NAME

       comedi_set_clock_source - set master clock for a subdevice

SYNOPSIS

       #include <comedilib.h>

       int comedi_set_clock_source(comedi_t * device, unsigned int subdevice,
                                   unsigned int channel, unsigned int clock,
                                   unsigned int period_ns);

STATUS

       alpha

DESCRIPTION

       This function selects a master clock for a subdevice. The clock 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 channel parameter will be ignored. The
       period_ns parameter specifies the clock's 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 TRIG_TIMER sources in commands while
       using the external clock.

       The clock may be queried with the comedi_get_clock_source function.

       This function is only useable on subdevices that provide support for the
       INSN_CONFIG_SET_CLOCK_SOURCE configuration instruction.

RETURN VALUE

       0 on success, -1 on error.

AUTHORS

       David Schleef <ds@schleef.org>
           Author.

       Frank Mori Hess <fmhess@users.sourceforge.net>
           Author.

       Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac.be>
           Author.

       Bernd Porr <tech@linux-usb-daq.co.uk>
           Author.

       Ian Abbott <abbotti@mev.co.uk>
           Author.

       Éric Piel <piel@delmic.com>
           Author.

COPYRIGHT

       Copyright © 1998-2003 David Schleef
       Copyright © 2001-2003, 2005, 2008 Frank Mori Hess
       Copyright © 2002-2003 Herman Bruyninckx
       Copyright © 2012 Bernd Porr
       Copyright © 2012 Ian Abbott
       Copyright © 2012 Éric Piel

       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.

       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.

       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.

       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.