CPRI Intel® FPGA IP User Guide

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ID 683595
Date 5/17/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the CPRI Intel® FPGA IP 2. Getting Started with the CPRI Intel® FPGA IP 3. CPRI IP Functional Description 4. CPRI Intel® FPGA IP Signals 5. CPRI Intel® FPGA IP Registers 6. CPRI Intel® FPGA IP User Guide Archives 7. Document Revision History for the CPRI Intel® FPGA IP User Guide
1. About the CPRI Intel® FPGA IP x
1.1. CPRI Intel® FPGA IP Core Supported Features 1.2. CPRI Intel® FPGA IP Device Family and Speed Grade Support 1.3. Intel® FPGA IP Verification 1.4. Resource Utilization for CPRI Intel® FPGA IP 1.5. CPRI IP Release Information
1.2. CPRI Intel® FPGA IP Device Family and Speed Grade Support x
1.2.1. CPRI IP Device Family Support 1.2.2. CPRI Intel® FPGA IP Device and Transceiver Speed Grade Support
2. Getting Started with the CPRI Intel® FPGA IP x
2.1. Installation and Licensing 2.2. Generating aCPRI Intel® FPGA IP 2.3. CPRI Intel® FPGA IP Generated Files 2.4. CPRI Intel® FPGA IP Parameters 2.5. Integrating the CPRI IP into your Design: Required External Blocks 2.6. Simulating Intel FPGA IP Cores 2.7. Running the CPRI IP Design Example 2.8. CPRI Design Example Clocks 2.9. About the Testbench 2.10. Compiling the Full Design and Programming the FPGA
2.1. Installation and Licensing x
2.1.1. Intel® FPGA IP Evaluation Mode
2.5. Integrating the CPRI IP into your Design: Required External Blocks x
2.5.1. Adding the Transceiver TX PLL IP Core 2.5.2. Adding the Reset Controller 2.5.3. Adding the Transceiver Reconfiguration Controller 2.5.4. Adding the Off-Chip Clean-Up PLL 2.5.5. Adding and Connecting the Single-Trip Delay Calibration Blocks 2.5.6. CPRI IP Transceiver PLL Calibration 2.5.7. Reference and System PLL Clock for your IP Design
2.5.7. Reference and System PLL Clock for your IP Design x
2.5.7.1. System PLL Connections for the Agilex® 7 F-tile Variations 2.5.7.2. System PLL Connections for the Agilex 5 Variations 2.5.7.3. Reset Sequencer Connections for the Agilex 5 Variations
3. CPRI IP Functional Description x
3.1. Interfaces Overview 3.2. CPRI Intel® FPGA IP Clocking Structure 3.3. CPRI Intel® FPGA IP Core 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 Intel® FPGA IP Registers 3.16. Auto-Rate Negotiation 3.17. Extended Delay Measurement 3.18. Deterministic Latency and Delay Measurement and Calibration 3.19. CPRI Intel® FPGA IP Transceiver and Transceiver Management Interfaces 3.20. Testing Features
3.2. CPRI Intel® FPGA IP Clocking Structure x
3.2.1. Example CPRI Intel® FPGA IP Core 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 Intel® FPGA 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
3.18. Deterministic Latency and Delay Measurement and Calibration x
3.18.1. Delay Measurement and Calibration Features 3.18.2. Delay Requirements 3.18.3. Single-Hop Delay Measurement 3.18.4. Multi-Hop Delay Measurement 3.18.5. Delay Calibration Features
3.18.3. Single-Hop Delay Measurement x
3.18.3.1. Rx Path Delay 3.18.3.2. Tx Path Delay 3.18.3.3. Round-Trip Delay
3.18.5. Delay Calibration Features x
3.18.5.1. Single-Trip Delay Calibration 3.18.5.2. Round-Trip Delay Calibration 3.18.5.3. Tx Bitslip Delay
3.18.5.1. Single-Trip Delay Calibration x
3.18.5.1.1. Single-Trip Latency Measurement and Calibration Interface Signals
3.19. CPRI Intel® FPGA 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, and Agilex® 7 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 Intel® FPGA IP Core Loopback Modes 3.20.2. CPRI Intel® FPGA IP Core Self-Synchronization Feature
4. CPRI Intel® FPGA IP Signals x
4.1. CPRI Intel® FPGA IP Core L2 Interface 4.2. CPRI Intel® FPGA IP Core L1 Direct Access Interfaces 4.3. CPRI Intel® FPGA IP Core Management Interfaces 4.4. CPRI Intel® FPGA IP Core Transceiver and Transceiver Management Signals
1. About the CPRI Intel® FPGA IP
2. Getting Started with the CPRI Intel® FPGA IP
3. CPRI IP Functional Description
4. CPRI Intel® FPGA IP Signals
5. CPRI Intel® FPGA IP Registers
6. CPRI Intel® FPGA IP User Guide Archives
7. Document Revision History for the CPRI Intel® FPGA IP User Guide

3.18.3.3. Round-Trip Delay

You can read the ROUND_TRIP_DELAY register or calculate the round-trip delay from the delay components (Rx path delay, Tx path delay,cable delay, and Rx-to-Tx switching latency). The round_trip_delay field of the ROUND_TRIP_DELAY register in an REC master records the total round-trip delay from the start of the internal transmit radio frame in the REC to the start of the internal receive radio frame in the REC, that is, from SAP to SAP, in CPRI REC and RE masters.

CPRI v7.0 Specification requirements R-20 and R-21 address the round-trip delay. Requirement R-20 addresses the measurement without including the cable delay, and requirement R-21 is the requirement for the cable delay. Both requirements state that the variation must be no more than ±16.276 ns.

To monitor the round-trip delay, you must check periodically to confirm that the variation in measurements over time is small enough that the requirements are met.

Note: The round trip delay is the sum of the Tx path delays through the REC master and the RE slave, the Rx path delays through the REC master and the RE slave, the cable delay, and the Tx-to-Rx switching delay, sometimes referred to as the loopback delay. The Tx-to-Rx switching delay is labeled T_S_Rx_Tx in the figure. The Tx-to-Rx switching delay depends on the loopback path and the device.
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