I have three new I2C modules, one with a Freescale MPL3115A2 pressure sensor and two with a Freescale MMA8451Q accelerometer.
The I2C_Scanner sketch detects an address response from each of them, at the expected address, but apart from that I cannot get any I2C communication to actually work. These Freescale devices apparently rely on an I2C scheme which is slightly different to (most) other I2C devices. The difference involves sending a "repeated start" bit between setting the register address to read from, and requesting the data.
I have tried using "Wire", I have tried using "I2C", I have tried using "I2CDEV", and none of them will work. I have tried using all three of those libraries with other I2C sensor modules, and they work just fine. I have also tried using 2.7k and 3.3k and 4.7k pullup resistors.
Has anyone actually succeeded in getting any of these modules using Freescale's version of I2C to actually work ? Are there any examples of sketches that work ?