SNLS647I December   2019  – August 2025 DP83826E , DP83826I

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Mode Comparison Tables
  6. 5 Pin Configuration and Functions (ENHANCED Mode)
  7. 6 Pin Configuration and Functions (BASIC Mode)
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Timing Diagrams
    8. 7.8 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Auto-Negotiation (Speed/Duplex Selection)
      2. 8.3.2  Auto-MDIX Resolution
      3. 8.3.3  Energy Efficient Ethernet
        1. 8.3.3.1 EEE Overview
        2. 8.3.3.2 EEE Negotiation
      4. 8.3.4  EEE for Legacy MACs Not Supporting 802.3az
      5. 8.3.5  Wake-on-LAN Packet Detection
        1. 8.3.5.1 Magic Packet Structure
        2. 8.3.5.2 Magic Packet Example
        3. 8.3.5.3 Wake-on-LAN Configuration and Status
      6. 8.3.6  Low Power Modes
        1. 8.3.6.1 Active Sleep
        2. 8.3.6.2 IEEE Power-Down
        3. 8.3.6.3 Deep Power Down State
      7. 8.3.7  RMII Repeater Mode
      8. 8.3.8  Clock Output
      9. 8.3.9  Media Independent Interface (MII)
      10. 8.3.10 Reduced Media Independent Interface (RMII)
      11. 8.3.11 Serial Management Interface
        1. 8.3.11.1 Extended Register Space Access
        2. 8.3.11.2 Write Address Operation
        3. 8.3.11.3 Read Address Operation
        4. 8.3.11.4 Write (No Post Increment) Operation
        5. 8.3.11.5 Read (No Post Increment) Operation
        6. 8.3.11.6 Example Write Operation (No Post Increment)
      12. 8.3.12 100BASE-TX
        1. 8.3.12.1 100BASE-TX Transmitter
          1. 8.3.12.1.1 Code-Group Encoding and Injection
          2. 8.3.12.1.2 Scrambler
          3. 8.3.12.1.3 NRZ to NRZI Encoder
          4. 8.3.12.1.4 Binary to MLT-3 Converter
        2. 8.3.12.2 100BASE-TX Receiver
      13. 8.3.13 10BASE-Te
        1. 8.3.13.1 Squelch
        2. 8.3.13.2 Normal Link Pulse Detection and Generation
        3. 8.3.13.3 Jabber
        4. 8.3.13.4 Active Link Polarity Detection and Correction
      14. 8.3.14 Loopback Modes
        1. 8.3.14.1 Near-end Loopback
        2. 8.3.14.2 MII Loopback
        3. 8.3.14.3 PCS Loopback
        4. 8.3.14.4 Digital Loopback
        5. 8.3.14.5 Analog Loopback
        6. 8.3.14.6 Far-End (Reverse) Loopback
      15. 8.3.15 BIST Configurations
      16. 8.3.16 Cable Diagnostics
        1. 8.3.16.1 Time Domain Reflectometry (TDR)
      17. 8.3.17 Fast Link-Drop Functionality
      18. 8.3.18 LED and GPIO Configuration
    4. 8.4 Programming
      1. 8.4.1 Hardware Bootstraps Configuration
        1. 8.4.1.1 Bootstrap Configurations (ENHANCED Mode)
        2. 8.4.1.2 Strap Configuration (BASIC Mode)
    5. 8.5 Register Maps
      1. 8.5.1 DP83826 Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Twisted-Pair Interface (TPI) Network Circuit
      2. 9.2.2 Transformer Recommendations
      3. 9.2.3 Capacitive DC Blocking
      4. 9.2.4 Design Requirements
        1. 9.2.4.1 Clock Requirements
          1. 9.2.4.1.1 Oscillator
          2. 9.2.4.1.2 Crystal
      5. 9.2.5 Detailed Design Procedure
        1. 9.2.5.1 MII Layout Guidelines
        2. 9.2.5.2 RMII Layout Guidelines
        3. 9.2.5.3 MDI Layout Guidelines
      6. 9.2.6 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Signal Traces
        2. 9.4.1.2 Return Path
        3. 9.4.1.3 Transformer Layout
        4. 9.4.1.4 Metal Pour
        5. 9.4.1.5 PCB Layer Stacking
          1. 9.4.1.5.1 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

8.3.2 Auto-MDIX Resolution

The DP83826 can determine if a “straight” or “crossover” cable is used to connect to the link partner. The DP83826 can automatically re-assign to Td (MDI) channel and Rd (MDIX) channel to establish link with the link partner. Auto-MDIX resolution precedes the actual Auto-Negotiation process that involves exchange of FLPs to advertise capabilities. Automatic MDI/MDIX is described in IEEE 802.3 Clause 40, section 40.8.2 and is not a required implementation for 10BASE-Te and 100BASE-TX. Auto-MDIX can also be used when operating the PHY in Force Mode.

Auto-MDIX can be enabled or disabled in hardware, using the hardware bootstrap, or by register configuration, using bit[15] of the PHY Control Register (PHYCR, address 0x0019). When Auto-MDIX is disabled, the PMA is forced to either MDI (“straight”) or MDIX (“crossover”). Manual configuration of MDI or MDIX can also be accomplished using register configuration, using bit[14] of the PHYCR or hardware bootstraps in ENHANCED mode.