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Annotation of 43BSDTahoe/man/man4/vax/tb.4, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1986 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)tb.4        6.3 (Berkeley) 6/1/86
                      6: .\"
                      7: .TH TB 4 "June 1, 1986"
                      8: .UC 6
                      9: .SH NAME
                     10: tb \- line discipline for digitizing devices
                     11: .SH SYNOPSIS
                     12: .B pseudo-device tb
                     13: .SH DESCRIPTION
                     14: This line discipline provides a polled interface to many common
                     15: digitizing devices which are connected to a host through a serial line.
                     16: When these devices stream data at high speed, the use of the
                     17: line discipline is critical in minimizing the number of samples
                     18: that would otherwise be lost due to buffer exhaustion in the
                     19: .IR tty (4)
                     20: handler.
                     21: .PP
                     22: The line discipline is enabled by a sequence:
                     23: .PP
                     24: .nf
                     25: .ft B
                     26:        #include <sys/tablet.h>
                     27:        int ldisc = TBLDISC, fildes; ...
                     28:        ioctl(fildes, TIOCSETD, &ldisc);
                     29: .fi
                     30: .ft R
                     31: .PP
                     32: A typical application program then polls the digitizing device by
                     33: reading a binary data structure which contains: the current X and
                     34: Y positions (in the device coordinate space),
                     35: up-down status of the buttons or pen stylus,
                     36: proximity information (when available), and a count
                     37: of the number of samples received from the input device
                     38: since it was opened.  In addition, devices such as the
                     39: GTCO append tilt and pressure information to the end of
                     40: the aforementioned structure.  For the Polhemus 3-D digitizer
                     41: the structure read is completely different. Refer to the
                     42: include file for a complete description.
                     43: .PP
                     44: While in tablet mode, normal teletype input and output functions take place.
                     45: Thus, if an 8 bit output data path is desired, it is necessary
                     46: to prepare the output line by putting it into RAW mode using
                     47: .IR ioctl (2).
                     48: This must be done
                     49: .B before
                     50: changing the discipline with TIOCSETD, as most
                     51: .IR ioctl (2)
                     52: calls are disabled while in tablet line-discipline mode.
                     53: .PP
                     54: The line discipline supports
                     55: .IR ioctl (2)
                     56: requests to get/set the operating mode, and to get/set the tablet type
                     57: and operating mode by \fIor\fP-ing the two values together.
                     58: .PP
                     59: The line discipline supports digitizing devices which are
                     60: compatible with Hitachi, GTCO, or Polhemus protocol formats.
                     61: For Hitachi there are several formats with that used in the
                     62: newer model HDG-1111B the most common.
                     63: .SH "SEE ALSO"
                     64: tty(4)
                     65: .SH DIAGNOSTICS
                     66: None.

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