113 lines
4.0 KiB
Groff
113 lines
4.0 KiB
Groff
.\" $NetBSD: leds.4,v 1.7 2004/10/04 19:12:52 rumble Exp $
|
|
.\"
|
|
.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by der Mouse and Jeremy Cooper.
|
|
.\"
|
|
.\" 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.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" 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
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd March 2, 1996
|
|
.Dt LEDS 4 sun2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm leds
|
|
.Nd sun2 diagnostic Light Emitting Diodes driver
|
|
.Sh SYNOPSIS
|
|
.In machine/leds.h
|
|
.Sh DESCRIPTION
|
|
All sun2 machines are equipped
|
|
a diagnostic display of eight Light Emitting Diodes (LEDs), located
|
|
on either the front (deskside chassis) or the back (desktop machine)
|
|
of the system unit.
|
|
.Pp
|
|
The kernel changes the display during periods of idle processor activity
|
|
according to a stored sequential pattern list.
|
|
The
|
|
.Pa /dev/leds
|
|
interface provides a way of manipulating the pattern list via simple file I/O.
|
|
.Pp
|
|
The structure of the file is as follows:
|
|
.Bd -literal
|
|
struct led_patterns {
|
|
u_char divisor;
|
|
u_char patlen;
|
|
u_char pat[256];
|
|
};
|
|
.Ed
|
|
.Bl -tag -width divisor
|
|
.It Sy divisor
|
|
The number of idle periods to wait before switching to the next pattern in
|
|
the array.
|
|
.It Sy patlen
|
|
The number of patterns stored in the array.
|
|
.It Sy pat
|
|
The array of patterns to display.
|
|
.El
|
|
.Pp
|
|
When a clock interrupt occurs while the processor is idle, a pattern
|
|
countdown timer is decremented.
|
|
When the countdown timer reaches zero
|
|
it is reset with the
|
|
.Sy divisor
|
|
value and the next pattern in the array is selected and displayed.
|
|
.Pp
|
|
Each 8-bit pattern describes the state of the diagnostic LEDs.
|
|
A set bit in a pattern indicates that its
|
|
corresponding LED should be extinguished,
|
|
while a reset bit indicates an LED to be illuminated.
|
|
.Sh FILES
|
|
.Bl -tag -width /dev/leds -compact
|
|
.It Pa /dev/leds
|
|
.El
|
|
.Sh EXAMPLES
|
|
The following example uses
|
|
.Xr awk 1
|
|
to display the repeating animation of a single lit LED scrolling from one end
|
|
of the display to the other, using six clock ticks between each update.
|
|
.Bd -ragged -offset indent
|
|
# echo 5 8 254 253 250 247 239 223 191 127 |
|
|
awk '{ for (i=1;i\*[Le]NF;i++) printf("%c",$i+0); }' \*[Gt] /dev/leds
|
|
.Ed
|
|
.Sh ERRORS
|
|
An I/O transfer to
|
|
.Pa /dev/leds
|
|
will complete successfully unless:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EIO
|
|
A read or write starting beyond the end of the file was attempted.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ppt 6
|
|
.Sh HISTORY
|
|
.Pa /dev/leds
|
|
first appeared in
|
|
.Nx 1.2 .
|