DMX2-24 - Interesting Flickering

Skymaster said:
All my testing with the new firmware was successful. Very happy with the outcome. Just got my box installed today, was going to do a "Christmas" final test but then the stupid dog decided to run in there and rip a few of the fairy light cables. Idiot. @AAH out of interest, do you have any malec pigtails, or should I chop up some extensions?


In regards to the DMX2 board, If anyone in Sydney area needs their updated, please drop me a note here and we can make some arrangement. Happy to flash a few boards before sending the programmer back to Alan.
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Hi my dmx2-24 has this bug , any chance to borrow the pickit to fix my one ?
 
Hi. I am likely the user that contacted you by email. I have flashed the new FW, but I am still having this problem. I did notice that my PIC is a PIC16F887. Alan didn't mention this in his previous post so not sure if that would make a difference.

EDIT:
I see the PIC16F887 now. I did program with the "classic" switch in the on position when flashing. MPLAB said it was complete so I assume it worked.
 
Juddge said:
Hi my dmx2-24 has this bug , any chance to borrow the pickit to fix my one ?
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Hi @Juddge, I have returned the PicKit back to @AAH already to allow it to be sent elsewhere as needed. I believe everyone should have received an email by now about next steps.
 
Does this only affect half the channels?

I am only planning to use half of the channels this blinky season, can I put off the firmware upgrade until next year?
 
In my case it was only affecting the even pairs. So 3/4, 7/8, 11/12 etc.
The others were fine so 50% were unaffected
 
Hi Guys. I did some more testing last night. I found that with more light strings connected, the flickering was less pronounced. I had originally tested with only 1 string of 500 LEDs (250 each polarity). Once I connected 6 strings it smoothed out significantly, but still has a bit of flicker - especially when dimming.
 
So , upgraded my board with the new hex file , instantly the flicker is fixed
Thanks Alan , if anyone near the Penrith area needs the file upgraded let me know I have my own pickit for this now
 
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The dimming flicker is different to the fault described above. There is always a low frequency flicker as the H bridge is constantly alternating polarity to control the individual channels.

The fault above is a very obviously switch between channels where it's a misread of the DMX or timing issue I believe.




Juddge said:
So , upgraded my board with the new hex file , instantly the flicker is fixed
Thanks Alan , if anyone near the Penrith area needs the file upgraded let me know I have my own pickit for this now
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@GrantBirrell Have a chat to @Juddge 😁
 
Skymaster said:
The dimming flicker is different to the fault described above. There is always a low frequency flicker as the H bridge is constantly alternating polarity to control the individual channels.

The fault above is a very obviously switch between channels where it's a misread of the DMX or timing issue I believe.





@GrantBirrell Have a chat to @Juddge 😁
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The fault was actually the board restarting due to a stack overflow error caused by subsequent bytes of dmx data coming in while the Pic is sending out the 24 channels worth of data to the pixel IC's that do the dimming. Depending on the start channel, and the number of channels being sent to the DMX2-24 the Pic could get in a loop where it kept trying to send out the data each time a byte occurred. Took ages to work out that this is what was the root cause and in hindsight the many dozens of lines of code that I changed could have been a single one.
 
AAH said:
The fault was actually the board restarting due to a stack overflow error caused by subsequent bytes of dmx data coming in while the Pic is sending out the 24 channels worth of data to the pixel IC's that do the dimming.
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Wow, that's pretty quick recovery then if it was restarting that frequently. I'll hand it to you, that's a horrible bug to chase down.
 
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