GTS JESD204B IP User Guide

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ID 832100
Date 8/29/2025
Public
Document Table of Contents
Document Table of Contents x
1. GTS JESD204B IP Quick Reference 2. About the GTS JESD204B Intel® FPGA IP 3. Getting Started 4. GTS JESD204B IP Functional Description 5. GTS JESD204B IP Deterministic Latency Implementation Guidelines 6. GTS JESD204B IP Debug Guidelines 7. Document Revision History for the GTS JESD204B User Guide
2. About the GTS JESD204B Intel® FPGA IP x
2.1. Release Information 2.2. Device Family Support 2.3. Datapath Modes 2.4. IP Variation 2.5. GTS JESD204B IP Configuration 2.6. Channel Bonding 2.7. Performance and Resource Utilization
3. Getting Started x
3.1. Introduction to Intel® FPGA IP Cores 3.2. Installing and Licensing Intel® FPGA IP Cores 3.3. Intel® FPGA IP Evaluation Mode 3.4. Upgrading IP Cores 3.5. IP Catalog and Parameter Editor 3.6. Design Walkthrough 3.7. GTS JESD204B IP Design Considerations 3.8. GTS JESD204B IP Parameters 3.9. Analog Parameter Settings 3.10. GTS JESD204B IP Component Files
3.6. Design Walkthrough x
3.6.1. Creating a New Quartus® Prime Project 3.6.2. Parameterizing and Generating the IP 3.6.3. Compiling the GTS JESD204B IP Core Design 3.6.4. Programming an FPGA Device
3.7. GTS JESD204B IP Design Considerations x
3.7.1. Integrating the GTS JESD204B IP in Platform Designer 3.7.2. Pin Assignments 3.7.3. Configuring the GTS Reset Sequencer Intel® FPGA IP
4. GTS JESD204B IP Functional Description x
4.1. Transmitter 4.2. Receiver 4.3. Dual Simplex Support 4.4. Operation 4.5. Clocking Scheme 4.6. Reset Scheme 4.7. Signals 4.8. Registers
4.1. Transmitter x
4.1.1. TX Data Link Layer 4.1.2. TX PHY Layer
4.1.1. TX Data Link Layer x
4.1.1.1. TX CGS 4.1.1.2. TX ILAS 4.1.1.3. User Data Phase
4.2. Receiver x
4.2.1. RX Data Link Layer 4.2.2. RX PHY Layer
4.2.1. RX Data Link Layer x
4.2.1.1. RX CGS 4.2.1.2. Frame Synchronization 4.2.1.3. Frame Alignment 4.2.1.4. Lane Alignment 4.2.1.5. ILAS Data 4.2.1.6. Initial Lane Synchronization
4.4. Operation x
4.4.1. Operating Modes 4.4.2. Scrambler/Descrambler 4.4.3. SYNC_N Signal 4.4.4. Link Reinitialization 4.4.5. Link Startup Sequence 4.4.6. Error Reporting Through SYNC_N Signal
4.4.1. Operating Modes x
4.4.1.1. Subclass 0 Operating Mode 4.4.1.2. Subclass 1 Operating Mode 4.4.1.3. Subclass 2 Operating Mode
4.5. Clocking Scheme x
4.5.1. Device Clock 4.5.2. Link Clock 4.5.3. Local MultiFrame Clock 4.5.4. Clock Correlation 4.5.5. GTS Reset Sequencer Intel® FPGA IP Clock
4.6. Reset Scheme x
4.6.1. Reset Sequence 4.6.2. TX Reset Entry and Exit Sequence 4.6.3. RX Reset Entry and Exit Sequence
4.7. Signals x
4.7.1. Transmitter Signals 4.7.2. Receiver Signals
4.8. Registers x
4.8.1. Register Access Type Convention 4.8.2. Register Map and Definition 4.8.3. Transmitter Registers 4.8.4. Receiver Registers
5. GTS JESD204B IP Deterministic Latency Implementation Guidelines x
5.1. Constraining Incoming SYSREF Signal 5.2. Programmable RBD Offset 5.3. Programmable LMFC Offset 5.4. Maintaining Deterministic Latency during Link Reinitialization
6. GTS JESD204B IP Debug Guidelines x
6.1. Clocking Scheme 6.2. GTS JESD204B Parameters 6.3. SPI Programming 6.4. Converter and FPGA Operating Conditions 6.5. Signal Polarity and FPGA Pin Assignment 6.6. Transceiver Toolkit
1. GTS JESD204B IP Quick Reference
2. About the GTS JESD204B Intel® FPGA IP
3. Getting Started
4. GTS JESD204B IP Functional Description
5. GTS JESD204B IP Deterministic Latency Implementation Guidelines
6. GTS JESD204B IP Debug Guidelines
7. Document Revision History for the GTS JESD204B User Guide

4.5.1. Device Clock

In a converter device, the sampling clock is typically the device clock.

For the GTS JESD204B IP in an FPGA logic device, you need two reference clocks as shown in the JESD204B Subsystem with Separate Transceiver Reference Clock and Core Clock figure. In the dual reference clock design, the device clock is used as the core PLL reference clock and the other reference clock is used as the transceiver PLL reference clock. Use a common clock source on the board to generate two separate clocks of the same frequency to drive the inputs. The available frequency depends on the PLL type, data rate, number of lanes, and device family. During IP core generation, you can select one of the options provided in the PLL/CDR reference clock frequency parameter in the GTS JESD204B IP parameter editor.

Note: Due to the clock network architecture in the FPGA, Altera recommends that you use the device clock to generate the link clock and use the link clock as the timing reference. You need to use the IOPLL Intel® FPGA IP core to generate the link clock and frame clock. The link clock is used in the GTS JESD204B IP (MAC) and the transport layer. You are recommended to supply the reference clock source through a dedicated reference clock pin.

Based on the JESD204B specification for Subclass 1, the device clock is the timing reference and is source synchronous with SYSREF. To achieve deterministic latency, match the board trace length of the SYSREF signal with the device clock. Maintain a constant phase relationship between the device clock and SYSREF signal pairs going to the FPGA and converter devices. Ideally, the SYSREF pulses from the clock generator should arrive at the FPGA and converter devices at the same time. To avoid half link clock latency variation, you must supply the device clock at the same frequency as the link clock.

The JESD204B protocol does not support rate matching. Therefore, you must ensure that the TX or RX device clock (pll_ref_clk) and the PLL reference clock that generates link clock (txlink_clk or rxlink_clk) and frame clock (txframe_clk or rxframe_clk) have 0 ppm variation. Both PLL reference clocks should come from the same clock chip.

Figure 17. JESD204B Subsystem with Separate Transceiver Reference Clock and Core Clock
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