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Diffstat (limited to 'libraries/Servo/Servo.cpp')
| -rw-r--r-- | libraries/Servo/Servo.cpp | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/libraries/Servo/Servo.cpp b/libraries/Servo/Servo.cpp new file mode 100644 index 0000000..a716433 --- /dev/null +++ b/libraries/Servo/Servo.cpp @@ -0,0 +1,337 @@ +/*
+ Servo.cpp - Interrupt driven Servo library for Arduino using 16 bit timers- Version 2
+ Copyright (c) 2009 Michael Margolis. All right reserved.
+
+ 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
+
+ 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 ) - 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
+
+ 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
+ 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.
+
+*/
+
+#include <avr/interrupt.h>
+#include <Arduino.h>
+
+#include "Servo.h"
+
+#define usToTicks(_us) (( clockCyclesPerMicrosecond()* _us) / 8) // converts microseconds to tick (assumes prescale of 8) // 12 Aug 2009
+#define ticksToUs(_ticks) (( (unsigned)_ticks * 8)/ clockCyclesPerMicrosecond() ) // converts from ticks back to microseconds
+
+
+#define TRIM_DURATION 2 // compensation ticks to trim adjust for digitalWrite delays // 12 August 2009
+
+//#define NBR_TIMERS (MAX_SERVOS / SERVOS_PER_TIMER)
+
+static servo_t servos[MAX_SERVOS]; // static array of servo structures
+static volatile int8_t Channel[_Nbr_16timers ]; // counter for the servo being pulsed for each timer (or -1 if refresh interval)
+
+uint8_t ServoCount = 0; // the total number of attached servos
+
+
+// convenience macros
+#define SERVO_INDEX_TO_TIMER(_servo_nbr) ((timer16_Sequence_t)(_servo_nbr / SERVOS_PER_TIMER)) // returns the timer controlling this servo
+#define SERVO_INDEX_TO_CHANNEL(_servo_nbr) (_servo_nbr % SERVOS_PER_TIMER) // returns the index of the servo on this timer
+#define SERVO_INDEX(_timer,_channel) ((_timer*SERVOS_PER_TIMER) + _channel) // macro to access servo index by timer and channel
+#define SERVO(_timer,_channel) (servos[SERVO_INDEX(_timer,_channel)]) // macro to access servo class by timer and channel
+
+#define SERVO_MIN() (MIN_PULSE_WIDTH - this->min * 4) // minimum value in uS for this servo
+#define SERVO_MAX() (MAX_PULSE_WIDTH - this->max * 4) // maximum value in uS for this servo
+
+/************ static functions common to all instances ***********************/
+
+static inline void handle_interrupts(timer16_Sequence_t timer, volatile uint16_t *TCNTn, volatile uint16_t* OCRnA)
+{
+ if( Channel[timer] < 0 )
+ *TCNTn = 0; // channel set to -1 indicated that refresh interval completed so reset the timer
+ else{
+ if( SERVO_INDEX(timer,Channel[timer]) < ServoCount && SERVO(timer,Channel[timer]).Pin.isActive == true )
+ digitalWrite( SERVO(timer,Channel[timer]).Pin.nbr,LOW); // pulse this channel low if activated
+ }
+
+ Channel[timer]++; // increment to the next channel
+ if( SERVO_INDEX(timer,Channel[timer]) < ServoCount && Channel[timer] < SERVOS_PER_TIMER) {
+ *OCRnA = *TCNTn + SERVO(timer,Channel[timer]).ticks;
+ if(SERVO(timer,Channel[timer]).Pin.isActive == true) // check if activated
+ digitalWrite( SERVO(timer,Channel[timer]).Pin.nbr,HIGH); // its an active channel so pulse it high
+ }
+ else {
