Well, I am back to my original post. I want to connect a PCA9685 to a Feather ESP32, SDA and SCL and here is what is said about those 2 devices. ESP32: Note that the I2C pins do not have pullup resistors already! You must add them if you want to communicate
PCA9685 SCL - I2C clock pin, connect to your microcontrollers I2C clock line. Can use 3V or 5V logic, and has a weak pullup to VCC SDA - I2C data pin, connect to your microcontrollers I2C data line. Can use 3V or 5V logic, and has a weak pullup to VCC
It sounds like the pullup resistors is there. Being weak is probably important but I sure don't know why or if it is important. This is getting me nowhere as I can't seem to get a straight answer. Let me see if I can re-phrase it. Given the above 2 devices that I want to connect via SDA and SCL, do I need a resistor in series with the connection? If yes, what value?