1.\" $NetBSD: rtfps.4,v 1.8 2002/01/21 18:05:27 wiz Exp $ 2.\" 3.\" Copyright (c) 1990, 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the Systems Programming Group of the University of Utah Computer 8.\" Science Department. 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 University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91 38.\" from: Id: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp 39.\" 40.Dd August 7, 1994 41.Dt RTFPS 4 42.Os 43.Sh NAME 44.Nm rtfps 45.Nd multiplexing serial communications interface 46.Sh SYNOPSIS 47.Cd "rtfps0 at isa? port 0x1230 irq 10" 48.Cd "com2 at rtfps0 slave 0" 49.Cd "com3 at rtfps0 slave 1" 50.Cd "com4 at rtfps0 slave 2" 51.Cd "com5 at rtfps0 slave 3" 52.Sh DESCRIPTION 53The 54.Nm rtfps 55driver provides support for IBM RT PC boards that multiplex together up to four 56.Tn EIA 57.Tn RS-232C 58.Pf ( Tn CCITT 59.Tn V.28 ) 60or 61.Tn RS-422A 62communications interfaces. 63.Pp 64Each 65.Nm 66device is the master device for up to four 67.Nm com 68devices. The kernel configuration specifies these 69.Nm com 70devices as slave devices of the 71.Nm 72device, as shown in the synopsis. 73The 74.Tn port 75specification for the 76.Nm 77device is used to compute the base addresses for the 78.Nm com 79subdevices. 80.Sh FILES 81.Bl -tag -width Pa 82.It Pa /dev/tty0? 83.El 84.Sh SEE ALSO 85.Xr com 4 86.Sh HISTORY 87The 88.Nm 89driver was written by Charles Hannum, based on the 90.Nm ast 91driver. 92.Sh BUGS 93The 94.Nm 95driver is unlikely to work on non-EISA and non-PCI machines. The ISA 96bus only asserts 10 I/O address lines, and this is not enough. 97.Pp 98Even on EISA and PCI machines, some address conflicts have been observed. 99On one machine, the second port always conflicted with something (though 100it's not clear what) and caused strange results. Disabling the second 101port in the kernel config allowed the other three ports to function 102correctly. 103