Result

A byte that is assigned with the socket number you requested. When the operation fails, it will return 255.

socket

A numeric constant or variable with the socket number.

The socket number is in range of 0-3. And 0-7 for the W5200 and W5300.

Mode

The socket mode. Use sock_stream(1), sock_dgram(2), sock_ipl_raw(3)  or macl_raw(4). The modes are defined with constants.

The W5100,W5200,W5300 also have the sock_ppoe(5) mode.

For TCP/IP communication you need to specify sock_stream or the equivalent value 1.

For UDP communication you need to specify sock_dgram or the equivalent value 2.

Port

This is the local port that will be used for the communication. You may specify any value you like but each socket must have it’s own local port number.

When you use 0, the value of LOCAL_PORT will be used.

LOCAL_PORT is assigned with CONFIG TCPIP.

After the assignment, LOCAL_PORT will be increased by 1. So the simplest way is to setup a local port with CONFIG TCPIP, and then use 0 for port.

Param

Optional parameter. Use 0 for default.

W3100

128 : send/receive broadcast message in UDP

64 : use register value with designated timeout value

32 : when not using no delayed ack

16: when not using silly window syndrome

Consult the W3100A documentation for more information.

W5100,W5200,W5300

128 : enable multicasting in UDP

32 : enable 'No delayed ACK' operation. Only for TCP/IP.

    In case of UDP multicast : 1 : use IGMP version 1, otherwise V 2.

Consult the wiznet documentation for more information.