205 lines
7.4 KiB
Groff
205 lines
7.4 KiB
Groff
.\" 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. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. 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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.\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
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.\" $Id: sio.4,v 1.10 1994/05/07 01:15:10 ache Exp $
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.\"
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.Dd February 9, 1994
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.Dt SIO 4 i386
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.Os FreeBSD
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.Sh NAME
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.Nm sio
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.Nd
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fast interrupt driven asynchronous serial communications interface
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.Sh SYNOPSIS
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For standard ports:
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.Cd "device sio0 at isa? port" \&"IO_COM1\&" tty irq 4 vector siointr
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.Cd "device sio1 at isa? port" \&"IO_COM2\&" tty irq 3 vector siointr
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.Cd "device sio2 at isa? port" \&"IO_COM3\&" tty irq 5 vector siointr
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.Cd "device sio3 at isa? port" \&"IO_COM4\&" tty irq 9 vector siointr
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.sp
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For multiport cards:
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.Cd "options" \&"COM_MULTIPORT\&"
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.Cd "device sio4 at isa? port 0x2a0 tty irq 12 flags 0x701 vector siointr"
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.Cd "device sio5 at isa? port 0x2a8 tty flags 0x701 vector siointr"
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.Cd "device sio6 at isa? port 0x2b0 tty flags 0x701 vector siointr"
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.Cd "device sio7 at isa? port 0x2b8 tty flags 0x701 vector siointr"
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.sp
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Use 0x02 bit in flags field to disable FIFO on specified port.
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.Sh DESCRIPTION
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The
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.Nm sio
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driver provides support for NS8250-, NS16450-, NS16550 and NS16550A-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.24 )
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communications interfaces. The NS8250 and NS16450 have single character
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buffers, the NS16550A has a 16 character FIFO 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. Your hardware may limit your baud
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rate choices.
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.Pp
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The driver supports `multiport' cards.
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Multiport cards are those that have one or more groups of ports
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that share a common IRQ and Interrupt Request register set per group.
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Frequently 4 ports share 1 IRQ, some 8 port cards have 2 groups of 4 ports,
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thus using 2 IRQs.
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Some cards allow the first 2 serial ports to have seperate IRQs per port
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(as per DOS PC standard).
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.sp
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The
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.Nm flags
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keyword specifies for each
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.Nm device sio
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line in the kernel configuration file,
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whether the port is part of an IRQ sharing group, & if so,
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which port is the master device for
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the group (ie which port has the IRQ control registers).
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The master device is the port which
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has registers through which all interrupts of the port group are funneled.
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All ports of a port group report pending interrupts using this
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single register.
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.sp
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The master device is an integer embedded in the high byte of the
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.Nm flags
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bitfield, so all sio entries in the kernel config file that are part of a
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multiport card must include the correct
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.Nm flags
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specification.
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The bitwise assignment allows multiple port groups to
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be configured in one system. It does
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.Nm not
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imply that more than one port group (or card) can share
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the same physical interrupt line!
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.Pp
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In the synopsis the
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.Nm flags 0x701
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means that the 8th port (sio7) is the master
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device (so the MSB of the flags), and that the ports are part of a
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multiport card (the LSB of the flags, actually only the LS
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.Nm bit
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).
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F.e. if you have only two standard ports in addition to multiport
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card, this
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.Nm flags
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will be
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.Nm 0x501
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(assuming the control port is
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.Nm sio5
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).
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.Pp
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Which port is the master device depends on the card type. Consult
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the hardware documentation of your card.
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.Pp
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Serial ports controlled by the
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.Nm sio
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driver can be used for both dialin and dialout.
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The minor number of the dialout
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port is 128 higher than that of the corresponding dialin port. Use
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.Xr stty 1
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to enable or disable modem control as required by your setup.
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.Pp
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While testing new cards & resolving card config DIP header &
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.Nm sio flags
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settings, to avoid coms. failure from lack of full modem DC level
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settings on ports,
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you are recommended to temporarily use syntax such as:
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.Nm stty -f /dev/tty03 clocal
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.Sh FILES
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.Bl -tag -width /dev/tty0? -compact
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.It Pa /dev/tty0?
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for hardwired terminals
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.El
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or
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.Bl -tag -width /dev/tty0? -compact
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.It Pa /dev/ttyd?
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for dialin ports
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.It Pa /dev/cua0?
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for dialout ports
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.El
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.Pp
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The devices numbers are made from the set [0-9a-z] so that more than
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10 ports can be supported.
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/dev/tty0? and /dev/ttyd? are mutually exclusive, if you have
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/dev/tty0? corresponding /dev/ttyd? must be removed and vice versa.
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.Sh DIAGNOSTICS
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.Bl -diag
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.It sio%d: silo overflow.
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The single-character 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: %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 tty 4 ,
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.Xr comcontrol 8 ,
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.Xr stty 1 .
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.Sh HISTORY
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The
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.Nm
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driver is derived from the
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.Nm HP9000/300
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.Nm dca
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driver and is
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.Ud
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.Sh BUGS
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Data loss is not near as likely on busy systems as they are with the
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.Xr com 4
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driver but they still can occur at very high baud rates on slow systems. The
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use of NS16550A's helps lot to handle high baud rates.
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.Pp
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Stay away from NS16550 (so without the trailing A). These are early
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implementations of the chip with non-functional FIFO hardware.
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.Pp
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The constants which define the locations
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of the various serial ports are holdovers from
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.Nm DOS .
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As shown, hex addresses can be and for clarity probably should be used instead.
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.Pp
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As usual, you get what you pay for; cheap NS16550 clones generally don't work.
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.Pp
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The multiport example is based on an AST/4 card, your
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mileage may vary however. Note that on the AST/4 the card's dipswitches should
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.Nm not
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be set to use interrupt sharing. AST/4-like interrupt sharing is only used when
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.Nm multiple
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AST/4 cards are installed in the same system. The sio driver does not
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support more than 1 AST/4 on one IRQ.
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