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