W5200 datasheet(48/88 Pages) WIZNET

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{

START:

Sn_MR = 0x01;

// sets TCP mode

Sn_PORT0 = source_port;

// sets source port number

Sn_CR = OPEN;

// sets OPEN command

/* wait until Sn_SR is changed to SOCK_INIT */

if (Sn_SR != SOCK_INIT) Sn_CR = CLOSE; goto START;

}

LISTEN

Run as “TCP SERVER” by LISTEN command.

{

/* listen SOCKET */

Sn_CR = LISTEN;

/* wait until Sn_SR is changed to SOCK_LISTEN */

if (Sn_SR != SOCK_LISTEN) Sn_CR = CLOSE; goto START;

}

ESTABLISHMENT

When the status of Sn_SR is SOCK_LISTEN, if it receives a SYN packet, the status of Sn_SR

is changed to SOCK_SYNRECV and transmits the SYN/ACK packet. After that, the Socket

n makes a connection. After it makes the connection of Socket n , it enables the data

communication. There are two methods to confirm the connection of Socket n .

First method :

{

if (Sn_IR(CON) == ‘1’)

/* When an interrupt occurs and the mask bit of Sn_IMR is ‘1’, the interrupt bit of Sn_IR

becomes ‘1’ */

Sn_IR(CON) = ‘1’;

/*In order to clear the Sn_IR bit, the host should write the bit as ‘1’. When all the bits

of Sn_IR is cleared (‘0’), IR(n) is automatically cleared.*/

goto ESTABLISHED stage;

/* In this case, if the interrupt of Socket n is activated, interrupt occurs. Refer to IR,

IMR Sn_IMR and Sn_IR. */

}

Second method :

{

if (Sn_SR == SOCK_ESTABLISHED) goto ESTABLISHED stage;

}

ESTABLISHMENT : Check received data

W5200 Datasheet(PDF) 48 Page - WIZnet Co., Ltd