How do I communicate with serial port in PowerBuilder

Hi,

you will need the following OCX -->MSCOMM32.OCX
im sure u have it on ur machine already.
Now using OLE u can communicate with ur serial port.

Check the following links for more info,
https://www.experts-exchange.com/questions/20560721/Read-Write-in-ports-COM1-COM2.html
https://www.experts-exchange.com/questions/21349512/HOW-TO-CONTROL-A-CUSTOMER-DISPLAY-DEVICE-USING-COM-PORT.html

Attaching exported objects from below link,
https://www.experts-exchange.com/questions/20876598/accessing-COM-port.html


Hope This Helps...

Cheers,
Rosh

$PBExportHeader$n_cst_serialcom.sru
forward
global type n_cst_serialcom from nonvisualobject
end type
end forward
 
global type n_cst_serialcom from nonvisualobject autoinstantiate
end type
 
type prototypes
/* To create a file */
function ulong CreateFileA( ref string lpszName,  &
  ulong fdwAccess,  &
  ulong fdwShareMode,  &
  ulong lpsa,    &
  ulong fdwCreate,  &
  ulong fdwAttrsAndFlags,  &
  ulong hTemplateFile ) library "kernel32.dll"
 
/* to write to the file */
function boolean WriteFile( ulong hFile,  &
  ref string lpBuffer,  &
  ulong nNumberOfBytesToWrite, &
  ulong lpNumberOfBytesWritten, &
  st_overlapped lpOverlapped ) library "kernel32.dll" 
 
/* To get error information */
function ulong GetLastError() library "kernel32.dll"
 
/* To close the file */
function boolean CloseHandle(ulong hObject ) library "kernel32.dll" 
 
function boolean ReadFile( ulong fFile,    &
  ref string lpBuffer,    &
  ulong nNumberOfBytesToRead, &
  ulong lpNumberOfBytesRead, &
  ref st_overlapped lpOverlapped)  &
  library "Kernel32.dll"
 
/* Flush the file buffer */
function boolean FlushFileBuffers(  ulong hFile) library "kernel32.dll" 
 
/* Setup the Communications Port */
function boolean SetupComm( ulong hFile,  &
  ulong dwInQueue,  &
  ulong dwOutQueue) library "kernel32.dll"
 
/* Setup Com Port Timeouts */
function boolean SetCommTimeouts( ulong hFile,  &
    st_commtimeouts lpCommTimeouts) &
    library "kernel32.dll"
 
/* Setup Comm Mask */
function boolean SetCommMask( ulong hFile,  &
    ulong dwEvtMask)  &
    library "kernel32.dll"
 
/* Wait Comm Event */
function boolean WaitCommEvent(      ulong hFile,  &
    ref ulong lpEvtMask,  &
    st_overlapped lpOverlapped)  &
    library "kernel32.dll"
 
/* Purge Comm port */
function boolean PurgeComm(ulong hFile,  &
    ulong dwFlags)  &
    library "kernel32.dll"
 
/* Clear Comm Error 
function boolean ClearCommError( ulong hFile,      &
    ref ulong lpErrors,  &
    ref st_comstat lpStat) &
    library "kernel32.dll"*/
  
/* Set up the port */
function ulong BuildCommDCBA( ref string port_description,  &
  ref st_DCB DCB_structure) library "kernel32.dll"
  
function ulong SetCommState( ulong comm_id,  &
  ref st_DCB DCB_structure) library "kernel32.dll"
end prototypes
 
type variables
integer ii_comPort
integer il_comTimeout
 
end variables
 
forward prototypes
public function string read (integer al_read_length)
public function integer open (integer ai_comport)
public function integer close ()
public function integer write (ref string as_buffer)
public function long getcomtimeout ()
public subroutine setcomtimeout (long al_timeout)
public function integer readcharacter (ref string as_readstring)
end prototypes
 
public function string read (integer al_read_length);string        ls_buffer
long          ll_bytes_read = 0
long          ll_bytes_written = 0
boolean       lb_return
st_overlapped lst_overlapped
 
ls_buffer = space(al_read_length)
 
lst_overlapped.internal = 0
lst_overlapped.internalhigh = 0
lst_overlapped.offset = 0
lst_overlapped.offsethigh = 0
lst_overlapped.hevent = 0
 
