SNLA443A December   2023  – August 2025 DP83869HM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1DP83869 Application Overview
  5. 2Troubleshooting the Application
    1. 2.1 Schematic and Layout Checklist
    2. 2.2 Device Health Checks
      1. 2.2.1 Voltage Checks
      2. 2.2.2 Probe the RESET_N Signal
      3. 2.2.3 Probe RBIAS
      4. 2.2.4 Probe the XI Clock
      5. 2.2.5 Probe the Strap Pins During Initialization
        1. 2.2.5.1 Configuring Correct Operational Mode
      6. 2.2.6 Probe the Serial Management Interface (MDC, MDIO)
        1. 2.2.6.1 Read and Check Register Values
    3. 2.3 MDI Health Checks
      1. 2.3.1 Magnetics
      2. 2.3.2 Probe the MDI Signals
      3. 2.3.3 Check the Link Quality
        1. 2.3.3.1 Improving Short Cable Link Margin
        2. 2.3.3.2 Improving Inter-channel Link Margin
      4. 2.3.4 Compliance
    4. 2.4 MII Health Checks
      1. 2.4.1 MII Check
      2. 2.4.2 RGMII Check
      3. 2.4.3 SGMII Check
    5. 2.5 Loopback and PRBS
      1. 2.5.1 Loopback Modes
      2. 2.5.2 Transmitting and Receiving Packets with the MAC
      3. 2.5.3 Transmitting and Receiving Packets with BIST
  6. 3Operational Mode Clarification
    1. 3.1 Bridge Modes
    2. 3.2 Fiber Configuration
      1. 3.2.1 Fiber Registers
      2. 3.2.2 Media Converter LED Behavior
  7. 4Tools and References
    1. 4.1 Extended Register Access
      1. 4.1.1 Read (No Post Increment) Operation
      2. 4.1.2 Write (No Post Increment) Operation
    2. 4.2 Software and Driver Debug on Linux
      1. 4.2.1 Common Terminal Outputs
  8. 5Summary
  9. 6References
  10. 7Revision History

2 Troubleshooting the Application

The following sections approach the debug from a high level, basic check approach which isolates subsystems of the PHY design to check if the subsystems contribute to an application issue. This document is intended to address common Ethernet issues such as:

  • Inability to ping
  • Cannot get link OR intermittent linkup
  • Linkup but seeing packet errors
  • Cannot access registers

The recommendation is to go through the following sections in order unless otherwise specified.