W5100 datasheet(27/72 Pages) WIZNET

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4.2 Socket Registers

Sn1_MR (Socket n Mode Register) [R/W] [0x0400, 0x0500, 0x0600, 0x0700] [0x00]2

This register sets up socket option or protocol type for each socket.

MULTI

ND / MC

Bit

Symbol

Description

MULTI

Multicasting

0 : disable Multicasting

1 : enable Multicasting

It is applied only in case of UDP.

For using multicasting, write multicast group address to Socket n Destination

IP and multicast group port number to Socket n Destination Port Register,

before OPEN command.

MAC Filter (S0_MR support only)

0 : Disable MAC filter

1 : Enable MAC filter

It is used in MACRAW (P3~P0: “0100”).

When this bit is set as ‘1’, W5100 can receive packet that is belong in itself

or broadcasting. When this bit is set as ‘0’, W5100 can receive all packets

on Ethernet. When using the hybrid TCP/IP stack, it is recommended to be

set as ‘1’ for reducing the receiving overhead of host.

ND/MC

Use No Delayed ACK

0 : Disable No Delayed ACK option

1 : Enable No Delayed ACK option,

It is applied only in case of TCP. If this bit is set as ‘1’, ACK packet is

transmitted whenever receiving data packet from the peer. If this bit is

cleared to ‘0’, ACK packet is transmitted according to internal Timeout

mechanism.

Multicast

0 : using IGMP version 2

1 : using IGMP version 1

n is socket number (0, 1, 2, 3).

[Read/Write] [address of socket 0, address of socket 1, address of socket 2, address of socket 3] [Reset

value]

W5100 Datasheet(PDF) 27 Page - WIZnet Co., Ltd