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/servo.h

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/*! \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
//
// NOTE: you need the latest version (3.2+) of the AVR-GCC compiler to use this
//  function library.  Download it from http://www.avrfreaks.net/AVRGCC
//
// Description : 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.
//
// 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"

// constants/macros/typdefs

// set number of servo channels (1 to 8)
//      This is the number of servos you would like to drive
//      Each "Channel" can control one servo and by default will
//      map directly to the port pin of the same number on the
//      SERVO_DEFAULT_PORT.  You can change this default port/pin
//      assignment for a given channel to any port/pin you like.
//      See the "servoSetChannelIO" function below.
#define SERVO_NUM_CHANNELS      4
// set default SERVO output port
//      This is the AVR port which you have connected to your servos 
//      See top of file for how servo "channels" map to port pins
#define SERVO_DEFAULT_PORT      PORTB
// set servo characteristics (min and max position)
//      You must find these by testing using your brand/type of servos.
//      The min/max settings will change proportional to F_CPU, the CPU
//      clock frequency.  These numbers are good for parallax servos at
//      an F_CPU of 8MHz.
#define SERVO_MAX                   71
#define SERVO_MIN                   17
#define POSITION_MAX                255

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

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