AN 814: Intel Arria 10 Two x8-Lane JESD204B (Duplex) IP Cores Multi-Device Synchronization Reference Design

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ID 683731
Date 1/30/2018
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Document Table of Contents
Document Table of Contents x
1. Intel® Arria® 10 Two x8-Lane JESD204B IP Cores (Duplex) Multi-Device Synchronization Reference Design
1. Intel® Arria® 10 Two x8-Lane JESD204B IP Cores (Duplex) Multi-Device Synchronization Reference Design x
1.1. Hardware and Software Requirements 1.2. Reference Design Walkthrough 1.3. Reference Design Functional Description 1.4. Document Revision History for AN 814: Intel® Arria® 10 Two x8-Lane JESD204B IP Cores (Duplex) Multi-Device Synchronization Reference Design
1.2. Reference Design Walkthrough x
1.2.1. Hardware Setup 1.2.2. Running the Reference Design 1.2.3. Software Parameters 1.2.4. Software Functions Description 1.2.5. Reconstructing Design and Running in Hardware 1.2.6. Viewing the Results
1.2.2. Running the Reference Design x
1.2.2.1. Configuring the FPGA 1.2.2.2. Executing the Software C Code and Initializing the JESD204B Link
1.2.4. Software Functions Description x
1.2.4.1. Functions in main.c Source File 1.2.4.2. Custom Peripheral Access Macros in macros.c Source File
1.2.5. Reconstructing Design and Running in Hardware x
1.2.5.1. Regenerating Files, Recompiling Design and Configuring the FPGA 1.2.5.2. Rebuilding Software and Initializing the JESD204B Link
1.3. Reference Design Functional Description x
1.3.1. Top Level HDL 1.3.2. Clocking Scheme 1.3.3. FPGA Pin Assignments
1.3.1. Top Level HDL x
1.3.1.1. Platform Designer Top System Component 1.3.1.2. Transport Layer 1.3.1.3. Test Pattern Generator 1.3.1.4. Test Pattern Checker 1.3.1.5. Deterministic Latency Measurement Module 1.3.1.6. Frequency Checker
1.3.1.1. Platform Designer Top System Component x
1.3.1.1.1. JESD204B Subsystem 1.3.1.1.2. Nios® II Subsystem in Platform Designer 1.3.1.1.3. Core PLL 1.3.1.1.4. PLL Reconfiguration Controller 1.3.1.1.5. SPI Master
1.3.1.1.2. Nios® II Subsystem in Platform Designer x
1.3.1.1.2.1. Nios® II Processor 1.3.1.1.2.2. Nios® II Subsystem Address Map
1. Intel® Arria® 10 Two x8-Lane JESD204B IP Cores (Duplex) Multi-Device Synchronization Reference Design

1.3.1.5. Deterministic Latency Measurement Module

The link latency of the design is measured from the TX core is ready to accept data (the rise of) until the data to the RX transport layer is valid. The RBD count varies from 0 to ((FxK/4)-1), which is 0 to 7. You may observe the RBD count=0 or 7 in this FMC external loopback setup. In this scenario, deterministic latency is not guaranteed because the RBD elastic buffer can be released either at the current LMFC boundary when RBD count=0 or one local multi-frame period later at the next LMFC boundary when RBD count=7. During multiple power cycles of the board, you may observe the link latency of 26 or 34 link clock cycles when RBD count is 0 or 7. Due to this, the lane de-skew error could happen during link initialization. To fix the deterministic latency issue, the csr_rbd_offset is programmed to 5 to force the release of RBD elastic buffer 5 LMFC counts before the next LMFC boundary. By setting RBD offset value equal to 5, the counter consistently shows link latency of 29 link clock cycles from one power cycle to another power cycle.

Figure 14. Early RBD Release Opportunity for Latest Arrival Lane Across Two Multi-frames
Level Two Title