CPRI Intel® FPGA IP User Guide

ID 683595
Date 5/19/2023
Public

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2.5.1. Adding the Transceiver TX PLL IP Core

The CPRI Intel® FPGA IP core requires that you generate and connect a TX transceiver PLL IP core for V-series, Intel® Arria® 10, and Intel® Stratix® 10 L- and H-tile device variations. The transceiver PLL IP core configures the TX PLL in the transceiver on the device, but you must generate the transceiver PLL IP core separately from the CPRI IP core in the Intel® Quartus® Prime software. If you do not generate and connect the transceiver PLL IP core, the CPRI IP core does not compile.

In the Intel® Stratix® 10 E-tile and Intel Agilex® 7 E- tile device variations, the PHY includes a transceiver TX PLL and you do not need to instantiate and connect a TX transceiver PLL IP core.

You can use the IP Catalog to generate the external PLL IP core that configures a TX PLL on the device. In the IP Catalog, select an IP core that configures an appropriate PLL on your target device.

For your Stratix V, Arria V, and Cyclone V designs, you can select Intel FPGA PLL (FPLL) or Transceiver PLL in the IP Catalog. In the parameter editor for the TX PLL IP core you select, you must set the PLL output frequency to the expected input frequency for the CPRI IP core xcvr_ext_pll_clk input signal.

For your Intel® Arria® 10 design, you can select Arria 10 Transceiver ATX PLL, Arria 10 Transceiver CMU PLL, or Arria 10 FPLL in the IP Catalog.

For your Intel® Stratix® 10 L- and H-tile designs, you can select L-Tile/H-Tile Transceiver ATX PLL Intel Stratix 10 FPGA IP, L-Tile/H-Tile Transceiver CMU PLL Intel Stratix 10 FPGA IP, or L-Tile/H-Tile fPLL Intel Stratix 10 FPGA IP in the IP Catalog.

In the parameter editor for the TX PLL IP core you select, you must set the following parameter values:

  • Set the PLL output frequency to one half the per-lane data rate of the IP core variation, multiplied by the value of the Transmitter local clock division factor parameter of the CPRI IP core.

    For example, if your CPRI IP variation has a CPRI line bit rate of 10.1376 Gbps and you set the Transmitter local clock division factor to the value of 1, you must set the TX PLL PLL output frequency parameter to the value of 5068.8 MHz.

  • Set the PLL reference clock frequency to a frequency at which you can drive the TX PLL input reference clock. You must drive the external PLL reference clock input signal at the frequency you specify for this parameter.

    For example, if your CPRI IP variation has a CPRI line bit rate of 10.1376 Gbps and you set the Transmitter local clock division factor parameter to the value of 1, you can set the PLL reference clock frequency to the value of 307.2 MHz.

You must connect the external TX PLL signals and the CPRI IP core transceiver TX PLL interface signals according to the following rules.

Table 13.  Required Connections Between Transceiver TX PLL and CPRI Intel® FPGA IP CoreConnect the xcvr_ext_pll_clk input signal of the CPRI IP to the pll_clkout, tx_serial_clk, or outclk0 output signal of the external PLL IP core. Information about connecting the transceiver TX PLL to the Reset Controller is available in Adding the Reset Controller.
CPRI IP Signal TX PLL Type Device TX PLL Signal
xcvr_ext_pll_clk (input) CMU and ATX PLL Intel® Arria® 10 and Intel® Stratix® 10 tx_serial_clk
V-series pll_clkout
fPLL Intel® Arria® 10 and Intel® Stratix® 10 tx_serial_clk
V-series outclk0

If your CPRI IP core is an RE slave, drive the input signal of the external PLL IP core with the output of the off-chip cleanup PLL.

User logic must provide the connections. Refer to the Figure 1 to see how to connect the external TX PLL to a single CPRI IP core.

For your Intel® Stratix® 10 E-tile and Intel Agilex® 7 E- tile designs, clock signals ehip_clk_806 and ehip_clk_403 handle the clock-crossing in Embedded Multi-die Interconnect Bridge (EMIB) interface. These clocks must be frequency locked to each other. You need to use the E-Tile Transceiver Native PHY IP in PLL mode as the clock source to the CPRI IP core as shown in figure below.
Note: The E-Tile Transceiver Native PHY IP used in a PLL mode generates clocks necessary for Application Interface Block (AIB). The PHY includes a transceiver TX PLL that generates PMA high-speed serial clock.
Figure 7. Required External Block for the Intel® Stratix® 10 E-tile and Intel Agilex® 7 E- tile Device Variations

You can create E-Tile Transceiver Native PHY from the IP Catalog:
  • Select the E-Tile Transceiver Native PHY
  • In the parameter editor, set the following parameter values:
    • Set the Transceiver configuration rules to PLL
    • Set the SerDes/Output Driver Enable Mode to Disable output drivers
    • Set the PLL output clock frequency to 805.6640625 MHz
    • Set the PLL reference clock frequency to 156.250000 MHz