Now that the initialization of MPU9250 is shared between the
AP_InertialSensor and other drivers using it as a backend, we can reset
the MPU9250 in order to put it in a known state.
Now we have the initialization code split in 2 parts:
1) Making sure the MPU9250 chip is alive and working: this is now in a
static function that may be called by other drivers that use MPU9250 as
backend.
2) The configuration of gyro and accel. Once the first part is completed
successfully the AP_InertialSensor_MPU9250 finishes the configuration of
the sensors it uses.
The only change in behavior here is that before we would try 25 time (5x
inside _hardware_init time 5x inside _init_sensor() that calls the first
function) to "boot the chip" and now we are doing "only" 5.
Add static methods to do the SPI transactions and provide the wrapper
methods when we have an instance of the object. This is useful so these
methods can be called from other contexts when the AP_InertialSensor
hasn't been initialized yet.
The Compass library is initialized before the InertialSensor. AK8963 with
MPU9250 as backend already takes care of resetting MPU9250. The problem with
also resetting it in the MPU9250 initialization code is that if the reset
happens during an internal I2C transaction, the AK8963 may hang. So here we
remove the reset inside MPU9250. There still a possibility that the first
MPU9250 initialization is not successful and it resets the chip, but it's not
happening in tests.
As we intend to eventually get board related parameters from a configuration
file, this commit makes the GPIO numbers for data-ready pins be instance
variables instead of from C constant macros.
Another advantage of using instance variables in this context is the
possibility of using more than one LSM9DS0.
If the data-ready polling is done entirely on GPIO pins, it isn't necessary to
hold the semaphore before we now we have data to consume. In that case, only
take the SPI semaphore if there's new data available.
On the other hand, if at least one SPI transaction is done in order to check
for new data, then it makes sense to take the semaphore beforehand.
This commit makes accel and gyro initialization routines use bitfield macros
instead of hardcoding the literal value when wrinting on registers. That is
less prone to typos and a lot of times self-explanatory. Also, due to the
latter, the long comments explaining each register field were removed (any
detail can be checked on the datasheet).
This adds the backend driver for LSM9DS0. This implementation is based on the
legacy driver coded by Víctor Mayoral Vilches (under folder LSM9DS0) and makes
some necessary adaptations and fixes in order to work properly. The legacy
driver folder was removed.
The calibration on LSM9DS0 was giving offsets between 4.0 and 4.2 on x-axis and
around 3.6 on y-axis. It turned out that those offsets were actually right.
The maximum absolute values of calibration offset should be a sensor
characteristic rather than a constant value for all sensors.
The constant value previously used (3.5 m/s/s for all axes) is set here as a
default maximum absolute calibration offset for every instance to keep it
working.
The previous implementation made some boards apply two rotations to suit
their default orientation. That was happening because there was an
unconditional rotation being done (commented as "rotate for bbone
default").
This commit makes that unconditional rotation as a default rotation
instead and adjusts the former additional rotations to be single
rotations.
As the datasheet says: "To prevent switching into I2C mode when using
SPI, the I2C interface should be disabled by setting the I2C_IF_DIS
configuration bit."
We also reset the sensor like PX4Firmware does for initializing the
MPU6000. See: ee1d8cd770/src/drivers/mpu6000/mpu6000.cpp (L695)
The main thread would always be blocked on the semaphore to read the
data from accelerometer and gyroscope. Especially if we have a slow
update of these values in _accumulate() due to the I2C transfer function
taking too much time: the timer thread would never give up the CPU,
causing starvation on the main thread.
This fixes the issue by reducing the critical region using a flip-buffer
so _accumulate() can work on its own copy of the data. Now that the
critical region is smaller, also avoid the semaphore and use a spinlock
instead.
we must not update _gyro_offset[] until we have completed calibration
of that gyro, or we will end up using the new offsets when asking for
the raw gyro vector
during 3D accel cal it is possible to get data which passes the sphere
fit but which has very poor coverage and does not provide sufficient
data for a good result. This checks that each axis covers a range of
at least 12 m/s/s in body frame
this allows us to detect if accel calibration was done in sensor frame
or not. If it was done in sensor frame then the accel calibration is
independent of AHRS_ORIENTATION, which makes it easier to move a board
to a new airframe without having to recalibrate.
Tom Pittenger
Lucas De Marchi
Andrew Tridgell
Julien BERAUD
mirkix
Staroselskii Georgii
Gustavo Jose de Sousa
Randy Mackay
Peter Barker
Peter Barker
Jonathan Challinger
ahcorde