- update to NuttX with stm32f4 and stm32f7 SPI DMA internal buffers
- remove explicit DMA buffer allocations from new IMU drivers
- restore original BOARD_DMA_ALLOC_POOL_SIZE
- decrease SPI DMA thresholds based on fmu-v2/v3/v4/v5 bench testing
This avoids the need for recalibration, and also cleans up other driver
ID's (merge separate accel/gyro).
The SPI address was previously set to a board-specific (arbitrary) value,
and is now set to 0. This will allow extending for multiple sensors of the
same type on the same bus.
I've added a queue depth of 4 for sensor_accel and sensor_gyro. This is initially added because it's not always possible for the `vehicle_acceleration` to keep up with every publication of the primary accelerator as it runs in the same thread as ekf2, various controllers, etc.
Later this mechanism will be used in a few areas
- rate limit `vehicle_angular_velocity` and `vehicle_acceleration` without missing any raw data
- move IMU integration to `vehicle_imu` and out of the actual driver threads, eliminating the need for sensor_accel_integrated and sensor_gyro_integrated
- integrate raw gyro synchronized with optical flow measurements
- gyro filtering (low-pass and notch) only performed on primary gyro in `sensors/vehicle_angular_velocity` instead of every gyro in `PX4Gyroscope`
- sample rate is calculated from actual updates (the fixed value was slightly wrong in many cases, and very wrong in a few)
- In the FIFO case the array is now averaged and published in `sensor_gyro` for filtering downstream. I'll update this in the future to use the full FIFO array (if available), but right now it should be fine.
- this provides some extra space when the FIFO transfers don't align perfectly
- I've also made an effort to keep the different drivers (icm20602, icm20608g, ism330ldc) in sync so we can factor out the common portions later once we've confident in the pattern.
Beat Küng