3.6 Hardware Issue - Ethernet Interface Configuration Issue

  1. MAC Address: Every Ethernet component on a network must have a unique MAC Address. If two components in the network share the same MAC Address, communication issues will occur. Typically, MAC Addresses are obtained through the IEEE Registration Authority and programmed to each Ethernet interface during production. Verify the MAC Address of your equipment and ensure a unique value is being programmed before using in a network.

    Note: The MAC Address is not a property of the PHY, this is configured via the MAC. However, without the proper MAC address configuration, data may be flowing through the PHY, get blocked by the MAC, and look like a PHY issue.
  2. IP Address: Ensure that the IP address is not being manually set to a static value through the network options in the operating system. In most cases, the IP Address should be assigned automatically by the network at the time of connection.
  3. Auto-negotiation and Forced Speed Selection: Its highly recommended to always enable all connection speeds and leave auto-negotiation enabled on KSZ8081MNX. Manually disabling auto-negotiation and forcing specific connection speeds is acceptable but should be done with great care and only if there is a specific reason to do so.
  4. Known Errata: Once all of these configuration issues are confirmed, re-visit the published errata of the KSZ8081MNX. There may be some known symptoms and root causes described that match the behavior observed. Make sure to evaluate each errata and determine if the workaround described (or known issue) is able to match the observed behavior.
  5. Submit a Support Case to Microchip: If The Ethernet connectivity issue is still not resolved or understood after following these debug items, go back to the Fundamental PCB Design and PCB Assembly Damage sections and review all guidance again. If the issue is still not resolved or understood, submit a support case to Microchip support with all of your findings clearly documented. Be sure to include the answers to the Problem Statement Questionnaire and all data logs described in Data Logging with the support case submission to accelerate the time to submission (if you cannot collect any of the request logs for any reason, state this upfront in the case submission as well). The more information the Microchip support team has about the system setup and tests run so far, the faster they can identify new tests that can be done to isolate the problem.