+ // finished all channels so wait for the refresh period to expire before starting over
+ if( ((unsigned)*TCNTn) + 4 < usToTicks(REFRESH_INTERVAL) ) // allow a few ticks to ensure the next OCR1A not missed
+ *OCRnA = (unsigned int)usToTicks(REFRESH_INTERVAL);
+ else
+ *OCRnA = *TCNTn + 4; // at least REFRESH_INTERVAL has elapsed
+ Channel[timer] = -1; // this will get incremented at the end of the refresh period to start again at the first channel
+ }
+}
+
+#ifndef WIRING // Wiring pre-defines signal handlers so don't define any if compiling for the Wiring platform
+// Interrupt handlers for Arduino
+#if defined(_useTimer1)
+SIGNAL (TIMER1_COMPA_vect)
+{
+ handle_interrupts(_timer1, &TCNT1, &OCR1A);
+}
+#endif
+
+#if defined(_useTimer3)
+SIGNAL (TIMER3_COMPA_vect)
+{
+ handle_interrupts(_timer3, &TCNT3, &OCR3A);
+}
+#endif
+
+#if defined(_useTimer4)
+SIGNAL (TIMER4_COMPA_vect)
+{
+ handle_interrupts(_timer4, &TCNT4, &OCR4A);
+}
+#endif
+
+#if defined(_useTimer5)
+SIGNAL (TIMER5_COMPA_vect)
+{
+ handle_interrupts(_timer5, &TCNT5, &OCR5A);
+}
+#endif
+
+#elif defined WIRING
+// Interrupt handlers for Wiring
+#if defined(_useTimer1)
+void Timer1Service()
+{
+ handle_interrupts(_timer1, &TCNT1, &OCR1A);
+}
+#endif
+#if defined(_useTimer3)
+void Timer3Service()
+{
+ handle_interrupts(_timer3, &TCNT3, &OCR3A);
+}
+#endif
+#endif
+
+
+static void initISR(timer16_Sequence_t timer)
+{
+#if defined (_useTimer1)
+ if(timer == _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__)
+ TIFR |= _BV(OCF1A); // clear any pending interrupts;
+ TIMSK |= _BV(OCIE1A) ; // enable the output compare interrupt
+#else
+ // here if not ATmega8 or ATmega128
+ TIFR1 |= _BV(OCF1A); // clear any pending interrupts;
+ TIMSK1 |= _BV(OCIE1A) ; // enable the output compare interrupt
+#endif
+#if defined(WIRING)
+ timerAttach(TIMER1OUTCOMPAREA_INT, Timer1Service);
+#endif
+ }
+#endif
+
+#if defined (_useTimer3)
+ if(timer == _timer3) {
+ TCCR3A = 0; // normal counting mode
+ TCCR3B = _BV(CS31); // set prescaler of 8
+ TCNT3 = 0; // clear the timer count
+#if defined(__AVR_ATmega128__)
+ TIFR |= _BV(OCF3A); // clear any pending interrupts;
+ ETIMSK |= _BV(OCIE3A); // enable the output compare interrupt
+#else
+ TIFR3 = _BV(OCF3A); // clear any pending interrupts;
+ TIMSK3 = _BV(OCIE3A) ; // enable the output compare interrupt
+#endif
+#if defined(WIRING)
+ timerAttach(TIMER3OUTCOMPAREA_INT, Timer3Service); // for Wiring platform only
+#endif
+ }
+#endif
+
+#if defined (_useTimer4)
+ if(timer == _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
+ }
+#endif
+
+#if defined (_useTimer5)
+ if(timer == _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
+ }
+#endif
+}
+
+static void finISR(timer16_Sequence_t timer)
+{
+ //disable use of the given timer
+#if defined WIRING // Wiring
+ if(timer == _timer1) {
+ #if defined(__AVR_ATmega1281__)||defined(__AVR_ATmega2561__)
+ TIMSK1 &= ~_BV(OCIE1A) ; // disable timer 1 output compare interrupt
+ #else
+ TIMSK &= ~_BV(OCIE1A) ; // disable timer 1 output compare interrupt
+ #endif
+ timerDetach(TIMER1OUTCOMPAREA_INT);
+ }
+ else if(timer == _timer3) {
+ #if defined(__AVR_ATmega1281__)||defined(__AVR_ATmega2561__)
+ TIMSK3 &= ~_BV(OCIE3A); // disable the timer3 output compare A interrupt
+ #else
