W5500 Datasheet, PDF (41/65 Pages) List of Unclassifed Manufacturers – Supports 8 independent sockets simultaneously

UIPR (Unreachable IP Address Register) [R] [0x0028-0x002B] [0x00000000]
UPORTR (Unreachable Port Register) [R] [0x002C-0x002D] [0x0000]
W5500 receives an ICMP packet(Destination port unreachable) when data is sent to
a port number which socket is not open and UNREACH bit of IR becomes „1‟ and UIPR
& UPORTR indicates the destination IP address & port number respectively.
Ex) In case of “192.168.0.11”
0x0028
0x0029
192 (0xC0)
168 (0xA8)
Ex) In case of “0x1234”
0x002C
18 (0x12)
0x002A
0 (0x00)
002D
52(0x34)
0x002B
11 (0x0E)
W5500 Datasheet Version1.0 (August 2013)
41 / 65