.\"	$OpenBSD: elansc.4,v 1.10 2004/06/14 17:18:14 grange Exp $
.\"	$NetBSD: elansc.4,v 1.1 2002/08/12 03:45:25 thorpej Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Jason R. Thorpe.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
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.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\"
.Dd August 11, 2002
.Dt ELANSC 4 i386
.Os
.Sh NAME
.Nm elansc
.Nd AMD Elan SC520 System Controller driver
.Sh SYNOPSIS
.Cd "elansc* at pci? dev ? function ?"
.Cd "gpio* at elansc?"
.Sh DESCRIPTION
The
.Nm
driver supports the system controller of the AMD Elan SC520 microcontroller.
The SC520 consists of an AMD Am5x86 processor core, integrated PCI host
controller, and several standard on-chip devices, such as NS16550-compatible
UARTs, real-time clock, and timers.
.Pp
The Elan SC520 also provides several special on-chip devices.
The following are supported by the
.Nm
driver:
.Bl -bullet
.It
Watchdog timer.
The watchdog timer may be configured for a 1 second, 2 second, 4 second,
8 second, 16 second, or 32 second expiration period.
.It
Programmable Input/Output.
The SC520 microcontroller supports 32 programmable I/O signals (PIOs)
that can be used on the system board to monitor signals or control devices
that are not handled by the other functions in the SC520 microcontroller.
These signals can be programmed to be inputs or to be driven out
.Dq high
or
.Dq low
as outputs.
Pins can be accessed through the
.Xr gpio 4
framework.
The
.Xr gpioctl 8
program allows easy manipulation of pins from userland.
.El
.Sh SEE ALSO
.Xr geodesc 4 ,
.Xr gpio 4 ,
.Xr intro 4 ,
.Xr gpioctl 8 ,
.Xr sysctl 8
.Sh HISTORY
Support for the
.Nm
was added in
.Ox 3.3 .
PIO function support appeared in
.Ox 3.6 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Jason R. Thorpe Aq thorpej@netbsd.org .
.An Jasper Wallace
provided the work-around for a hardware bug related to the watchdog timer
in some steppings of the SC520 CPU.
.An Alexander Yurchenko Aq grange@openbsd.org
added support for the PIO function.