W5300 datasheet(96/128 Pages) WIZNET

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if (Sn_SSR == SOCK_ESTABLISHED) goto ESTABLISHED stage;

}



ESTABLISHED : Received Data ?

It checks if TCP data is received from the peer.

First method :

{

f (Sn_IR(RECV) == ‘1’) Sn_IR(RECV) = ‘1’; goto Receiving Process stage;

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

Sn_IMR and Sn_IR. */

}

Second Method :

{

if (Sn_RX_RSR != 0x00000000) goto Receiving Process stage;

}

At the first method, Sn_IR(RECV) is set as '1' whenever receiving DATA packet. In this case,

if the host could not process the Sn_IR(RECV) of the previously received DATA packet yet

but W5300 receives the next DATA packet, the host holding the previous Sn_IR(RECV)

could not recognize the Sn_IR(RECV) of the next DATA packet. Therefore if the host doesn't

have enough capability to process each Sn_IR(RECV) of all DATA packets, this method is

not recommended.



ESTABLISHED : Receiving Process

It processes TCP data received in internal RX memory. The format of received TCP data is

as below.

Fig 11. The received TCP data format

TCP data is composed of PACKET-INFO and DATA packet in case of Sn_MR(ALIGN)='0'.

In case of Sn_MR(ALIGN) = '1', TCP data has only DATA packet by removing PACKET-

INFO.

At the TCP mode, if the data size transmitted by the peer, is bigger than RX memory free

W5300 Datasheet(PDF) 96 Page - WIZnet Co., Ltd