I have a myRio and hence am using LabView real-time. I read an accelerometer and gyro from an external sensor using i2C. This works fine.
Then I add a PWM motor part. For the H bridge I require two logic outs. I find that if I connect my H bridge logic outputs to A/Dioo that it stops the I2C working. Almost as if the Dio is in some way connected to the I2C, yet it is not.
In frustration I connected to the B port and it works fine again. Does using I2C in some way restrict you using the rest of the Port A? Seems a little odd. I had a problem in the past when I tried to use I2C and the FPGA at the same time - that's another story. Never resolved that either.
I made the I2C handle multiple opens (=True in the vi) in case it had something to do with that. didn't make any difference.