109 lines
4.0 KiB
Groff
109 lines
4.0 KiB
Groff
.\" Copyright (c) 1986, 1991 Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)tb.4 6.4 (Berkeley) 3/27/91
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.\"
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.Dd March 27, 1991
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.Dt TB 4 vax
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.Os BSD 4.3
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.Sh NAME
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.Nm tb
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.Nd line discipline for digitizing devices
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.Sh SYNOPSIS
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.Cd pseudo-device tb
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.Sh DESCRIPTION
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This line discipline provides a polled interface to many common
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digitizing devices which are connected to a host through a serial line.
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When these devices stream data at high speed, the use of the
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line discipline is critical in minimizing the number of samples
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that would otherwise be lost due to buffer exhaustion in the
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.Xr tty 4
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handler.
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.Pp
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The line discipline is enabled by a sequence:
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.Bd -literal -offset indent
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#include <sys/tablet.h>
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int ldisc = TBLDISC, fildes; ...
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ioctl(fildes, TIOCSETD, &ldisc);
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.Ed
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.Pp
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A typical application program then polls the digitizing device by
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reading a binary data structure which contains: the current X and
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Y positions (in the device coordinate space),
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up-down status of the buttons or pen stylus,
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proximity information (when available), and a count
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of the number of samples received from the input device
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since it was opened. In addition, devices such as the
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.Tn GTCO
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append tilt and pressure information to the end of
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the aforementioned structure. For the Polhemus 3-D digitizer
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the structure read is completely different. Refer to the
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include file for a complete description.
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.Pp
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While in tablet mode, normal teletype input and output functions take place.
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Thus, if an 8 bit output data path is desired, it is necessary
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to prepare the output line by putting it into
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.Tn RAW
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mode using
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.Xr ioctl 2 .
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This must be done
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.Em before
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changing the discipline with
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.Dv TIOCSETD ,
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as most
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.Xr ioctl 2
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calls are disabled while in tablet line-discipline mode.
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.Pp
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The line discipline supports
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.Xr ioctl 2
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requests to get/set the operating mode, and to get/set the tablet type
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and operating mode by
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.Em or Ns -ing
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the two values together.
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.Pp
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The line discipline supports digitizing devices which are
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compatible with Hitachi,
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.Tn GTCO ,
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or Polhemus protocol formats.
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For Hitachi there are several formats with that used in the
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newer model
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.Tn HDG-1111B
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the most common.
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.Sh DIAGNOSTICS
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None.
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.Sh SEE ALSO
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.Xr tty 4
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.Sh HISTORY
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The
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.Nm
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interface appeared in
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.Bx 4.3 .
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