Announcement

**Lance Edmonds** · 11 Aug 1999, 04:59 AM

(Also see the thread in the PB/DOS forum).

In Windows, you'll need to use the Win32 API to manipulate a comm port. PowerBASIC and libraries such as WSC4PB wrap these API calls into a "programmer friendly" set of functions to make your life easier. While doing this with native PB code is admirable, it's a huge task! If you consider that it will take more than just a few hours to write your own functions (which it will definitely do), then a commercial library for less than US$100 is actually very economic. I do have some raw API code around here somewhere (written by a PB/DLL 5.0 user) that may help you get started.

I dont mean to be too negative on this, but I've "been there, done that, brought the T-Shirt"...

Lance
PowerBASIC Support

**Loren M Williams** · 11 Aug 1999, 12:28 PM

Thank you, Lance. You're just great!

Loren

**Michael Burns** · 8 Oct 2001, 10:58 AM

Did you ever find a solution?

I'm running into a problem right now that
seems to stem from PowerBASIC opening the
serial port and THEN setting the control
line behavior. I'm talking to an instrument
that resets (and loses all of its data) whenever
the DTR line goes high. The instrument makers
programming environment clearly can open the
serial port without having the DTR go high, but
PowerBASIC DLL always opens with it high, and then
lowers it when DTRLINE = %FALSE is set in a following
COMM SET command. Anyone know how to get PB to
set the control line behavior before the serial port
is opened?

------------------
Michael Burns

**Lance Edmonds** · 8 Oct 2001, 11:49 AM

I don't know whether this will help you, but the following is some code I put together to open a serial port via the API. It was for PB/CC 1.0 (before the advent of the COMM statements in PB/C 2.0).

Code:

FUNCTION OpenPort&(szPort AS ASCIIZ)
    DIM hComm AS LONG, fSuccess AS LONG, CommMask AS LONG
    DIM cDCB AS DCB, ComProp AS COMMPROP, CTO AS COMMTIMEOUTS
    DIM szDCB AS ASCIIZ * 64
    DIM x%

    hComm = CreateFile( szPort, _
                          %GENERIC_READ OR %GENERIC_WRITE, _
                          BYVAL 0, _
                          BYVAL 0, _
                          BYVAL %OPEN_EXISTING, _
                          BYVAL 0, _
                          BYVAL 0)
    IF hComm = %INVALID_HANDLE_VALUE OR hComm = %ERROR_FILE_NOT_FOUND THEN
        PRINT "ComPort Open Error!"
        EXIT FUNCTION
    END IF

    fSuccess = GetCommState(hComm, cdcb)
    IF ISFALSE fSuccess THEN
        PRINT "ComPort GetState Error!"
        EXIT FUNCTION
    END IF

    szDCB = "19200,n,8,1,p"
    IF ISFALSE BuildCommDCB(szDCB, cdcb) THEN
        PRINT "BuildCommDCB failure"
        EXIT FUNCTION
    END IF

    cdcb.BaudRate = 19200
    cdcb.ByteSize = 8
    cdcb.Parity   = %NOPARITY
    cdcb.StopBits = %ONESTOPBIT

    BIT SET cdcb.fBits,2          ' CTS       (set to 1)
    BIT RESET cdcb.fBits,3        ' DSR       (set to 0)

'$IF 0
    BIT SET cdcb.fBits,4          ' DTR 1/2    (= DTR_CONTROL_ENABLE) (set to 1)
    BIT RESET cdcb.fBits,5        ' DTR 2/2    (= DTR_CONTROL_ENABLE) (set to 0)

    BIT SET cdcb.fBits,6          ' DSRSensitivity
    BIT SET cdcb.fbits,7          ' ContinueOnXOFF

    BIT RESET cdcb.fBits,8        ' XON/XOFF output (Set to 0)       ' Halts Class 2 XON!!! Force to 0!
    BIT RESET cdcb.fBits,9        ' XON/XOFF input  (Set to 0)

