SNLA452 August   2025 DP83TD510E

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Troubleshooting the Application
    1. 2.1 Schematic and Layout Checklist
    2. 2.2 Component Checklist
    3. 2.3 Device Health Checks
      1. 2.3.1 Check Voltage Supply Pins
      2. 2.3.2 Probe the RST_N Pin
      3. 2.3.3 Probe the CLKOUT Pin
      4. 2.3.4 Probe the SMI Pins
    4. 2.4 Read and Check Register Values
    5. 2.5 Verifying Strap Configuration
    6. 2.6 Loopbacks
    7. 2.7 MDI Health Checks
      1. 2.7.1 Link Up Common Issues
      2. 2.7.2 Transmit Level
        1. 2.7.2.1 Change Transmit Level
      3. 2.7.3 Time-Domain Reflectometry
      4. 2.7.4 Signal Quality Check
      5. 2.7.5 MDI Test Modes
    8. 2.8 MII Health Checks
      1. 2.8.1 RGMII
      2. 2.8.2 RMII
      3. 2.8.3 MII
  6. 3Summary
  7. 4References

2.7.1 Link Up Common Issues

If the DP83TD510E is having trouble linking up with a link partner, check for the following common reasons.

Make sure that the device is sending Normal Link Pulses (NLPs) on the MDI lines when connected to an non-powered link partner, or properly terminated with 50Ω. These signals act as an exchange of information between the 2 PHYs sharing the link, so that the signals are able to link up in a configuration designed for both devices. The following waveforms show the expected signal.

Normal Link Pulse (Zoomed In)Figure 2-4 Normal Link Pulse (Zoomed In)
Normal Link PulsesFigure 2-5 Normal Link Pulses

The DP83TD510 can also bypass this auto-negotiation stage and force a link by manually disabling auto-negotiation and configuring each device, one to host, and the other to client. The scripts for these functions are given in the following. The transmit level selected is the same as what the device has been strapped to and is reflected in register 0x18F6[12].

begin

000D 0007
000E 0200
000D 4007
000E 0000 // Disable AN

000D 0001
000E 08F6
000D 4001
000E 1000 // Force transmit level to 2.4V, write 0000 for 1V

000D 0001
000E 0834
000D 4001
000E 4002 // Configure Device as Master, write 0002 for Slave

end