BME280 works w UNO but Not micro

I have a simple project that reads the temp, humidity, and press from the BME280 and displays the results on 3, 7-seg displays. Going to mount it outside on a window. I use a shift reg to run the displays. The measured parameters display one at a time. Project works as designed on the UNO but trying to use the Arduino Micro board for the final build. On the micro the displays work fine but I get no data from the BME280. Have checked the power and setup several times. I have swapped back to the UNO and again it works. Using I2C communication from the BME280 on both with SDA/SCL connected to A4/A5 respectively. With the micro the results don't change if I unplug the SDA/SCL leads. It appears the I2C is not working on the micro.

I'm missing something simple I'm sure.

Someone school me please.


On the Micro I2C is on pins 2 (SDA) and 3 (SCL).

Have a look at the datasheet/pinout of the micro and you will find oquibidipo's advice confirmed.

Well that would be it! Thanks for the help.

I'll be back with a smarter question in the future.