.\"   $OpenBSD: mavb.4,v 1.4 2007/05/31 19:19:56 jmc Exp $
.\"
.\" Copyright (c) 2005 Mark Kettenis
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt MAVB 4 sgi
.Os
.Sh NAME
.Nm mavb
.Nd Moosehead A/V Board audio device
.Sh SYNOPSIS
.Cd "mavb0 at macebus0 sys 0x18 base 0x00300000 irq 7"
.Cd "audio* at mavb?"
.Sh DESCRIPTION
The
.Nm
driver provides support for the Moosehead A/V Board found on SGI
.Tn O2
machines.
.Pp
The Moosehead A/V Board uses an AD1843 codec that supports 8- and
16-bit audio sample recording and playback at rates from 5 to 54 kHz,
with 1 Hz resolution.
The
.Nm
driver also makes it possible to control the playback volume by using
the buttons on the front of the
.Tn O2 .
.Sh SEE ALSO
.Xr audio 4 ,
.Xr intro 4 ,
.Xr macebus 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 3.7 .
.Sh AUTHORS
The
.Nm
driver was written by Mark Kettenis.
.Sh CAVEATS
The analog mixer in the AD1843 codec does not provide a master volume
control.
Therefore, the
.Tn O2
volume buttons only control the output volume of the DAC.
.Sh BUGS
Currently only sample rates up to 48 kHz are supported.
Recording is not implemented yet.
The second DAC on the AD1843 codec sits idle.