Data Sheet

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60
iEthernet
W5200
Check send data / sending process
The size of DATA that the user wants to transmit cannot be larger than Internal TX
memory. If it is larger than MTU, it is automatically divided by MTU unit and
transmitted. The Sn_DIPR0 is set “255.255.255.255” when user wants to broadcast.
{
/* first, get the free TX memory size */
FREESIZE:
freesize = Sn_TX_FSR0;
if (freesize<len) goto FREESIZE; // len is send size
/* Write the value of remote_ip, remote_port to the Socket n Destination IP Address
Register(Sn_DIPR), Socket n Destination Port Register(Sn_DPORT). */
Sn_DIPR0 = remote_ip;
Sn_DPORT0 = remote_port;
/* calculate offset address */
dst_mask = Sn_TX_WR0 & gSn_TX_MASK; // dst_mask is offset address
/* calculate start address(physical address) */
dst_ptr = gSn_TX_BASE + dst_mask; // dst_ptr is physical start address
/* if overflow SOCKETTX memory */
if ( (dst_mask + len) > (gSn_TX_MASK + 1) )
{
/* copy upper_size bytes of source_address to dst_ptr */
upper_size = (gSn_TX_MASK + 1) – dst_mask;
memcpy(src_ptr, destination_addr, upper_size);
/* update source_address*/
source_address += upper_size;
/* copy left_size bytes of source_address to gSn_TX_BASE */
left_size = send_size – upper_size;
memcpy(src_ptr, destination_addr, left_size);
else
{
/* copy len bytes of source_address to dst_ptr */
memcpy(src_ptr, destination_addr, len);
}
/* increase Sn_TX_WR0 as length of len */
Sn_TX_WR0 += len;