Ethernet 1000BASE-X PCS/PMA or SGMII v7.0
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47
UG145 January 18, 2006
SGMII Example Design / Dynamic Switching Example Design
R
Receiver Rate Adaptation Module
The Receiver Rate Adaptation module is described in the following files:
VHDL
project_dir>
/
<component_name>
/example_design/
sgmii_adapt/
rx_rate_adapt.vhd
Verilog
project_dir>
/
<component_name>
/example_design/
sgmii_adapt/
rx_rate_adapt.v
This module accepts received data from the Ethernet 1000BASE-X PCS/PMA or SGMII
core. This data is sampled and sent out of the GMII receiver interface for the attached client
MAC. The 1 Gbps and 100 Mbps cases are illustrated in
Figure 4-11
.
At 1 Gbps, the data is valid on every clock cycle of the 125 MHz reference clock (
clk125m
).
Data received from the core is clocked straight through the Receiver Rate Adaptation
module.
Figure 4-10:
Transmitter Rate Adaptation Module Data Sampling
sgmii_clk_en_fall
clk125 m
'1'
Speed is 1 Gbps
D0 D1 D2
D0 D1 D2
gmii_txd_in[7:0]
gmii_txd_out[7:0]
sgmii_clk_en_fall
Speed is 100 Mbps
gmii_txd_in[7:0]
gmii_txd_out[7:0]
D0
D0
D1
D1
D2
10 clk125 m
cycles
clk125 m
sgmii_clk