SNLU353 October   2024 DP83867CR , DP83867CS , DP83867E , DP83867IR , DP83867IS , DP83869HM

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Specification
    3. 1.3 Device Information
  7. 2Evaluation Tutorial
    1. 2.1 How to Set Up the EVM
    2. 2.2 EVM Evaluation
  8. 3Hardware
    1. 3.1 Separate Power Rail
    2. 3.2 Status LEDs
    3. 3.3 MDC/MDIO Headers
    4. 3.4 MDC/MDIO Level Shifters
    5. 3.5 Manual Reset
  9. 4Software
    1. 4.1 GUI Installation
  10. 5Hardware Design Files
    1. 5.1 Schematics
  11. 6Additional Information
    1. 6.1 Trademarks

3.3 MDC/MDIO Headers

The EVM contains headers for access to the MDC and MDIO lines of each PHY independent of the ASPEED EVB. This is useful for debugging purposes when the user would like to read and write to a PHY's registers without connecting the EVM to the ASPEED AST2600 EVB.

To read/write registers through these headers, the user must disconnect the EVM from the ASPEED EVB and separately power the EVM using the J701 jumper header as described here. Once the board is powered on this rail, the user can connect jumper wires from a microcontroller like Texas Instruments's LaunchPad here. Connect the LaunchPad's MDC/MDIO jumpers to the EVM's MDC/MDIO jumpers of the desired PHY. Please reference the silkscreen below for jumper selection.

Once the LaunchPad is connected, users can use the USB2MDIO tool to read and write to each register for each PHY. More information about the tool is provided here.

DP83867 DP83869 MDC/MDIO Access Headers Figure 3-4 MDC/MDIO Access Headers