    BIT SET cdcb.fBits,12       ' RTS 1/2    (= RTS_CONTROL_ENABLE)
    BIT SET cdcb.fBits,13       ' RTS 2/2    (= RTS_CONTROL_ENABLE)
'$ENDIF

    fSuccess = SetCommState(hComm, cdcb)
    IF ISFALSE fSuccess THEN
        PRINT "ComPort SetState Error!"
        EXIT FUNCTION
    END IF

$IF 0
PRINT "DCB Bits..."
FOR x% = 0 TO (LEN(cdcb.fbits) -1) * 8
    PRINT BIT(cdcb.fbits,x%);
NEXT x%
PRINT
    PRINT "Baud Rate         ", cdcb.BaudRate
    PRINT "ByteSize          ", cdcb.ByteSize
    PRINT "Parity            ", cdcb.Parity
    PRINT "Stop Bits         ", cdcb.StopBits

    PRINT "0  fBinary        ", BIT(cdcb.fbits,0)
    PRINT "1  fParity        ", BIT(cdcb.fbits,1)
    PRINT "2  fOutxCtsFlow   ", BIT(cdcb.fbits,2)
    PRINT "3  fOutxDsrFlow   ", BIT(cdcb.fbits,3)
    PRINT "45 fDtrControl    ", BIT(cdcb.fbits,4) BIT(cdcb.fbits,5)
    PRINT "6  fDsrSensitivity", BIT(cdcb.fbits,6)
    PRINT "7  fContinueOnXoff", BIT(cdcb.fbits,7)
    PRINT "8  fOutX          ", BIT(cdcb.fbits,8)
    PRINT "9  fInX           ", BIT(cdcb.fbits,9)
    PRINT "10 fErrorChar     ", BIT(cdcb.fbits,10)
    PRINT "11 fNull          ", BIT(cdcb.fbits,11)
    PRINT "12 fRtsControl    ", BIT(cdcb.fbits,12) BIT(cdcb.fbits,13)
    PRINT "14 fAbortOnError  ", BIT(cdcb.fbits,14)
WAITKEY$
$ENDIF

    fSuccess = GetCommProperties(hComm, ComProp)
    IF ISFALSE fSuccess THEN
        PRINT "ComPort GetCommProperties Error!"
        EXIT FUNCTION
    END IF

    IF (ComProp.dwProvCapabilities AND %PCF_RTSCTS) THEN _
        PRINT "RTS/CTS capable modem detected"

    SetupComm hComm, MAX%(%BufferSize,Comprop.dwCurrentRxQueue), MAX%(%BufferSize,Comprop.dwCurrentTxQueue)
    fSuccess = GetCommProperties(hComm, ComProp)
    PRINT "TX Que size =" Comprop.dwCurrentTxQueue
    PRINT "RX Que size =" Comprop.dwCurrentRxQueue

    IF ISFALSE (ComProp.dwMaxBaud AND %BAUD_19200) AND ComProp.dwMaxBaud <> %BAUD_USER THEN
        PRINT "Modem does not support 19200 Baud!"
        EXIT FUNCTION
    END IF

    IF ISFALSE (ComProp.dwProvSubType AND %PST_FAX) THEN
        PRINT "Modem does not support Fax mode!"
        EXIT FUNCTION
    END IF

    GetCommTimeouts hComm, CTO
    IF ISFALSE (ComProp.dwProvCapabilities AND %PCF_INTTIMEOUTS) THEN
        PRINT "Modem Timeouts NOT available"
    ELSE
        CTO.ReadIntervalTimeout = %MAXDWORD
        CTO.ReadTotalTimeoutMultiplier = 50
        CTO.ReadTotalTimeoutConstant = 50
        CTO.WriteTotalTimeoutMultiplier = 1
        CTO.WriteTotalTimeoutConstant = 20000

        SetCommTimeouts hComm, CTO
    END IF

    PurgeComm hComm, %PURGE_TXCLEAR OR %PURGE_RXCLEAR OR %PURGE_TXABORT OR %PURGE_RXABORT

'    sleep 100
    FUNCTION = hComm
END FUNCTION

From there you use ReadFile() and WriteFile(), and finally CloseHandle().

