Clock Outputs Based on the Synchronized RTC Nanoseconds Field - 9.0 English

Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051)

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9.0 English

The clk8k (8 kHz clock) output, derived from the Synchronized RTC, is provided as an output from the core. The synchronized RTC counter, unlike the controlled frequency version, has no long-term drift (assuming the provided software drivers are used correctly). Therefore, the clk8k signal is synchronized exactly to the network RTC frequency.

The 8 kHz clock is the period of the shortest class measurement interval for an SR class as specified in IEEE802.1Q. This clock could also be useful for external applications (for example, a 1722 implementation of the AV traffic).