Invalid readings from MPU9150

[chrisspen]

I was able to compile an example program for the MPU9150. It appears to pass all the initial start up routines and display "DMP ready!" but all the motion data shown is 0. It's just an endless stream of:

quat    0.00    0.00    0.00    0.00    ypr (degrees)   180.00     nan     nan    areal (raw)      0      0      0    areal (m/s^2)      0      0      0  

Do you know why this is?