Tool/software:
Hello,
I'm trying to get an PPS output synchronized with PTP.
I will detail how I get my PPS signal:
I use a National Instrument platform that works as a PTP grandmaster. I can get the PPS signal from the NI board.
By ajusting the dtb file, I can get a PPS signal on SYNC1_OUT (header J12 of the EVM board).
/usr/kernel-selftest/ptp/testptp -d /dev/ptp0 -P 1
The green signal is my PPS signal from NI board; the yellow signal is SYNC1_OUT.
After synchronizing the EVM with PTP from NI:
ptp4l -i eth0 -s -q -f /home/ptp.cfg -m > /home/ptp4l.log & phc2sys -s eth0 -w -q -f /home/ptp.cfg -m > /home/phc2sys.log &
By disabling pps signal and re-enabling it, I get a PPS signal that seems synhcronized with NI PPS signal:
/usr/kernel-selftest/ptp/testptp -d /dev/ptp0 -P 0 /usr/kernel-selftest/ptp/testptp -d /dev/ptp0 -P 1
Synchronizing PTP seems to synchronize PPS signal but the yellow signal (SYNC1_OUT) has an offset of 30µs:
I guess this offset could be corrected by that command:
/usr/kernel-selftest/ptp/testptp -d /dev/ptp0 -n -30000
Even if I am able to correct it, this offset was not expected. Am I doing something wrong?
Also, the jitter of the PPS signal from SYNC1_OUT is around 1,3µs which seems high to me:
How can I reduce this jitter?
Julien
