Atto84 with I2C?

Just wondering if anyone has gotten I2C working with an Atto84? My code and hardware work with other boards, but when using them with the Atto84 I get nothing (it’s an MCP23016 with some LED’s for now, so about as basic as i2c gets). I tried swapping the scl/sda lines and got nothing. Tried adding external power thinking that maybe the tiny load of the MCP and LED’s was overwhelming it, no change. I tried adding a digital write to pin 8 so that the led would flash as the program ran…sometimes it does, sometimes it doesn’t, seems to be random if it will blink or not after hitting reset. Take out the i2c parts from the code and it’s always flashing. Thought maybe it was defective, but I have 5 of these boards and none of them are working with I2C.

Using Arduino 1.8.5 because newer versions don’t seem to like this board (or some of my other boards).

It’s not exactly a rush; the rest of my code is only about half done and already almost too big for this board so I’m moving to a Teensy LC…but would like to know in advance for next time if there is some trick to I2C on the Atto84 or if I should just use it for low pin-count projects.

OK, nevermind. Fixed by changing to lower ohm pull-up resistors. Works good now.