87e61f9770
If software time stamping is to be used, then the servo will want to have appropriate filtering. Signed-off-by: Richard Cochran <richardcochran@gmail.com>
80 lines
2.5 KiB
C
80 lines
2.5 KiB
C
/**
|
|
* @file servo.h
|
|
* @brief Implements a generic clock servo interface.
|
|
* @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
#ifndef HAVE_SERVO_H
|
|
#define HAVE_SERVO_H
|
|
|
|
/** Opaque type */
|
|
struct servo;
|
|
|
|
/**
|
|
* Defines the caller visible states of a clock servo.
|
|
*/
|
|
enum servo_state {
|
|
|
|
/**
|
|
* The servo is not yet ready to track the master clock.
|
|
*/
|
|
SERVO_UNLOCKED,
|
|
|
|
/**
|
|
* The is ready to track and requests a clock jump to
|
|
* immediately correct the estimated offset.
|
|
*/
|
|
SERVO_JUMP,
|
|
|
|
/**
|
|
* The servo is tracking the master clock.
|
|
*/
|
|
SERVO_LOCKED,
|
|
};
|
|
|
|
/**
|
|
* Create a new instance of a clock servo.
|
|
* @param name The name of the servo flavor to create.
|
|
* @param max_ppb The absolute maxinum adjustment allowed by the clock
|
|
* in parts per billion. The clock servo will clamp its
|
|
* output according to this limit.
|
|
* @param sw_ts Indicates that software time stamping will be used,
|
|
* and the servo should use more aggressive filtering.
|
|
* @return A pointer to a new servo on success, NULL otherwise.
|
|
*/
|
|
struct servo *servo_create(char *name, int max_ppb, int sw_ts);
|
|
|
|
/**
|
|
* Destroy an instance of a clock servo.
|
|
* @param servo Pointer to a servo obtained via @ref servo_create().
|
|
*/
|
|
void servo_destroy(struct servo *servo);
|
|
|
|
/**
|
|
* Feed a sample into a clock servo.
|
|
* @param servo Pointer to a servo obtained via @ref servo_create().
|
|
* @param offset The estimated clock offset in nanoseconds.
|
|
* @param local_ts The local time stamp of the sample in nanoseconds.
|
|
* @param state Returns the servo's state.
|
|
* @return The clock adjustment in parts per billion.
|
|
*/
|
|
double servo_sample(struct servo *servo,
|
|
double offset,
|
|
double local_ts,
|
|
enum servo_state *state);
|
|
|
|
#endif
|