from a string of WS2811 bullet nodes to the very end of the WS2813 strip light DO Data wire strip light not lit up WS2811 string running test pattern.
Connected data wire from a string of WS2811 bullet nodes to the very end of the WS2813 strip light BO Data wire strip light not lit up WS2811 string running test pattern.


So data is getting through the strip light and coming out the other end fine on both Data wire and Backup wire with only the data wire connected to the control board.


Next test was suggested by i13.


WS2811 string connected to control board, Connected DI data wire from WS2813 strip to the end of the WS2811 string and finally we have test pattern showing up on the WS2813 strip.


Conclusion.


Sandevice E682 is not sending out the correct data for the WS2813 strip to work correctly, having a WS2811 pixel before the strip means that the WS2811 is getting the data and fixing up the formatting before sending it out which then enables the WS2813 to work correctly.


Will email Jim to see if he can do something about a firmware update to correct this.


Thanks all for your suggestions, now I might have to put a "null" pixel in line before all of my strips just for this year.
 
What R-packs do you have in your 682s? I had the stock R-packs (270 ohms I think) and it wouldn't work with mine, had to swap them out for 33 ohm ones, which work fine.


Dennis the Menace
 
I have the standard ones that were shipped with the e682.


I have an e682 for my mega tree which is all WS2811 12v bullet nodes and that works fine with the standard r-packs, this e682 is my backup that I bought at the same time which is now being purposed for my sleigh.


I have emailed Jim for his advice, however I could try swapping the R-Pack to 33 ohm and see if that works. Thanks for the tip.
 
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