LVDS Tunneling Protocol and Interface (LTPI) IP User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs

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ID 844310
Date 8/15/2025
Public
Document Table of Contents
Document Table of Contents x
1. Overview 2. Configuring and Generating the IP 3. Simulating the IP 4. Validating the IP 5. Troubleshooting and Debugging Issues 6. Appendix A: Functional Description 7. Appendix B: Registers 8. Document Revision History for the LVDS Tunneling Protocol and Interface (LTPI) IP User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs
1. Overview x
1.1. About the LVDS Tunneling Protocol and Interface (LTPI) IP 1.2. About the Document 1.3. Applicable Applications 1.4. Key Concepts 1.5. IP Design Flow 1.6. Design Considerations/Guidelines
1.1. About the LVDS Tunneling Protocol and Interface (LTPI) IP x
1.1.1. IP Release Information 1.1.2. IP Features 1.1.3. IP High-level Block Diagram 1.1.4. Licensing the IP 1.1.5. Device Family Support 1.1.6. Device Speed Grade Support 1.1.7. IP Core Support Levels 1.1.8. IP Performance and Resource Utilization
1.2. About the Document x
1.2.1. Target Audience 1.2.2. Conventions Used in the Document 1.2.3. Acronyms 1.2.4. Reference Documents and Training
1.4. Key Concepts x
1.4.1. Interface Tunneling Principle 1.4.2. LTPI Tunneling Methodology 1.4.3. Clock Topology 1.4.4. LTPI Frame 1.4.5. System-level Block Diagram 1.4.6. Link Management 1.4.7. Signal Description
1.4.4. LTPI Frame x
1.4.4.1. Link Detect and Link Speed Selection Frames 1.4.4.2. Link Detect Frame 1.4.4.3. Link Speed Frame 1.4.4.4. Advertise, Configure, and Accept Frames 1.4.4.5. Advertise Frames 1.4.4.6. Configure Frame 1.4.4.7. Accept Frame 1.4.4.8. LTPI Operational Frames 1.4.4.9. Default I/O Frame 1.4.4.10. Default Data Frame
1.4.6. Link Management x
1.4.6.1. Link Training 1.4.6.2. Link Configuration 1.4.6.3. Operational Mode
1.4.7. Signal Description x
1.4.7.1. Clock and Power Signals 1.4.7.2. Channel Signals 1.4.7.3. Avalon® Memory-Mapped Primary Interface Signals 1.4.7.4. Avalon® Memory-Mapped Secondary Interface Signals 1.4.7.5. Avalon® Memory-Mapped CSR Interface Signals 1.4.7.6. Miscellaneous Interface Signals
2. Configuring and Generating the IP x
2.1. Configuring the Quartus® Prime Pro Edition Project 2.2. Configuring the LVDS Tunneling Protocol and Interface (LTPI) IP 2.3. Generating HDL for Synthesis and Simulation 2.4. Generating the Simulation Design Example
2.2. Configuring the LVDS Tunneling Protocol and Interface (LTPI) IP x
2.2.1. Configuring the LVDS Tunneling Protocol and Interface (LTPI) IP Parameters
2.3. Generating HDL for Synthesis and Simulation x
2.3.1. Generated File Structure
2.4. Generating the Simulation Design Example x
2.4.1. Generated Directory Structure and Files
3. Simulating the IP x
3.1. Design Example Features 3.2. Design Example Components 3.3. Configuring the Design Example Parameters 3.4. Simulating the Design Example
3.4. Simulating the Design Example x
3.4.1. Simulation Testbench Flow 3.4.2. Simulation Output
4. Validating the IP x
4.1. Validating the IP Using Agilex™ 5 Device
4.1. Validating the IP Using Agilex™ 5 Device x
4.1.1. Compiling the Design Example in Hardware on Agilex™ 5 Device 4.1.2. Validating the Design Example in Hardware on Agilex™ 5 Device
4.1.2. Validating the Design Example in Hardware on Agilex™ 5 Device x
4.1.2.1. Configuring the Clocks in Hardware 4.1.2.2. Programming the FPGA 4.1.2.3. Running the Hardware Test
6. Appendix A: Functional Description x
6.1. GPIO Channel 6.2. I2C Channel 6.3. UART Channel 6.4. Data Channel 6.5. OEM Channel
1. Overview
2. Configuring and Generating the IP
3. Simulating the IP
4. Validating the IP
5. Troubleshooting and Debugging Issues
6. Appendix A: Functional Description
7. Appendix B: Registers
8. Document Revision History for the LVDS Tunneling Protocol and Interface (LTPI) IP User Guide: Agilex™ 3 and Agilex™ 5 FPGAs and SoCs

1.1.3. IP High-level Block Diagram

The LTPI interface can be implemented with two FPGA or CPLD devices for configurations with typical BMC devices:
  • HPM FPGA
    • Facilitating the connection between local HPM interfaces and LTPI.
    • HPM is a key component that communicates with SCM.
    • HPM uses LTPI to send and receive different types of control signals to and from the SCM, ensuring efficient and reliable communication within the system.
  • SCM FPGA or CPLD
    • Connecting LTPI with local SCM interfaces.
    • SCM is responsible for managing and securing the communication between different components in a data center.
    • SCM ensures that various low-speed signals are transmitted securely and efficiently over the LVDS interface.

Both HPM and SCM work together to manage and secure communication within a system by tunneling control signals over the LVDS interface within the system.

Figure 1. High-Level Diagram of LTPI Usage
Figure 2. Block Diagram of LTPI
Table 2.  Design Component Descriptions
Component Description
Fabric PLL Generates system clock and reference clock to the IP.
PHY PLL Internal clock that drives the LTPI TX and RX channels.
Link Management
Manages LVDS link training and Link FSM. This block is responsible for:
  • Link state machine control (link training and interface configuration)
  • Generation of outgoing LTPI frames
  • Parsing of incoming LTPI frames
  • CRC checksum generation and verification
  • Comma symbol chasing and locking
  • 8b/10b encoding and decoding
Channel Interface (Controller/Target) Samples or drives the I/O pins for capturing and reconstructing of the physical interfaces on the LTPI channels:
  • GPIO
  • I2C/SMBus
  • UART
  • OEM
  • Data
Configuration and Status Registers (CSRs) Manages BMC or other device on the SCM or HPM to read the status/error signals and to configure advertise capability.
Level Two Title