---
title: "SYSR cannot be changed"
url: "https://maker.wiznet.io/forum/14286"
markdown_url: "https://maker.wiznet.io/forum/14286/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "gagaqq11"
created: "2021-07-07T09:08:51+09:00"
last_activity: "2021-07-13T06:17:58+09:00"
language: "en"
views: 378
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# SYSR cannot be changed

## Question

Asked by gagaqq11 on 2021-07-07 in Ethernet Chips.

Hello. I use FPGA to access w6100 via parallel bus. I confirmed that by parallel bus, I successfully read and wrote the register. For example, I write to the register 0x4200 with value 0xcc. It is also 0xcc to read back. And value of the read 0x0000 is 0x61. But I write 0x41f5 0x3a, the value of the read 0x2000 is still 0xE2. Although the data sheet 0x41f5 is written only, I found that the return value of the read 0x41f5 was also 0x3a, that is, the value I wrote.

## Replies

### Reply 1 by gagaqq11, 2021-07-09

The problem is solved.

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Source: https://maker.wiznet.io/forum/14286