W5300 datasheet(72/128 Pages) WIZNET

72 / 128 page

Passive close : When receiving disconnect-request (FIN

packet) from the peer, it transmits FIN packet.

If disconnect-request is successful (when receiving FIN/ACK packet),

Sn_SSR is changed to SOCK_CLOSED.

If disconnect-request is failed, TCPTO occurs (Sn_IR(3)='1') and

Sn_SSR is changed to SOCK_CLOSED.

cf> If CLOSE is used instead of DISCON, only Sn_SSR is changed to

SOCK_CLOSED without disconnect-process(disconnect-request). If

RST packet is received from the peer during communication, Sn_SSR

is unconditionally changed to SOCK_CLOSED.

0x10

It closes SOCKETn.

Sn_SSR is changed to SOCK_CLOSED.

0x20

SEND

It transmits data as big as the size of Sn_TX_WRSR.

At the TCP or UDP mode, if Sn_TX_WRSR is bigger than maximum

segment size (MSS), W5300 automatically divides data in MSS unit,

and transmits the divided data(DATA packet).

However, this function is not supported in IPRAW or MACRAW mode.

The host should divide the data in MSS unit and transmit the divided

data.

When completing the SEND process, Sn_IR (SENDOK) becomes '1'.

After checking Sn_IR(SENDOK) = '1', the host can give SEND

command to the next data.

If DATA packet is successfully transmitted to the peer by SEND (when

DATA/ACK packet is received from the peer), Sn_TX_FSR is increased

by the size of transmitting DATA packet. If not (when DATA/ACK packet

is not received), TCPTO occurs (Sn_IR(3)='1') and Sn_SSR is changed

to SOCK_CLOSED.

cf> Host copies TX data into internal TX memory of SOCKETn through

Sn_TX_FIFOR before SEND command, and set

the data size to

Sn_TX_WRSR.

0x21

SEND_MAC

Valid

only

UDP

(Sn_MR(P3:P0)=Sn_MR_UDP)

IPRAW((Sn_MR(P3:P0) = Sn_MR_IPRAW) mode.

W5300 Datasheet(PDF) 72 Page - WIZnet Co., Ltd