Xilinx 1000BASE-X - Manual (Page 32)

32 www.xilinx.com Ethernet 1000BASE-X PCS/PMA or SGMII v9.1
UG155 March 24, 2008
Chapter 2: Core Architecture R
Table 2-1: GMII Interface Signal Pinout
Signal Direction Description
gmii_txd[7:0] 1
1. When the Transmitter Elastic Buffer is present these signals are synchronous to gmii_tx_clk. When the
Transmitter Elastic Buffer is omitted, see Note 2.
Input GMII Transmit data from MAC.
gmii_tx_en 1 Input GMII Transmit control signal from MAC.
gmii_tx_er 1 Input GMII Transmit control signal from MAC.
gmii_rxd[7:0] 2
2. These signals are synchronous to the core’s internal 125 MHz reference clock. This is userclk2 when the
core is used with the RocketIO transceiver; gtx_clk when the core is used with TBI.
Output GMII Received data to MAC.
gmii_rx_dv 2 Output GMII Received control signal to MAC.
gmii_rx_er 2 Output GMII Received control signal to MAC.
gmii_isolate 2 Output IOB Tri-state control for GMII Isolation. Only of use
when implementing an External GMII as illustrated by
the example design HDL.