2 .\" $FreeBSD: src/share/man/man4/man4.i386/spkr.4,v 1.13.2.6 2001/12/17 11:30:13 ru Exp $
10 .Nd console speaker device driver
12 .Cd pseudo-device speaker
15 The speaker device driver allows applications to control the PC console
17 .Tn IBM-PC Ns --compatible
21 Only one process may have this device open at any given time;
25 are used to lock and relinquish it.
26 An attempt to open when
27 another process has the device locked will return -1 with an
31 Writes to the device are interpreted as `play strings' in a
32 simple ASCII melody notation.
36 for tone generation at arbitrary
37 frequencies is also supported.
39 Sound-generation does not monopolize the processor; in fact, the driver
40 spends most of its time sleeping while the PC hardware is emitting
42 Other processes may emit beeps while the driver is running.
46 on a speaker file descriptor to control the
47 speaker driver directly; definitions for the
50 .Pa /usr/include/machine/speaker.h .
53 structure used in these calls has two fields,
54 specifying a frequency (in Hz) and a duration (in 1/100ths of a second).
55 A frequency of zero is interpreted as a rest.
57 At present there are two such
61 accepts a pointer to a
62 single tone structure as third argument and plays it.
65 pointer to the first of an array of tone structures and plays them in
66 continuous sequence; this array must be terminated by a final member with
69 The play-string language is modelled on the PLAY statement conventions of
71 Advanced BASIC 2.0. The
76 primitives of PLAY are not
77 useful in a timesharing environment and are omitted.
79 feature and the slur mark are new.
81 There are 84 accessible notes numbered 1-84 in 7 octaves, each running from
82 C to B, numbered 0-6; the scale is equal-tempered A440 and octave 3 starts
83 with middle C. By default, the play function emits half-second notes with the
84 last 1/16th second being `rest time'.
86 Play strings are interpreted left to right as a series of play command groups;
87 letter case is ignored.
88 Play command groups are as follows:
89 .Bl -tag -width CDEFGABxx
91 Letters A through G cause the corresponding note to be played in the
92 current octave. A note letter may optionally be followed by an
93 .Dq Em "accidental sign" ,
94 one of # + or -; the first two of these cause it to be sharped one
95 half-tone, the last causes it to be flatted one half-tone. It may
96 also be followed by a time value number and by sustain dots (see
97 below). Time values are interpreted as for the L command below.
101 is numeric, this sets the current octave.
107 to enable or disable octave-tracking (it is disabled by default).
108 When octave-tracking is on, interpretation of a pair of letter notes
109 will change octaves if necessary in order to make the smallest
110 possible jump between notes.
111 Thus ``olbc'' will be played as
112 ``olb>c'', and ``olcb'' as ``olc<b''. Octave locking is disabled for
113 one letter note following >, < and O[0123456]. (The octave-locking
114 feature is not supported in
118 Bump the current octave up one.
120 Drop the current octave down one.
125 being 1 to 84 or 0 for a rest of current time value.
126 May be followed by sustain dots.
128 Sets the current time value for notes. The default is
130 quarter or crotchet notes.
131 The lowest possible value is 1; values up
138 sets quarter notes, etc.
145 sustain dots. May also be written
148 Sets the number of quarter notes per minute; default is 120. Musical
149 names for common tempi are:
150 .Bd -literal -offset indent
151 Tempo Beats Per Minute
152 very slow Larghissimo
167 very fast Prestissimo
173 for normal) is the default; the last 1/8th of
174 the note's value is rest time.
177 for legato (no rest space) or
179 for staccato (1/4 rest space).
186 command character groups) may be followed by
188 Each dot causes the note's value to be lengthened by one-half
190 Thus, a note dotted once is held for 3/2 of its undotted value;
191 dotted twice, it is held 9/4, and three times would give 27/8.
193 A note and its sustain dots may also be followed by a slur mark (underscore).
194 This causes the normal micro-rest after the note to be filled in, slurring it
195 to the next one. (The slur feature is not supported in
199 Whitespace in play strings is simply skipped and may be used to separate
202 Due to roundoff in the pitch tables and slop in the tone-generation and timer
203 hardware (neither of which was designed for precision), neither pitch accuracy
204 nor timings will be mathematically exact.
205 There is no volume control.
207 The action of two or more sustain dots does not reflect standard musical
208 notation, in which each dot adds half the value of the previous dot
209 modifier, not half the value of the note as modified. Thus, a note dotted
210 once is held for 3/2 of its undotted value; dotted twice, it is held 7/4,
211 and three times would give 15/8. The multiply-by-3/2 interpretation,
212 however, is specified in the
214 BASIC manual and has been retained for
217 In play strings which are very long (longer than your system's physical I/O
218 blocks) note suffixes or numbers may occasionally be parsed incorrectly due
219 to crossing a block boundary.
221 .Bl -tag -width /dev/speakerxx
228 .An Eric S. Raymond Aq esr@snark.thyrsus.com
231 .An Andrew A. Chernov Aq ache@astral.msk.su