1.\" $NetBSD: com.4,v 1.7 2003/05/06 19:05:35 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.\" 39.Dd April 9, 2003 40.Dt COM 4 41.Os 42.Sh NAME 43.Nm com 44.Nd serial communications interface 45.Sh SYNOPSIS 46.Cd "com0 at isa? port" \&"IO_COM1\&" irq 4 47.Cd "com1 at isa? port" \&"IO_COM2\&" irq 3 48.Cd "com* at acpi?" 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 COM_HAYESP 59.Cd options RND_COM 60.Ss Arm32 61.Cd "com0 at mainbus? base 0x00210fe0" 62.Cd "com1 at mainbus? base 0x00210be0" 63.Sh DESCRIPTION 64The 65.Nm 66driver provides support for NS8250-, NS16450-, and NS16550-based 67.Tn EIA 68.Tn RS-232C 69.Pf ( Tn CCITT 70.Tn V.28 ) 71communications interfaces. The NS8250 and NS16450 have single character 72buffers, and the NS16550 has a 16 character buffer. 73.Pp 74Input and output for each line may set to one of following baud rates; 7550, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 7619200, 38400, 57600, or 115200, or any other baud rate which is a factor 77of 115200. 78.Pp 79The ttyXX devices are traditional dial-in devices; the dtyXX devices are 80used for dial-out. (See 81.Xr tty 4 . ) 82.Pp 83The 84.Va COM_HAYESP 85kernel option adds support for the Hayes ESP serial board. 86.Pp 87With options RND_COM enabled, the 88.Nm 89driver can be used to collect entropy for the 90.Xr rnd 4 91entropy pool. The entropy is generated from interrupt randomness. 92.Ss Arm32 specific 93If 94.Dq flags 1 95is specified, the 96.Nm 97driver will not set the MCR_IENABLE bit on the UART. This is mainly for 98use on AST multiport boards, where the MCR_IENABLE bit is used to control 99whether or not the devices use a shared interrupt. 100.Sh FILES 101.Bl -tag -width Pa -compact 102.It Pa /dev/dty00 103.It Pa /dev/dty01 104.It Pa /dev/dty02 105.It Pa /dev/tty00 106.It Pa /dev/tty01 107.It Pa /dev/tty02 108.El 109.Sh DIAGNOSTICS 110.Bl -diag 111.It com%d: %d silo overflows 112The input 113.Dq silo 114has overflowed and incoming data has been lost. 115.It com%d: weird interrupt: iir=%x 116The device has generated an unexpected interrupt 117with the code listed. 118.El 119.Sh SEE ALSO 120.Xr acpi 4 , 121.Xr ast 4 , 122.Xr cardbus 4 , 123.Xr isa 4 , 124.Xr isapnp 4 , 125.Xr mca 4 , 126.Xr mhzc 4 , 127.Xr ofisa 4 , 128.Xr pcmcia 4 , 129.Xr pcmcom 4 , 130.Xr pnpbios 4 , 131.Xr puc 4 , 132.Xr rtfps 4 , 133.Xr tty 4 134.Sh HISTORY 135The 136.Nm 137driver was originally derived from the HP9000/300 138.Ic dca 139driver. 140.Sh BUGS 141Data loss is possible on busy systems with unbuffered UARTs at high speed. 142.Pp 143The name of this driver and the constants which define the locations 144of the various serial ports are holdovers from 145.Tn DOS . 146