SNLA487 May   2025 DP83826AE , DP83826AI

 

  1.   1
  2.   KSZ8081MNX/RNB to DP83826A System Rollover
  3.   Trademarks
  4. 1Purpose
  5. 2Required Changes
    1. 2.1 Strap Resistor Value
    2. 2.2 External Capacitor on Pin 2
    3. 2.3 Duplex Strap on Pin 16 (DP83826A Basic Mode)
    4. 2.4 Selecting 10M with Auto-Negotiation Enabled (DP83826A Basic Mode)
    5. 2.5 Configuring LED_1 for Tx and Rx Activity for EtherCAT Slave (DP83826A Basic Mode)
    6. 2.6 Thermal Pad Adjustments in Layout
    7. 2.7 Physical Layer ID Register
  6. 3Potential Changes
    1. 3.1 MDIO Pull-Up Resistor on Pin 11
    2. 3.2 MDIO Register Writes
    3. 3.3 Capacitors on Center Tap of Magnetics
  7. 4Informational Changes
  8. 5Pinout Mapping
    1. 5.1 Pin Mapping
  9. 6DP83826A Strap Configurations
    1. 6.1 Bootstrap Configurations

3.2 MDIO Register Writes

The DP83826A and KSZ8081MNX/RNB have both standard and extended SMI/MIIM (MDIO) registers.

DP83826A can access the standard registers through the indirect method (using standard registers 0x000D and 0x000E as outlined in IEEE 802.3). However, Microchip KSZ8081MNX/RNB can only access the standard register set through the direct method (without using 0x000D and 0x000E registers).

KSZ8081MNX/RNB also specifies the MMD address for all extended registers (for example 2 h) while DP83826A only uses MMD address 31 (0x001F) for all extended register writes and reads.