---
title: "MACraw & IGMP"
url: "https://maker.wiznet.io/forum/11105"
markdown_url: "https://maker.wiznet.io/forum/11105/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "reza"
created: "2015-06-10T14:52:46+09:00"
last_activity: "2017-05-04T08:35:56+09:00"
language: "en"
views: 863
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# MACraw & IGMP

## Question

Asked by reza on 2015-06-10 in Ethernet Chips.

Hi
I open Socket 0 in MACRAW mode & socket 1 in Multicast mode but i cant receive any packet on my Multicast socket

how can i do that???

## Replies

### Reply 1 by lawrence, 2015-06-11

Hi, reza.

W5200 supports multicast but needs setting some registers also.

I don’t know if you follow these steps or not.

To use multicast, you should assign the group you will communicate. Before opening a socket, Set Multi-group hardware address, Multi-group IP address, Multi-group port number, UDP and Multicast Enable with Sn_DHAR, Sn_DIPR, Sn_DPORT, Sn_PORT, Sn_MR.

You can find more details with W5200 datasheet.
[wiznethome.cafe24.com/wp-content … _V130E.pdf](http://wiznethome.cafe24.com/wp-content/uploads/wiznethome/Chip/W5200/Documents/W5200_DS_V130E.pdf)

If it is not fix your problem, please upload your code or more details about it.

Thank you.

Lawrence

### Reply 2 by reza, 2015-06-11

Hi, Lawrence.

I had configured my multicast socket (on Socket 1) and it worked perfectly.
but when i configured MACRAW mode on socket 0 , and open it,
i cant receive any data on multicast socket (my Sn_RX_RSR on socket 1 is always 0).

whats the problem !!!?
W5200 can not work with two socket on MACRAW & Multicast modes Simultaneously !!!???

thanks for your attention.

### Reply 3 by lawrence, 2015-06-12

Hello, reza

First, It works to open Socket 0 as MACRAW and Socket 1 as Multicast Socket.
But the point is Sn_MR[7:0].

[quote]Sn_MR[5] set enable or disable Multicast Blocking (this bit works on only MACRAW mode [3:0]=‘0100’)
0: disable Multicast Blocking
1: enable Multicast Blocking[/quote]
So, make sure if your S0_MR[5] is 0 or 1 then If it is set, Reset this bit and try again.

Thank you,

Lawrence

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Source: https://maker.wiznet.io/forum/11105