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Chapter 7

1000BASE-X with RocketIO Transceivers

This chapter provides general guidelines for creating 1000BASE-X designs that use RocketIO transceivers for Virtex-II Pro, Virtex-4, and Virtex-5 devices. Information about RocketIO transceiver and core logic in all supported device families is provided, as well as information about designs requiring multiple instantiations of the core. Note that clock sharing should occur whenever possible to save device resources.

RocketIO Transceiver Logic

The example is split between two discrete hierarchical layers, as illustrated in Figure 4-1. The block level is designed so that it can be instantiated directly into customer designs and provides the following functionality:

Instantiates the core from HDL

Connects the physical-side interface of the core to a Virtex-II Pro, Virtex-4, or Virtex-5 RocketIO transceiver

The logic implemented in the block level is illustrated in all the figures in this chapter.

Virtex-II Pro Devices

The core is designed for seamless integration with the Virtex-II Pro RocketIO Multi-Gigabit Transceiver (MGT). Figure 7-1illustrates the connections and logic required between the core and the MGT—the signal names and logic in the figure precisely match those delivered with the example design when an MGT is used.

Some modifications can be made to the MGT. For example, REFCLK may be used instead of BREFCLK. See the RocketIO Transceiver User Guide (UG024) for details.

The placement of the flip-flop that connects to ENMCOMMAALIGN and ENPCOMMAALIGGN is important (see Figure 7-1). For detailed information, see “Virtex-II Pro RocketIO MGTs for 1000BASE-X Constraints,” and the RocketIO Transceiver User Guide.

Note: The brefclk differential pair applied to the MGT is of frequency 62.5 MHz.

Ethernet 1000BASE-X PCS/PMA or SGMII v9.1

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UG155 March 24, 2008

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Xilinx manual 1000BASE-X with RocketIO Transceivers, RocketIO Transceiver Logic, Virtex-II Pro Devices