---
title: "Reseting w5100"
url: "https://maker.wiznet.io/forum/12144"
markdown_url: "https://maker.wiznet.io/forum/12144/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "mhortalr"
created: "2017-02-10T09:50:22+09:00"
last_activity: "2018-09-30T19:33:53+09:00"
language: "en"
views: 4516
replies: 6
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Reseting w5100

## Question

Asked by mhortalr on 2017-02-10 in Ethernet Chips.

Good morning,
I have a w5100 connected to an Arduino UNO. From time to time, the shield gets unreachable until I reboot the whole system or press the “reset” button. Is there a way to reset the shield by software, so that the button doesn’t need to be pressed?

## Replies

### Reply 1 by Eugeny, 2017-02-10

Yes, using MR register setting bit 7 to 1. See 4.1 “common registers”.

### Reply 2 by mhortalr, 2017-02-11

Thank you very much for your answer but, in which document is point 4.1 “common registers”?

### Reply 3 by mhortalr, 2017-02-11

The question really is: Which command of the Arduino Ethernet Library should I use to reset the shield?

### Reply 4 by Eugeny, 2017-02-11

![](https://avatars.discourse-cdn.com/v4/letter/m/a3d4f5/48.png) mhortalr:

> in which document is point 4.1 “common registers”?

<http://www.wiznet.io/wp-content/uploads/wiznethome/Chip/W5100/Document/W5100_Datasheet_v1.2.6.pdf>

![](https://avatars.discourse-cdn.com/v4/letter/m/a3d4f5/48.png) mhortalr:

> Which command of the Arduino Ethernet Library should I use to reset the shield?

If you know command which is used to write to chip’s register you can use it writing to register #0000 (MR).

### Reply 5 by mhortalr, 2017-02-12

Thank you very much

### Reply 6 by RicardoMariz63, 2018-09-30

Ethernet.init(53)

Use native library Arduino.

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Source: https://maker.wiznet.io/forum/12144