guspnp(4) - NetBSD Manual Pages

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GUSPNP(4)               NetBSD Kernel Interfaces Manual              GUSPNP(4)


NAME

     guspnp - Am78C201 audio device driver


SYNOPSIS

     guspnp* at isapnp?
     audio*  at guspnp?

     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 Inter-
     wave (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 probably
     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 abstrac-
     tion has been used from the beginning, so it should work.

NetBSD 2.0                      October 5, 1997                     NetBSD 2.0