Data Sheet

iEthernet

W5200

Sn_CR (Socket n Command Register) [R/W] [0x4001+0x0n00] [0x00]

This is used to set the command for Socket n such as OPEN, CLOSE, CONNECT, LISTEN, SEND,

and RECEIVE. After W5200 identifies the command, the Sn_CR register is automatically

cleared to 0x00. Even though Sn_CR is cleared to 0x00, the command is still being processed.

To verify whether the command is completed or not, please check the Sn_IR or Sn_SR

registers.

Value

Symbol Description

0x01

OPEN

Socket n is initialized and opened according to the protocol selected in

Sn_MR (P3:P0). The table below shows the value of Sn_SR corresponding

to Sn_MR

Sn_MR(P3:P0) Sn_SR

Sn_MR_CLOSE (0x00) -

Sn_MR_TCP (0x01) SOCK_INIT (0x13)

Sn_MR_UDP (0x02) SOCK_UDP (0x22)

Sn_MR_IPRAW (0x03) SOCK_IPRAW (0x32)

S0_MR_MACRAW (0x04) SOCK_MACRAW (0x42)

S0_MR_PPPoE (0x05) SOCK_PPPoE (0x5F)

0x02

LISTEN

This is valid only in TCP mode (Sn_MR(P3:P0) = Sn_MR_TCP). In this

mode, the Socket n is configured as a TCP server which is waiting for

connection-request (SYN packet) from any “TCP CLIENT”. The Sn_SR

When a client’s connection request is successfully established, the Sn_SR

changes from SOCK_LISTEN to SOCK_ESTABLISHED and the Sn_IR(0)

becomes ‘1’. On the other hand, Sn_IR(3) is set as ‘1’ and Sn_SR changes

to SOCK_CLOSED during a connection failure(SYN/ACK packet failed to

transfer)

cf> If the destination port of the TCP Client does not exist during a

connection request, W5200 will transmit a RST packet and Sn_SR is

unchanged.

0x04

CONNECT

This mode is only valid in TCP mode and operates the Socket n as a TCP

client.A connect-request (SYN packet) is sent to the TCP server by

connecting to the IP address and port stored in destination address and

port registers (Sn_DIPR0 and Sn_DPORT0)

When a client’s connection request is successfully established, the Sn_SR

‘1’.In the following cases, the connect-request fails When a ARPTO

occurs (Sn_IR(s)=‘1’) because the Destination Hardware Address is not

acquired through the ARP process

When a SYN/ACK packet is not received and TCPTO(Sn_IR(3)) is’1’