What's the GlobalTimeStamp

Autonomous Vehicles DRIVE AGX Xavier DRIVE AGX Xavier General
1

Please provide the following info (check/uncheck the boxes after clicking “+ Create Topic”):
Software Version
DRIVE OS Linux 5.2.0
DRIVE OS Linux 5.2.0 and DriveWorks 3.5
NVIDIA DRIVE™ Software 10.0 (Linux)
NVIDIA DRIVE™ Software 9.0 (Linux)
other DRIVE OS version
other

Target Operating System
Linux
QNX
other

Hardware Platform
NVIDIA DRIVE™ AGX Xavier DevKit (E3550)
NVIDIA DRIVE™ AGX Pegasus DevKit (E3550)
other

SDK Manager Version
1.5.0.7774
other

Host Machine Version
native Ubuntu 18.04
other

Hello.
I want to know how the camera timestamp is given.

I’m using NvMediaImageRec::captureGlobalTimeStamp to know the time of the camera.

When PTP is disabled, the captureGlobalTimeStamp contains the time since the system started.
When PTP is enabled, the captureGlobalTimeStamp contains system time.

What time does CaptureGlobalTimeStamp use?
Is it the Xavier A hardware clock or the Aulix time?

2

You’re right. captureGlobalTimeStamp uses PTP time. If not available, it uses CLOCK_MONOTONIC clock.

3

Thank you for your reply.

I don’t know about PTP, so please tell me.
Does PTP change hardware clock of Xavier A?
Or PTP change system clock of Xavier A?

I tried changing the system time by “date” command.
But captureGlobalTimeStamp is not changed.

In addition, I tried to change the hardware clock by “hwclock” command, but couldn’t.
The following error is displayed, Xavier doesn’t seem to be have a hardware clock.

hwclock: Cannot access the Hardware Clock via any known method.

Thank you.

4

Please take a look at the following doc/topic for the information.

5

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.