Action
Establishes a connection to a TCP/IP server.
Syntax
Result = SOCKETCONNECT(socket, IP, port [,nowait])
Remarks
Result |
A byte that is assigned with 0 when the connection succeeded. It will return 1 when an error occurred. |
socket |
The socket number in the range of 0-3. Or 0-7 for W5200/W5300. |
IP |
The IP number of the server you want to connect to.
This may be a number like 192.168.0.2 or a LONG variable that is assigned with an IP number.
Note that the LSB of the LONG, must contain the MSB of the IP number. |
Port |
The port number of the server you are connecting to. |
NoWait |
This is an optional parameter. Make it 1 to suppress waiting for a connection. By default, when you create a connection, the code waits for the connect flag. But waiting will block program execution. When you specify, not to wait, the code returns immediately. But you must use SOCKETSTAT to determine the outcome of the socketconnect. NOWAIT parameter is implemented for : -W5100 -W5200 -W5500 |
You can only connect to a server. Standardized servers have dedicated port numbers. For example, the HTTP protocol(web server) uses port 80.
After you have established a connection the server might send data. This depends entirely on the used protocol. Most servers will send some welcome text, this is called a banner.
You can send or receive data once the connection is established.
The server might close the connection after this or you can close the connection yourself. This also depends on the protocol.
You need to obtain a valid socket first with the GETSOCKET function.
See also
CONFIG TCPIP, GETSOCKET , SOCKETSTAT , TCPWRITE, TCPWRITESTR, TCPREAD, SOCKETCLOSE , SOCKETLISTEN , SOCKETDISCONNECT, URL2IP
Example
'-----------------------------------------------------------------------------------------
'name : servertest_SPI.bas
'copyright : (c) 1995-2021, MCS Electronics
'purpose : start the easytcp after the chip is programmed
' and create 2 connections
'micro : Mega88
'suited for demo : yes
'commercial addon needed : no
'-----------------------------------------------------------------------------------------
$regfile = "m88def.dat" ' specify the used micro
$crystal = 8000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 128 ' default use 32 for the hardware stack
$swstack = 128 ' default use 10 for the SW stack
$framesize = 128 ' default use 40 for the frame space
Config Spi = Hard , Interrupt = Off , Data Order = Msb , Master = Yes , Polarity = Low , Phase = 0 , Clockrate = 4 , Noss = 0
'Init the spi pins
Spiinit ' xram access
Print "Init , set IP to 192.168.1.70" ' display a message
Enable Interrupts ' before we use config tcpip , we need to enable the interrupts
Config Tcpip = Int1 , Mac = 12.128.12.34.56.78 , Ip = 192.168.1.70 , Submask = 255.255.255.0 , Gateway = 192.168.1.1 , Localport = 1000 , Tx = $55 , Rx = $55 , Chip = W5100 , Spi = 1
Dim Bclient As Byte ' socket number
Dim Idx As Byte
Dim Result As Word , Result2 As Word ' result
Dim S As String * 80
Dim Flags As Byte
Dim Peer As Long
Dim L As Long
Do
Waitms 1000
For Idx = 0 To 3
Result = Socketstat(idx , 0) ' get status
Select Case Result
Case Sock_established
If Flags.idx = 0 Then ' if we did not send a welcome message yet
Flags.idx = 1
Result = Tcpwrite(idx , "Hello from W5100A{013}{010}") ' send welcome
End If
Result = Socketstat(idx , Sel_recv) ' get number of bytes waiting
Print "Received : " ; Result
If Result > 0 Then
Do
Print "Result : " ; Result
Result = Tcpread(idx , S)
Print "Data from client: " ; Idx ; " " ; Result ; " " ; S
Peer = Getdstip(idx)
Print "Peer IP " ; Ip2str(peer)
Print "Peer port : " ; Getdstport(idx)
'you could analyse the string here and send an appropiate command
'only exit is recognized
If Lcase(s) = "exit" Then
Closesocket Idx
Elseif Lcase(s) = "time" Then
Result2 = Tcpwrite(idx ,"12:00:00{013}{010}") ' you should send date$ or time$
End If
Loop Until Result = 0
End If
Case Sock_close_wait
Print "close_wait"
Closesocket Idx
Case Sock_closed
Print "closed"
Bclient = Getsocket(idx , Sock_stream , 5000 , 64) ' get socket for server mode, specify port 5000
Print "Socket " ; Idx ; " " ; Bclient
Socketlisten Idx
Print "Result " ; Result
Flags.idx = 0 ' reset the hello message flag
Case Sock_listen ' this is normal
Case Else
Print "Socket status : " ; Result
End Select
Next
Loop
End