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

**Roger Garstang** · 10 Aug 2010, 04:54 PM

The only thread I could find about setting up all these values is using the old BIT commands...

I have a need to use WaitCommEvent, but with issues in it blocking the thread as well as the port from having anything done to it so I can abort the wait I have to use example code from CodeProject and http://www.powerbasic.com/support/pb...=WaitCommEvent to create a WinAPI version. For anyone using this with current compilers a better/easier layout is (Hopefully this will make it to .06 builds):

Code:

Type DCBnew
  DCBlength As Dword
  BaudRate As Dword
  fBinary As Bit * 1 In Dword
  fParity As Bit * 1
  fOutxCtsFlow As Bit * 1
  fOutxDsrFlow As Bit * 1
  fDtrControl As Bit * 2
  fDsrSensitivity As Bit * 1
  fTXContinueOnXoff As Bit * 1
  fOutX As Bit * 1
  fInX As Bit * 1
  fErrorChar As Bit * 1
  fNull As Bit * 1
  fRtsControl As Bit * 2
  fAbortOnError As Bit * 1
  fDummy2 As Bit * 17
  wReserved As Word
  XonLim As Word
  XoffLim As Word
  ByteSize As Byte
  Parity As Byte
  StopBits As Byte
  XonChar As Byte
  XoffChar As Byte
  ErrorChar As Byte
  EofChar As Byte
  EvtChar As Byte
  wReserved2 As Integer
End Type

**Paul Dixon** · 10 Aug 2010, 05:26 PM

Roger,

but with issues in it blocking the thread

If something is blocking your thread then a common solution is to create a new thread and run the blocking code in that. The new thread then blocks but the original thread continues.

as well as the port from having anything done to it

Isn't that what the lpOverlapped parameter in WaitCommEvent is for?

Paul.

**Cliff Nichols** · 10 Aug 2010, 05:58 PM

For quite some time now I have been working on and off on my SerialPort.inc file that would make handling the serial port much easier.

But from my archives (Sorry I do not know who to give credit to, as I found this years ago) is serial port routines to directly control lines (may need some modifications, since I think I got it back in PB6???)

Anyways, this should help

Code:

