TLC5947 flashes when data received


I am using three TLC5947 chained modules from Adafruit and two Arduinos Zero connected by the Serial1 port (Rx and Tx pins). One Arduino is connected to the three TLC5947 and operates as expected. There are several LEDs connected and they all perform smooth transitions between different colors. The other Arduino sends, via Serial1 pins, information that, once processed, can change the values of the different LED channels.

Every time that the Arduino connected to the TLC5947 modules receives information from the other Arduino, it work as expected but I can see a tiny flash in the light emitted by the LEDs. Something similar happens when I try to get information from the SDA and SCL pins.

Obviously I want to avoid this flash. Any idea?

Thank you very much!

Official Adafruit TLC5947 library: GitHub - adafruit/Adafruit_TLC5947: Adafruit's Arduino driver for the TLC5947
Datasheet of TLC5947:

I would say it's a problem with your circuit design. Or your code. Or both. Hope this helps you to figure out what you should do next...