1.\" $NetBSD: com.4,v 1.13 2007/06/01 11:24:22 jnemeth 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. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91 34.\" 35.Dd June 1, 2007 36.Dt COM 4 37.Os 38.Sh NAME 39.Nm com 40.Nd serial communications interface 41.Sh SYNOPSIS 42.Cd "com0 at isa? port" \&"IO_COM1\&" irq 4 43.Cd "com1 at isa? port" \&"IO_COM2\&" irq 3 44.Cd "com* at acpi?" 45.Cd "com* at cardbus?" 46.Cd "com* at isapnp?" 47.Cd "com* at mca? slot ?" 48.Cd "com* at mhzc?" 49.Cd "com* at ofisa?" 50.Cd "com* at pcmcia?" 51.Cd "com* at pcmcom?" 52.Cd "com* at pnpbios? index ?" 53.Cd "com* at puc? port ?" 54.Cd "com* at xirc?" 55.Cd options COM_HAYESP 56.Cd options RND_COM 57.Ss Arm32 58.Cd "com0 at mainbus? base 0x00210fe0" 59.Cd "com1 at mainbus? base 0x00210be0" 60.Ss HP 9000/300 and 400 Series 61.Cd "com* at dio? scode ?" 62.Cd "com* at frodo? offset ?" 63.Ss IBM PowerPC 4xx 64.Cd "com* at opb?" 65.Ss SPARC 66.Cd "com* at ebus?" 67.Cd "com* at obio0" 68.Sh DESCRIPTION 69The 70.Nm 71driver provides support for NS8250-, NS16450-, and NS16550-based 72.Tn EIA 73.Tn RS-232C 74.Pf ( Tn CCITT 75.Tn V.28 ) 76communications interfaces. The NS8250 and NS16450 have single character 77buffers, and the NS16550 has a 16 character buffer. 78.Pp 79Input and output for each line may set to one of following baud rates; 8050, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 8119200, 38400, 57600, or 115200, or any other baud rate which is a factor 82of 115200. 83.Pp 84The ttyXX devices are traditional dial-in devices; the dtyXX devices are 85used for dial-out. (See 86.Xr tty 4 . ) 87.Pp 88The 89.Va COM_HAYESP 90kernel option adds support for the Hayes ESP serial board. 91.Pp 92With options RND_COM enabled, the 93.Nm 94driver can be used to collect entropy for the 95.Xr rnd 4 96entropy pool. The entropy is generated from interrupt randomness. 97.Ss Arm32 specific 98If 99.Dq flags 1 100is specified, the 101.Nm 102driver will not set the MCR_IENABLE bit on the UART. This is mainly for 103use on AST multiport boards, where the MCR_IENABLE bit is used to control 104whether or not the devices use a shared interrupt. 105.Sh FILES 106.Bl -tag -width Pa -compact 107.It Pa /dev/dty00 108.It Pa /dev/dty01 109.It Pa /dev/dty02 110.It Pa /dev/tty00 111.It Pa /dev/tty01 112.It Pa /dev/tty02 113.El 114.Sh DIAGNOSTICS 115.Bl -diag 116.It com%d: %d silo overflows 117The input 118.Dq silo 119has overflowed and incoming data has been lost. 120.It com%d: weird interrupt: iir=%x 121The device has generated an unexpected interrupt 122with the code listed. 123.El 124.Sh SEE ALSO 125.Xr acpi 4 , 126.Xr ast 4 , 127.Xr cardbus 4 , 128.Xr isa 4 , 129.Xr isapnp 4 , 130.Xr mca 4 , 131.Xr mhzc 4 , 132.Xr ofisa 4 , 133.Xr pcmcia 4 , 134.Xr pcmcom 4 , 135.Xr pnpbios 4 , 136.Xr puc 4 , 137.Xr rtfps 4 , 138.Xr tty 4 , 139.Xr xirc 4 140.Sh HISTORY 141The 142.Nm 143driver was originally derived from the HP9000/300 144.Ic dca 145driver. 146.Sh BUGS 147Data loss is possible on busy systems with unbuffered UARTs at high speed. 148.Pp 149The name of this driver and the constants which define the locations 150of the various serial ports are holdovers from 151.Tn DOS . 152