dsptech started following MPU6050+HMC5883L - put compass values in FIFO while DMP is enabled
dsptech replied to anistor's topic in MPU-6050 6-axis accelerometer/gyroscope (InvenSense)I see that this a very old thread but in these days I'm facing the thread subject. Using an MPU9250 and the Invensense motion driver (6.1), I'm able to put compass data in the fifo while DMP is enabled, without hacks on the original DMP firmware. I achieved this result by changing the original fifo reset function: the slave 1 fifo bit must be enabled before activating the fifo and dmp features in user control register. The resulting saved record is: 8 byte of compass data (compass status1 + 6 bytes of true data + compass status 2) followed by the original DMP record. Another way: the slave 1 fifo bit can be enabled after the FIFO and DMP enabling (for example: elsewhere in the user code), but a proper fifo purge is required to discard the incomplete records and gain the correct sync against the FIFO. These solutions work on my device using 200 hz DMP sample rate + 100Hz compass sample rate (every compass sample is repeated two times in FIFO, gestures enabled and quaternion disabled), but them are totally undocumented and more testing is needed, so, I would like to know if anyone use similar solutions and if there are know issues. Regards.