What is jetson agx orin [RCE sof eof] time accuracy

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

what is jetson agx orin [RCE sof eof] time accuracy?

/* Read SOF from capture descriptor */
ts = ns_to_timespec64((s64)descr->status.sof_timestamp);
trace_tegra_channel_capture_frame("sof", &ts);
vb->vb2_buf.timestamp = descr->status.sof_timestamp;

if (frame_err)
	buf->vb2_state = VB2_BUF_STATE_ERROR;
else
	buf->vb2_state = VB2_BUF_STATE_DONE;
/* Read EOF from capture descriptor */
ts = ns_to_timespec64((s64)descr->status.eof_timestamp);
trace_tegra_channel_capture_frame("eof", &ts);
2

Hi,

For the camera basic functionality first needs to check the device and driver configuration.
You can reference to below program guide for the detailed information of device tree and driver implementation.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#sensor-software-driver-programming

Please refer to Applications Using V4L2 IOCTL Directly by using V4L2 IOCTL to verify basic camera functionality.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#to-run-a-v4l2-ctl-test

Once confirm the configure and still failed below link help to get log and some information and some tips for debug.
https://elinux.org/Jetson/l4t/Camera_BringUp#Steps_to_enable_more_debug_messages

Thanks!

4

Hello,
The camera is currently usable, I just want to know the time accuracy of SOF and EOF.
In other words, since the SOF and EOF timestamps come from RCE, I would like to know the time accuracy of RCE.

5

hello MushroomHunter,

it’s timestamp of START_OF_FRAME/END_OF_FRAME from VI capture status.
they’re coming from RTCPU vi-notifier FW driver, it’s TSC timestamp.
you may see-also Argus::Ext::ISensorTimestampTsc class for reference.

6

Hello, Jerry.
I know how to use this API. I need to know the accuracy of this timestamp.
How much is the difference between RCE’s 1s and real-world 1s

7

hello MushroomHunter,

please refer to Topic 159220 as see-also.
may I also confirm which Jetpack release version you’re working with? please check with $ cat /etc/nv_tegra_release for verification.

8

Jerry,
Thank you for your reply.
You want me to know the differences between different time domains within Orin. But I want to know the time accuracy of the RCE module. Similar to physical crystal oscillators, there are some PPM accuracy requirements.

10

The main TSC is a high accuracy NCO operating on the 32,768 Hz clock which is from a crytal with +/-20ppm tolerance.

12

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