comedi_set_clock_source(3) set master clock for a subdevice


#include <comedilib.h>

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




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.


0 on success, -1 on error.


David Schleef <[email protected]>


Frank Mori Hess <[email protected]>


Herman Bruyninckx <[email protected]>


Bernd Porr <[email protected]>


Ian Abbott <[email protected]>


Éric Piel <[email protected]>



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.