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IEEE 1588 PTP synchronization in combination with PPS output signal

Question asked by Andreas Aichhorn on Apr 27, 2015

Hello Community!


I have a problem with the i.MX 6 while using IEEE1588 PTP time synchronization in combination with the related PPS signal.


For the PTP synchronization I'm using the linuxptp application from, which seems to be working according the logging messages. The code (fec_ptp.c) is changed to get a PPS signal at the output. PPS is just working with the TMODE setting "toggle output on compare" at the ENET_TCSRn register. I would prefer to use the TMODE setting "clear output on compare" as I need a falling edge with a frequency of 1 Hz. The (working) toggle mode changes the output each second and I do not know exactly where I define the period, as for initialization the timer period register (ENET_ATPER) is set to 0 initially that PTP is working. Is this correct?

=> Does anyone know what to change/set to use TMODE "clear output on compare", respectively how to set the output after clearing it?


What is also unclear to me is that the logging messages of the PTP app. show a very high accuracy (in the 10th or 100th ns region after some periods), whereas the PPS output signal stays the same and it seem that this signal is not synchronized with the PTP clock!

=> Does anyone know where I have to make the settings that the pulse is adjusted to the PTP clock?


Attached is the file fec_ptp.c.



Thanks in advance!

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