lb_return = ReadFile(ii_comPort,ls_buffer,al_read_length,ll_bytes_read,lst_overlapped)
 
if lb_return = FALSE then
      messagebox("Read Failed","Handle = "+string(ii_comPort) + "~r~nError = "+string(getlasterror()))
else
      if lb_return = true and len(ls_buffer) = 0 then
      setnull(ls_buffer)      
   end if
end if
 
return ls_buffer
end function
 
public function integer open (integer ai_comport);CONSTANT long   EV_RXCHAR = 0
CONSTANT long   GENERIC_READ = 2147483648
CONSTANT long   GENERIC_WRITE = 1073741824
CONSTANT long   FILE_SHARE_NONE = 0 
CONSTANT long   OPEN_EXISTING = 1
CONSTANT long   PURGE_TXABORT = 1
CONSTANT long   PURGE_RXABORT = 1
CONSTANT long   PURGE_TXCLEAR = 1
CONSTANT long   PURGE_RXCLEAR = 1
CONSTANT long   FF_OVERLAPPED = 0
 
string ls_port
string ls_port_description
long   ll_null
long   ll_return_cd
st_commtimeouts     str_commtimeouts
st_DCB              str_DCB
 
ii_comPort = ai_comPort
 
if ai_comPort = 1 then
      ls_port = "COM1:"
      ls_port_description = "COM1: 9600,N,8,1"
elseif ai_comPort = 2 then
      ls_port = "COM2:"
      ls_port_description = "COM2: 9600,N,8,1"
elseif ai_comPort = 3 then
      ls_port = "COM3:"
      ls_port_description = "COM3: 9600,N,8,1"
elseif ai_comPort = 4 then
      ls_port = "COM4:"
      ls_port_description = "COM4: 9600,N,8,1"
else
      ai_comPort = 0
      messagebox("Port Error","An invalid com port was passed to the open port function")
end if
 
setnull(ll_null)
 
ii_comPort = CreateFileA(ls_port, GENERIC_READ + GENERIC_WRITE, FILE_SHARE_NONE, ll_null, OPEN_EXISTING, FF_OVERLAPPED, ll_null)
 
IF ii_comPort < 0 THEN
   MessageBox("OPEN ERROR", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
else
      // Set the port variables
      ll_return_cd = BuildCommDCBA(ls_port_description,str_DCB)
      
      if ll_return_cd = 0 then
            messagebox("Build Comm Error","Error code = "+string(ll_return_cd))
      else
            ll_return_cd = SetCommState(ii_comPort,str_DCB)
      end if
      
   // Setup the Comm mask
   if SetCommMask(ii_comPort, EV_RXCHAR) = FALSE then 
            MessageBox("SETCOMMMASK", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
      end if
      
      // Setup the buffers
   if SetupComm(ii_comPort, 4096, 4096) = FALSE then 
            MessageBox("SETUPCOMM", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
      end if
 
   // Flush the Port's buffer
   if FlushFileBuffers(ii_comPort) = FALSE then 
            MessageBox("FLUSH", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
      end if
 
   // Purge the Port
   if PurgeComm(ii_comPort, PURGE_TXABORT + PURGE_RXABORT + PURGE_TXCLEAR + PURGE_RXCLEAR) = FALSE then 
            MessageBox("PURGECOMM", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
      end if
 
   // Setup Timeouts
      SetComTimeout(1500)
end if
 
return ii_comPort
end function
 
public function integer close ();boolean lb_return
int     li_return_cd = -1
 
lb_return = CloseHandle(ii_comPort)
 
if lb_return = false then
   messagebox("Close Failed","Com port id = " + string(ii_comPort))
else
      li_return_cd = 1
end if
 
return li_return_cd
end function
 
public function integer write (ref string as_buffer);long          ll_bytes_read = 0
long          ll_bytes_written = 0
boolean       lb_return
st_overlapped lst_overlapped
 
lst_overlapped.internal = 0
lst_overlapped.internalhigh = 0
lst_overlapped.offset = 0
lst_overlapped.offsethigh = 0
lst_overlapped.hevent = 0
 
