marlin/Marlin/src/HAL/AVR/Servo.cpp

/**
 * Marlin 3D Printer Firmware
 * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * 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 3 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, see <https://www.gnu.org/licenses/>.
 *
 */

/**
 * servo.cpp - Interrupt driven Servo library for Arduino using 16 bit timers- Version 2
 * Copyright (c) 2009 Michael Margolis.  All right reserved.
 */

/**
 * 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
 *
 * 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:
 *
 * Servo - Class for manipulating servo motors connected to Arduino pins.
 *
 * attach(pin)           - Attach a servo motor to an i/o pin.
 * attach(pin, min, max) - Attach to a pin, setting min and max values in microseconds
 *                         Default min is 544, max is 2400
 *
 * write()               - Set the servo angle in degrees. (Invalid angles —over MIN_PULSE_WIDTH— are treated as µs.)
 * writeMicroseconds()   - Set the servo pulse width in microseconds.
 * move(pin, angle)      - Sequence of attach(pin), write(angle), safe_delay(servo_delay[servoIndex]).
 *                         With DEACTIVATE_SERVOS_AFTER_MOVE it detaches after servo_delay[servoIndex].
 * read()                - Get the last-written servo pulse width as an angle between 0 and 180.
 * readMicroseconds()    - Get the last-written servo pulse width in microseconds.
 * attached()            - Return true if a servo is attached.
 * detach()              - Stop an attached servo from pulsing its i/o pin.
 */

#ifdef __AVR__

#include "../../inc/MarlinConfig.h"

#if HAS_SERVOS

#include <avr/interrupt.h>

#include "../shared/servo.h"
#include "../shared/servo_private.h"

static volatile int8_t Channel[_Nbr_16timers];              // counter for the servo being pulsed for each timer (or -1 if refresh interval)


/************ static functions common to all instances ***********************/

static inline void handle_interrupts(const timer16_Sequence_t timer, volatile uint16_t* TCNTn, volatile uint16_t* OCRnA) {
  int8_t cho = Channel[timer];                                        // Handle the prior Channel[timer] first
  if (cho < 0)                                                        // Channel -1 indicates the refresh interval completed...
    *TCNTn = 0;                                                       // ...so reset the timer
  else if (SERVO_INDEX(timer, cho) < ServoCount)                      // prior channel handled?
    extDigitalWrite(SERVO(timer, cho).Pin.nbr, LOW);                  // pulse the prior channel LOW

  Channel[timer] = ++cho;                                             // Handle the next channel (or 0)
  if (cho < SERVOS_PER_TIMER && SERVO_INDEX(timer, cho) < ServoCount) {
    *OCRnA = *TCNTn + SERVO(timer, cho).ticks;                        // set compare to current ticks plus duration
    if (SERVO(timer, cho).Pin.isActive)                               // activated?
      extDigitalWrite(SERVO(timer, cho).Pin.nbr, HIGH);               // yes: pulse HIGH
  }
  else {
    // finished all channels so wait for the refresh period to expire before starting over
    const unsigned int cval = ((unsigned)*TCNTn) + 32 / (SERVO_TIMER_PRESCALER), // allow 32 cycles to ensure the next OCR1A not missed
                       ival = (unsigned int)usToTicks(REFRESH_INTERVAL); // at least REFRESH_INTERVAL has elapsed
    *OCRnA = max(cval, ival);

    Channel[timer] = -1;                                              // reset the timer counter to 0 on the next call
  }
}

#ifndef WIRING // Wiring pre-defines signal handlers so don't define any if compiling for the Wiring platform

  // Interrupt handlers for Arduino
  #ifdef _useTimer1
    SIGNAL(TIMER1_COMPA_vect) { handle_interrupts(_timer1, &TCNT1, &OCR1A); }
  #endif

  #ifdef _useTimer3
    SIGNAL(TIMER3_COMPA_vect) { handle_interrupts(_timer3, &TCNT3, &OCR3A); }
  #endif

  #ifdef _useTimer4
    SIGNAL(TIMER4_COMPA_vect) { handle_interrupts(_timer4, &TCNT4, &OCR4A); }
  #endif

