Curie IMU module gives incorrect values

[srware]

The Curie IMU module seems to have issues with incorrect bit-masking applied to register values. According the to the datasheet it is a 16-bit IMU but the module seems to be masking for 8 bits which means values are always positive and jump from 0 to 16000 when it should be going into negative values.

I have confirmed this using the latest MRAA and UPM versions.

[Propanu]

Hi @srware thanks for pointing this out. I can add it to our todo list however, if you only need the data and no advanced features, take a look at the bmi160 driver we have. Patching the Firmata sketch as mentioned in #505 should enable this alternate driver too.