lb_return = WriteFile(ii_comPort,as_buffer,len(as_buffer),ll_bytes_written,lst_overlapped)
 
if lb_return = FALSE then
      messagebox("WriteFailed","Handle = "+string(ii_comPort) + "~r~nError = "+string(getlasterror()))
end if
 
return 1
end function
 
public function long getcomtimeout ();return il_ComTimeout
 
end function
 
public subroutine setcomtimeout (long al_timeout);st_commtimeouts     str_commtimeouts
 
il_comTimeout = al_timeout
 
// set read timeout
str_commtimeouts.ReadIntervalTimeout      = al_timeout
str_commtimeouts.ReadTotalTimeoutConstant = al_timeout
      
str_commtimeouts.ReadTotalTimeoutMultiplier  = 0
str_commtimeouts.WriteTotalTimeoutMultiplier = 0
str_commtimeouts.WriteTotalTimeoutConstant   = 0
 
// Setup Timeouts
if SetCommTimeouts(ii_comPort, str_commtimeouts) = FALSE then
  MessageBox("SETCOMMTIMEOUTS", "Handle = " + string(ii_comPort) + "~r~nError = " + string(GetLastError()))
end if
 
return 
end subroutine
 
public function integer readcharacter (ref string as_readstring);string        ls_buffer
long          ll_bytes_read = 0
long          ll_bytes_written = 0
boolean       lb_return
st_overlapped lst_overlapped
 
ls_buffer = space(1)
 
lst_overlapped.internal = 0
lst_overlapped.internalhigh = 0
lst_overlapped.offset = 0
lst_overlapped.offsethigh = 0
lst_overlapped.hevent = 0
 
lb_return = ReadFile(ii_comPort,ls_buffer,1,ll_bytes_read,lst_overlapped)
 
if lb_return = FALSE then
      messagebox("Read Failed","Handle = "+string(ii_comPort) + "~r~nError = "+string(getlasterror()))
else
      ll_bytes_read = len(ls_buffer)
      if lb_return = true and len(ls_buffer) = 0 then
      setnull(ls_buffer)      
   end if
end if
as_readString = ls_buffer
 
return ll_bytes_read
end function
 
on n_cst_serialcom.create
call super::create
TriggerEvent( this, "constructor" )
end on
 
on n_cst_serialcom.destroy
TriggerEvent( this, "destructor" )
call super::destroy
end on

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Thank you for the assistance on this.
I tried to import your uo script but get an error message "illegal data type st_overlapped"  Do you have the export for this?  I assume it is a structure?

I do have the mscomm32.ocx on my PC, when I try to add an OLE object using it, I try CREATE FROM FILE and it does not give me the OLE properties I expect.  So I try to use INSERT CONTROL and get an error message "License file required"

I looked the links you give me above, some of them lead to dead ends and other one has the exported uo which gives me same error on import.

Once I do make communication, all I need to do is listen for data to come in through COM1 and read it byte by byte.

Thank you for your time.

I tried to register the mscomm32.ocx and got a successful message.  Still did not help the license issue.  Then I tried to unregister it and re register it.  No good still.

joda

Hi,

sorry abt the delayed reply... kinda lost the thread....

st_overlapped is a structure we need when writing to the communication ports. It is defined as follows:
$PBExportHeader$st_overlapped.srs
global type st_overlapped from structure
long Internal
long Internalhigh
long offset
long offsethigh
long hevent
end type


Please refer:
http://eric.aling.tripod.com/PB/tips/pbtip12.htm

Cheers,
Rosh

Rosh, Thank you for the help.

Now anther structure is needed.     st_DCB

Thanks,
John

Hi,

i dont see the above structure st_DCB in the code provided by me above.
Please refer the URL http://eric.aling.tripod.com/PB/tips/pbtip12.htm

I dont thing u need anything beyond the code provided there to achieve wat u want in ur original question.

Or,
provide the code ur using.wonder wat st_DCB is???

Cheers,
Rosh

Please see line 142 in the code of your first reply.  There it has this variable defined.  

st_DCB              str_DCB

When I attempt an import on the n_cst_serialcom.sru file, I need to have that strructure defined.

Thanks for the help Rosh.  Greatly appreciated.