Microsoft Programmer's Library 1.3/Microsoft-Programers-Library-v1.3.iso/sampcode/msj/msjv4_6/unix/unixbsc.arc/IODEMO.BAS

BASIC Source File | 1989-06-19 | 13.5 KB | 455 lines

' == [ GENERAL NOTES   ] ================================================
'                                                                       =
'    This Basic program demonstrates how to interface to the     =
'    AsyncTermio device driver.  The interface used finds it's    =
'    origin on AT&T's UNIX systems.                     =
'                                    =
'    The generalized UNIX serial link interface was originally moved    =
'    to MS-DOS for C programmers that desire to port serial comm    =
'    software between MS-DOS and UNIX.                =
'                                    =
'    Most Basic programmers will tell you that Basic's COM port    =
'    management is sufficient for most applications.  We agree.    =
'    However, should you desire to use the generalized UNIX serial    =
'    port interface, Async TermIO will suffice.            =
'                                    =
'    With the OPEN COM statement, Basic provides:            =
'                                    =
'        + Speed, Parity, Stopbits, Character Length Control.    =
'        + Asynchronous buffering of input and output.        =
'        + Call back functions that are invoked on COM activity.    =
'        + Exception handling.                    =
'        + Timing.                        =
'                                    =
'    With the OPEN COM statement, Basic DOES NOT provide:        =
'                                    =
'        + Xon/Xoff Flow Control.                =
'        + The interface is not generalized across environments.    =
'            and is not portable to other operating systems.    =
'        + Not as diverse as the generalized UNIX interface.    =
'                                    =
'    The trade-offs of writing serial communications software are     =
'    discussed at length in the Async TermIO documentation.        =
'                                    =
'    Please review the publication (See Async TermIO    User's Manual)    =
'        "Portable Serial Communications Between MS-DOS & UNIX"    =
'                                    =
' =======================================================================
'                                    =
'    Copyright (c) 1988    Boulder Software Group            =
'                P.O. BOX 14200                =
'                Boulder, CO   80308-4200        =
'                                    =
'                [phone] (Voice)            =
'                [phone] (FAX)            =
'                                                                       =
' =======================================================================
'

'
' == [ INCLUDE FILES   ] ================================================
'                                                                       =
'    The include file TERMIO.H contains several constants that are    =
'    use to set flags, compare values, function declarations, etc.    =
'                                                                       =
' =======================================================================
'

    ' $INCLUDE: 'TERMIO.H'


'
' == [ GLOBAL VARS     ] ================================================
'                                                                       =
'                                                                       =
' =======================================================================
'

    DIM         TtyParams        AS    Termio
    DIM        FileNumberTty        AS    INTEGER
    DIM        FileHandle        AS    INTEGER
    DIM        FileMode        AS    INTEGER


'
' == [ MAIN            ] ================================================
'                                                                       =
'    Main driver program used to demonstrate how to use the        =
'    AsyncTermIO device driver.  Each meaningful code fragment    =
'    is commented.                            =
'                                                                       =
' =======================================================================
'
    '
    '    Set up primitive error trapping (exception handling)
    '    in case something goes "wrong."
    '

    ON ERROR GO TO ErrorHandler

    '
    '    Obtain a free file number for the I/O stream we wish
    '    to open for the terminal device "TTY01" which is a
    '    device driver you should have installed in your
    '    CONFIG.SYS file.
    '

    FileNumberTty    = FREEFILE

    '
    '    There are several ways to open a file in Basic, the
    '    method shown below is recommended when you intend
    '    to use the AsyncTermIO driver.
    '

    OPEN "TTY01" FOR BINARY ACCESS READ WRITE AS #FileNumberTty

    '
    '    Set set up the flags in the struct termio
    '
        '    Request that the BREAK character be ignored.
    '    Ignore parity errors .
        '    Start the XON/XOFF mechanism.
    '
    '

    TtyParams.Ciflag        = BRKINT OR IGNPAR OR IXON OR IXOFF

        '
    '    Request no delays after NL, CR, TAB or VT.  Expand tabs
        '    to spaces and delay on sending a FF character.
    '

    TtyParams.Coflag        = NL0 OR CR0 OR TAB3 OR BS1 OR VT0 OR FF1

    '
    '    Request that the baud (symbols/sec) rate at 9600, eight
    '    bits of data, one stop bit (default), enable the
    '    the receiver, and hang-up on the last close of the file.
    '    No parity was requested (PARENB flag not present).
    '

    TtyParams.Ccflag        = B9600 OR CS8 OR CREAD OR HUPCL

    '
    '    Request no Clflag options.
    '

    TtyParams.Clflag        = 0

    '
    '    Line discipline is always zero for this device driver
    '

    TtyParams.Cline            = CHR$(0)


    '
    '    Since ICANON is not set the MIN/TIME parameters are
    '    used.  So set both their values to zero.  If the ICANON
    '    flag is set, some of these entries have different meanings.
    '    See the Async TermIO documentation on "MIN/TIME Interaction"
    '    (Somewhere around page 12 for Doc version 4.02, see also
    '    Pages 2 and 3).
    '

