ServoExtend.h

/*
 ServoExtend.cpp - Extended interrupt driven Servo library for Arduino using 16 bit timers- Version 1
 Copyright (c) 2009 Michael Margolis.  All right reserved.
 Edit by Timo Engelgeer (Septillion) December 11, 2014
 
 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; either
 version 2.1 of the License, or (at your option) any later version.
 
 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/* 
 
 A servo is activated by creating an instance of the Servo class passing the desired pin to the attach() method.
 The servos are pulsed in the background using the value most recently written using the write() method
 
 ************EXTEND*******************
 Added option is to drive with the internal ticks for more resolution as well as a function for DCC steed steps times 4 (gives 0-1012)

 Added a reattach() function without giving the pin number again
 
 Small change to setting just 4 ticks for a disabled servo.
 
 Now accepts all Arduino pins up to 126 (7-bit instead of 6-bit) with 127 as return for no pin.
 *************************************
 
 Note that analogWrite of PWM on pins associated with the timer are disabled when the first servo is attached.
 Timers are seized as needed in groups of 12 servos - 24 servos use two timers, 48 servos will use four.
 
 The methods are:
 
 ServoExtend - Class for manipulating servo motors connected to Arduino pins.
 
 attach(pin )  - Attaches a servo motor to an i/o pin.
 attach(pin, min, max  ) - Attaches to a pin setting min and max values in microseconds
 default min is 544, max is 2400  
 reattach(pin) - Reataches a pin if it was once atteched, returns 127 is nog pin set.
 
 write()     - Sets the servo angle in degrees.  (invalid angle that is valid as pulse in microseconds is treated as microseconds)
 writeMicroseconds() - Sets the servo pulse width in microseconds
 writeTicks() -Sets the servo pulse width in ticks of the uC. Smalles possible step. Between 1088 and 4800 by default (F_OSC/8)
 writeDccStep() - Sets the pulse width in a 4 times multiple of DCC staps (2*127) * 4 gives a range of 0-1012
 read()      - Gets the last written servo pulse width as an angle between 0 and 180. 
 readMicroseconds()   - Gets the last written servo pulse width in microseconds. (was read_us() in first release)
 attached()  - Returns true if there is a servo attached. 
 detach()    - Stops an attached servos from pulsing its i/o pin. 
 
*/

#ifndef ServoExtend_h
#define ServoExtend_h

#include <inttypes.h>

/* 
 * Defines for 16 bit timers used with  Servo library 
 *
 * If _useTimerX is defined then TimerX is a 16 bit timer on the curent board
 * timer16_Sequence_t enumerates the sequence that the timers should be allocated
 * _Nbr_16timers indicates how many 16 bit timers are available.
 *
 */

// Say which 16 bit timers can be used and in what order
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
#define _useTimer5
#define _useTimer1 
#define _useTimer3
#define _useTimer4 
typedef enum { _timer5, _timer1, _timer3, _timer4, _Nbr_16timers } timer16_Sequence_t ;

#elif defined(__AVR_ATmega32U4__)  
#define _useTimer1 
typedef enum { _timer1, _Nbr_16timers } timer16_Sequence_t ;

#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
#define _useTimer3
#define _useTimer1
typedef enum { _timer3, _timer1, _Nbr_16timers } timer16_Sequence_t ;

#elif defined(__AVR_ATmega128__) ||defined(__AVR_ATmega1281__)||defined(__AVR_ATmega2561__)
#define _useTimer3
#define _useTimer1
typedef enum { _timer3, _timer1, _Nbr_16timers } timer16_Sequence_t ;

#else  // everything else
#define _useTimer1
typedef enum { _timer1, _Nbr_16timers } timer16_Sequence_t ;                  
#endif

#define Servo_VERSION           2      // software version of this library

#define MIN_PULSE_WIDTH       544     // the shortest pulse sent to a servo  
#define MAX_PULSE_WIDTH      2400     // the longest pulse sent to a servo 
#define DEFAULT_PULSE_WIDTH  1500     // default pulse width when servo is attached
#define REFRESH_INTERVAL    20000     // minumim time to refresh servos in microseconds 

#define SERVOS_PER_TIMER       12     // the maximum number of servos controlled by one timer 
#define MAX_SERVOS   (_Nbr_16timers  * SERVOS_PER_TIMER)

#define INVALID_SERVO         255     // flag indicating an invalid servo index
#define INVALID_SERVO_PIN	  127

typedef struct  {
  uint8_t nbr        :7 ;             // a pin number from 0 to 127, 127 is for no port
  uint8_t isActive   :1 ;             // true if this channel is enabled, pin not pulsed if false 
} ServoPin_t   ;  

typedef struct {
  ServoPin_t Pin;
  unsigned int ticks;
} servo_t;

class ServoExtend
{
public:
  ServoExtend();
  uint8_t attach(int pin);           // attach the given pin to the next free channel, sets pinMode, returns channel number or 0 if failure
  uint8_t attach(int pin, int min, int max); // as above but also sets min and max values for writes. 
  uint8_t reattach();				 //same as above only uses the same pin as befor
  void detach();
  void write(int value);             // if value is < 200 its treated as an angle, otherwise as pulse width in microseconds 
  void writeMicroseconds(int value); // Write pulse width in microseconds 
  void writeTicks(int value);		 // Write pulse width in ticks (F_OSC/8)
  void writeDccStep(int value);		 // write pulse width as as a 4 times multiple of DCC speed steps, 0-1012
  int read();                        // returns current pulse width as an angle between 0 and 180 degrees
  int readMicroseconds();            // returns current pulse width in microseconds for this servo (was read_us() in first release)
  bool attached();                   // return true if this servo is attached, otherwise false 
private:
   uint8_t servoIndex;               // index into the channel data for this servo
   int8_t min;                       // minimum is this value times 4 added to MIN_PULSE_WIDTH    
   int8_t max;                       // maximum is this value times 4 added to MAX_PULSE_WIDTH   
};

#endif