IMU0: fast fifo reset 1

ArduPlane Plane 4.4
1

I just flew AP4.4.dev on a plane yesterday. I spent the first flight running autotune, then the second flight to tweak TECS params. In the 3rd flight I just had the plane fly some generic waypoint missions to evaluate the tune. Everything seemed fine, but digging through the logs, the 3rd log has 50Hz of: IMU0: fast fifo reset 1. Any idea what would cause this? The plane seemed to fly great.

If it makes a difference, it has a mRobotics PixRacer R15.

2

Here’s a quick update on this. The setup is a PixRacer with an Odroid C0 or C4 as a secondary controller, connected through Telem2. For debuggung I have a 900MHz telemetry radio plugged into Telem1. We’re running AP4.4.0.dev.

We had 2 flights with both the Odroid and telemerty radios active, with no IMU0 fast fifo reset 1 messages. On the 3rd flight, the messages were recorded at 50Hz - the loop rate. They do not show up in the message tab in MissionPlanner - just the logs.

I unplugged the Odroid - messages are still there.

I reflashed the autopilot with the latest official release. The messages are gone.

I reflashed with the dev branch, no Odroid - the messages are back.

I unplugged the telemetry radio - the messages are gone.

I don’t know what the messages mean, i.e., should I be worried? Looking at the log from the flight with the messages, data from both IMU0 and IMU1 are there and are very similar. To my knowledge, nothing changed between the first 2 flights and the 3rd flight, other than one TECS parameter we slightly adjusted.

If anyone has any ideas, any feedback would be greatly appreciated.

3

OK - one more update - and one that doesn’t appear to help at all.

After powering with no telemetry radio, and seeing no reset messages. I plugged the radio back in, booted up the system, and still am not getting the reset messages. I’ve now duplicated all of these tests on 2 autopilots, and get the same result.

Does this make any sense - unplugging the radio and powering, then plugging the radio back in and powering changes something in the behavior of the system - eliminating the reset messages?