GUSPNP(4)						   BSD Kernel Interfaces Manual 						 GUSPNP(4)

NAME

     guspnp -- Am78C201 audio device driver

SYNOPSIS

     guspnp* at isapnp?
     audio*  at audiobus?

     There should be no limit caused by the driver on the number of drivers or cards active in the system.

DESCRIPTION

     The guspnp driver provides support for audio subsystems using the Interwave (Am78C20x) family of ICs, usually the Gravis Ultrasound Plug and
     Play.  Unlike the gus driver guspnp driver does not require any local memory for the IC, but uses the codec for both playback and recording.
     The guspnp driver can simultaneously playback and record 8- and 16-bit samples at frequencies from 5.51kHz to 48kHz.

     The guspnp driver relies on isapnp to allocate suitable resources for it.	This version of the driver only uses the first logical device of
     the five the Interwave IC has.  The four unused logical devices are the ATAPI CD-ROM device, PnP Joystick device, legacy soundcard emulation
     device (SoundBlaster) and MIDI serial device.  Support for at least ATAPI CD-ROM and Joystick is being worked on.	This version of the driver
     will use 1 IRQ and 2 DRQs.

HARDWARE

     Cards supported by the guspnp driver include:

	   Gravis Ultrasound PNP, and compatibles

SEE ALSO

     audio(4), gus(4), isapnp(4)

REFERENCES

     Interwave(tm) IC Am78C201/202 Programmer's Guide Rev. 2. 1996. Advanced Micro Devices.

HISTORY

     The guspnp driver appeared in NetBSD 1.3.

AUTHORS

     Kari Mettinen <Kari.Mettinen@helsinki.fi>, University of Helsinki.

BUGS

     Sometimes you can cause a hiss on either left or right channel, or both.  You can usually make it disappear by playing random data, however
     this might not be a very nice thing to your audio equipment, but it is the only way I have found out to be effective.

     Only the Codec is used in this version of the driver, therefore only 2 channels are supported (left and right). Also sound quality is proba-
     bly worse at lower kHz compared to playing through the synthesizer which does interpolation.

     If the implementation has a 'bad' oscillator, using frequencies 44.8kHz and 38.4kHz will result in incorrect playback frequency. The author
     has a GUS PnP Pro which displays this behavior.

     Other members of the Interwave family have not been tested and don't have the glue needed to make them work. Should someone need to implement
     it, not many changes in the existing code are needed.  Output voltage control in register CFIG2 [7] should be set differently for some other
     members of the family.

     Other architectures than i386 haven't been tested. The bus_space abstraction has been used from the beginning, so it should work.

BSD
								   June 22, 2005							       BSD