NetBSD/share/man/man4/attimer.4

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.\" $NetBSD: attimer.4,v 1.4 2009/03/09 19:24:28 joerg Exp $
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.Dd March 22, 2005
.Dt ATTIMER 4
.Os
.Sh NAME
.Nm attimer
.Nd AT Timer (8253) driver
.Sh SYNOPSIS
.Cd "attimer* at acpi?"
.Cd "attimer0 at isa?"
.Sh DESCRIPTION
The
.Nm
driver handles the so-called AT Timer device, initially found as chip
model 8253.
It is used as the main counter for the clock on the i386 port,
but also offers control over the pitch of the PC speaker.
.Pp
The
.Nm
driver currently only implements the access to the ISA register
.Dq TIMER1
which controls the pitch of the PC speaker,
and should be configured along with
.Xr pcppi 4
to be of any actual use.
.Sh SEE ALSO
.Xr acpi 4 ,
.Xr isa 4 ,
.Xr pcppi 4