'enhanced serial port functions including handshake
'signal manipulation/checking etc.
'
'Requires WINAPI32.INC
'
'Sets default parameters for COM port
SUB INITCOMM(HCOM AS LONG,COMMSTR AS STRING)
    COMM OPEN COMMSTR AS HCOM
    COMM RESET HCOM,FLOW
    COMM SET HCOM, BAUD = 9600 ' 9600 baud
    COMM SET HCOM, BYTE = 8 ' 8 bits
    COMM SET HCOM, PARITY = 0 ' No parity
    COMM SET HCOM, STOP = 0 ' 1 stop bit
    COMM SET HCOM, TXBUFFER = 1024 ' 1k transmit buffer
    COMM SET HCOM, RXBUFFER = 32768 '32k receive buffer
END SUB
'Write single binary byte to COM port
SUB SERWRTBIN(HCOM AS LONG,DAT AS BYTE)
    COMM SEND HCOM,CHR$(DAT)
END SUB
'Get single binary byte from COM port
'TOSEC specifies timeout in seconds,error status is returned in SERERR
'Timeout must guard against midnight rollover for timer
FUNCTION SERRDBIN(HCOM AS LONG,TOSEC AS LONG,SERERR AS LONG) AS BYTE
    DIM LL1 AS LONG,LL2 AS LONG,LL3 AS LONG,SS AS STRING
    LL1=TIMER
    LL2=(LL1 + TOSEC)-86399
    IF LL2>0 THEN
        DO
            LL3=TIMER
        LOOP UNTIL LL3<LL1
        LL1=LL3
        TOSEC=LL2
    END IF
    DO
        LL2=TIMER
        LL3=COMM(HCOM,RXQUE)
    LOOP UNTIL LL2>(LL1+TOSEC) OR LL3>0
    IF LL2>(LL1+TOSEC) THEN
        SERERR=255
        FUNCTION=0
        EXIT FUNCTION
    END IF
    COMM RECV HCOM, 1,SS
    FUNCTION=ASC(SS)
END FUNCTION
'Write string to COM port
SUB SERWRTSTR(HCOM AS LONG,DAT AS STRING)
    COMM SEND HCOM,DAT
END SUB
'Get received string from COM port
FUNCTION SERGETSTR(HCOM AS LONG) AS STRING
    DIM LL AS LONG,SS AS STRING
    LL=COMM(HCOM,RXQUE)
    COMM RECV HCOM,LL,SS
    FUNCTION=SS
END FUNCTION
'Get string terminated by linefeed-TOSEC specifies timeout,error status returned in SERERR
'Linefeed is last byte in string
FUNCTION SERGETLINESTR(HCOM AS LONG,TOSEC AS LONG,SERERR AS LONG) AS STRING
    DIM SS AS STRING,BB AS BYTE,LL AS LONG
    LL=TOSEC
    SERERR=0
    SS=""
    DO
        BB=SERRDBIN(HCOM,LL,SERERR)
        SS=SS + CHR$(BB)
    LOOP UNTIL BB=10 OR SERERR>0
    FUNCTION=SS
END FUNCTION
'Gets single byte string from COM port-TOSEC specifies timeout
'Error status is returned in SERERR
FUNCTION SERRDSTR(HCOM AS LONG,TOSEC AS LONG,SERERR AS LONG) AS STRING
    DIM BB AS BYTE,SS AS STRING
    BB= SERRDBIN(HCOM,TOSEC,SERERR)
    FUNCTION=CHR$(BB)
END FUNCTION
'Clear receive buffer
SUB RXCLEAR(HCOM AS LONG)
    DIM SS AS STRING
    SS=SERGETSTR(HCOM)
END SUB
'SETS RTS
SUB SETRTS(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM,%SETRTS)
END SUB
'CLEARS RTS
SUB CLRRTS(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM&,%CLRRTS)
END SUB
'SETS DTR
SUB SETDTR(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM&,%SETDTR)
END SUB
'CLEAR DTR
SUB CLRDTR(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM&,%CLRDTR)
END SUB
'ASSERT BREAK
SUB SETBREAK(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM&,%SETBREAK)
END SUB
'CLEAR BREAK
SUB CLRBREAK(HCOM AS LONG)
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL&=ESCAPECOMMFUNCTION(APIHCOM&,%CLRBREAK)
END SUB
'GET MODEM STATUS SIGNALS
FUNCTION GETCOMSTS(HCOM AS LONG)AS LONG
    DIM APIHCOM AS LONG
    DIM LL AS LONG
    DIM STS AS LONG
    APIHCOM&=FILEATTR(HCOM,2)
    LL=GETCOMMMODEMSTATUS(APIHCOM&,STS )
    FUNCTION=STS
END FUNCTION
'CHECK CTS
FUNCTION GETCTS(HCOM AS LONG) AS LONG
    FUNCTION=GETCOMSTS(HCOM) AND %MS_CTS_ON
END FUNCTION
'CHECK DSR
FUNCTION GETDSR(HCOM AS LONG) AS LONG
    FUNCTION=GETCOMSTS(HCOM) AND %MS_DSR_ON
END FUNCTION
'CHECK CD
FUNCTION GETCD(HCOM AS LONG) AS LONG
    FUNCTION=GETCOMSTS(HCOM) AND %MS_RLSD_ON
END FUNCTION
'CHECK RING
FUNCTION GETRING(HCOM AS LONG) AS LONG
    FUNCTION=GETCOMSTS(HCOM) AND %MS_RING_ON
END FUNCTION
'------------------

**Roger Garstang** · 10 Aug 2010, 06:13 PM

Originally posted by Paul Dixon View Post

Roger,
...