    MID$( TtyParams.ccc, VINTR,    1 )    = "A"
    MID$( TtyParams.ccc, VQUIT,    1 )    = "B"
    MID$( TtyParams.ccc, VERASE,    1 )     = CHR$( 00 )
    MID$( TtyParams.ccc, VKILL,    1 )     = CHR$( 00 )
    MID$( TtyParams.ccc, VEOF,    1 )    = CHR$( 00 )
    MID$( TtyParams.ccc, VEOL,    1 )    = CHR$( 00 )
    MID$( TtyParams.ccc, RESERVED,    1 )    = CHR$( 00 )
    MID$( TtyParams.ccc, SWTCH,    1 )    = CHR$( 00 )

    '
    '    Obtain the file's handle and attribute (mode)
    '

    FileMode    = FILEATTR( FileNumberTty, 1 )
    FileHandle    = FILEATTR( FileNumberTty, 2 )

    '
    '    Attempt to set the new parameters for the device
    '
    '    Uncomment the next line of code if you desire to
    '    see what is in the record TtyParams thus far
    '
    '
    '    CALL    PrintTermioRecord( TtyParams )
    '
    '
    '    Normally the function TtyDeviceIoctl() would be named
    '    Ioctl() (as it is in C), however, Basic reserves IOCTL
    '    as a keyword and thus we can't use it as an identifier.
    '
    '    The name TtyDeviceIoctl() was arbitrarily chosen, the
    '    source code is provided in the file IOCTL.BAS, so feel free
    '    to change it to what ever you want.  The make file MAKEDEMO
    '    will convert IOCTL.BAS to a library that can be linked to
    '    your application under the Microsoft Basic 6.0 compiler;
    '    (IOCTL.LIB).
    '
    '    Note that TtyDeviceIoctl() will be described as the
    '    function ioctl() in all accompanying Async TermIO documentation.
    '

    IF TtyDeviceIoctl( FileHandle, TCSETS, TtyParams ) <> PASS THEN

        PRINT    "TtyDeviceIoctl() can't set new parameters"
        RESET
        SYSTEM
    END IF

    '
    '    Call a function to echo characters from the device
    '    attached to the serial link tty01 (COM1).
    '

    CALL    Tty2Con2Tty( FileNumberTty )

    '
    '    Close the device that we opened
    '

    CLOSE    #FileNumberTty

    '
    '    Clear the screen and exit the program.
    '

    CLS
    PRINT    "Exit from Basic Demo Program for AsyncTermIO"

    END


'
' == [ ERRORHANDLER    ] ================================================
'                                                                       =
'    This is a very lazy error handler, it does not try to recover    =
'    from any errors that may trap to it.  All it does is print    =
'    out the exception handling information and kill this process.    =
'                                                                       =
' =======================================================================
'

ErrorHandler:

    CLS
    PRINT    "There has been a runtime error deemed critical"
    PRINT    "enough to terminate the program."
    PRINT    ""
    PRINT    "Errortype: ", ERDEV
    PRINT    "On device: ", ERDEV$
    PRINT    "Basic ERR: ", ERR

    SELECT CASE( ERR AND &h00FF )
        CASE    0
            PRINT    "MS-DOS   : Attempt to write on a write-protected diskette"
        CASE    1
            PRINT    "MS-DOS   : Unknown Unit"
        CASE    2
            PRINT    "MS-DOS   : Drive (or Device) Not Ready"
        CASE    3
            PRINT    "MS-DOS   : Unknown Command"
        CASE    4
            PRINT    "MS-DOS   : Data Error (CRC)"
        CASE    5
            PRINT    "MS-DOS   : Bad Request Structure Length"
        CASE    6
            PRINT    "MS-DOS   : Seek Error"
        CASE    7
            PRINT    "MS-DOS   : Unknown Media Type"
        CASE    8
            PRINT    "MS-DOS   : Sector Not Found"
        CASE    9
            PRINT    "MS-DOS   : Printer Out Of Paper"
        CASE    10
            PRINT    "MS-DOS   : Write Fault On Device"
        CASE    11
            PRINT    "MS-DOS   : Read Fault On Device"
        CASE    12
            PRINT    "MS-DOS   : General MS-DOS Device Failure"

        CASE    ELSE
            PRINT    "MS-DOS   : Unrecognized MS-DOS Error"
    END SELECT

    '
    '    To bomb out with Basic Runtime error messages uncomment
    '    the next line of code.
    '
    '
    '    ON ERROR GOTO 0
    '
    '

    RESET
    SYSTEM

'
' == [ DOSOMETHINGELSE ] ================================================
'                                                                       =
'    The user can place code that can be executed between arriving    =
'    characters.  If a character arrives, it will be buffered and    =
'    readable later.                            =
'                                                                       =
' =======================================================================
'
'
'
SUB    DoSomeThingElse

    '
    '    Your code here to process other things while waiting for
    '    characters to arrive.
    '
    '
    '

