W5500 Datasheet, PDF (58/65 Pages) List of Unclassifed Manufacturers – Supports 8 independent sockets simultaneously

Sn_FRAG (Socket n Fragment Register) [R/W] [0x002D-0x002E] [0x4000]
Sn_FRAG configures the FRAG(Fragment field in IP header).
Ex) Sn_FRAG0 = 0x0000 (Don‟t Fragment)
0x002D
0x00
0x002E
0x00
Sn_KPALVTR (Socket n Keep Alive Time Register) [R/W] [0x002F] [0x00]
Sn_KPALVTR configures the transmitting timer of „KEEP ALIVE(KA)‟ packet of
SOCKETn. It is valid only in TCP mode, and ignored in other modes. The time unit is
5s.
KA packet is transmittable after Sn_SR is changed to SOCK_ESTABLISHED and after
the data is transmitted or received to/from a peer at least once. In case of
'Sn_KPALVTR > 0', W5500 automatically transmits KA packet after time-period for
checking the TCP connection (Auto-keepalive-process). In case of 'Sn_KPALVTR = 0',
Auto-keep-alive-process will not operate, and KA packet can be transmitted by
SEND_KEEP command by the host (Manual-keep-alive-process). Manual-keep-alive-
process is ignored in case of 'Sn_KPALVTR > 0'.
Ex) Sn_KPALVTR = 10 (Keep Alive packet will be transmitted every 50 seconds.)
0x002F
0x0A
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W5500 Datasheet Version1.0 (August 2013)