LVDS SERDES Transmitter / Receiver IP Cores User Guide

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ID 683062
Date 12/15/2017
Public
Document Table of Contents
Document Table of Contents x
1. LVDS SERDES Transmitter/Receiver IP Cores User Guide
1. LVDS SERDES Transmitter/Receiver IP Cores User Guide x
1.1. Features 1.2. Parameter Settings 1.3. Ports 1.4. Prototypes and Component Declarations 1.5. Functional Description 1.6. Simulating Intel® FPGA IP Cores 1.7. Generating ALTLVDS IP Core Using Clear Box Generator 1.8. LVDS SERDES Transmitter/Receiver IP Cores User Guide Archives 1.9. Document Revision History for LVDS SERDES Transmitter/Receiver IP Cores User Guide
1.1. Features x
1.1.1. Resource Utilization and Performance
1.2. Parameter Settings x
1.2.1. ALTLVDS_TX Parameter Settings 1.2.2. ALTLVDS_RX Parameter Settings 1.2.3. Command Line Interface Parameters
1.3. Ports x
1.3.1. ALTLVDS_TX Ports 1.3.2. ALTLVDS_RX Ports
1.4. Prototypes and Component Declarations x
1.4.1. Verilog HDL Prototype 1.4.2. VHDL Component Declaration 1.4.3. VHDL LIBRARY-USE Declaration
1.5. Functional Description x
1.5.1. Receiver Modes 1.5.2. DPA PLL Calibration 1.5.3. Initialization and Reset 1.5.4. Source-Synchronous Timing Analysis and Timing Constraints 1.5.5. Arria II GX, Arria® V, Arria® V GZ, Cyclone® V, and Stratix® V LVDS Package Skew Compensation Report Panel 1.5.6. ALTLVDS IP Core in External PLL Mode
1.5.1. Receiver Modes x
1.5.1.1. DPA Mode 1.5.1.2. Non-DPA Mode 1.5.1.3. Soft-CDR Mode
1.5.1.3. Soft-CDR Mode x
1.5.1.3.1. Clock Forwarding 1.5.1.3.2. Standard Mode 1.5.1.3.3. No Output Register Mode
1.5.2. DPA PLL Calibration x
1.5.2.1. DPA PLL Calibration in Stratix IV ES Devices 1.5.2.2. DPA PLL Calibration in Arria II and Stratix IV Devices and Later 1.5.2.3. Effects of DPA PLL Calibration
1.5.3. Initialization and Reset x
1.5.3.1. Initializing ALTLVDS_TX and ALTLVDS_RX 1.5.3.2. Resetting the DPA 1.5.3.3. Aligning the Word Boundaries 1.5.3.4. Recommended Initialization and Reset Flow
1.5.4. Source-Synchronous Timing Analysis and Timing Constraints x
1.5.4.1. Dedicated SERDES 1.5.4.2. SERDES in LEs 1.5.4.3. Receiver Skew Margin and Transmitter Channel-to-Channel Skew 1.5.4.4. Setting Timing Constraints Using the TimeQuest Timing Analyzer GUI 1.5.4.5. Setting Timing Constraints Manually in the Synopsys Design Constraint File
1.5.4.3. Receiver Skew Margin and Transmitter Channel-to-Channel Skew x
1.5.4.3.1. Obtaining the RSKM Report 1.5.4.3.2. Obtaining the TCCS Report
1.5.4.4. Setting Timing Constraints Using the TimeQuest Timing Analyzer GUI x
1.5.4.4.1. Constraining the Input Clock Signal
1.5.6. ALTLVDS IP Core in External PLL Mode x
1.5.6.1. PLL Clock Signals for LVDS Interface in External PLL Mode 1.5.6.2. External PLL Compensation Mode for ALTLVDS IP Core in External PLL Mode
1. LVDS SERDES Transmitter/Receiver IP Cores User Guide

1.5.2.1. DPA PLL Calibration in Stratix IV ES Devices

Applications using a fixed, cyclical training pattern with sparse data transitions can cause the PLL phase to remain unchanged, which results in DPA misalignment. When DPA misaligns the DPA circuitry remains at the initial configured phase or takes a significantly longer time to lock onto the optimum phase. A non-ideal phase might result in data bit errors, even after the DPA lock signal goes high. Resetting the DPA circuit may not solve the problem.

The following figure shows that the DPA takes longer time to lock onto the optimum phase even after the rx_reset and rx_dpa_locked signals are asserted, resulting in data errors.

Figure 3. DPA Misalignment Issue


In the Intel® Quartus® Prime software versions 9.0 and later, the DPA PLL calibration feature is added to the ALTLVDS_RX IP core to overcome the DPA misalignment issue found in Stratix IV ES devices; the Stratix IV production devices are not affected. The DPA PLL calibration feature is available when the LVDS receiver is configured in DPA or soft-CDR mode. DPA PLL calibration phase-shifts the PLL outputs to induce progress in the PLL’s phase-detect up and down counter and to facilitate a new phase selection.

The following events occur during the DPA PLL calibration process:

  1. The ALTLVDS_RX IP core counts 256 data transitions; the PLL calibrates the phase forward by two clocks.
  2. The ALTLVDS_RX IP core counts 256 transitions; the PLL calibrates the phase backward by two clocks so that the PLL timing returns to normal.
  3. The ALTLVDS_RX IP core counts 256 data transitions, and then asserts the rx_dpa_locked signal.
Note: For more information about DPA lock time specification, refer to the Device Data Sheet chapter in the respective device handbook.
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