CPRI IP User Guide

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ID 683595
Date 10/31/2025
Public
Document Table of Contents
Document Table of Contents x
1. About the CPRI IP 2. Getting Started with the CPRI IP 3. CPRI IP Functional Description 4. CPRI IP Signals 5. CPRI IP Registers 6. CPRI Altera® FPGA IP User Guide Archives 7. Document Revision History for the CPRI IP User Guide
1. About the CPRI IP x
1.1. CPRI IP Features 1.2. CPRI IP Device Family and Speed Grade Support 1.3. IP Verification 1.4. Resource Utilization for CPRI IP 1.5. CPRI IP Release Information
1.2. CPRI IP Device Family and Speed Grade Support x
1.2.1. CPRI IP Device Family Support 1.2.2. CPRI IP Device and Transceiver Speed Grade Support
2. Getting Started with the CPRI IP x
2.1. Installation and Licensing 2.2. Generating a CPRI IP 2.3. CPRI IP Parameters 2.4. Integrating the CPRI IP into your Design: Required External Blocks 2.5. Simulating Intel FPGA IP Cores 2.6. Running the CPRI IP Design Example 2.7. CPRI IP Design Example Clocks 2.8. About the Testbench 2.9. Compiling the Full Design and Programming the FPGA
2.1. Installation and Licensing x
2.1.1. IP Evaluation Mode
2.2. Generating a CPRI IP x
2.2.1. CPRI IP Generated Files
2.4. Integrating the CPRI IP into your Design: Required External Blocks x
2.4.1. Adding the Transceiver TX PLL IP 2.4.2. Adding the Reset Controller 2.4.3. Adding the Transceiver Reconfiguration Controller 2.4.4. Adding the Off-Chip Clean-Up PLL 2.4.5. Adding and Connecting the Single-Trip Delay Calibration Blocks 2.4.6. CPRI IP Transceiver PLL Calibration 2.4.7. Reference and System PLL Clock for your IP Design
2.4.7. Reference and System PLL Clock for your IP Design x
2.4.7.1. System PLL Connections for the Agilex® 7 F-tile Variations 2.4.7.2. System PLL Connections for the Agilex 5 Variations 2.4.7.3. Reset Sequencer Connections for the Agilex 5 Variations
3. CPRI IP Functional Description x
3.1. Interfaces Overview 3.2. CPRI IP Clocking Structure 3.3. CPRI IP Reset Requirements 3.4. Start-Up Sequence Following Reset 3.5. AUX Interface 3.6. Direct IQ Interface 3.7. Ctrl_AxC Interface 3.8. Direct Vendor Specific Access Interface 3.9. Real-Time Vendor Specific Interface 3.10. Direct HDLC Serial Interface 3.11. Direct L1 Control and Status Interface 3.12. L1 Debug Interface 3.13. Media Independent Interface (MII) to External Ethernet Block 3.14. Gigabit Media Independent Interface (GMII) to External Ethernet Block 3.15. CPU Interface to CPRI IP Registers 3.16. Auto-Rate Negotiation 3.17. Extended Delay Measurement 3.18. CPRI IP Deterministic Latency 3.19. CPRI IP Transceiver and Transceiver Management Interfaces 3.20. Testing Features
3.2. CPRI IP Clocking Structure x
3.2.1. Example CPRI IP Clock Connections in Different Clocking Modes
3.4. Start-Up Sequence Following Reset x
3.4.1. Start-Up Sequence Interface Signals
3.5. AUX Interface x
3.5.1. AUX Interface Signals 3.5.2. AUX Interface Synchronization 3.5.3. Auxiliary Latency Cycles 3.5.4. Direct Interface CPRI Frame Data Format
3.14. Gigabit Media Independent Interface (GMII) to External Ethernet Block x
3.14.1. GMII Normal Mode 3.14.2. Ethernet PCS Bypass Mode 3.14.3. Ethernet PCS Run-Time Switching
3.15. CPU Interface to CPRI IP Registers x
3.15.1. CPU Interface Signals 3.15.2. Accessing the Hyperframe Control Words
3.15.2. Accessing the Hyperframe Control Words x
3.15.2.1. Specifying the Control Word 3.15.2.2. Specifying the Position in the Control Word 3.15.2.3. Retrieving the Hyperframe Control Words 3.15.2.4. Writing the Hyperframe Control Words
3.17. Extended Delay Measurement x
3.17.1. Extended Delay Measurement for Soft Internal Buffers 3.17.2. Extended Delay Measurement for Stratix® 10 Hard FIFOs 3.17.3. Extended Delay Measurement Interface
3.19. CPRI IP Transceiver and Transceiver Management Interfaces x
3.19.1. CPRI Link 3.19.2. Main Transceiver Clock and Reset Signals 3.19.3. Arria V, Arria V GZ, Cyclone V, and Stratix V Transceiver Reconfiguration Interface 3.19.4. Arria® 10, Stratix® 10, Agilex® 7, and Agilex™ 5 Transceiver Reconfiguration Interface 3.19.5. RS-FEC Interface 3.19.6. Interface to the External Reset Controller 3.19.7. Interface to the External PLL 3.19.8. Transceiver Debug Interface
3.20. Testing Features x
3.20.1. CPRI IP Loopback Modes 3.20.2. CPRI IP Self-Synchronization Feature
4. CPRI IP Signals x
4.1. CPRI IP Core L2 Interface 4.2. CPRI IP Core L1 Direct Access Interfaces 4.3. CPRI IP Core Management Interfaces 4.4. CPRI IP Core Transceiver and Transceiver Management Signals
1. About the CPRI IP
2. Getting Started with the CPRI IP
3. CPRI IP Functional Description
4. CPRI IP Signals
5. CPRI IP Registers
6. CPRI Altera® FPGA IP User Guide Archives
7. Document Revision History for the CPRI IP User Guide

