---
title: "W5200 sending issue"
url: "https://maker.wiznet.io/forum/9962"
markdown_url: "https://maker.wiznet.io/forum/9962/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "zorz"
created: "2014-02-20T10:59:38+09:00"
last_activity: "2017-05-04T08:31:35+09:00"
language: "en"
views: 461
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5200 sending issue

## Question

Asked by zorz on 2014-02-20 in Ethernet Chips.

hi

I have one issue at my hend …
-I configure TCP protocol and everything else
-than issue OPEN socket command
at this point Sn_TX_RD gets written with some number ussualy > 1k, but the Sn_TX_WR is 0
-after issue CONNECT command Sn_TX_WR have the same value as Sn_TX_RD

is this normal ???

after that if i issue SEND command …even i do not write anything i receive >1k of data on on the server?
if i write some data to TX memory and send it, i receive this data + some garbage data from before

any idea ?

regards zorz

## Replies

### Reply 1 by irinakim, 2014-02-24

Hi,

Sn_TX_WR is changed after the send command is successfully executed to Sn_CR.
With the SEND command of Socket n Command Register, it transmits data from the current Sn_TX_RD to the Sn_TX_WR and automatically updates after transmission is finished.
Therefore, after transmission is finished, Sn_TX_RD and Sn_TX_WR will have the same value.

thanks ![:slight_smile:](https://emoji.discourse-cdn.com/twitter/slight_smile.png?v=12)

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Source: https://maker.wiznet.io/forum/9962