library

/*! \file servo.h \brief Interrupt-driven RC Servo function library. */
//*****************************************************************************
//
// File Name    : 'servo.h'
// Title                : Interrupt-driven RC Servo function library
// Author               : Pascal Stang - Copyright (C) 2002
// Created              : 7/31/2002
// Revised              : 8/02/2002
// Version              : 1.0
// Target MCU   : Atmel AVR Series
// Editor Tabs  : 4
//
///     \ingroup driver_sw
/// \defgroup servo Interrupt-driven RC Servo Function Library (servo.c)
/// \code #include "servo.h" \endcode
/// \par Overview
///             This code allows you to drive up to 8 RC servos from any
///     combination of ports and pins on the AVR processor. Using interrupts,
///     this code continuously sends control signals to the servo to maintain
///     position even while your code is doing other work.
///
///     The servoInit and servoOff effectively turn on and turn off servo
///     control.  When you run ServoInit, it automatically assigns each
///     "channel" of servo control to be output on the SERVO_DEFAULT_PORT.
///     One "channel" of servo control can control one servo and must be
///     assigned single I/O pin for output.
///
///     If you're using all eight channels (SERVO_NUM_CHANNELS = 8), then
///     then by default the code will use SERVO_DEFAULT_PORT pins 0-7.
///     If you're only using four channels, then pins 0-3 will be used by
///     default.
///
///     The command servoSetChannelIO(channel, port, pin) allows you to
///     reassign the output of any channel to any port and I/O pin you
///     choose.  For exampe, if you have an RC servo connected to PORTC, pin 6,
///     and you wish to use channel 2 to control it, use:
///
///             servoSerChannelIO( 2, _SFR_IO_ADDR(PORTC), 6)
///
///             (NOTE: you must include the "_SRF_IO_ADDR()" part around your port)
///
///     The servoSetPostion and servoGetPosition commands allow you to command
///     a given servo to your desired position.  The position you request must
///     lie between the SERVO_MIN and SERVO_MAX limit you defined.
///
/// \WARNING: This servo library has been tested to work without issue on
///     several different AVR processors and with several different brands/kinds
/// of servos.  However:
/// - Proper output duty cylces are dependent upon a user calibation and
///             configuration.
/// - IF YOUR SERVOS ARE EXCEPTIONALLY POWERFUL, AN ERRONEOUS OUTPUT DUTY
///             CYCLE GENERATED FROM THIS CODE OR ANY OTHER SOURCE CAN DAMAGE YOUR
///             SERVO'S INTERNAL DRIVER CHIP OR ITS GEARS!
/// - I have never experienced any servo damage from erroneous control signal
///             input, but it is possible.
//
// This code is distributed under the GNU Public License
//              which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#ifndef SERVO_H
#define SERVO_H

#include "global.h"
#include "timer.h"

// include configuration
#include "servoconf.h"

typedef struct struct_ServoChannel
{       
        // hardware I/O port and pin for this channel
        u08 port;
        u08 pin;
        // PWM duty setting which corresponds to servo position
        u16 duty;
} ServoChannelType;

// functions

// initializes servo system
//              You must run this to begin servo control
void servoInit(void);

// turns off servo system
//              This stops controlling the servos and
//              returns control of the SERVOPORT to your code
void servoOff(void);

// set the port and I/O pin you wish to use for a given channel
//              If you do not assign a port and I/O pin for a channel (ie. you don't
//              use this command) then all output will be done through the
//              SERVO_DEFAULT_PORT.  See above definition of SERVO_DEFAULT_PORT.
void servoSetChannelIO(u08 channel, u08 port, u08 pin);

// set and get servo position on a given channel 
//              servoSetPosition() commands the servo on <channel> to the position you
//                      desire.  The position input must lie between 0 and POSITION_MAX and
//                      will be automatically scaled to raw positions between SERVO_MIN and
//                      SERVO_MAX
//              servoGetPosition() returns the most recently set postition of the
//                      servo on <channel>.  The return value will be scaled 0->POSITION_MAX
void servoSetPosition(u08 channel, u08 position);
u08 servoGetPosition(u08 channel);

// set and get raw servo position on a given channel
//              Works like non-raw commands but position is not scaled.  Position must
//              be between SERVO_MIN and SERVO_MAX
void servoSetPositionRaw(u08 channel, u16 position);
u16 servoGetPositionRaw(u08 channel);

// servo interrupt service routine
void servoService(void);

#endif