Yes. By default, the AC-IMX390 on the NRU-51V+ operates in Frame Sync mode. The source of Frame Sync is an onboard MCU.
Long Answer
When it comes to the "framesync" of a GMSL2 camera, the nature of the CMOS sensor plays a crucial role.
Although the NRU-51V+ includes an onboard MCU to generate a stable framesync pulse, and the I2C script pipes the MCU-generated framesync to the IMX390 via the GMSL2 protocol, the IMX390 CMOS behavior is somewhat complex:
The frame rate of the IMX390 is fixed and limited to 30 FPS.
The IMX390 imposes strict timing constraints on external framesync signals: if the external framesync is not received at the expected timing, the sensor switches to using its internal crystal to generate framesync.
Secondly, the framesync only guarantees the synchronization of the "start of auto exposure" for multiple AC-IMX390 cameras on the NRU-51V+. However, the auto exposure duration is determined by the ISP on the camera side. The auto exposure duration adjusts dynamically based on the lighting conditions detected by each camera.
