'\" t
.\"     Title: comedi_set_clock_source
.\"    Author: David Schleef <ds@schleef.org>
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 12/30/2018
.\"    Manual: Comedi reference
.\"    Source: Comedi
.\"  Language: English
.\"
.TH "COMEDI_SET_CLOCK_SOU" "3" "12/30/2018" "Comedi" "Comedi reference"
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.SH "NAME"
comedi_set_clock_source \- set master clock for a subdevice
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <comedilib\&.h>
.fi
.ft
.HP \w'int\ comedi_set_clock_source('u
.BI "int comedi_set_clock_source(comedi_t\ *\ " "device" ", unsigned\ int\ " "subdevice" ", unsigned\ int\ " "channel" ", unsigned\ int\ " "clock" ", unsigned\ int\ " "period_ns" ");"
.SH "STATUS"
.PP
alpha
.SH "DESCRIPTION"
.PP
This function selects a master clock for a subdevice\&. The
\fIclock\fR
parameter selects the master clock, and is driver\-dependant\&. If the subdevice does not support configuring its master clocks on a per\-channel basis, then the
\fIchannel\fR
parameter will be ignored\&. The
\fIperiod_ns\fR
parameter specifies the clock\*(Aqs period in nanoseconds\&. It may left unspecified by using a value of zero\&. Drivers will ignore the clock period if they already know what the clock period should be for the specified clock (e\&.g\&. for an on\-board 20MHz oscillator)\&. Certain boards which use a phase\-locked loop to synchronize to external clock sources must be told the period of the external clock\&. Specifying a clock period for an external clock may also allow the driver to support
\fBTRIG_TIMER\fR
sources in commands while using the external clock\&.
.PP
The clock may be queried with the
\fBcomedi_get_clock_source\fR
function\&.
.PP
This function is only useable on subdevices that provide support for the
\fBINSN_CONFIG_SET_CLOCK_SRC\fR
configuration instruction\&.
.SH "RETURN VALUE"
.PP
0
on success,
\-1
on error\&.
.PP
.SH "AUTHORS"
.PP
\fBDavid Schleef\fR <\&ds@schleef.org\&>
.RS 4
Author.
.RE
.PP
\fBFrank Mori Hess\fR <\&fmhess@users.sourceforge.net\&>
.RS 4
Author.
.RE
.PP
\fBHerman Bruyninckx\fR <\&Herman.Bruyninckx@mech.kuleuven.ac.be\&>
.RS 4
Author.
.RE
.PP
\fBBernd Porr\fR <\&tech@linux-usb-daq.co.uk\&>
.RS 4
Author.
.RE
.PP
\fBIan Abbott\fR <\&abbotti@mev.co.uk\&>
.RS 4
Author.
.RE
.PP
\fB\('Eric Piel\fR <\&piel@delmic.com\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br
Copyright \(co 1998-2003 David Schleef
.br
Copyright \(co 2001-2003, 2005, 2008 Frank Mori Hess
.br
Copyright \(co 2002-2003 Herman Bruyninckx
.br
Copyright \(co 2012 Bernd Porr
.br
Copyright \(co 2012 Ian Abbott
.br
Copyright \(co 2012, 2015 \('Eric Piel
.br
.PP
This document is part of Comedilib. In the context of this document, the term "source code" as defined by the license is interpreted as the XML source.
.PP
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, version 2.1 of the License.
.PP
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
.PP
You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
.sp