Wiznet W7500 Reference Manual page 65

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res Res Res res
This is used to set the command for Socket n such as OPEN, CLOSE, CONNECT, LISTEN, SEND,
and RECEIVE. After WZTOE accepts the command, the Sn_CR register is automatically
cleared to 0x00. Even though Sn_CR is cleared to 0x00, the command is still being processed.
To check whether the command is completed or not, please check the Sn_IR or Sn_SR.
Value Symbol
0x01 OPEN
0x02 LISTEN
0x04 CONNECT
W7500 Datasheet Version1.0.0
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res res res
Socket n is initialized and opened according to the protocol
selected in Sn_MR (P3:P0). The table below shows the value of
Sn_SR corresponding to Sn_MR.
Sn_MR_CLOSE („0000‟)
Sn_MR_TCP („0001‟)
Sn_MR_UDP („0010‟)
S0_MR_MACRAW („0100‟)
.
This is valid only in TCP mode (Sn_MR(P3:P0) = Sn_MR_TCP). In this
mode, Socket n operates as a „TCP server‟ and waits for
connection-request (SYN packet) from any „TCP client‟.
The Sn_SR changes the state from SOCK_INIT to SOCKET_LISTEN.
When a „TCP client‟ connection request is successfully established,
the Sn_SR changes from SOCK_LISTEN to SOCK_ESTABLISHED and
the Sn_IR(0) becomes „1‟. But when a „TCP client‟ connection
request is failed, Sn_IR(3) becomes „1‟ and the status of Sn_SR
changes to SOCK_CLOSED.
This is valid only in TCP mode and operates when Socket n acts as
„TCP client‟. To connect, a connect-request (SYN packet) is sent to
„TCP server‟ configured by Sn_DIPR & Sn_DPORT(destination
address & port). If the connect-request is successful, the Sn_SR is
changed to SOCK_ESTABLISHED and the Sn_IR(0) becomes „1‟.
The connect-request fails in the following three cases.
1. When a ARP
hardware address is not acquired through the ARP-process.
8 7 6 5
res
R/W R/W R/W
Description
Sn_MR (P[3:0])
-
SOCK_INIT (0x13)
SOCK_UDP (0x22)
SOCK_MACRAW (0x02)
occurs (Sn_IR(3)=„1‟) because the destination
TO
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Sn_CR[7:0]
R/W R/W R/W R/W
Sn_SR
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0
R/W