Xilinx UG492 manual PTP Signals, Signal Direction Description

Chapter 5: Core Architecture

PTP Signals

Table 5-11defines the signals which are output from the core by the “Precise Timing Protocol Blocks.” These signals are provided for reference only and may be used by an application. For example, the 1722 Packet Managers, as illustrated in Figure 3-2, require the following:

•clk8k: this marks the class measurement interval to be used for traffic shaping for SR class A AV traffic.

•rtc_nanosec_field and rtc_sec_field: used in the 1722 presentation time stamp logic.

Table 5-11: PTP Signals

Signal	Direction	Description
rtc_nanosec_field[31:0]	Output	This is the synchronized nanoseconds field
		from the “RTC.”
rtc_sec_field[47:0]	Output	This is the synchronized seconds field
		from the “RTC.”
clk8k	Output	This is an 8KHz clock which is derived
		from, and synchronized in frequency, to
		the “RTC.”
rtc_nanosec_field_1722[31:0]	Output	The IEEE1722 specification contains a
		different format for the “RTC,”provided
		here as an extra port. This is derived and is
		in sync with the IEEE802.1 AS RTC. If
		desired, this port can be used as the RTC
		reference for 1722 Packet Manager blocks,
		as illustrated in Figure 3-2. See also
		“IEEE1722 Real Time Clock Format,”
		page 81.

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		UG492 July 23, 2010