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GUSPNP(4)                    Device Drivers Manual                   GUSPNP(4)

     guspnp - Am78C201 audio device driver

     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.

     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.

     Cards supported by the guspnp driver include:

           Gravis Ultrasound PNP, and compatibles

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

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

     The guspnp driver appeared in NetBSD 1.3.

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

     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 probably
     worse at lower kHz compared to playing through the synthesizer which does

     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.

NetBSD 10.99                     June 22, 2005                    NetBSD 10.99