Hi! I have a teensy3.5 with 12 Adafruit dotstar 8*8 ledpanels connected, so 768 APA102 leds in total.
Running adafruits dotstar library works without any problems but when I run FastLEDs library, after running above ~450 leds I’m starting to get flickering in the last leds. Here is a video where I’m going through the 528 first leds: https://www.youtube.com/watch?v=Vk0iYPkuwgw
If I go through all 768 almost half of the leds light up in red and flicker a lot.
First I thought it was my wiring but if I flip the pannels the same thing still happens with the last leds and adafruits own library works flawlessly.
Any idea what’s going on?
Tried lowering the data rate yet? DATA_RATE_MHZ(12): https://github.com/FastLED/FastLED/wiki/Basic-usage
The more LEDs you have, or the longer your data & clock wires, the higher chance you’ll run into noise on those lines which will limit the rate you can update them.
The dotstar library might not even be trying to drive them at 24Mhz.
Same result. I forgot to say in my text that I’m running this on a teensy3.5
I ran at 120MHz. If I go down to 48MHz or below it works as intended but the refresh rate is now very slow even if I remove the delay I had in my code before.
Maybe FastLED don’t work at 120MHz
Does FastLED recognize 8 or 6 or 4 MHz? Adafruit’s code probably sends the bits very slowly. I believe 12 MHz is now the default for APA102, after so many didn’t work at 24 MHz for more than 100-200 LEDs. Maybe even 12 MHz is a problem for a really long strip?
I’m running 1200 leds and the only thing I found that removes this problem is running the APAs at 4MHz. I’m running my teensy 3.1 at 96mhz.
@Scott_Schipper Do you set DATA_RATE_MHZ(4): to do that?
FastLED drives the LEDs faster than other libraries. This can cause this type of error.
Slow down the led data rate, not the CPU clock speed.
@Jacob_Danell You got it. I have even tried 5MHz. But get strange flickering. Note that I’m using strips, not matrices though. Good luck!
@Jacob_Danell have you got enough power delivery to all the pixels? I notice that none of the pixels after a certain point on your video, light up at all…
@Leon_Yuhanov On the video I’m just using the first 450 leds as if I used all half of all leds gets lit and flicker. From 450 and forward the leds start to flicker. After lowering the cpu speed the flicker got removed. Next I’ll try and turn the data rate down a lot instead
@Jacob_Danell I see, dont bother lowering the CPU frequency, but definitely lower the SPI drive frequency to 5mhz or below AND feed more power.What power supply are you using?
@Leon_Yuhanov Now I have a 12v 7A that I take through a XL4015 DC-DC Converter to go down to 5V. The converter can handel 5A but I will never have all the LEDs lit at the same time, only maybe a total of 60-70 of them in total and never at full brightness.
Just to be clear, I should add DATA_RATE_MHZ(5); into the code?
@Jacob_Danell im not too familiar with hiw fastled configures the data rate, but that looks rigt
Can you show me your code?