1.\" $NetBSD: com.4,v 1.6 2003/04/09 17:21:48 jmmv 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.\" 39.Dd April 9, 2003 40.Dt COM 4 41.Os 42.Sh NAME 43.Nm com 44.Nd 45serial communications interface 46.Sh SYNOPSIS 47.Cd "com0 at isa? port" \&"IO_COM1\&" irq 4 48.Cd "com1 at isa? port" \&"IO_COM2\&" irq 3 49.Cd "com* at acpi?" 50.Cd "com* at cardbus?" 51.Cd "com* at isapnp?" 52.Cd "com* at mca? slot ?" 53.Cd "com* at mhzc?" 54.Cd "com* at ofisa?" 55.Cd "com* at pcmcia?" 56.Cd "com* at pcmcom?" 57.Cd "com* at pnpbios? index ?" 58.Cd "com* at puc? port ?" 59.Cd options COM_HAYESP 60.Cd options RND_COM 61.Ss Arm32 62.Cd "com0 at mainbus? base 0x00210fe0" 63.Cd "com1 at mainbus? base 0x00210be0" 64.Sh DESCRIPTION 65The 66.Nm 67driver provides support for NS8250-, NS16450-, and NS16550-based 68.Tn EIA 69.Tn RS-232C 70.Pf ( Tn CCITT 71.Tn V.28 ) 72communications interfaces. The NS8250 and NS16450 have single character 73buffers, and the NS16550 has a 16 character buffer. 74.Pp 75Input and output for each line may set to one of following baud rates; 7650, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 7719200, 38400, 57600, or 115200, or any other baud rate which is a factor 78of 115200. 79.Pp 80The ttyXX devices are traditional dialin devices; the dtyXX devices are 81used for dialout. (See 82.Xr tty 4 . ) 83.Pp 84The 85.Va COM_HAYESP 86kernel option adds support for the Hayes ESP serial board. 87.Pp 88With options RND_COM enabled, the 89.Nm 90driver can be used to collect entropy for the 91.Xr rnd 4 92entropy pool. The entropy is generated from interrupt randomness. 93.Ss Arm32 specific 94If 95.Dq flags 1 96is specified, the 97.Nm 98driver will not set the MCR_IENABLE bit on the UART. This is mainly for 99use on AST multiport boards, where the MCR_IENABLE bit is used to control 100whether or not the devices use a shared interrupt. 101.Sh FILES 102.Bl -tag -width Pa -compact 103.It Pa /dev/dty00 104.It Pa /dev/dty01 105.It Pa /dev/dty02 106.It Pa /dev/tty00 107.It Pa /dev/tty01 108.It Pa /dev/tty02 109.El 110.Sh DIAGNOSTICS 111.Bl -diag 112.It com%d: %d silo overflows 113The input 114.Dq silo 115has overflowed and incoming data has been lost. 116.It com%d: weird interrupt: iir=%x 117The device has generated an unexpected interrupt 118with the code listed. 119.El 120.Sh SEE ALSO 121.Xr acpi 4 , 122.Xr ast 4 , 123.Xr cardbus 4 , 124.Xr isa 4 , 125.Xr isapnp 4 , 126.Xr mca 4 , 127.Xr mhzc 4 , 128.Xr ofisa 4 , 129.Xr pcmcia 4 , 130.Xr pcmcom 4 , 131.Xr pnpbios 4 , 132.Xr puc 4 , 133.Xr rtfps 4 , 134.Xr tty 4 135.Sh HISTORY 136The 137.Nm 138driver was originally derived from the HP9000/300 139.Ic dca 140driver. 141.Sh BUGS 142Data loss is possible on busy systems with unbuffered UARTs at high speed. 143.Pp 144The name of this driver and the constants which define the locations 145of the various serial ports are holdovers from 146.Tn DOS . 147