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Chapter 8
Real Time Clock and Time Stamping
This chapter considers two of the logical components that are partially responsible for the AVB timing synchronization protocol.
•“Real Time Clock”
•“Time Stamping Logic”
These are both described in this chapter as they are closely related.
Real Time Clock
A significant component of the PTP network wide timing synchronization mechanism is the Real Time Counter (RTC), which provides the common time of the network. Every device on the network will maintain its own local version.
The RTC is effectively a large counter which consists of a
IEEE802.1AS Real Time Counter (RTC)
Seconds field (48 bits unsigned) | Nano Seconds field (32 bits unsigned) |
counts from 0 until fully saturated, | counts from 0 to 1 x 109 |
then wraps around to 0 | then resets to 0 |
|
Figure 8-1: Real Time Counter (RTC)
Ethernet AVB Endpoint User Guide | www.xilinx.com | 75 |
UG492 July 23, 2010