W6100 datasheet(97/149 Pages) WIZNET

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W6100 – Hardwired Dual TCP/IP Stack Controller

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 Auto PSH Flag : Sn_MR[FPSH] = ‘0’

If Force PSH option is cleared, SOCKET places the PSH flag in the last DATA packet sent by

Sn_CR[SEND].

 Destination Hardware Address by Sn_DHAR : Sn_MR2[DHAM] = ‘1’

If Sn_MR2[DHAM] is set, ARP/ND-process is skipped and Sn_DHAR is used as destination

hardware address.

 Destination Hardware Address by ARP : Sn_MR2[DHAM] = ‘0’

In ‘TCP SERVER’ mode, destination hardware address is acquired from received SYN packet.

In ‘TCP CLIENT’ mode, destination hardware address is acquired from ARP/ND-process.

 Destination Hardware Address by Sn_DHAR : Sn_MR2[FARP] = ‘1’

In 'TCP SERVER' mode, ARP process is performed before responding a SYN / ACK packet to

the SYN packet received from the "TCP client". And the address acquired from ARP/ND-

process is used as the destination hardware address.

If Sn_MR2 [DHAM] is also set, ARP/ND-process is performed but the Sn_DHAR is used as the

destination hardware address.

 Destination Hardware Address Mode by ARP : Sn_MR2[FARP] = ‘0’

In ‘TCP SERVER’ mode, destination hardware address is acquired from received SYN packet.

In ‘TCP CLIENT’ mode, destination hardware address is acquired from ARP/ND-process.

6.2.4.2

Keep Alive

Keep Alive (KA) is to retransmit the last 1 byte of the already transmitted DATA packet to check

whether the connection is valid. Data size of 1 byte or more must be transmitted before using

Keep Alive function. If there is no response to KA packet within the whole retransmission time,

Sn_IR[TIMEOUT] interrupt occurs.

The period of KA packet transmission is set in Sn_KPALVTR. If Sn_KPALVTR is set to zero, KA

packet is able to be transmitted by Sn_CR[SEND_KEEP] command.

W6100 Datasheet(PDF) 97 Page - WIZnet Co., Ltd