---
title: "Sw0"
url: "https://maker.wiznet.io/forum/11210"
markdown_url: "https://maker.wiznet.io/forum/11210/md"
type: "Forum topic"
category: "General"
author: "snowflake"
created: "2015-08-03T12:15:42+09:00"
last_activity: "2017-05-04T08:38:09+09:00"
language: "en"
views: 939
replies: 4
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Sw0

## Question

Asked by snowflake on 2015-08-03 in General.

What is sw0 for? If I push the sw0 button and reset my board, the two leds are blinking.

## Replies

### Reply 1 by Edward, 2015-08-03

Hi.

It is boot mode.

And checking the configure tool boot mode

If module erase internal firmware… update new firmware. check below URL

firmware download : [github.com/Wiznet/WIZ550web](https://github.com/Wiznet/WIZ550web)

module information : [wizwiki.net/wiki/doku.php?id=pro … 0web:start](http://wizwiki.net/wiki/doku.php?id=products:wiz550web:start)

### Reply 2 by snowflake, 2015-08-11

What does boot mode mean? wiki does not explain.

### Reply 3 by Edward, 2016-02-01

Hi.

refer to below URI

[wizwiki.net/wiki/doku.php?id=pro … 50webds_en](http://wizwiki.net/wiki/doku.php?id=products:wiz550web:wiz550webds_en)

It is just Switch for connecting the boot mode.

Thank you

### Reply 4 by irina, 2016-02-01

Hi, snowflake.
The WIZ550web’s firmware is consist of two parts, application boot and application.
Setting the D8 pin (GPIO_Pin_12, GPIOC = SW0 on EVB) to High state and reboot the WIZ550web, the device go into Boot mode. This function for firmware update and firmware recovery when a problem occurred. (malfunction of the application firmware)

Please utilize the D8 pin as a boot mode switching pin only and the other input pin in the board applying to your applications.

---

Source: https://maker.wiznet.io/forum/11210