Using Socket Services by Manipulating Dedicated Control Bits

Section 6-7

Up to 4,096 bytes of data are stored in the reception buffer, but the value stored is within the range (maximum: 1,984 bytes) that can be set by manipu- lating the control bits or sending the receive request in the CMND(490) instruction.

0000 hexadecimal: 0 bytes

07C0 hexadecimal: 1,984 bytes

TCP Connection Status (Ethernet Unit to CPU Unit)

The TCP Connection Status shows the status of a port that has been opened using the TCP socket. This port status is stored even after the port is closed, and remains until the socket is used to open the port again.

The TCP Connection Status Bits are not synchronized with the Socket Status words, however, so the status conversion timing is slightly different.

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

m+9 to m+16

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TCP connection status

The status is shown in bits 0 to 3 (1-digit hexadecimal), as follows:

Number

Status

Meaning

 

 

 

00000000

CLOSED

Connection closed.

 

 

 

00000001

LISTEN

Waiting for connection.

 

 

 

00000002

SYN SENT

SYN sent in active status.

 

 

 

00000003

SYN RECEIVED

SYN received and sent.

 

 

 

00000004

ESTABLISHED

Already established.

 

 

 

00000005

CLOSE WAIT

FIN received and waiting for completion.

 

 

 

00000006

FIN WAIT1

Completed and FIN sent.

 

 

 

00000007

CLOSING

Completed and exchanged FIN. Awaiting ACK.

 

 

 

00000008

LAST ACK

FIN sent and completed. Awaiting ACK.

 

 

 

00000009

FIN WAIT2

Completed and ACK received. Awaiting FIN.

 

 

 

0000000A

TIME WAIT

After closing, pauses twice the maximum seg-

 

 

ment life (2MSL).

 

 

 

6-7 Using Socket Services by Manipulating Dedicated Control Bits

6-7-1 Application Procedure

Procedure

1,2,3... 1. Set the socket service parameters in the CPU Bus Unit Area in the DM Ar- ea.

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Omron CJ1W-ETN21 Application Procedure, TCP Connection Status Ethernet Unit to CPU Unit, Number Status Meaning