Hi NevadaMark,
You are right! I used the mbed MCU to supply the IMU at 3.3 V, while multimeter told me only 15 mA flowed into the IMU...It seems like the MCU could not provide such current.
I changed to DC power supply and I got 3.3V 0.235A, which should be normal for the IMU. The good news is that registers started to update, however, unfortunately, the values keep changing randomly as shown below:( Again, the z_acc still did not show the gravity as well..)
Also, by writing to the PROD_ID register using the same code, I only got output 0 on the screen..
Regards,
RobinUofC