3.16. Auto-Rate Negotiation

If you turn on Enable line bit rate auto-negotiation in the CPRI parameter editor, the auto-rate negotiation control and status interface is available. This feature is supported in both simulation testbench and hardware for Stratix® 10 E-tile and Agilex® 7 E-tile and F-tile design example variants, while for Agilex™ 5, it is supported only in simulation testbench. The CPRI IP provides support for dynamically changing the CPRI line bit rate. The design example shows how to switch from highest CPRI rate to the lowest CPRI rate that you specify in IP configuration. However, you must add more logic such as T1 interval, to be compliant to auto negotiation in CPRI protocol. You control the process through the auto-rate negotiation control and status interface or the BIT_RATE_CONFIG register at offset 0x0C.

Table 39.  Auto-Rate Negotiation Control and Status Interface Signals

All interface signals are clocked by the cpri_clkout clock.

Signal Name

Direction

Description
nego_bitrate_in[5:0] Input CPRI line bit rate to be used in next attempt to achieve frame synchronization, encoded according to the following valid values:
  • 6'b000001: 0.6144 Gbps
  • 6'b000010: 1.2288 Gbps
  • 6'b000100: 2.4576 Gbps
  • 6'b000101: 3.0720 Gbps
  • 6'b001000: 4.9150 Gbps
  • 6'b001010: 6.1440 Gbps
  • 6'b001100: 8.11008 Gbps
  • 6'b010000: 9.8304 Gbps
  • 6'b010100: 10.1376 Gbps
  • 6b'011000: 12.16512 Gbps
  • 6'b110000 : 24.33024 Gbps

This signal has higher priority than the bit_rate field in the BIT_RATE_CONFIG register at offset 0x0C. When this signal has the value of 6'b000000, the CPRI IP core responds to the register field.
nego_bitrate_out[5:0] Output Reflects the current actual CPRI line bit rate.
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