W5500 not communicating properly with router

I designed my own protoboard which has ATmega328 communicating with W5500.
The board has RJ45 with integrated Transformer and connected CT.
I’m using the Arduino Wiznet library and I can upload code to the ATmega328 just fine.
However, as soon as it starts to request IP address from DHCP server with predefined MAC, it goes to an infinite loop.
The request is sent about every four seconds when I look at the data packets with Wireshark.
I’ve wired the W5500 with the reference schematic provided by wizwiki.net/wiki/doku.php?id=pro … fschematic
Except that I don’t have C23 and C24 connected.

Any ideas about what I’m doing wrong here?


First test,
Use the static IP address for ping-reply test to checking your transformer schematics.
Which your reference in the wiki site?
1.External Transformer Type?
2. RJ45 with Transformer Type?
3. RJ45 with integrated Transformer and connected CT?

Second Test (when ping test ok)
and Capture the packet of DHCP processing and post it.

Thank you.


I’m using reference 3. in our design.
After I connected C23 and C24 to the RXP and RXN lines the board started to work correctly.
DHCP works and I can communicate with ATmega328 trough W5500.

Thank you for your suggestions.
This thread can be marked as solved. :slight_smile: