NetBSD/share/man/man4/mk48txx.4

.\"	$NetBSD: mk48txx.4,v 1.4 2002/01/21 17:54:10 wiz Exp $
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.\" Copyright (c) 2000 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Paul Kranenburg.
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.Dd July 20, 2000
.Dt MK48TXX 4
.Os
.Sh NAME
.Nm mk48txx
.Nd
.Tn Mostek time-of-day clock driver
.Sh SYNOPSIS
.Fd #include <dev/ic/mk48txxreg.h>
.Cd "define mk48txx"
.Cd "file   dev/ic/mk48txx.c    mk48txx"
.Sh DESCRIPTION
The
.Nm
driver provides access to several models of
.Tn Mostek
time-of-day clock chips. Access methods to retrieve and set date and time
are provided through the
.Em TODR
interface defined in
.Xr todr 9 .
.Pp
To tie in instance of this device to the system, use
.nr nS 1
.Ft "todr_chip_handle_t"
.Fn mk48txx_attach "bus_space_tag_t bus_tag" "bus_space_handle_t bus_handle" \
"const char *model" "int year0"
.Pp
.Bl -tag -width -offset xxxxx
.It Fa bus_tag
.It Fa bus_handle
Specify bus space access to the chip's non-volatile memory
.Pq including the clock registers .
.It Fa model
The chip model which this instance should serve. Must be one of
.Dq mk48t02 ,
.Dq mk48t08
or
.Dq mk48t59 .
.It Fa year0
The actual year represented by the clock's
.Sq year
counter. This is generally dependent on the system configuration in which
the clock device is mounted. For instance, on Sun Microsystems machines
the convention is to have clock's two-digit year represent the year 1968.
.El
.Pp
Note that if the resulting date retrieved with the todr_gettime() method
is earlier that January 1, 1970, the driver will assume that the chip's
year counter actually represents a year in the 21st century. This
behaviour can be overridden by setting the global variable
.Va mk48txx_auto_century_adjust
to zero.
.Sh HARDWARE
The following models are supported:
.Pp
.Bl -tag -width -offset indent -compact
.It Tn Mostek MK48T02
.It Tn Mostek MK48T08
.It Tn Mostek MK48T59
.El
.Sh SEE ALSO
.Xr intro 4 ,
.Xr todr 9
.Sh HISTORY
The
.Nm mk48txx
driver first appeared in
.Nx 1.5 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Paul Kranenburg
.Aq pk@netbsd.org .