END    SUB


'
' == [ TTY2CON2TTY     ] ================================================
'                                                                       =
'    Simple SUB that loops looking for characters from the device.    =
'    If it finds one it echos it to the console.  Otherwise it    =
'    will process something else (DoSomeThingElse()).        =
'                                    =
'    If a key is pressed on the console, it is echoed to the device    =
'    driver.  I/O is somewhat clumsy, in that characters entered    =
'    at the console must each be followed by the <Enter> key to be    =
'    read by the INPUT statement.  You can tailor I/O specifically    =
'    for your application as is desired.                =
'                                    =
'    The SUBs GET and PUT can be used to send and receive blocks of    =
'    character data to and from the device driver.  There are     =
'    several examples, coded in C, that can be ported to Basic,    =
'    that demonstrate these techniques.  See the directories        =
'    \C\MSC\DEMO1, \C\MSC\DEMO2, and \C\MSC\DEMO3.            =
'                                                                       =
' =======================================================================
'
'
'
SUB    Tty2Con2Tty( FileNumber AS INTEGER )

    DIM        InChar            AS    STRING * 1
    DIM        OutChar            AS    STRING * 1
    DIM        TestChar        AS    STRING * 1

    '
    '    Loop looking for keys from the console.  If a key has
    '    been pressed send it to the terminal device.
    '
    '    When the user enters "Z" on the serial link, this SUB
    '    will return.
    '


    WHILE( InChar <> "Z" )

        '
        '    Get a character from the device.  If EOF is
        '    encountered, do something else in the meantime
        '

        GET    #FileNumber, , InChar

        IF EOF( FileNumber ) THEN

            CALL    DoSomeThingElse

        ELSE
            '
            '    Uncomment the next line if you desire to
            '    echo characters from the device back to the
            '    device
            '
            '    PUT    #FileNumber,, InChar
            '

            WRITE    InChar

        END    IF

        '
        '    See if there is anything hanging around in the
        '    stdin stream (CON).  If so, pick it up send it
        '    to the device
        '

        IF( KbHit = PASS ) THEN

            INPUT    ;"",    OutChar
            PUT    #FileNumber,, OutChar

        END    IF

    WEND

END    SUB


'
' == [ KBHIT             ] ==============================================
'                                    =
'    Can't find any function in Basic to see if a keyboard        =
'    character was hit, so gin up a quick one similar to         =
'    MS C's kbhit() function.  Most likely, a similar Basic function    =
'    exists, but I can't find it.                      =
'                                    =
' =======================================================================
'
FUNCTION    KbHit

    DIM        InRegs            AS    RegType
    DIM        OutRegs            AS    RegType

    InRegs.AX        = &H0B00

    CALL INTERRUPT( &H0021, InRegs, OutRegs )

    IF ( ( OutRegs.AX AND &H00FF ) <> 0 ) THEN
        KbHit    = PASS
    ELSE
        KbHit    = FAIL
    END    IF

END    FUNCTION


'
' == [ PRINTTERMIORECORD ] ==============================================
'                                                                       =
'    Debugging function that prints out the contents of the object    =
'    TtyParams.  Uses the same format as the "stty -g < \dev\tty01"    =
'    command line at the MS-DOS prompt.                =
'                                                                       =
' =======================================================================
'
'
'
SUB    PrintTermioRecord( TtyParams AS Termio )

    PRINT    "Ciflag               : ", OCT$( TtyParams.Ciflag )
    PRINT    "Coflag               : ", OCT$( TtyParams.Coflag )
    PRINT    "Ccflag               : ", OCT$( TtyParams.Ccflag )
    PRINT    "Clflag               : ", OCT$( TtyParams.Clflag )

    PRINT    "Cline               : ", OCT$( ASC( TtyParams.Cline ) )

    PRINT    "Ccc( VINTR )      : ", OCT$( ASC( MID$( TtyParams.ccc, VINTR,        1 ) ) )
    PRINT    "Ccc( VQUIT )      : ", OCT$( ASC( MID$( TtyParams.ccc, VQUIT,        1 ) ) )
    PRINT    "Ccc( VERASE )     : ", OCT$( ASC( MID$( TtyParams.ccc, VERASE,     1 ) ) )
    PRINT    "Ccc( VKILL )      : ", OCT$( ASC( MID$( TtyParams.ccc, VKILL,        1 ) ) )
    PRINT    "Ccc( VEOF )       : ", OCT$( ASC( MID$( TtyParams.ccc, VEOF,        1 ) ) )
    PRINT    "Ccc( VEOL )       : ", OCT$( ASC( MID$( TtyParams.ccc, VEOL,        1 ) ) )
    PRINT    "Ccc( RESERVED )   : ", OCT$( ASC( MID$( TtyParams.ccc, RESERVED,    1 ) ) )
    PRINT    "Ccc( SWTCH )      : ", OCT$( ASC( MID$( TtyParams.ccc, SWTCH,        1 ) ) )

END    SUB