1.\" $NetBSD: leds.4,v 1.3 1998/06/11 09:03:46 fair Exp $ 2.\" 3.\" Copyright (c) 1997 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by der Mouse and Jeremy Cooper. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd March 2, 1996 38.Dt LEDS 4 sun3 39.Os NetBSD 1.2 40.Sh NAME 41.Nm leds 42.Nd sun3 diagnostic Light Emitting Diodes driver 43.Sh SYNOPSIS 44.nf 45.ft B 46#include <machine/leds.h> 47.ft R 48.fi 49.Sh DESCRIPTION 50With the exception of the Sun 3/80, all sun3 machines are equipped 51a diagnostic display of eight Light Emitting Diodes (LEDs), located 52on the back of the system unit. 53The Sun 3/80 has a single LED, which is located on the front panel. 54.Pp 55The kernel changes the display during periods of idle processor activity 56according to a stored sequential pattern list. 57The 58.Pa /dev/leds 59interface provides a way of manipulating the pattern list via simple file I/O. 60.Pp 61The structure of the file is as follows: 62.Bd -literal 63struct led_patterns { 64 u_char divisor; 65 u_char patlen; 66 u_char pat[256]; 67}; 68.Ed 69.Bl -tag -width divisor 70.It Sy divisor 71The number of idle periods to wait before switching to the next pattern in 72the array. 73.It Sy patlen 74The number of patterns stored in the array. 75.It Sy pat 76The array of patterns to display. 77.El 78.Pp 79When a clock interrupt occurs while the processor is idle, a pattern 80countdown timer is decremented. 81When the countdown timer reaches zero 82it is reset with the 83.Sy divisor 84value and the next pattern in the array is selected and displayed. 85.Pp 86Each 8-bit pattern describes the state of the diagnostic LEDs. 87With the exception of the 3/80, a set bit in a pattern indicates that its 88corresponding LED should be be extinguished, 89while a reset bit indicates an LED to be illuminated. 90On the 3/80 the polarity of the bits is reversed and only the lowest order bit 91is used. 92.Sh EXAMPLES 93The following example uses 94.Xr awk 1 95to display the repeating animation of a single lit LED scrolling from one end 96of the display to the other, using six clock ticks between each update. 97.Bd -ragged -offset -ident 98# echo 5 8 254 253 250 247 239 223 191 127 | 99 awk '{ for (i=1;i<=NF;i++) printf("%c",$i+0); }' > /dev/leds 100.Ed 101.Sh "ERRORS" 102An I/O transfer to 103.Pa /dev/leds 104will complete successfully unless: 105.Bl -tag -width Er 106.It Bq Er EIO 107A read or write starting beyond the end of the file was attempted. 108.El 109.Sh FILES 110.Bl -tag -width /dev/leds -compact 111.It Pa /dev/leds 112.El 113.Sh "SEE ALSO" 114.Xr ppt 6 115.Sh HISTORY 116.Pa /dev/leds 117first appeared in 118.Nx 1.2 . 119