RuntimeError: Failed to initialize WIZnet module

Hello Everyone,

I have designed own wiznet module board using the wiznet ic and the same schematic as mentioned in the wiznet documentation. When I am trying to connect the Ethernet to the designed mosule. it is showing run time error and it is showing failed to initialize the wiznet module. The Ethernet LED are not activated. Can anyone please help me to resolve the issue.


Thank you for reaching out. To assist you better, could you please provide more specific details about your setup? It would be helpful if you could share the materials you referenced, such as the circuit diagram and artwork guide. Additionally, if you can provide the circuit diagram and artwork of the Wiznet IC you used, I would be able to review it and offer more precise guidance.

Hi Bruno,
Thanks for your response. Please find the reference design which i an using for my design. I have used the adafruit libraries for wiznet. I am also trying to establish the connection using the evaluation board. for this evaluation board the ethernet is connecting but the wiznet is not able to initialize. it is showing runtime error.

In the schematic, i have connected the MOD pins to ground and the capacitor values for the clock are 18pF.

Please review the document and suggest the further steps.

Schematic_wiznet_lan_connection_2024-03-19 (1).pdf (93.4 KB)


We have reviewed the circuit you sent us. Could you please let us know which reference materials you used to design this circuit? We need to check if there are any issues with the guide materials.

Based on the information you provided, it appears to be a circuit issue. Although we have not fully reviewed the entire circuit you sent, it seems more appropriate to connect pin 5 of the HR911105A, the RX CT pin, to 3.3V. Please ensure that the VCC connected to the CT pin is separated from the digital power supply.

Thank you.

Hi Bruno,
Please find the link which i have followed for designing the schematic.

Please let me know if the above reference material is suitable or not.

Thank You.

Hi Bruno,
Now, i am able to initialize the wiznet module using the pi pico. But I am facing an issue with ethernet connection. The ethernet is not getting connected and the Status LED’s are not blinking.

Can you please advice regarding this issue.

It looks like the status LED is not working yet.
The status LED does not work when it is not properly connected to the router or other devices.
Have you modified the HW? Unlike the guide document, the existing circuit had a design difference between W5500-HR911105A, so we requested confirmation.
Please share your changes so we can review them.

Hi Bruno,
Thanks for your reply. Please find the reference and the modified schematic design for the wiznet IC. Can you please review the design and let me know if any further changes to be made.

Hey there,
I totally got your problem what you can do is check hardware connections and software setup to ensure they match WIZnet documentation. Review error logs for insights. Let me know if you need further assistance.

Hi Onjoo,

I have cross verified all the hardware connections and compared them with the evaluation board all the connections are matching. Can you please suggest any software suggestions for making the ethernet status LEDs work.

If there is no improvement yet, please send us your circuit and Gerber file~