Chapter 5: Miscellaneous Functions; Clock Frequency Support - Xilinx Virtex-4 User Manual

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Miscellaneous Functions
This chapter provides useful design information for the Virtex®-4 FPGA Embedded Tri-
Mode Ethernet MAC. It contains the following sections:
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Clock Frequency Support

Table 5-1
MAC. All clock signal output frequencies for both the transmit and receive modules are
generated in the clock-generation module of the Ethernet MAC.
Table 5-1: Transmit Clock Speeds (PHYEMAC#GTXCLK)
Clock Signals
PHYEMAC#GTXCLK
Table 5-2: Receive Clock Speeds (PHYEMAC#RXCLK)
Clock Signals
PHYEMAC#RXCLK
Table 5-3: Client Clock Frequency
Data Rate
EMAC#CLIENTRXCLIENTCLKOUT/
CLIENTEMAC#RXCLIENTCLKIN
EMAC#CLIENTTXCLIENTCLKOUT/
CLIENTEMAC#TXCLIENTCLKIN
Table 5-4: MII/GMII/RGMII Clock Frequency
Clock Signals
EMAC#CLIENTTXGMIIMIICLKOUT/
CLIENTEMAC#TXGMIIMIICLKIN
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Embedded Tri-Mode Ethernet MAC User Guide
UG074 (v2.2) February 22, 2010
"Clock Frequency Support"
"Ethernet MAC Configuration," page 149
"Auto-Negotiation Interrupt," page 151
through Table 5-5 summarize the supported clock frequencies of the Ethernet
Direction
Input
Direction
Input
Direction
Output/
Input
Output/
Input
Direction
Output/
Input
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1000 Mb/s 100 Mb/s
125 MHz 125 MHz
1000 Mb/s 100 Mb/s
125 MHz 25 MHz
1000 Mb/s 100 Mb/s
125 MHz 12.5 MHz
125 MHz 12.5 MHz
1000 Mb/s 100 Mb/s
125 MHz 25 MHz
Chapter 5
10 Mb/s
125 MHz
10 Mb/s
2.5 MHz
10 Mb/s
1.25 MHz
1.25 MHz
10 Mb/s
2.5 MHz
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