FWIW we have been using the MPU9250 on an Edison adapter board and communicating between them on the I2C1 bus at a measured bus clock speed of 350 kHz with very few problems. I have 4K7 pullups on the adapter board and have not configured the Edison internal pullups (since I don't know how and Intel hasn't been able to tell me how). We do notice some variable delay in our loops which I assume is do to software errors but could also be due to variations of I2C communication rates. We are trying to track this down. It is somewhat limiting to have to use 1V8 for the I2C since some sensors (like the MPU9x50) need at least 2V4 for the analog section to drive the sensors. But so far we have it working without having to do anything extraordinary except select I2C1 in the Edison Arduino library. I would like to know how to set the I2C bus speed using same; ~400 kHz is what we want but I would like to see if we get different behavior at 100 kHz or if we can run the commo at 1 MHz. Any idea how to set the I2C bus speed with the Arduino IDE? On the Teensy you just change the number on the Wire.begin line. How convenient! Can we hope for such convenience for the Edison?
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