SNLA364C March   2021  – June 2022 DP83TD510E

 

  1.   Abstract
  2.   Trademarks
  3. 1 Introduction
  4. 2 1-V and 2.4-V p2p Mode Scripts
  5. 3 Time-Domain Reflectometry
    1. 3.1 TDR Application Startup
      1. 3.1.1 TDR_CFG (Address = 0x001E) [Reset = 0x0000]
      2. 3.1.2 TDR_Fault_Status (Address = 0x030C) [Reset = 0x0000]
    2. 3.2 TDR Test Procedure
  6. 4 Active Link Cable Diagnostics
    1. 4.1 ALCD Application Startup
    2. 4.2 ALCD Test Procedure
      1. 4.2.1 Cable Calibration
      2. 4.2.2 Cable Quality Measurement
  7. 5 Signal Quality Indicator
    1. 5.1 SQI Application Startup
      1. 5.1.1 MSE Detection (Address = 0x0A85 ) [Reset = 0x0000]
    2. 5.2 SQI Test Procedure
  8. 6 Cable Diagnostics Summary
  9. 7 Loopback Modes
    1. 7.1 BISCR (Address = 0x0016) [Reset = 0x0100]
  10. 8 Pseudo-Random Bit Sequence Functions
    1. 8.1 PRBS_CFG_1 (Address = 0x0119) [Reset = 0x0574]
    2. 8.2 PRBS_STATUS_4 (Address = 0x011F) [Reset = 0x0000]
  11. 9 USB to MDIO Procedure
  12. 10IEEE 802.3cg PMA Compliance
  13. 11Revision History

3.1 TDR Application Startup

The primary cable faults in Ethernet applications are open and short circuit conditions. The 802.3cg standard states that a PHY can withstand open and short circuits without sustaining damage, up to 60 V. The DP83TD510E implements TDR to identify open and short conditions in the cable and to identify the distance from the PHY the cable fault occurs.

Note:

TDR cannot be run while the PHY is actively linked to a link partner. TDR works by injecting high energy pulses into the cable and measuring the reflected signal. Activity on the channel will interfere with the transmitted pulses and corrupt the received signal.