
Chapter 3: 10GBASE-R PHY IP Core 3–17
Clocks for Stratix V Devices
November 2012 Altera Corporation Altera Transceiver PHY IP Core
User Guide
Clocks for Stratix V Devices
Figure 3–10 illustrates the clock generation and distribution for Stratix V devices.
1 To ensure proper functioning of the PCS, the maximum PPM difference between the
pll_ref_clk
and
xgmii_tx_clk
clock inputs is 0 PPM. The FIFO in the RX PCS can
compensate
100 PPM between the RX PMA clock and
xgmii_rx_clk
. You should use
xgmii_rx_clk
to drive
xgmii_tx_clk
. The CDR logic recovers 257.8125 MHz clock
from the incoming data.
Register Interface and Register Descriptions
The Avalon-MM PHY management interface provides access to the 10GBASER-R
PHY PCS and PMA registers. You can use an embedded controller acting as an
Avalon-MM master to send read and write commands to this Avalon-MM slave
interface.
Figure 3–10. Stratix V Clock Generation and Distribution
pll_ref_clk
644.53125 MHz
10.3125
Gbps serial
257.8125
MHz
257.8125
MHz
156.25 MHz
10GBASE-R Hard IP Transceiver Channel - Stratix V
TX
RX
TX PCS
40
TX PMA
10.3125
Gbps serial
RX PCS
40
RX PMA
TX PLL
8/33
fPLL
xgmii_rx_clk
rx_coreclkin
xgmii_tx_clk
64-bit data, 8-bit control
64-bit data, 8-bit control
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