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Pixcon16 - Random Flickering when idle


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Has anyone seen random flickering on the pixels attached to the PixCon?


It looks like random pixels flash, when nothing is being sent to the board.


Here is a video...




The board is configured to use E1.31.  When running the Sequence Editor - the same thing happens, when no pixels are being directed to turn on.  The random flashes continue once the Sequence is stopped and the I exit the SE.


My computer is directly connected to a switch, and so is the PixCon.  Nothing else is connected to the switch.  The WiFi is turned off on my PC.


Any ideas?

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An update...


I connected a E681 to my network, configured the universes, etc, modified my sequence to use the E681 instead of the PixCon and it worked.


When nothing was running (sequences, etc) I did NOT observe any random pixels flickering on and off when using the E681.


Not sure what is going on with the Pixcon, but at this point it is not usable.  I was going to buy a few more to use this year, but at this point in time it makes no sense.

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Ok, that is weird.


I have seen random pixels firing because of bad wiring - that is, not getting the screw terminals down properly onto the wire of the pixel string.  But it doesn't look like that.  That looks like spurious data being sent up the line that should not be happening.


Power down the board and move the pixels to another port and see if they exhibit the same issue.    When you move the pixels, move them to another group of 4, like 5-8.


Factory reset the board.  Ensure that it has the 1.4.8 firmware or above loaded (the status lights look like you do, but I want to make sure).


Ensure your power supply is the correct size and voltage for your pixels.  I doubt it is under powered with only 2 strings connected, so double check the voltage.  Bring up the config program for the PixCon16 and look at the Misc tab and ensure the voltage isn't too high/low.


If you are still having issues after that, please open a help desk ticket and we will get you fixed up.  That board should not be doing that.

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Okay - I will factory reset the board.  I did that once already when I was having issues communicating with the board.


The power supply is...



It has plenty of power to run I have connected - and then a lot more.


Not sure if this makes a difference - but when I configured the PixCon - I set max intensity to 85%

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I reset the board and confirmed that the firmware version is 1.4.8.


Following the reset, the Pixels continued to randomly flash so I did some investigation.


First, the Pixels are configured as TM1804 - high speed - even though they are marked as WS2811.  (They do not work when configured as WS2811).


I have the board configured as 48 pixels, TM1804, and 85% intensity.


I connected a logic analyzer to the board and found some interesting info.


The Pixcon is clocking the data at a rate of 666.7K...




1152 bits are clocked out in 1.7255ms... Interesting to note the very long reset time 5.261ms.  Spec says reset can be as short as 65 microseconds.



The flashing of the pixels is actually coming from the data stream sent to the pixels.  I captured one occurrence...



Notice how data changes from sending zeros... to sending one's (from a high pulse (zero) to the longer high pulse (one).

-----Even more important..... at the point the high pulses get longer (turn into 1's), the low period after the last short high pulse is not 1 microsecond... but it then starts outputting 1's.


While this was going on, no network cable was connected to the PixCon.



Compare this to the E681...

The 681 takes 3.2895ms to send the 1152 bits...



It has a 65.5 microsecond reset after each stream.


Data 'Low" periods are a consistent 0.5 microseconds, time between bits varies which is why it takes the E681 longer to send the 1152 bits.



Could what I have seen with the PixCon be a firmware issue?





Edited by wbaker4
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Thanks for the heavy duty analysis!  Yes, that could be a firmware issue, but I am not the hardware/firmware guy so I can't say for certain.  When you were checking the data stream, were you between 2 nodes, or between the PixCon16 and the first node?

Please open a help desk ticket since we want to track this and see if we can find the root cause.  Go ahead and note that you have this out in the forums and everything you have done so far.  You can ask that it be assigned to Mike since I am familiar with this post.

We may want you to send us a string of those pixels that are not working (if you are willing) so that we can duplicate the issue.  I know we have had multiple reports of TM1804s not behaving properly (including the WS2811 issue you have described).

No matter what we will either figure out what is wrong or will be happy to refund your money for the board.

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The probes were right on the connector of the board.  One on port 1 and the other on port 5.  Port 1 had no pixels attached to it, so this issue can be duplicated without any pixels.

Just letting the board sit idle, after it is configured.  Granted it is tough to see when this occurs without any pixels attached!

The random flashing does occur when playing a sequence, during a period when all of the pixels should be off.

I'll open up a ticket.  Thanks!


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Thanks.  With all the recent issues we are seeing with TM1804s we really need to get to the bottom of what the root cause is.  I suspect (like you) that in this case it is going to be board/firmware related -- but it could still be whomever is mfg those 1804s.  

I don't know anything about the protocol that runs on the wire so I need to forward the whole thing over to engineering.

As I hear more, I will update your ticket and keep you in the loop.   Sorry again for the issues!

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Thanks Mike.

I did open up a ticket - and referenced this thread and you.

I am convinced it is not the pixel strings, since it happens on channels that the pixels are not connected to.

Also, when the data line of the pixel string is disconnected, the strings do not flash.

I am willing to test out any new firmware if that helps any.  

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I've seen lite flickering on other controllers and it was due to 12v pixels actually wanting to be run below 12v (not seen as much with older pixels). I adjusted down the little screw on my psu to around 11.75-11.80v and it resolved the problem, esp where I didn't have an extension wire. 

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