I am hoping to use Cube Pilot Orange+ with either PX4 or Ardupilot, but am hoping to achieve very accurate sensor measurement timestamps for IMU, Baro, Mag, and Camera all timestamped with respect to the flight controller’s processor time.
For the Invensense ICM42688P IMU datasheet, it seems that there are a few different features available to support accurate time stampping. Specifically: 1) an interrupt pin can be programmed to toggle when new data is ready; presumably the flight controller would listen for this toggle on a GPIO interrupt event and grab its clock timestamp at that time 2) CLKIN - the device supports an external clock input; assuming the sensor samples at a fixed frequency relative to this external clock we’d at least accurately know the time deltas between each measurement 3) timestamp bytes in the packet.
I’m definitely not an expert here, but it at least looks like the PX4 driver (PX4-Autopilot/src/drivers/imu/invensense/icm42688p/ICM42688P.cpp at main · PX4/PX4-Autopilot · GitHub) contains logic to support 1) the GPIO data ready interrupt. It doesn’t appear to make use of 3) the timestamp bytes in the packet.
What I can not tell is whether 1) is supported by the Cube Pilot Orange+ hardware as I believe the IMU’s INT line would need to be connected to one of the STM32H7’s GPIO lines. I also can not tell whether CLKIN is connected in the Cube Pilot Orange+ hardware such that the STM32H7 and ICM42688P share a clock.
Does anyone have access to the schematic or can help answer these questions? Note that I have similar questions about the baro and mag devices, but lets start with the IMU