CPRI Intel® FPGA IP User Guide

ID 683595
Date 5/17/2024
Public
Document Table of Contents

2.5.2. Adding the Reset Controller

The CPRI Intel® FPGA IP requires that you provide reset control logic to handle the required reset sequence for the IP core transceiver on the device. For a duplex CPRI IP, you must generate and connect two Transceiver PHY Reset Controller IPs to perform this function, one reset controller for the TX transceiver and one reset controller for the RX transceiver in the CPRI IP. If you do not implement the device-specific transceiver reset sequence, the IP does not function correctly in hardware.

You can use the IP Catalog to generate Transceiver PHY Reset Controller IPs for the device family that your CPRI IP core targets.

The CPRI IP configures the Native PHY IP for the target device family. You must configure the reset controllers to coordinate reset of the CPRI IP including the Native PHY IP core, and the transceiver PLL IP. In the case of Arria V, Arria V GZ, Cyclone V, and Stratix V variations, the reset controllers must also coordinate with the transceiver reconfiguration controller. Refer to the device specific PHY user guide for more information.

The CPRI IP that targets Stratix® 10 E-tile or Agilex® 7 devices uses the embedded reset controller and do not require external reset controller.

To configure a TX reset controller, in the Transceiver PHY Reset Controller parameter editor, you must set the following parameter values:

  • Set Input clock frequency to a value in the range of 100–150 MHz. You must drive the CPRI IP reconfig_clk at the same frequency you specify for this parameter.
  • Turn on Synchronize reset input.
  • Turn on Use fast reset for simulation.
  • Turn on Enable TX PLL reset control.
  • Set pll_powerdown duration to the value of 10.
  • Turn on Enable TX channel reset control.
  • Leave all other parameters turned off or for the parameters that do not turn on or off, at their default values.

To configure an RX reset controller, in the Transceiver PHY Reset Controller parameter editor, you must set the following parameter values:

  • Set Input clock frequency to a value in the range of 100–150 MHz. You must drive the CPRI IP reconfig_clk at the same frequency you specify for this parameter.
  • Turn on Synchronize reset input.
  • Turn on Use fast reset for simulation.
  • Turn on Enable RX channel reset control.
  • Leave all other parameters turned off or for the parameters that do not turn on or off, at their default values.

You must connect the external reset controller signals to the CPRI IP core reset controller interface signals and transceiver TX PLL signals according to the following rules. Refer to Integrating the CPRI IP into your Design: Required External Blocks for an illustration of the connections.

Table 14.  Required Connections to and From Reset Controllers in CPRI DesignLists the required connections between the reset controllers and the CPRI IP and the transceiver TX PLL IP core. For information about connecting the transceiver TX PLL to the CPRI IP, refer to Adding the Transceiver TX PLL IP Core.
Transmit-Side Reset Controller Signal Connect to
clock (input) Clock source for CPRI IP reconfig_clk input signal
reset (input) Source of CPRI IP reset_tx_n input signal, inverted
pll_powerdown (output) TX PLL pll_powerdown
pll_locked (input) TX PLL pll_locked
tx_analogreset (output) CPRI IP xcvr_tx_analogreset
tx_digitalreset (output) CPRI IP xcvr_tx_digitalreset
tx_cal_busy (input) CPRI IP xcvr_tx_cal_busy
tx_ready (output) CPRI IP xcvr_reset_tx_ready
Receive-Side Reset Controller Signal Connect to
clock (input) Clock source for CPRI IP reconfig_clk input signal
reset (input) Source of CPRI IP reset_rx_n input signal, inverted
rx_is_lockedtodata (input) CPRI IP xcvr_rx_is_lockedtodata
rx_analogreset (output) CPRI IP xcvr_rx_analogreset
rx_digitalreset (output) CPRI IP xcvr_rx_digitalreset
rx_cal_busy (input) CPRI IP xcvr_rx_cal_busy
rx_ready (output) CPRI IP xcvr_reset_rx_ready

User logic must provide the connections. Refer to the demonstration testbench for example working user logic including one correct method to instantiate and connect the external reset controllers. Refer to the Figure 1 diagram to see the connections.