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

2.3.4 Probe the SMI Pins

If register reads or writes are successful, this section can be skipped.

If register reads or writes are unsuccessful, probe the MDC pin (pin 12) to verify that there is a ≤1.75MHz clock signal being sourced from the Host Controller. Since this is a lower speed device, at 10Mbps, the supported MDC Clock rate is also lower. Also make sure that the MDIO pin has a external pull-up resistor 2.2kΩ - 4.0kΩ. Additionally, the MDIO signal (pin 11) can be decoded using a Logic Analyzer.

MDC/MDIO SignalingFigure 2-2 MDC/MDIO Signaling

The signal ib Figure 2-2 shows a simple read command for register 0x3, which contains the device model number, and must always read as 0x0181 for the DP83TD510.

Note, to access registers beyond 0x1F, the extended register access procedure must be followed, which is given in section 6.3.10 of the data sheet..