D. tod synchronizer, Tod synchronizer – Altera Triple Speed Ethernet MegaCore Function User Manual
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D
ToD Synchronizer
2014.06.30
UG-01008
The ToD Synchronizer provides a high accuracy synchronization of time of day from a master ToD clock
to a slave ToD clock. This synchronizer provides more user flexibility for your design.
The IEEE 1588v2 specifies multiple type of PTP devices, which include the following clocks:
• ordinary clock
• boundary clock
• transparent clock
• peer to peer transparent clock
Some of these PTP devices, boundary clock for example, consists of multiple ports that act as master or slave
in the IEEE 1588v2 system. All these ports may share a common system clock or have its own individual
clock. If every port has an individual ToD running on its own clock, then you must implement a method to
instantiate one ToD clock as the master and the rest of the ToD clocks synchronized to this master ToD
clock.
For this purpose, Altera provides the ToD synchronizer module. This module synchronizes a master ToD
and a slave ToD in the following conditions:
• Master and slave ToD clock are in the same frequency (within 125 MHz to 312.5 MHz) but different
phase.
• Master and slave ToD clock are in the same frequency (within 125 MHz to 312.5 MHz) but different
PPM.
• Master and slave ToD clock are in different frequencies of either 125 MHz or 156.25 MHz.
• Master and slave ToD clock are in different frequencies of either 125 MHz or 312.5 MHz.
• Master and slave ToD clock are in different frequencies of either 156.25 MHz or 312.5 MHz.
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