---
title: "W5500 not communicating properly with router"
url: "https://maker.wiznet.io/forum/10259"
markdown_url: "https://maker.wiznet.io/forum/10259/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Timotei"
created: "2014-05-23T07:36:13+09:00"
last_activity: "2017-05-04T08:33:02+09:00"
language: "en"
views: 686
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 not communicating properly with router

## Question

Asked by Timotei on 2014-05-23 in Ethernet Chips.

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](http://wizwiki.net/wiki/doku.php?id=products:w5500:refschematic)
Except that I don’t have C23 and C24 connected.

Any ideas about what I’m doing wrong here?

## Replies

### Reply 1 by Timotei, 2014-05-30

Hi,

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:](https://emoji.discourse-cdn.com/twitter/slight_smile.png?v=12)

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Source: https://maker.wiznet.io/forum/10259