---
title: "W5500 Network stability Issue"
url: "https://maker.wiznet.io/forum/15003"
markdown_url: "https://maker.wiznet.io/forum/15003/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Priya Garg"
created: "2023-08-07T08:12:03+09:00"
last_activity: "2023-08-18T10:07:39+09:00"
language: "en"
views: 463
replies: 5
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 Network stability Issue

## Question

Asked by Priya Garg on 2023-08-07 in Ethernet Chips.

Dear All,

Seeking for help with W5500 Chip integration with Atmega chips. I have integrated the W5500 with ATMEGA64 over SPI and attached the minimalistic schematic for your reference. The Ethernet is working completely fine most of the times but I am facing some issues with the link status randomly.
Sometimes, the LINK Led on the LAN Connector side starts blinking and it doesn’t connect to the internet then. I have to power reset the complete system to make it work. Ethernet cable unplug/plug doesn’t work at that time.

Can you please let me know what could be the reason if the link status led continuous blink at a period of 1 sec roughly??
I would appreciate for the help. I am stuck with my complete development. Let me know if you need any other details from my side.

Priya G.

[![Screenshot 2023-08-07 at 1.34.12 PM](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/72a3074863adb0d8dab9919fb386fa36bab4ce87.png) Screenshot 2023-08-07 at 1.34.12 PM1813×987 107 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/7/72a3074863adb0d8dab9919fb386fa36bab4ce87.png)

## Replies

### Reply 1 by Priya Garg, 2023-08-08

Would be great if anyone can guide.

### Reply 2 by Alan, 2023-08-10

Hello, I reviewed your circuit diagram. There’s quite a lot of trouble. In particular, please review the MDI circuit part again. Reference circuit link.

![](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/d/d703689e80a5d521b0f0a45511c5153c0e931792.png) [docs.wiznet.io](http://docs.wiznet.io/Product/iEthernet/W5500/ref-schematic)

![](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/1c62c3ee6ae3ce074bf59833f86d4e440a16c970.png)

### [Reference Schematic | WIZnet Document System](http://docs.wiznet.io/Product/iEthernet/W5500/ref-schematic)

W5500 chip is a Hardwired Internet controller designed as a full hardwired TCP/IP stack with WIZnet technology

### Reply 3 by Priya Garg, 2023-08-10 (in reply to reply 2)

Hi [@Alan](https://maker.wiznet.io/u/alan) ,
Thank you for reviewing the circuit. I have referred the official reference circuit while designing the schematic. And I see that in your circuit, Differential RX is pulled down and in mine, it is pulled up. Other circuit remains same.
Can you please let me know if this change really affects the stability?

### Reply 4 by Alan, 2023-08-10

![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/3/38d5286c20c3d1a7f288545fc25cdc79d2631235.png)
Please review the reference circuit carefully… It’s very different…

### Reply 5 by Alan, 2023-08-10

Aren’t you going to distinguish GND?
Resistance values are also important. The resistance of the TC should not be high.

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Source: https://maker.wiznet.io/forum/15003