W5300 datasheet(97/128 Pages) WIZNET

97 / 128 page

size of the SOCKETn then W5300 can't receive the data, keeps the connection, and waits

until RX memory free size becomes bigger than the data size.

{

/* first, check Sn_MR(ALIGN) */

if (Sn_MR

(ALIGN) == ‘0’)

{

pack_size = Sn_RX_FIFOR; /* extract size of DATA packet from internal RX memory */

}

else

{

pack_size = Sn_RX_RSR; /* check the total received data size */

}

/* calculate the read count of Sn_RX_FIFOR */

if (pack_size is odd ?) read_cnt = (pack_size + 1) / 2;

read_cnt = pack_size / 2;

/* extract DATA packet from internal RX memory */

for( i = 0; i < read_cnt; i++)

{

data_buf[i] = Sn_RX_FIFOR; /* data_buf is array of 16bit */

}

/* set RECV command */

Sn_CR = RECV;

}

<Notice> In case that SOCKETn is used only to receive data without transmitting data

The slow data receiving process by the host can cause internal RX memory full.

In this case, even though W5300 window size (the maximum size of receivable data) is not

‘0’, by misunderstanding the window size as ‘0’, the peer does not transmit the data, and

waits until window size is increased. It is the cause of decreasing data receiving

performance of W5300. In order to solve the problem, the host processes the data received

in internal RX memory first and notify the peer that the window size of W5300 is increased

by received data size. To the above code, add the below code after RECV command.

W5300 Datasheet(PDF) 97 Page - WIZnet Co., Ltd