SPEAKER(4) NetBSD Programmer's Manual SPEAKER(4) NNAAMMEE speaker - console speaker device driver SSYYNNOOPPSSIISS ppsseeuuddoo--ddeevviiccee ssppeeaakkeerr DDEESSCCRRIIPPTTIIOONN The speaker device driver allows applications to control the PC console speaker on an IBM-PC-compatible machine running UNIX. Only one process may have this device open at any given time; open() and close() are used to lock and relinquish it. An attempt to open() when an- other 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. Sound-generation does _n_o_t 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. Applications may call ioctl() on a speaker file descriptor to control the speaker driver directly; definitions for the ioctl() interface are in ma- chine/spkr.h. The tone_t structure used in these calls has two fields, specifying a frequency (in hz) and a duration (in 1/100ths of a second). A frequency of zero is interpreted as a rest. At present there are two such ioctls. 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. The play-string language is modelled on the PLAY statement conventions of IBM BASIC 2.0. The MB, MF and X primitives of PLAY are not useful in a UNIX environment and are omitted. The `octave-tracking' feature is also new. There are 84 accessible notes numbered 1-83 in 7 octaves, each running from C to B, numbered 0-6; the scale is equal-tempered A440 and octave 3 starts with middle C. By default, the play function emits 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. Play command groups are as follows: CDEFGAB -- letters A through G cause the corresponding note to be played in the current octave. A note letter may optionally be followed by an _a_c_- _c_i_d_e_n_t_a_l _s_i_g_n, 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 be- low). Time values are interpreted as for the L command below;. O -- if is numeric, this sets the current octave. may also be one of 'L' or 'N' to enable or disable 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 pos- sible jump between notes. Thus "olbc" will be played as "olb>c", and "ol- cb" as "olc, < and O[0123456]. > -- bump the current octave up one. < -- drop the current octave down one. N -- play note n, n being 1 to 84 or 0 for a rest of current time value. May be followedv by sustain dots. L -- sets the current time value for notes. The default is L4, quar- ter 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.. P -- pause (rest), with interpreted as for L. May be followed by sustain dots. May also be written '~'. T -- Sets the number of quarter notes per minute; default is 120. Mu- sical names for common tempi are: _T_e_m_p_o _B_e_a_t_s _p_e_r _M_i_n_u_t_e 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 M[LNS] -- set articulation. MN (N 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 space) or MS (staccato) 1/4 rest space. Notes (that is, CDEFGAB 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 undot- ted value; dotted twice, it is held 9/4, and three times would give 27/8. Whitespace in play strings is simply skipped and may be used to separate melody sections. BBUUGGSS 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 vol- ume control. In play strings which are very long (longer than your system's physical I/O blocks) note suffixes or numbers may occasionally be parsed incor- rectly due to crossing a block boundary. FFIILLEESS /dev/speaker AAUUTTHHOORR Eric S. Raymond (esr@snark.thyrsus.com) Feb 1990 NetBSD 0.8a October 19, 1994 2