  #ifdef _useTimer5
    SIGNAL(TIMER5_COMPA_vect) { handle_interrupts(_timer5, &TCNT5, &OCR5A); }
  #endif

#else // WIRING

  // Interrupt handlers for Wiring
  #ifdef _useTimer1
    void Timer1Service() { handle_interrupts(_timer1, &TCNT1, &OCR1A); }
  #endif
  #ifdef _useTimer3
    void Timer3Service() { handle_interrupts(_timer3, &TCNT3, &OCR3A); }
  #endif

#endif // WIRING

/****************** end of static functions ******************************/

void initISR(const timer16_Sequence_t timer_index) {
  switch (timer_index) {
    default: break;

    #ifdef _useTimer1
      case _timer1:
        TCCR1A = 0;             // normal counting mode
        TCCR1B = _BV(CS11);     // set prescaler of 8
        TCNT1 = 0;              // clear the timer count
        #if defined(__AVR_ATmega8__) || defined(__AVR_ATmega128__)
          SBI(TIFR, OCF1A);      // clear any pending interrupts;
          SBI(TIMSK, OCIE1A);    // enable the output compare interrupt
        #else
          // here if not ATmega8 or ATmega128
          SBI(TIFR1, OCF1A);     // clear any pending interrupts;
          SBI(TIMSK1, OCIE1A);   // enable the output compare interrupt
        #endif
        #ifdef WIRING
          timerAttach(TIMER1OUTCOMPAREA_INT, Timer1Service);
        #endif
        break;
    #endif

    #ifdef _useTimer3
      case _timer3:
        TCCR3A = 0;             // normal counting mode
        TCCR3B = _BV(CS31);     // set prescaler of 8
        TCNT3 = 0;              // clear the timer count
        #ifdef __AVR_ATmega128__
          SBI(TIFR, OCF3A);     // clear any pending interrupts;
          SBI(ETIMSK, OCIE3A);  // enable the output compare interrupt
        #else
          SBI(TIFR3, OCF3A);   // clear any pending interrupts;
          SBI(TIMSK3, OCIE3A); // enable the output compare interrupt
        #endif
        #ifdef WIRING
          timerAttach(TIMER3OUTCOMPAREA_INT, Timer3Service);  // for Wiring platform only
        #endif
        break;
    #endif

    #ifdef _useTimer4
      case _timer4:
        TCCR4A = 0;             // normal counting mode
        TCCR4B = _BV(CS41);     // set prescaler of 8
        TCNT4 = 0;              // clear the timer count
        TIFR4 = _BV(OCF4A);     // clear any pending interrupts;
        TIMSK4 = _BV(OCIE4A);   // enable the output compare interrupt
        break;
    #endif

    #ifdef _useTimer5
      case _timer5:
        TCCR5A = 0;             // normal counting mode
        TCCR5B = _BV(CS51);     // set prescaler of 8
        TCNT5 = 0;              // clear the timer count
        TIFR5 = _BV(OCF5A);     // clear any pending interrupts;
        TIMSK5 = _BV(OCIE5A);   // enable the output compare interrupt
        break;
    #endif
  }
}

void finISR(const timer16_Sequence_t timer_index) {
  // Disable use of the given timer
  #ifdef WIRING
    switch (timer_index) {
      default: break;

      case _timer1:
        CBI(
          #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
            TIMSK1
          #else
            TIMSK
          #endif
          , OCIE1A    // disable timer 1 output compare interrupt
        );
        timerDetach(TIMER1OUTCOMPAREA_INT);
        break;

      case _timer3:
        CBI(
          #if defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2561__)
            TIMSK3
          #else
            ETIMSK
          #endif
          , OCIE3A    // disable the timer3 output compare A interrupt
        );
        timerDetach(TIMER3OUTCOMPAREA_INT);
        break;
    }
  #else // !WIRING
    // For arduino - in future: call here to a currently undefined function to reset the timer
    UNUSED(timer_index);
  #endif
}

#endif // HAS_SERVOS

#endif // __AVR__