+ ETIMSK &= ~_BV(OCIE3A); // disable the timer3 output compare A interrupt
+ #endif
+ timerDetach(TIMER3OUTCOMPAREA_INT);
+ }
+#else
+ //For arduino - in future: call here to a currently undefined function to reset the timer
+#endif
+}
+
+static boolean isTimerActive(timer16_Sequence_t timer)
+{
+ // returns true if any servo is active on this timer
+ for(uint8_t channel=0; channel < SERVOS_PER_TIMER; channel++) {
+ if(SERVO(timer,channel).Pin.isActive == true)
+ return true;
+ }
+ return false;
+}
+
+
+/****************** end of static functions ******************************/
+
+Servo::Servo()
+{
+ if( ServoCount < MAX_SERVOS) {
+ this->servoIndex = ServoCount++; // assign a servo index to this instance
+ servos[this->servoIndex].ticks = usToTicks(DEFAULT_PULSE_WIDTH); // store default values - 12 Aug 2009
+ }
+ else
+ this->servoIndex = INVALID_SERVO ; // too many servos
+}
+
+uint8_t Servo::attach(int pin)
+{
+ return this->attach(pin, MIN_PULSE_WIDTH, MAX_PULSE_WIDTH);
+}
+
+uint8_t Servo::attach(int pin, int min, int max)
+{
+ if(this->servoIndex < MAX_SERVOS ) {
+ pinMode( pin, OUTPUT) ; // set servo pin to output
+ servos[this->servoIndex].Pin.nbr = pin;
+ // todo min/max check: abs(min - MIN_PULSE_WIDTH) /4 < 128
+ this->min = (MIN_PULSE_WIDTH - min)/4; //resolution of min/max is 4 uS
+ this->max = (MAX_PULSE_WIDTH - max)/4;
+ // initialize the timer if it has not already been initialized
+ timer16_Sequence_t timer = SERVO_INDEX_TO_TIMER(servoIndex);
+ if(isTimerActive(timer) == false)
+ initISR(timer);
+ servos[this->servoIndex].Pin.isActive = true; // this must be set after the check for isTimerActive
+ }
+ return this->servoIndex ;
+}
+
+void Servo::detach()
+{
+ servos[this->servoIndex].Pin.isActive = false;
+ timer16_Sequence_t timer = SERVO_INDEX_TO_TIMER(servoIndex);
+ if(isTimerActive(timer) == false) {
+ finISR(timer);
+ }
+}
+
+void Servo::write(int value)
+{
+ if(value < MIN_PULSE_WIDTH)
+ { // treat values less than 544 as angles in degrees (valid values in microseconds are handled as microseconds)
+ if(value < 0) value = 0;
+ if(value > 180) value = 180;
+ value = map(value, 0, 180, SERVO_MIN(), SERVO_MAX());
+ }
+ this->writeMicroseconds(value);
+}
+
+void Servo::writeMicroseconds(int value)
+{
+ // calculate and store the values for the given channel
+ byte channel = this->servoIndex;
+ if( (channel < MAX_SERVOS) ) // ensure channel is valid
+ {
+ if( value < SERVO_MIN() ) // ensure pulse width is valid
+ value = SERVO_MIN();
+ else if( value > SERVO_MAX() )
+ value = SERVO_MAX();
+
+ value = value - TRIM_DURATION;
+ value = usToTicks(value); // convert to ticks after compensating for interrupt overhead - 12 Aug 2009
+
+ uint8_t oldSREG = SREG;
+ cli();
+ servos[channel].ticks = value;
+ SREG = oldSREG;
+ }
+}
+
+int Servo::read() // return the value as degrees
+{
+ return map( this->readMicroseconds()+1, SERVO_MIN(), SERVO_MAX(), 0, 180);
+}
+
+int Servo::readMicroseconds()
+{
+ unsigned int pulsewidth;
+ if( this->servoIndex != INVALID_SERVO )
+ pulsewidth = ticksToUs(servos[this->servoIndex].ticks) + TRIM_DURATION ; // 12 aug 2009
+ else
+ pulsewidth = 0;
+
+ return pulsewidth;
+}
+
+bool Servo::attached()
+{
+ return servos[this->servoIndex].Pin.isActive ;
+}
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