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I have a Jetson Nano and an ethernet-connected sensor (specifically, a LiDAR that supports PTP) that I'd like to set up PTP synchronisation between, and I'm kind of confused by the documentation (I'm mainly trying to follow the guide at https://static.ouster.dev/sensor-docs/image_route1/image_route2/appendix/ptp-quickstart.html). I'd like to force the Jetson Nano system clock to be the 'master' clock. On the Jetson Nano, the ethernet port that the sensor is connected on does not seem to support hardware timestamping:

$ sudo ethtool -T eth0
Time stamping parameters for eth0:
Capabilities:
        software-transmit     (SOF_TIMESTAMPING_TX_SOFTWARE)
        software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
        software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
PTP Hardware Clock: none
Hardware Transmit Timestamp Modes: none
Hardware Receive Filter Modes: none

so I tried to set up the PTP server in software mode.

My setup steps were:

sudo apt install linuxptp chrony ethtool

sudo nano /etc/linuxptp/ptp4l.conf


set priority1 and priority2 to 0 so that the Jetson Nano system clock is always the master? Is this correct?


set time_stamping to software


set free_running to 1 so that the Jetson system clock is not modified


sudo systemctl daemon-reload
sudo systemctl restart ptp4l

Is this the right way to set up the PTP server to use the Jetson system clock as the master clock? What is the use of phc2sys?

kekpirat
  • 861

0 Answers0