Operating instructions
SEA M300USERSGUIDE
GENERALINFORMATION
52
• We can synchronize to NTP server prior to running M300 (using ntpdate). While M300 is running time
adjustments are not desirable from NTP server. The M300 Time, NTP time will drift. The QNX 4 time is
adjusted to M300 time.
• We can synchronize to GPS NMEA data with 'timesync' utility. This again is done prior to running the
M300. This utility takes the time from the GPS and sets the QNX 4 clock. When the M300 runs, it reads
the QNX 4 clock, sets our own internal clock and keep trap of time with the interrupts provided by the
System/SBUS interface. The M300 Time, GPS time will drift. The QNX 4 time is adjusted to M300 time.
• We can synchronize to BC635PCI/BC637PCI time. This is done using the BC635PCI/BC637PCI
interfaces. M300 adjusts time based on the BC635PCI/BC637PCI time. M300 also adjusts the QNX 4
time when using the BC635PCI/BC637PCI interface. This is the best possible scenario for time
synchronization, assuming the BC635PCI/BC637PCI is synced.
Provide time to other systems.
• QNX 4 can run the necessary software to provide time over NTP (using xntpd). We setup our system to act
as a NTP server. The QNX 4 time is adjusted to either BC635PCI/BC637PCI time or M300 time.
• BC635PCI/BC637PCI interface will provide time to other systems if necessary. Must have the BC635PCI/
BC637PCI interface connected to an accurate time source. Fly wheeling the BC635PCI/BC637PCI is not
recommended, since it doesn't provide accurate time. M300 will not use BC635PCI/BC637PCI in fly
wheeling mode unless we are connected to an external clock source.