this moves to using a 1p filter on the high rate data, followed by
averaging down to 1kHz then a 2p filter to apply configured cutoff
frequency.
It also fixes the FIFO reset to not cause data corruption. We need to
disable all FIFO channels before doing the reset, and wait for the
FIFO to stop in the sensor.
Finally it moves sampling of the MPU6000 and MPU9250 into the main
thread. That significantly improves scheduling performance as we no
longer get long FIFO SPI transfers happening during other tasks. All
transfers happen at the start of the fast loop. That makes timing much
more predictable.
Thanks to Leonard and Paul for help with this design!
When blocking forever there's no reason to call panic later since it
will never going to be reached. This reduces binary size in a few bytes
since the message isn't required anymore.
this allows enable/disable of fast sampling per IMU, making
experimentation easier.
It also fixes the fast sampling to always average over 8 samples, and
fixes the 9250 to use the correct accumulator when not doing fast
sampling
Two cases of what seems to be FIFO alignment errors have been seen on
a Pixracer-beta board with a ICM-20608. At a cost of 2 extra bytes per
transfer we can catch these by looking for sudden temperature changes
caused by bad data in the temperature registers.
When registering accel and gyro we use the upper 16bits of the id to
store the driver version. When changing the driver behavior in
non-compatible ways, changing this version will trigger a request for
calibration.
This allows each sensor to be uniquely identified in the system by using
either the index inside the backend or for those that use the Device
interface, to use the bus type, location, and device id.
We leave 16-bit for each sensor to be able to change its own
identification in future, which allows them to be changed in an
incompatible manner forcing a re-calibration.
We only leave the parameter there for backward-compatibility. However
product id on the inertial sensor is not much useful since it's only
kept for the first instance.
A better implementation per-gyro and per-accel is needed in order to
avoid problems with sensors taking the offsets configured for another
sensor.