I have Arduino Due and PCA9685.

I use this library: https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library

The board does not do anything with servo connected. I tried to use SDA/SCL pins and SDA1/SCL1 pins, I tried to use or not use pullup resistors. The board does not react in any case.

The PCA9685 is 100% working, because it operates properly when I connect it to my Arduino Mega using the same library, it works without pullups.

Also I noticed the following indicium, when I tried to use this scanner http://playground.arduino.cc/Main/I2cScanner I have no detected devices on SCL1/SDA1 but have detected 2 devices at 0x40 and 0x70 when I connect the board SDA/SCL pins.

1 Answer 1


I made it working by this way: despite PCA9685 datasheet recommendations, we do not need to connect OE pin to VCC. Also we do not need to connect OE to ground as it recommended in some instructions related to other Arduinos.

So we should leave OE pin unconnected. Also we should use 4,7K pull-up resistors to connect SDA and SCL to VCC.

The board can be used without level converters.

No special program/libraries changes needed. So it was a hardware problem.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.