Simtel MSDOS - Coast to Coast/simteldosarchivecoasttocoast2.iso/fido/gendrivr.zip/DRIVER.DOC

Text File | 1987-07-07 | 7KB | 204 lines

Universal Drivers for Telink, Minitel, Fido, FidoNet,
Sysop, and Rolodex.

T. Jennings     27 Nov 84
         7 Jul 87    _mbusy

    All IO drivers MUST conform to this standard. All software will do
screen, clock, and modem IO through these drivers.

GENERAL

    You should put certain functions into seperate files, along the
following guidelines. The reason is that some programs use only the screen
functions (Rolodex, etc) some use only the modem functions (ViaDev, etc)
and some use both (Fido, Telink, etc). Seperating them will allow not
loading the whole damn thing everytime.

    Also, lconout must be in a seperate file; sometimes it is necessary
to use the standard MSDOS lconout() so that redirection can still be used.
PLINK will complain about multiple defineds unless you seperate them.

    DRIVER.H defines the static variables that must be set. These are:


CRT Variables

int lines;    Number of lines on the screen, i.e. 24 for a
        24 line screen.

int cols;    The number of columns on the screen, i.e. 80
        for an 80 column screen.

int top;    A mistake, but this is the top line NUMBER. Zero
        is just about universal, though, if the hardware
        starts its line numbering at 1, set it to 1.

int bottom;    The last line NUMBER, i.e. if the first line
        number is 0, then for a 24 line screen this will
        be 23.


char ulcorner = '+';    These are the characters used in drawing
char urcorner = '+';    boxes on the screen. if DRIVER.H is used,
char llcorner = '+';    they have the indicated defaults.
char lrcorner = '+';    They can be changed at init() time.
char vertbar = '|';
char horizbar = '-';

char graph_on[];    These are null terminated strings, used to
char graph_of[];    enable and disable graphics mode. If they are
            not null, then they are sent out before any
            attempts are made to draw the graphic
            characters above. These must be set at init()
            time.


MODEM PARAMETERS

unsigned cd_bit;    A bit mask for the modem input status
            function. This should be used by the
            _dsr() function (below) for testing
            for Carrier Detect. It is set by the
            main() of the program, with some sort
            of default. If desired, the default can
            be changed by the driver at init() time.

TIMER PARAMETERS:

long millisec;        These are incremented as millisecond
long millis2;        counters. The resolution is 1 millisec;
            however, high accuracy is not required. For
            the IBM PC, 55 is added every timer tick,
            and is close enough. For a 10 mS timer tick,
            add 10, etc.

int seconds;        Incremented at the same time as millisec,
int minutes;        above. Seconds should run from 0 to 59, then
            be cleared to zero, and minutes incremented.
            Minutes increments indefinitely; there is
            no hours counter.



FUNCTIONS:

scrinit()        Set all the abovementioned screen variables.
            This is always called before any screen
            access is done.

init()            Full hardware initialization. This sets up
            any interrupt structures, calls scrinit(),
            and performs any other initialization
            necessary to make the hardware usable. This
            should also raise the DTR line, if any
            (described below). There is a matching
            function, uninit().

            This should start the clock ticking, and the
            'minutes' variable incremented once per
            minute. See NOTES, below, on a function to
            perform this.

uninit()        Take down any initialization necessary before
            returning to DOS, such as clock interrupts.
            NOTE: This should NEVER disturb the current
            state of DTR. This is to allow one program
            to terminate, and take control of the modem,
            without losing carrier. See NOTES on taking
            down the clock.

baud(rate)        Set the baud rate of the serial port or
            modem. 'rate' is the desired baud rate; it
            returns the baud rate set, or zero if that
            rate is not supported.

_mconstat()        Returns 0 if no character ready at the modem,
            else any non-zero value. Do not remove the
            character from the modem. Non-destructive
            reads are performed at the next highest layer.

_mconin()        Returns the contents of the modem data port.
            Wait for a character if necessary. Must return
            an 8 bit value.

_mconostat()        Return true if the modem is ready to accept
            a character.

_mconout(c)        Output character 'c' to the modem. Wait for
            output ready if necessary.

_cd()            Return true if CD is
            true. This reads whatever status port, masks
            it with the cd_bit value, and if true, returns
            true.

lower_dtr()        Drop a modem output control line. The
            actual line used depends on the hardware.

raise_dtr()        Raise a modem control line. This also
            depends on the hardware. It should be
            called by init().

_mflush()        Flushes both (if any) input and output
            buffers.

_mbusy()        Returns true if there is anything in the
            output buffer; ie. returns zero when the
            output buffer is empty.
            If there is no output buffer, then this
            can return zero immediately.

_mbreak(n)        Set a line break (n != 0) or remove a line
            break. (n == 0).


TIMER FUNCTIONS:

set_clk();        Start the timer running, and incrementing
            the TIMER PARAMETERS, mentioned above.

clr_clk();        Clears all of the timer counters to zero;
            millisec, millis2, seconds, minutes.

reset_clk();        Removes the clock timer.


CRT FUNCTIONS:


_lconout()        Optional function. The default one is in the
            XENIX library, which goes through the DOS.
            Create this one for custom applications
            or raw speed.

            Note that MSDOS redirection cannot be used
            if this function is invoked. If redirection
            is needed, write an _lconout() in the main
            function, that uses MSDOS calls.

place(line,col)        Place cursor at the specified line and
            column. Input has already been bounded and
            error checked; code for speed. The passed
            line number starts at 0 (top of screen)
            and columns start at 0 (left edge of screen.)

            Avoid the use of printf(), etc, or anything
            else in "higher" level libraries. Use the
            local _lconout(), as this function wont be
            used if the program can use redirection.

clreol()        Clear from current cursor position to end
            of line. Do not move the cursor.

insline()        Insert a blank line at the current cursor
            line, and scroll the line under the cursor,
            and all below it, down one. The inserted
            line does not have to have any specific
            contents. Code for speed.

delline()        Delete a line at the current cursor line.
            The line under the cursor disappears, and
            all lines below it scroll up one. The
            bottom line does not have to be cleared.