.\"	$OpenBSD: nmeaattach.8,v 1.5 2006/11/29 00:16:35 mbalmer Exp $
.\"
.\" Copyright (c) 2006 Marc Balmer <mbalmer@openbsd.org>
.\"
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.Dd June 12, 2006
.Dt NMEAATTACH 8
.Os
.Sh NAME
.Nm nmeaattach
.Nd attach serial lines as timedelta sensors
.Sh SYNOPSIS
.Nm nmeaattach
.Op Fl dhm
.Op Fl s Ar baudrate
.Op Fl t Ar cond
.Ar device
.Sh DESCRIPTION
.Nm
is used to designate a serial line with a device that outputs NMEA 0183 data as
a source of timedelta sensors.
The following operands are supported by
.Nm nmeaattach :
.Bl -tag -width Ar
.It Fl d
Do not daemonize.
.It Fl h
Turn on RTS/CTS flow control.
By default, no flow control is done.
.It Fl m
Maintain modem control signals after closing the line.
Specifically, this disables HUPCL.
.It Fl s Ar baudrate
Specifies the speed of the connection.
If not specified, the default of 4800 baud is used.
.It Fl t Ar cond
Chooses the condition which will cause the current system time to be
immediately copied to the terminal timestamp storage for subsequent use by
.Xr nmea 4 .
Only one can be used.
.Pp
.Bl -tag -width DCDXX -offset indent -compact
.It dcd
Copy the timestamp when DCD is asserted.
.It !dcd
Copy the timestamp when DCD is deasserted.
.It cts
Copy the timestamp when CTS is asserted.
.It !cts
Copy the timestamp when CTS is deasserted.
.El
.Pp
If no condition is specified, the
.Xr nmea 4
line discipline will timestamp on receiving the leading
.Sq $
character of each GPRMC sentence.
.Pp
Configuring the NMEA device to issue a PPS signal is device specific and
should be done by device specific applications.
.It Ar device
Specifies the name of the serial line.
.Ar device
should be a string of the form
.Dq cuaXX ,
or
.Dq /dev/cuaXX .
.El
.Pp
Only the superuser may designate NMEA devices.
.Pp
To detach the interface, kill off the
.Nm
process.
.Sh SEE ALSO
.Xr nmea 4 ,
.Xr tty 4
.Sh HISTORY
The
.Nm
command first appeared in
.Ox 4.0 .