---
title: "W5500 Common mode register (MR ) allways readed as 0"
url: "https://maker.wiznet.io/forum/13128"
markdown_url: "https://maker.wiznet.io/forum/13128/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "NickB53"
created: "2018-11-22T13:13:46+09:00"
last_activity: "2018-11-29T23:26:28+09:00"
language: "en"
views: 706
replies: 4
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 Common mode register (MR ) allways readed as 0

## Question

Asked by NickB53 on 2018-11-22 in Ethernet Chips.

Now I begin to study ths chip The problem is - common MR allways readed as 0 But other regs may be written fnd realed correct

## Replies

### Reply 1 by Eugeny, 2018-11-22

![](https://avatars.discourse-cdn.com/v4/letter/n/b5e925/48.png) NickB53:

> The problem is - common MR allways readed as 0

Why did you decide that it is a problem? What you expect to read from there and when (after what actions)?

Did you read the datasheet?

### Reply 2 by NickB53, 2018-11-23 (in reply to reply 1)

I try to set PB and FARP bits to MR but register readed as 0. But GAR , SUBR registers I can write and read correct. PHYCFGR and VERSION registers also readed correct. And - device did no connect LINKLED and ACTLED flased in ~1sec interval

### Reply 3 by Eugeny, 2018-11-23

![](https://avatars.discourse-cdn.com/v4/letter/n/b5e925/48.png) NickB53:

> I try to set PB and FARP bits to MR but register readed as 0.

What exact value(s) you write to common MR register?

### Reply 4 by becky, 2018-11-29

Hello,

Check the address value of MR register and if you set RST bit MR register.
Setting RST to 1 resets all register values.

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Source: https://maker.wiznet.io/forum/13128