Juergen Kosel <[email protected]> writes: >Hello,
>I have a system with hardware support for PTP (IEEE 1588 time >synchronisation) [ http://en.wikipedia.org/wiki/Precision_Time_Protocol ]. >So the system can read from two 32 bit registers seconds and nanoseconds >since 1.1.1970. It appears like the system time, but is n't the system time. >To synchronize the system time to the PTP synchronized time and to >provide it to other systems, I want to write a reference clock driver. Don't bother. they already exist. Just write an program which uses shm to place the PTP time and the computer system time into a shared memory segment, and use the shm refclock driver. >I have already read http://www.eecis.udel.edu/~mills/ntp/html/howto.html >and started with a copy of refclock_local.c. >But from the documentation it is not clear, in what way the offset >should be calculated and used. E.g.: >offset = ref_clock_time - system_time; >or >offset = system_time - ref_clock_time; ntp calculates offset. You supply it with the system time and the true time, and ntp will do the rest. Ie, write a little program which reads the PTP time and the system time once a second say, and place the two times into the shared memory registers for the shm driver. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
