Updated: 2021/Apr/14


SPEAKER(4)                   Device Drivers Manual                  SPEAKER(4)

NAME
     speaker - console speaker audio device driver

SYNOPSIS
     spkr*     at pcppi?
     spkr*     at audio?

     #include <dev/spkrio.h>

DESCRIPTION
     The speaker device driver allows applications to control the console
     speaker on machines with a PC-like 8253 timer implementation or a
     synthesized speaker from an audio device/soundcard.

     Only one process may have this device open at any given time; open(2) and
     close(2) are used to lock and relinquish it.  An attempt to open(2) when
     another process has the device locked will return -1 with an EBUSY error
     indication.  Writes to the device are interpreted as "play strings" in a
     simple ASCII melody notation.  An ioctl() for tone generation at
     arbitrary frequencies is also supported.

     For the pcppi(4) device sound-generation does not monopolize the
     processor; in fact, the driver spends most of its time sleeping while the
     PC hardware is emitting tones.  Other processes may emit beeps while the
     driver is running.

     For the audio device speaker, the speaker uses one of the virtual audio
     channels.  Enabling this device will also provide a wsbell(4) keyboard
     bell.

     Applications may call ioctl() on a speaker file descriptor to control the
     speaker driver directly; definitions for the ioctl() interface are in
     <dev/spkrio.h>.

     The tone_t structure is as follows:

           typedef struct {
                   int     frequency;      /* in hertz */
                   int     duration;       /* in 1/100ths of a second */
           } tone_t;

     A frequency of zero is interpreted as a rest.

     At present there are four ioctls:

     SPKRGETVOL    Returns an integer, which is the current bell volume as a
                   percentage (0-100).

     SPKRSETVOL    Accepts an integer, which is the desired volume as a
                   percentage.

     SPKRTONE      Accepts a pointer to a single tone structure as third
                   argument and plays it.

     SPKRTUNE      Accepts a pointer to the first of an array of tone
                   structures and plays them in continuous sequence; this
                   array must be terminated by a final member with a zero
                   duration.

   Play string language
     The play string language is modelled on the PLAY statement conventions of
     IBM BASIC 2.0.  The MB, MF and X commands of PLAY are not useful in a
     UNIX environment and are not implemented.  The "octave-tracking" feature
     is also new.

     There are 84 accessible notes numbered 1-84 in 7 octaves numbered 0-6;
     octave 2 starts with middle C.  The tuning is equal-tempered A440.

     In the initial state the current octave is 4, the default note duration
     is quarter notes, the tempo is 120 bpm, and the articulation is non-
     legato or normal, i.e. half-second notes with the last 1/16th second
     being "rest time".

     Play strings are interpreted left to right as a series of play command
     groups.  Letter case is ignored.  Whitespace between groups is ignored
     and may be used to separate melody sections.  Play command groups are as
     follows:

     C, D, E, F, G, A, B
                 Letters `A' through `G' cause the corresponding note to be
                 played in the current octave.  A note letter may optionally
                 be followed by an accidental sign, one of `#', `+', or `-';
                 the first two of these cause it to be sharped one half-tone,
                 the last causes it to be flatted one half-tone.  It may also
                 be followed by a time value number and by sustain dots (see
                 below).  Time values are interpreted as for the `L' command
                 below;.

     On, OL, ON  If n is numeric, this sets the current octave.  `OL' enables,
                 and `ON' disables octave-tracking (it is disabled by
                 default).  When octave-tracking is on, interpretation of a
                 pair of letter notes will change octaves if necessary in
                 order to make the smallest possible jump between notes.  Thus
                 "olbc" will be played as "olb>c", and "olcb" as "olc<b".
                 Octave tracking is temporarily disabled for one letter note
                 that follows `>', `<' or `On'.

     >           Bump the current octave up one.

     <           Drop the current octave down one.

     Nn          Play note n, n being 1 to 84 or 0 for a rest of current time
                 value.  May be followed by sustain dots.

     Ln          Sets the current time value for notes.  The default is "L4",
                 quarter notes.  The lowest possible value is 1; values up to
                 64 are accepted.  "L1" sets whole notes, "L2" sets half
                 notes, "L4" sets quarter notes, etc...

     Pn, ~n      Pause (rest), with n interpreted as for `L'.  May be followed
                 by sustain dots.

     Tn          Sets the number of quarter notes per minute; default is 120.
                 Musical names for common tempi are:

                                    Tempo          BPM
                       very slow    Larghissimo
                                    Largo          40-60
                                    Larghetto      60-66
                                    Grave
                                    Lento
                                    Adagio         66-76
                       slow         Adagietto
                                    Andante        76-108
                       medium       Andantino
                                    Moderato       108-120
                       fast         Allegretto
                                    Allegro        120-168
                                    Vivace
                                    Veloce
                                    Presto         168-208
                       very fast    Prestissimo

     ML, MN, MS  Set articulation.  `MN' (for normal) is the default; the last
                 1/8th of the note's value is rest time.  You can set `ML' for
                 legato (no rest time) or `MS' for staccato (1/4 rest time).

     Notes, that is, C, D, E, F, G, A, B, or N command character groups, may
     be followed by sustain dots.  Each dot causes the note's value to be
     lengthened by one-half for each one.  Thus, a note dotted once is held
     for 3/2 of its undotted value; dotted twice, it is held 9/4, and three
     times would give 27/8.

FILES
     /dev/speaker

SEE ALSO
     audio(4), pcppi(4), wsbell(4), sysctl(8)

HISTORY
     This speaker device was originally for the pcppi PC timer interface.
     Support was added for a synthesized device by Nathanial Sloss, first
     appearing in NetBSD 8.0.

AUTHORS
     Eric S. Raymond <esr@snark.thyrsus.com>

BUGS
     Due to roundoff in the pitch tables and slop in the tone-generation and
     timer hardware (neither of which was designed for precision), neither
     pitch accuracy nor timings will be mathematically exact.

     There is no volume control.

     The action of two or more sustain dots does not reflect standard musical
     notation, in which each dot adds half the value of the previous dot
     modifier, not half the value of the note as modified.  Thus, a note
     dotted once is held for 3/2 of its undotted value; dotted twice, it is
     held 7/4, and three times would give 15/8.  The multiply-by-3/2
     interpretation, however, is specified in the IBM BASIC manual and has
     been retained for compatibility.

     In play strings which are very long (longer than your system's physical
     I/O blocks) note suffixes or numbers may occasionally be parsed
     incorrectly due to crossing a block boundary.

NetBSD 9.99                      June 13, 2017                     NetBSD 9.99