---
title: "Setting the W550io in to sleep or Low power mode"
url: "https://maker.wiznet.io/forum/12093"
markdown_url: "https://maker.wiznet.io/forum/12093/md"
type: "Forum topic"
category: "IO Modules"
author: "funvill"
created: "2017-01-13T02:05:54+09:00"
last_activity: "2017-05-04T08:39:37+09:00"
language: "en"
views: 1225
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Setting the W550io in to sleep or Low power mode

## Question

Asked by funvill on 2017-01-13 in IO Modules.

I have the W550io board connected to an ESP8266 device using the ESP8266 arduino library. it is functioning normally, and I can send and receive packets. I am using this W550io libary created by Wiznet [github.com/Wiznet/WIZ_Ethernet_Library](https://github.com/Wiznet/WIZ_Ethernet_Library)

I would like to turn off or reduce the power consumption of the W550io board as much as possible. After the W550io is put into low power mode I will not need to wake it up until the entire system is power cycled.

Q1) How do I force the Wiznet W550io to use 10mb connection instead of 100mb? As described here [forum.arduino.cc/index.php?topic=367999.0](https://forum.arduino.cc/index.php?topic=367999.0)
Q2) How do I force the Wiznet W550io into using low power mode or shut off the PHY?

## Replies

### Reply 1 by funvill, 2017-01-13

I have tried the following code snippet to turn off the Phy, but the LEDs are still illuminated and consuming power.
This code snippet came from this post [Power down PHY from Arduino Mega](https://forum.wiznet.io/t/power-down-phy-from-arduino-mega/2717/1)

This did not work.

`int readback = W5100.getPHYCFGR(); Serial.print("readback of the phys: "); Serial.println(readback); W5100.setPHYCFGR(0b10110000);`

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Source: https://maker.wiznet.io/forum/12093