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OpenIL is an open source project based on Buildroot and designed for embedded industrial solution.
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PPS signal on LS1021A TSN? #96

Open mu-aslam opened 3 years ago

mu-aslam commented 3 years ago

Hi, Currently, I am using LS1021A TSN for clock synchronization. I wonder if the switch has exposed PPS port to measure clock synchronization? If yes, may I learn how to configure it? I could not find much information about it in user manual. https://www.nxp.com/docs/en/user-guide/OPEN-LINUX-IND-UM-1-10.pdf

vladimiroltean commented 3 years ago

Try this

cat pps.sh
#!/bin/bash

# enum ptp_pin_function
PTP_PF_NONE=0
PTP_PF_EXTTS=1
PTP_PF_PEROUT=2
PTP_PF_PHYSYNC=2

PTP1_CHANNEL0=0
PTP1_PEROUT_PERIOD="1 0" # 1.000000000 seconds

PTP1_PEROUT_START="0 0" # 0.000000000 base time, will be advanced into the future by the driver

echo "$PTP_PF_PEROUT $PTP1_CHANNEL0" > /sys/class/ptp/ptp1/pins/ptp_clk
echo "$PTP1_CHANNEL0 $PTP1_PEROUT_START $PTP1_PEROUT_PERIOD" > /sys/class/ptp/ptp1/period

There is a LED on the board (D10) which should blink when the signal from PTP_CLK is high. Using the PTP periodic output (perout) functionality you can modify the period of the waveform but not the duty cycle (that is fixed at 50%). Hope this helps.

mu-aslam commented 3 years ago

Thanks for the reply, Actually I want to compare the PPS signal of the LS1021A TSN (acting as master) with the end-station (acting as slave) on oscilloscope. I attached the setup I am using. Please let me know if it is possible with the LS1021A TSN. If so, let me know which port I can use. dfdf

vladimiroltean commented 3 years ago

The PTP_CLK pin (routed to the D10 LED and the TP1 test point) is emitted by the sja1105 switch. The LS1021A SoC does not have the option to emit PPS without some board rework because the IEEE 1588 pins are pinmuxed with the RGMII port eth2, the same port that is used as a host port for the switch. So the answer is: any of swp2, swp3, swp4, swp5.