Embedded Tri-Mode Ethernet MAC User Guide www.xilinx.com 119
UG074 (v2.2) February 22, 2010
10/100/1000 RGMII
R
The CLIENTEMAC#DCMLOCKED port must be tied HIGH. The RGMII_RXC_# is
generated from the PHY and connected to the PHYEMAC#RXCLK pin and receive logic
through a DCM and a BUFG. A DCM must be used on the RGMII_RXC_# clock path as
illustrated in Figure 4-14 to meet the RGMII 1 ns setup and 1 ns hold requirements at
1 Gb/s. Phase shifting may then be applied to the DCM to fine-tune the setup and hold
Figure 4-15: Alternative Tri-Mode RGMII v2.0 Clock Management
EMAC#
PHYEMAC#GTXCLK
CLIENTEMAC#TXGMIIMIICLKIN
EMAC#CLIENTTXGMIIMIICLKOUT
CLIENTEMAC#TXCLIENTCLKIN
EMAC#CLIENTTXCLIENTCLKOUT
EMAC#PHYTXD[3:0]
EMAC#PHYTXD[7:4]
PHYEMAC#MIITXCLK
CLIENTEMAC#DCMLOCKED
CLIENTEMAC#RXCLIENTCLKIN
EMAC#CLIENTRXCLIENTCLKOUT
GTX_CLK
TX Client
Logic
RX Client
Logic
BUFG
BUFG
OBUF
IBUF
ODDR
D1
D2
Q
RGMII_TXD_#[3:0]
BUFG
(1)
IDELAY
RGMII_IOB_#
OBUF
RGMII_TXC_#
IOBUF
ODDR
D1
D2
Q
0
1
0
1
SPEED_IS_10_100
D1
D2
V
CC
V
CC
V
CC
GND
GND
GND
D1
D2
No Connection
PHYEMAC#RXCLK
PHYEMAC#RXD[3:0]
PHYEMAC#RXD[7:4]
RGMII_RXD_#[3:0]
Q1
Q2
D
Notes:
1) A regional buffer (BUFR) can replace this BUFG.
Refer to the Virtex-4 User Guide for BUFR usage guidelines.
UG074_3_79_031009
CLKIN
CLKFB
DCM
CLK0
SPEED_IS_10_100
BUFGMUX
RGMII_RXC_#
IBUFG
0
1
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