---
title: "Unable to write to the Tx buffer of w5500"
url: "https://maker.wiznet.io/forum/12359"
markdown_url: "https://maker.wiznet.io/forum/12359/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "dhanunjay"
created: "2017-07-06T11:45:55+09:00"
last_activity: "2017-07-06T23:31:34+09:00"
language: "en"
views: 753
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Unable to write to the Tx buffer of w5500

## Question

Asked by dhanunjay on 2017-07-06 in Ethernet Chips.

Hi,

I am unable Write to the buffer until i change the command register to the send.

here is my code:

void readflash(uint32_t addr, uint16_t size){
uint16_t v,j,k, len, pointer;
j = size/256;
len = size - (j * 256);
if (j > 0){
for(v = 0; v < j; v++){
SerialFlash_ReadArray(addr, &read, 256);
addr = addr + 0x000100;
wiz_send_data(SOCK_WEBSERVER, read, 256);
Delay_ms(10);
}
if(len > 0){
SerialFlash_ReadArray(addr, &read, len);
wiz_send_data(SOCK_WEBSERVER, read, len);
Delay_ms(10);
}
}
else{
SerialFlash_ReadArray(addr, &read, size);
wiz_send_data(SOCK_WEBSERVER, *read, size);
}
}

While i am trying to write the 1381 bytes and change the command register to send. i am seeing only a packet of length 101 which is the last set i am writing the to the TX Buffer.

## Replies

### Reply 1 by jim, 2017-07-06

Please refer to a reply in [Unable to read the TX Buffer of w5500](https://forum.wiznet.io/t/Unable-to-read-the-TX-Buffer-of-w5500/3292)

Thanks.

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Source: https://maker.wiznet.io/forum/12359