1.\" $OpenBSD: ast.4,v 1.13 2008/05/21 19:05:51 kettenis Exp $ 2.\" $NetBSD: ast.4,v 1.7 1996/03/16 00:07:07 thorpej Exp $ 3.\" 4.\" Copyright (c) 1990, 1991 The Regents of the University of California. 5.\" All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the Systems Programming Group of the University of Utah Computer 9.\" Science Department. 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91 35.\" from: Id: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp 36.\" 37.Dd $Mdocdate: May 21 2008 $ 38.Dt AST 4 39.Os 40.Sh NAME 41.Nm ast 42.Nd multiplexing serial communications interface 43.Sh SYNOPSIS 44.Cd "ast0 at isa? port 0x1a0 irq 5" 45.Cd "ast1 at isa? port 0x2a0 irq 6" 46.Cd "com* at ast?" 47.Sh DESCRIPTION 48The 49.Nm 50driver provides support for boards that multiplex together up to four 51.Tn EIA 52.Tn RS-232C 53.Pf ( Tn CCITT 54.Tn V.28 ) 55communications interfaces. 56Apparently the original master of hardware using this multiplexing protocol 57was AST. 58.Pp 59Each 60.Nm 61device is the master device for up to four 62.Nm com 63devices. 64The kernel configuration specifies these 65.Nm com 66devices as slave devices of the 67.Nm 68device, as shown in 69.Sx SYNOPSIS . 70The slave ID given for each 71.Nm com 72device determines which bit in the interrupt multiplexing register is 73tested to find interrupts for that device. 74The 75.Tn port 76specification for the 77.Nm 78device is used to compute the base addresses for the 79.Nm com 80subdevices and the port for the interrupt multiplexing register. 81.Pp 82On a real AST card, the jumpers are as follows: 83.Bl -tag -width xxxxx 84.It SW1-1 85Turn ON for irq 2. 86Default is OFF. 87.It SW1-2 88Turn ON for irq 3. 89Default is OFF. 90.It SW1-3 91Turn ON for irq 4. 92Default is OFF. 93.It SW2-1 94Turn ON for irq 5. 95This is ON for the first card, OFF otherwise. 96.It SW2-2 97Turn ON for irq 6. 98This is ON for the second card, OFF otherwise. 99.It SW2-3 100Turn ON for irq 7. 101Default is OFF. 102.It SW3-1 103.Dq Compatible mode . 104The 105.Nm ast 106driver needs extended mode, so leave this OFF. 107.It SW3-2 108I/O Address. 109In extended mode, this should be OFF for the first card at 1100x1a0-0x1a7 and ON for the second card at 0x2a0-0x2a7. 111.It SW3-3 112Interrupt sharing. 113Default is OFF. 114.It SW3-4 115Reserved, must be OFF. 116.El 117.Sh FILES 118.Bl -tag -width Pa 119.It Pa /dev/tty0? 120.El 121.Sh SEE ALSO 122.Xr com 4 , 123.Xr intro 4 , 124.Xr isa 4 125.Sh HISTORY 126The 127.Nm 128driver was written by Roland McGrath and placed into the public 129domain. 130