1.\" $NetBSD: com.4,v 1.12 2003/12/14 22:30:12 mbw 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 December 14, 2003 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 options COM_HAYESP 55.Cd options RND_COM 56.Ss Arm32 57.Cd "com0 at mainbus? base 0x00210fe0" 58.Cd "com1 at mainbus? base 0x00210be0" 59.Ss HP 9000/300 and 400 Series 60.Cd "com* at dio? scode ?" 61.Cd "com* at frodo? offset ?" 62.Ss IBM PowerPC 4xx 63.Cd "com* at opb?" 64.Ss SPARC 65.Cd "com* at ebus?" 66.Cd "com* at obio0" 67.Sh DESCRIPTION 68The 69.Nm 70driver provides support for NS8250-, NS16450-, and NS16550-based 71.Tn EIA 72.Tn RS-232C 73.Pf ( Tn CCITT 74.Tn V.28 ) 75communications interfaces. The NS8250 and NS16450 have single character 76buffers, and the NS16550 has a 16 character buffer. 77.Pp 78Input and output for each line may set to one of following baud rates; 7950, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 8019200, 38400, 57600, or 115200, or any other baud rate which is a factor 81of 115200. 82.Pp 83The ttyXX devices are traditional dial-in devices; the dtyXX devices are 84used for dial-out. (See 85.Xr tty 4 . ) 86.Pp 87The 88.Va COM_HAYESP 89kernel option adds support for the Hayes ESP serial board. 90.Pp 91With options RND_COM enabled, the 92.Nm 93driver can be used to collect entropy for the 94.Xr rnd 4 95entropy pool. The entropy is generated from interrupt randomness. 96.Ss Arm32 specific 97If 98.Dq flags 1 99is specified, the 100.Nm 101driver will not set the MCR_IENABLE bit on the UART. This is mainly for 102use on AST multiport boards, where the MCR_IENABLE bit is used to control 103whether or not the devices use a shared interrupt. 104.Sh FILES 105.Bl -tag -width Pa -compact 106.It Pa /dev/dty00 107.It Pa /dev/dty01 108.It Pa /dev/dty02 109.It Pa /dev/tty00 110.It Pa /dev/tty01 111.It Pa /dev/tty02 112.El 113.Sh DIAGNOSTICS 114.Bl -diag 115.It com%d: %d silo overflows 116The input 117.Dq silo 118has overflowed and incoming data has been lost. 119.It com%d: weird interrupt: iir=%x 120The device has generated an unexpected interrupt 121with the code listed. 122.El 123.Sh SEE ALSO 124.Xr acpi 4 , 125.Xr ast 4 , 126.Xr cardbus 4 , 127.Xr isa 4 , 128.Xr isapnp 4 , 129.Xr mca 4 , 130.Xr mhzc 4 , 131.Xr ofisa 4 , 132.Xr pcmcia 4 , 133.Xr pcmcom 4 , 134.Xr pnpbios 4 , 135.Xr puc 4 , 136.Xr rtfps 4 , 137.Xr tty 4 138.Sh HISTORY 139The 140.Nm 141driver was originally derived from the HP9000/300 142.Ic dca 143driver. 144.Sh BUGS 145Data loss is possible on busy systems with unbuffered UARTs at high speed. 146.Pp 147The name of this driver and the constants which define the locations 148of the various serial ports are holdovers from 149.Tn DOS . 150