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GUS(4)                    NetBSD Programmer's Manual                    GUS(4)


NAME

     gus - Gravis UltraSound/UltraSound MAX device driver


SYNOPSIS

     gus0 at isa? port 0xPPP irq X drq Y drq2 Z
     audio* at gus?


DESCRIPTION

     The gus driver provides support for the Gravis UltraSound (GUS) and GUS
     MAX audio cards.  Both cards have on-board memory which is used for seam-
     less playback of samples.  They can play back 8- or 16-bit samples at up
     to 44.1kHz.  They can record 8-bit samples at up to 44.1kHz.  The Ultra-
     Sound MAX is a full-duplex sound device, and if configured with two DRQ
     channels can be used for simultaneous playback and recording.  The I/O
     port base is jumper-selected, and may be chosen from 0x210-0x260 in steps
     of 0x10.  (The normal setting is 0x220.)  The GUS takes 16 ports at its
     base address and 8 ports at its base address + 0x100.

     The IRQ is software programmed, so you may select any IRQ from the set
     {3,5,7,9,11,12,15}.  The DRQ lines are software programmed, and may be
     chosen from {1,3,5,6,7}.  The drq2 field in the configuration file line
     specifies a second DRQ line for recording.  If there is no drq2 field in
     the config file, the playback channel will be used for recording DMA and
     only half-duplex mode will be available.

     The Gravis UltraSound MAX has an additional CODEC onboard which is ad-
     dressed with four ports at an offset of 0x10C from the base ports
     (0x31C-0x36C).


BUGS

     The full-duplex features of the GUS MAX have not been fully tested, and
     full-duplex on the original GUS may not be possible at all.

     Only two voices on the GF1 synthesizer chip are used by this driver (for
     left and right channels).

     Manipulating the mixer while audio samples are playing can lead to device
     driver confusion (and maybe even a system panic).

     Manipulating the mixer device seems to create pregnant system pauses,
     probably due to excessive interrupt masking.

     The joystick and MIDI port interfaces are not supported.


SEE ALSO

     audio(4)


REFERENCES

     Gravis UltraSound Low-Level Toolkit, Revision 2.01, 20 May 1993, pub-
     lished by Advanced Gravis and Forte Technologies.


HISTORY

     The gus device driver appeared in NetBSD 1.1.

NetBSD                         November 4, 1995                              1