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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.
