Data Sheet

iEthernet

W5200

At the UDP mode, the destination port number is set in the Sn_DPORT to be used for

transmitting UDP DATA packets before performing SEND or SEND_MAC command.

At the PPPoE mode, the PPP session ID that is already known is set in the S0_DPORT. PPP

session ID (set by S0_DPORT0) is applied to PSIDR after performing the OPEN command.

Ex) In case of Socket 0 Destination Port = 5000(0x1388), configure as below,

0x4010 0x4011

0x13 0x88

Sn_MSS (Socket n Maximum Segment Size Register)[R/W][0x4012+0x0n00-0x4013+0x0n00]

[0x0000]

This register is used for MSS (Maximum Segment Size) of TCP, and the register displays MSS

set by the other party when TCP is activated in Passive Mode. It just supports TCP or UDP

mode. When using PPPoE (MR(PPPoE)=‘1’), the MTU of TCP or UDP mode is assigned in the

range of MTU of PPPoE.

Mode

Normal (MR(PPPoE)=‘0’) PPPoE (MR(PPPoE)=‘1’)

Default

MTU

Range Default

MTU

Range

TCP 1460 1 ~ 1460 1452 1 ~ 1452

UDP 1472 1 ~ 1472 1464 1 ~ 1464

IPRAW 1480 1472

MACRAW 1514

At the IPRAW or MACRAW, MTU is not processed internally, but default MTU is used.

Therefore, when transmitting the data bigger than default MTU, the host should manually

divide the data into the unit of default MTU.

At the TCP or UDP mode, if transmitting data is bigger than MTU, W5200 automatically divides

the data into the unit of MTU. MTU is called as MSS at the TCP mode. By selecting from Host-

Written-Value and peer's MSS, MSS is set as smaller value through TCP connection process.

Ex) In case of Socket 0 MSS = 1460(0x05B4), configure as below,

0x4012 0x4013

0x05 0xB4

Sn_PROTO (Socket n IP Protocol Register) [R/W] [0x4014+0x0n00] [0x00]

It is a 1 byte register that sets the protocol number field of the IP header at the IP layer. It is

valid only in IPRAW mode, and ignored in other modes. Sn_PROTO is set before OPEN

command. When Socket n is opened in IPRAW mode, it transmits and receives the data of

the protocol number set in Sn_PROTO. Sn_PROTO can be assigned in the range of 0x00 ~ 0xFF,

but W5200 does not support TCP(0x06) and UDP(0x11) protocol number

Protocol number is defined in IANA(Internet assigned numbers authority). For the detail, refer