192 lines
5.2 KiB
Groff
192 lines
5.2 KiB
Groff
.\" $NetBSD: com.4,v 1.23 2017/05/21 09:12:19 wiz Exp $
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.\"
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.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the Systems Programming Group of the University of Utah Computer
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.\" Science Department.
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91
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.\"
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.Dd March 4, 2017
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.Dt COM 4
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.Os
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.Sh NAME
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.Nm com
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.Nd serial communications interface for
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.Tn RS-232C
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.Sh SYNOPSIS
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.Cd "com0 at isa? port" \&"IO_COM1\&" irq 4
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.Cd "com1 at isa? port" \&"IO_COM2\&" irq 3
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.Cd "com* at acpi?"
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.Cd "com* at cardbus?"
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.Cd "com* at isapnp?"
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.Cd "com* at mca? slot ?"
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.Cd "com* at mhzc?"
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.Cd "com* at ofisa?"
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.Cd "com* at pcmcia?"
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.Cd "com* at pcmcom?"
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.Cd "com* at pnpbios? index ?"
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.Cd "com* at puc? port ?"
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.Cd "com* at xirc?"
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.Cd options COM_HAYESP
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.Cd options PPS_SYNC
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.Cd options PPS_TRAILING_EDGE
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.Cd options RND_COM
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.Ss Amiga
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.Cd "com* at clockport?"
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.Ss Arm32
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.Cd "com0 at mainbus? base 0x00210fe0"
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.Cd "com1 at mainbus? base 0x00210be0"
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.Cd "com0 at pxaip?"
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.Ss HP 9000/300 and 400 Series
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.Cd "com* at dio? scode ?"
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.Cd "com* at frodo? offset ?"
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.Ss HP 9000/700 and 800 Series
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.Cd "com* at dino?"
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.Cd "com* at gsc?"
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.Cd "com* at ssio?"
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.Ss IBM PowerPC 4xx
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.Cd "com* at opb?"
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.Ss SPARC
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.Cd "com* at ebus?"
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.Cd "com* at obio0"
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.Ss x68k
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.Cd "com0 at intio0 addr 0xefff00 intr 240"
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.Cd "com1 at intio0 addr 0xefff10 intr 241"
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.Sh DESCRIPTION
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The
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.Nm
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driver provides support for NS8250-, NS16450-, and NS16550-based
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.Tn EIA
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.Tn RS-232C
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.Pf ( Tn CCITT
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.Tn V.28 )
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communications interfaces.
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The NS8250 and NS16450 have single character
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buffers, and the NS16550 has a 16 character buffer.
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.Pp
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Input and output for each line may set to one of following baud rates;
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50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
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19200, 38400, 57600, or 115200, or any other baud rate which is a factor
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of 115200.
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.Pp
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The ttyXX devices are traditional dial-in devices; the dtyXX devices are
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used for dial-out.
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(See
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.Xr tty 4 . )
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.Pp
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.Cd options COM_HAYESP
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adds support for the Hayes ESP serial board.
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.Pp
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.Cd options PPS_SYNC
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enables code to use the Data Carrier Detect (DCD) signal line for attachment
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to an external precision clock source
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.Po
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e.g.,
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.Tn GPS ,
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.Tn CDMA
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.Pc
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which generates a Pulse Per Second (PPS) signal.
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This is used by
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.Xr ntpd 8
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to discipline the system clock, and more accurately count/measure time.
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See
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.Xr options 4
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for more discussion.
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.Pp
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With
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.Cd options RND_COM
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enabled, the
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.Nm
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driver can be used to collect entropy for the
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.Xr rnd 4
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entropy pool.
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The entropy is generated from interrupt randomness.
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.Ss Arm32 specific
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If
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.Dq flags 1
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is specified, the
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.Nm
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driver will not set the
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.Dv MCR_IENABLE
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bit on the UART.
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This is mainly for use on AST multiport boards, where the
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.Dv MCR_IENABLE
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bit is used to control whether or not the devices use a shared
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interrupt.
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.Sh FILES
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.Bl -tag -width Pa -compact
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.It Pa /dev/dty00
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.It Pa /dev/dty01
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.It Pa /dev/dty02
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.It Pa /dev/tty00
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.It Pa /dev/tty01
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.It Pa /dev/tty02
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.El
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.Sh DIAGNOSTICS
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.Bl -diag
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.It com%d: %d silo overflows
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The input
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.Dq silo
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has overflowed and incoming data has been lost.
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.It com%d: weird interrupt: iir=%x
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The device has generated an unexpected interrupt
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with the code listed.
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.El
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.Sh SEE ALSO
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.Xr acpi 4 ,
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.Xr ast 4 ,
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.Xr cardbus 4 ,
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.Xr i386/pnpbios 4 ,
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.Xr isa 4 ,
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.Xr isapnp 4 ,
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.Xr mca 4 ,
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.Xr mhzc 4 ,
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.Xr ofisa 4 ,
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.Xr options 4 ,
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.Xr pcmcia 4 ,
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.Xr pcmcom 4 ,
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.Xr puc 4 ,
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.Xr pxaip 4 ,
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.Xr rtfps 4 ,
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.Xr tty 4 ,
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.Xr xirc 4 ,
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.Xr ntpd 8
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.Sh HISTORY
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The
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.Nm
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driver was originally derived from the HP9000/300
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.Ic dca
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driver.
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.Sh BUGS
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Data loss is possible on busy systems with unbuffered UARTs at high speed.
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.Pp
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The name of this driver and the constants which define the locations
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of the various serial ports are holdovers from
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.Tn DOS .
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