F-Tile CPRI PHY Intel® FPGA IP User Guide

ID 683284
Date 3/28/2022
Public

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5.1. Clock Signals

Each CPRI PHY channel has its own pair of datapath clocks and each transceiver has its own reference clock. The reconfiguration clock is shared.
Table 14.  CPRI PHY Clock Input Signals
Port name Width (Bits) Description
system_pll_clk_link 1 System PLL clock link port.
tx_pll_refclk_link 1 TX PLL reference clock link port.
rx_cdr_refclk_link 1 RX CDR reference clock link port.
i_reconfig_clk 1 Reconfiguration clock.
i_sampling_clk 1 Sampling clock for deterministic latency logic.
Table 15.  Clock Source SignalsThis table lists the clock source ports for the CPRI core. The IP core provides locally generated PLL clocks and recovered clocks that can be used for the datapath.
Signal Name Width (Bits) I/O Direction Description
o_tx_clkout 1 Output System clock divided by 2.
o_tx_clkout2 1 Output Parallel TX clock:
  • For 64B/66B PCS, running at line rate/66.
  • For 8B/10B PCS, running at line rate/20.

Hold circuits using this clock in reset until o_tx_pll_lock is high.

o_rx_clkout 1 Output System clock divided by 2.
o_rx_clkout2 1 Output Parallel RX recovered clock:
  • For 64B/66B PCS, running at line rate/66.
  • For 8B/10B PCS, running at line rate/20.

Hold circuits using this clock in reset until o_rx_cdr_lock is high.

Table 16.  Clock Status SignalsThis table lists the clock status ports for the CPRI core. Use these ports to hold the circuits that use clock sources from the IP core in reset until the PLLs driving the clocks are locked.
Signal Name Width (Bits) I/O Direction Description
o_tx_pll_lock 1 Output Indicates the TX PLL driving clock signals from the core is locked.

Do not use the o_tx_clkout or o_tx_clkout2 clocks until the o_tx_pll_lock clock is high.

o_rx_cdr_lock 1 Output Indicates that the recovered clocks are locked to data.

Do not use the o_rx_clkout or o_rx_clkout2 clocks until the o_rx_cdr_lock clock is high.