---
title: "How to detect W5100's phy link down and up"
url: "https://maker.wiznet.io/forum/14019"
markdown_url: "https://maker.wiznet.io/forum/14019/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "yj12345"
created: "2020-09-27T03:55:27+09:00"
last_activity: "2020-10-12T07:06:32+09:00"
language: "en"
views: 492
replies: 2
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# How to detect W5100's phy link down and up

## Question

Asked by yj12345 on 2020-09-27 in Ethernet Chips.

Who can tell me how to dectec W5100’s phy link down and up?

## Replies

### Reply 1 by irina, 2020-10-08

![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/9/9a1a2a70db151ac918db66c2eaf58eebc11bc85c.png)
Pin 17 is link status LED. You can check it using pin17

### Reply 2 by yj12345, 2020-10-12 (in reply to reply 1)

W5100 pin17 is Digital ground

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Source: https://maker.wiznet.io/forum/14019