Isn't that what the lpOverlapped parameter in WaitCommEvent is for?

Paul.

Yes, but how do you make an overlapped Com Port using internal PB commands? PB's COM and an non-Overlapped CreateFile API both hang when trying to close the port. I even tried things like Setting Break and having WaitCommEvent watch for it too, but it still hung.

I created the API version fine now. I have yet to create the needed event and overlapped stuff, but it is fairly quick. Main difference I notice is the API is picky about certain combinations of Stop Bits/Bits Per Byte/Parity and doesn't allow setting them and the PB docs for Com Set don't mention that...haven't tried them, but I'm curious if the calls fail there too or if it corrects them to be valid and re-submits them.

**Cliff Nichols** · 10 Aug 2010, 07:14 PM

Roger,
The PB wrapper functions are GREAT!!! (In most cases), in the few cases that PB did not make easier (For users to learn from, and lets face it "Windows API is quite intimidating" at first look)

One thing you will find (if working with multiple serial port devices) is that they each take their own spin on different settings. So be warned that if things work great at first, but years later does not work, then the most likely cause is another device used a setting that you did not think of (or change) when using your own code.

By the way...what is it that you are trying to communicate with??? (Simplifies things a lot)

**Michael Mattias** · 11 Aug 2010, 09:23 AM

Handle thread blocking calls with abort?

Put your 'blocking calls' in their own threads of execution and adapt this code:

Terminate Worker Threads Using Windows Events (and Using Thread Local Storage) Demo Dec 23 2005

**Roger Garstang** · 11 Aug 2010, 11:37 AM

Originally posted by Cliff Nichols View Post

Roger,
By the way...what is it that you are trying to communicate with??? (Simplifies things a lot)

In the end it is going to be a wedge type application to send handheld scanner data to the keyboard. I made it Overlapped and it didn't seem to do much other than not hanging now and still no way of closing the port. Making it overlapped seemed to almost make WaitCommEvent redundant too. I think it would be easier just to do the Readfile Call and a Wait function. Using WaitCommEvent seems to imply I can get my event set by other ways like Breaks and Errors, but I'd think Readfile would set it for those too.

A little bit more work to get the data, but I think it will be quicker and less CPU intense to Wait rather than poll. I may combine it with some of the Window code from my other Sendy app I posted here a while back to activate specific windows to give keys to, etc. I'm still debating if I want to monitor more than one COM port too (Other Wedge applications do, but I think the keys have too much of a chance of getting out of sync).

**Roger Garstang** · 17 Aug 2010, 12:17 PM

I've got this working pretty slick and fast. Only weird thing I've noticed now is the fParity value doesn't appear to get set with SetCommState. After setting it I can perform a GetCommState and it shows 0. The value itself is a little odd since it is just T/F and there is a Parity value already that has all the types of Parity and None, so fParity isn't really needed.

PB's built in COM doesn't appear to use or be able to set it either since I can set parity using it, disconnect, then connect with the API seeing all values set but fParity. Hyper Terminal doesn't have any luck either...so, how was this flag intended to be used?

**Tom Hanlin** · 17 Aug 2010, 02:19 PM

It looks as though fParity is intended to specify error trapping for parity errors. Whether it does anything at all is at the mercy of the comm driver.

**Roger Garstang** · 17 Aug 2010, 04:01 PM

Yeah, from the documentation and after going through 50+ pages of Google results the only thing that makes sense is a comment in one of the results about Parity being the type of Parity to send and fParity being if you use it or not on receive. It could be unsupported on the 3 ports/devices I tried it on. Everything seems to work fine though. A 0-1% CPU usage on wait is nice!

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Serial Port Control Lines

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