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 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.
when running off a 1kHz timer and reading at 1kHz it is better to
double sample than it is to skip a sample, as skipping samples will
throw the filter off, whereas a double sample will have minimal effect
Lucas De Marchi
Gustavo Jose de Sousa
Andrew Tridgell
Jonathan Challinger
Andrew Tridgell
Víctor Mayoral Vilches