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AR# 14971

Virtex-II Pro RocketIO - Can BREFCLK and RXRECCLK drive FPGA internal logic?

Description

Q1. Can a single BREFCLK pad drive all of MGTs in a design? 

Q2. Can BREFCLK be used to clock internal logic? 

Q3. Can RXRECCLK from the CDR unit be used to clock internal logic?

Solution

A1. The BREFCLK pins (BREFCLK and BREFCLK2) on the top of the chip can only drive the RocketIO transceivers on the top of the chip. The BREFCLK pins on the bottom of the chip can only drive the transceivers on the bottom of the chip. There is no other limitation. 

 

A2. Yes. The User Guide describes how you can use the REFCLK to create all of the other clocks for the transceiver. 

 

A3. RXRECCLK can be used to clock internal logic, although it is not necessary to use it.

AR# 14971
Date Created 08/29/2007
Last Updated 05/14/2014
Status Archive
Type General Article