1.\" $NetBSD: com.4,v 1.4 2002/08/19 00:00:48 gmcgarry 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 20, 2001 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 cardbus?" 50.Cd "com* at isapnp?" 51.Cd "com* at mca? slot ?" 52.Cd "com* at mhzc?" 53.Cd "com* at ofisa?" 54.Cd "com* at pcmcia?" 55.Cd "com* at pcmcom?" 56.Cd "com* at pnpbios? index ?" 57.Cd "com* at puc? port ?" 58.Cd options RND_COM 59.Ss Arm32 60.Cd "com0 at mainbus? base 0x00210fe0" 61.Cd "com1 at mainbus? base 0x00210be0" 62.Sh DESCRIPTION 63The 64.Nm 65driver provides support for NS8250-, NS16450-, and NS16550-based 66.Tn EIA 67.Tn RS-232C 68.Pf ( Tn CCITT 69.Tn V.28 ) 70communications interfaces. The NS8250 and NS16450 have single character 71buffers, and the NS16550 has a 16 character buffer. 72.Pp 73Input and output for each line may set to one of following baud rates; 7450, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 7519200, 38400, 57600, or 115200, or any other baud rate which is a factor 76of 115200. 77.Pp 78The ttyXX devices are traditional dialin devices; the dtyXX devices are 79used for dialout. (See 80.Xr tty 4 . ) 81.Pp 82With options RND_COM enabled, the 83.Nm 84driver can be used to collect entropy for the 85.Xr rnd 4 86entropy pool. The entropy is generated from interrupt randomness. 87.Ss Arm32 specific 88If 89.Dq flags 1 90is specified, the 91.Nm 92driver will not set the MCR_IENABLE bit on the UART. This is mainly for 93use on AST multiport boards, where the MCR_IENABLE bit is used to control 94whether or not the devices use a shared interrupt. 95.Sh FILES 96.Bl -tag -width Pa -compact 97.It Pa /dev/dty00 98.It Pa /dev/dty01 99.It Pa /dev/dty02 100.It Pa /dev/tty00 101.It Pa /dev/tty01 102.It Pa /dev/tty02 103.El 104.Sh DIAGNOSTICS 105.Bl -diag 106.It com%d: %d silo overflows 107The input 108.Dq silo 109has overflowed and incoming data has been lost. 110.It com%d: weird interrupt: iir=%x 111The device has generated an unexpected interrupt 112with the code listed. 113.El 114.Sh SEE ALSO 115.Xr ast 4 , 116.Xr cardbus 4 , 117.Xr isa 4 , 118.Xr isapnp 4 , 119.Xr mca 4 , 120.Xr mhzc 4 , 121.Xr ofisa 4 , 122.Xr pcmcia 4 , 123.Xr pcmcom 4 , 124.Xr pnpbios 4 , 125.Xr puc 4 , 126.Xr rtfps 4 , 127.Xr tty 4 128.Sh HISTORY 129The 130.Nm 131driver was originally derived from the HP9000/300 132.Ic dca 133driver. 134.Sh BUGS 135Data loss is possible on busy systems with unbuffered UARTs at high speed. 136.Pp 137The name of this driver and the constants which define the locations 138of the various serial ports are holdovers from 139.Tn DOS . 140