Read from Serial

BackupUser · Post by **BackupUser** » Fri Jul 26, 2002 12:24 pm

Restored from previous forum. Originally posted by plouf.

AFAIK to read from a serial port you need to open it and
read like a file but this simple read i try hangs the program in the
readbyte() command i have try to replace with readdata/string
offcourse the serial port is configured at correct baudrate parity etc

OpenConsole()
a$ = "a"
tra = OpenComPort(0,"COM1:")
PurgeComm_(*tra, #PURGE_RXCLEAR)
UseFile(0)
Repeat
ReadData(@a$, 1)
PrintN(a$)
UseFile(0)
Until a$ = "12"
CloseFile(0)
End

Christos

BackupUser · Post by **BackupUser** » Wed Jul 31, 2002 7:56 am

Restored from previous forum. Originally posted by tinman.

AFAIK to read from a serial port you need to open it and
read like a file but this simple read i try hangs the program in the
readbyte() command i have try to replace with readdata/string
offcourse the serial port is configured at correct baudrate parity etc

Don't you need to open the device as "\\.\COM1" ? I was reading the API docs this morning for this, so it would be nice if you got this working

--
It's not minimalist - I'm increasing efficiency by reducing input effort.
(Win98first ed. + SP1, PB3.20)

BackupUser · Post by **BackupUser** » Wed Jul 31, 2002 7:30 pm

Restored from previous forum. Originally posted by plouf.

Don't you need to open the device as "\\.\COM1" ? I was reading the API docs this morning for this, so it would be nice if you got this working

Not AFAIK the PureFrog opens it like this but ....

Christos

BackupUser · Post by **BackupUser** » Wed Jul 31, 2002 7:47 pm

Restored from previous forum. Originally posted by pusztry.

Can somebody put a quick code snippet on how to open the COM Port. I am new to this and I loofed at the Froggy example but I still can't figure it out.

Thanks

Ryan

WinXP, PIII 800 MHz, 512MB RAM, SB Live 5.1, NVidia TNT 2 Ultra

BackupUser · Post by **BackupUser** » Wed Jul 31, 2002 9:54 pm

Restored from previous forum. Originally posted by ebs.

Ryan,

Here's what I use. It's taken directly from the Froggy code, with a little bit of my own stuff.

Regards,
Eric

Code: Select all

; open COMM port
Procedure.l SetupCommPort(Port.b, BaudRate.l, Parity.b, StopBits.b)
  Structure DCB2
    DCBlength.l   ; sizeof(DCB) 
    BaudRate.l    ; current baud rate 
    Flags.l
    wReserved.w   ; not currently used 
    XonLim.w      ; transmit XON threshold 
    XoffLim.w     ; transmit XOFF threshold 
    ByteSize.b    ; number of bits/byte, 4-8 
    Parity.b      ; 0-4=no,odd,even,mark,space 
    StopBits.b    ; 0,1,2 = 1, 1.5, 2 
    XonChar.b     ; Tx and Rx XON character 
    XoffChar.b    ; Tx and Rx XOFF character 
    ErrorChar.b   ; error replacement character 
    EofChar.b     ; end of input character 
    EvtChar.b     ; received event character 
    wReserved1.w  ; reserved, do not use 
  EndStructure

  #CPFile = 999
  CPNum.l = #CPFile + Port
  
  *CPort = OpenComPort(CPNum,"COM" + Str(Port) + ":")
  If *CPort
    If GetCommState_(*CPort, @dcb.DCB2)
      ; Allocation des tampons d'E/S
      SetupComm_(*CPort, 4096, 4096)
      
      ct.COMMTIMEOUTS
      ct\ReadIntervalTimeout         = #MAXDWORD
      ct\ReadTotalTimeoutMultiplier  = 0
      ct\ReadTotalTimeoutConstant    = 0
      ct\WriteTotalTimeoutMultiplier = 0
      ct\WriteTotalTimeoutConstant   = 0
      SetCommTimeouts_(*CPort, ct)
      
      ; construction des donnees d'initialisation du port
      dcb\BaudRate  = BaudRate
      dcb\Parity    = Parity
      dcb\StopBits  = StopBits
      dcb\ByteSize  = 8    
      dcb\Flags     = 4227  ; Combined flags values got from the C.. PureBasic doesn't support flags in structures
      SetCommState_(*CPort, @dcb)

      PurgeComm_(*CPort, #PURGE_TXCLEAR | #PURGE_RXCLEAR)
    Else
      CPNum = -2
    EndIf
  Else
    CPNum = -1
  EndIf
    
  ProcedureReturn CPNum
EndProcedure

; read from COMM port until ,  or number of characters
Procedure.s ReadCommPort(CommPort.l, NumChars.l)
  UseFile(CommPort)
  InpBuffer.s = ""
  char.s = " "
  StopFlag.b = #FALSE
    
  While StopFlag = #FALSE
    If ReadData(@char, 1)
      If char = Chr(#CR) Or char = Chr(#LF)
        StopFlag = #TRUE
      Else
        InpBuffer + char
        If NumChars And Len(InpBuffer) >= NumChars
          StopFlag = #TRUE
        EndIf
      EndIf
    EndIf
  Wend
  
  ProcedureReturn InpBuffer
EndProcedure

; write string to COMM port - no newline
Procedure WriteCommPort(CommPort.l, Message.s)
  UseFile(CommPort)
  WriteString(Message)
EndProcedure

; write string to COMM port with newline
Procedure WriteCommPortN(CommPort.l, Message.s)
  UseFile(CommPort)
  WriteStringN(Message)
EndProcedure

[code]

You use it like this:

[code]
; initialize comm port: 9600,N,8,1
CommPtr = SetupCommPort(CommPort, #CBR_9600, #NOPARITY, #ONESTOPBIT) 
; abort if unable to open comm port
If CommPtr 
WinXP, PIII 800 MHz, 512MB RAM, SB Live 5.1, NVidia TNT 2 Ultra
[/quote]

BackupUser · Post by **BackupUser** » Fri Aug 02, 2002 7:55 am

Restored from previous forum. Originally posted by plouf.

Ebs

Your code is ok but i only get correct value the first time
after this i receive strange numbers !??!
i.e. not the ones that is send to serial
with a terminal always i got correct numbers .

Christos