---
title: "AVR-W5100"
url: "https://maker.wiznet.io/louis_m/projects/avr-w5100/"
markdown_url: "https://maker.wiznet.io/louis_m/projects/avr-w5100/md"
type: "UCC: User Created Content"
author: "nullx-dev"
author_url: "https://github.com/nullx-dev/AVR-W5100#avr-w5100"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "nullx-dev"
original_url: "https://github.com/nullx-dev/AVR-W5100#avr-w5100"
published: "2023-11-02"
language: "en"
tags: ["Internet of Things"]
hardware: ["WIZnet W5100"]
likes: 0
views: 327
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# AVR-W5100

> AVR-W5100

Original author: nullx-dev (source: https://github.com/nullx-dev/AVR-W5100#avr-w5100)

## Components

- **WIZnet W5100** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5100))

## Article

## [AVR-W5100](https://github.com/nullx-dev/AVR-W5100#avr-w5100)

A simple easy-to-use library for Wiznet W5100 Ethernet controller for AVR Microcontrollers

Tested on ATMega328P, can be easily ported to all SPI-enabled AVR microcontrollers by editing the `W51_regFunc.c` file.

Supported protocols are TCP and UDP, maximum 4 open sockets.

**This library is only for W5100, not W5500**

All examples are located in the example directory.

## [Function Descriptions](https://github.com/nullx-dev/AVR-W5100#function-descriptions)

### [W5100 Initialization Functions](https://github.com/nullx-dev/AVR-W5100#w5100-initialization-functions)

`void W51_init(void);`

This initializes the W5100. Please adjust the pin settings in `W51_regFunc.h` file by your microcontroller model.

If your microcontroller has SPI speed lower than 14MHz, you can remove this line in `W51_regFunc.c`: `SPSR |= (1 << SPI2X);`

`void W51_setINET(uint8_t* ipaddr, uint8_t* macaddr, uint8_t* gateaddr, uint8_t* subaddr);`

Function to assign static IPv4 address to W5100

`uint8_t* ipaddr`: Array that contains IPv4 address of W5100

`uint8_t* macaddr`: Array that contains W5100 MAC address

`uint8_t* gateaddr`: Array that contains gateway (router) address

`uint8_t* subaddr`: Array that contains subnet mask

### [Basic socket operations](https://github.com/nullx-dev/AVR-W5100#basic-socket-operations)

`SOCKET createSocket(uint8_t sockNum, uint8_t* IP, uint16_t port, uint8_t protocol);`

This function creates and returns socket structure.

`uint8_t sockNum`: Physical socket number (0 - 3)

`uint8_t* IP`: Array that contains the IPv4 address of socket. In case of listening socket, it should be set to 0.0.0.0

`uint16_t port`: Socket port number (0 - 65535)

`uint8_t protocol`: Socket protocol, use `W51_PROTOCOL_TCP` or `W51_PROTOCOL_UDP` defines

NOTE: It doesnt assign the socket to W5100, it only initializes the structure

`uint8_t W51_initSocket(SOCKET sock);`

This function writes the data from socket structure to W5100.

`SOCKET sock`: Socket structure with all necessary parameters

`uint8_t W51_openSocket(SOCKET sock);`

A function to open socket.

`SOCKET sock`: Initialized socket structure with all necessary parameters

`uint8_t W51_closeSocket(SOCKET sock);`

A function to close a socket.

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

NOTE: This function does not delete the socket structure, it only closes the physical socket on W5100

`uint8_t W51_connectSocket(SOCKET sock);`

A function to connect to the server **(Only used in TCP Mode)**

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`uint8_t W51_listenSocket(SOCKET sock);`

Function to listen for incoming connections

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`uint8_t W51_disconnectSocket(SOCKET sock);`

A function to disconnect from the server **(Only used in TCP Mode)**

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`uint8_t W51_sendData(SOCKET sock, uint8_t* data, unsigned int datalen);`

Function to send data through socket

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`uint8_t* data`: Data buffer to be sent

`unsigned int datalen`: Length of the data to be sent

NOTE: The maximum one transaction transmitting length is 2048 bytes

`uint16_t W51_getReceivedDataLen(SOCKET sock);`

Function to get received data length in bytes

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`uint8_t W51_receiveData(SOCKET sock, unsigned int length, uint8_t* data);`

Function to receive data from a socket

`SOCKET sock`: Opened, initialized socket structure with all necessary parameters

`unsigned int length`: Length of data to be received

`uint8_t* data`: Buffer for data to be received

---

Source: https://maker.wiznet.io/louis_m/projects/avr-w5100/