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authorDavid A. Mellis <d.mellis@arduino.cc>2009-07-12 00:33:02 +0000
committerDavid A. Mellis <d.mellis@arduino.cc>2009-07-12 00:33:02 +0000
commit1359d865c1732c471765177e410817e3e5dbd659 (patch)
tree37c744d862f62d5dbe5b31113f6e41ed800fb489 /libraries/Servo
parentcdeb912f7d94928f7de4974a68e4cf727e51e703 (diff)
Integrating the new Servo library (MegaServo) by Michael Margolis. Uses timer 1, and, on the Mega, timers 3, 4, and 5 for up to 12 servos (48 on the Mega).
Diffstat (limited to 'libraries/Servo')
-rwxr-xr-xlibraries/Servo/Servo.cpp401
-rwxr-xr-xlibraries/Servo/Servo.h98
-rwxr-xr-xlibraries/Servo/keywords.txt14
3 files changed, 345 insertions, 168 deletions
diff --git a/libraries/Servo/Servo.cpp b/libraries/Servo/Servo.cpp
index 8578fef..32cc0e7 100755
--- a/libraries/Servo/Servo.cpp
+++ b/libraries/Servo/Servo.cpp
@@ -1,133 +1,268 @@
-#include <avr/interrupt.h>
-#include <wiring.h>
-#include <Servo.h>
-
-/*
- Servo.h - Hardware Servo Timer Library
- Author: Jim Studt, jim@federated.com
- Copyright (c) 2007 David A. Mellis. 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
-*/
-
-
-uint8_t Servo::attached9 = 0;
-uint8_t Servo::attached10 = 0;
-
-void Servo::seizeTimer1()
-{
- uint8_t oldSREG = SREG;
-
- cli();
- TCCR1A = _BV(WGM11); /* Fast PWM, ICR1 is top */
- TCCR1B = _BV(WGM13) | _BV(WGM12) /* Fast PWM, ICR1 is top */
- | _BV(CS11) /* div 8 clock prescaler */
- ;
- OCR1A = 3000;
- OCR1B = 3000;
- ICR1 = clockCyclesPerMicrosecond()*(20000L/8); // 20000 uS is a bit fast for the refresh, 20ms, but
- // it keeps us from overflowing ICR1 at 20MHz clocks
- // That "/8" at the end is the prescaler.
-#if defined(__AVR_ATmega8__)
- TIMSK &= ~(_BV(TICIE1) | _BV(OCIE1A) | _BV(OCIE1B) | _BV(TOIE1) );
-#else
- TIMSK1 &= ~(_BV(OCIE1A) | _BV(OCIE1B) | _BV(TOIE1) );
-#endif
-
- SREG = oldSREG; // undo cli()
-}
-
-void Servo::releaseTimer1() {}
-
-#define NO_ANGLE (0xff)
-
-Servo::Servo() : pin(0), angle(NO_ANGLE) {}
-
-uint8_t Servo::attach(int pinArg)
-{
- return attach(pinArg, 544, 2400);
-}
-
-uint8_t Servo::attach(int pinArg, int min, int max)
-{
- if (pinArg != 9 && pinArg != 10) return 0;
-
- min16 = min / 16;
- max16 = max / 16;
-
- pin = pinArg;
- angle = NO_ANGLE;
- digitalWrite(pin, LOW);
- pinMode(pin, OUTPUT);
-
- if (!attached9 && !attached10) seizeTimer1();
-
- if (pin == 9) {
- attached9 = 1;
- TCCR1A = (TCCR1A & ~_BV(COM1A0)) | _BV(COM1A1);
- }
-
- if (pin == 10) {
- attached10 = 1;
- TCCR1A = (TCCR1A & ~_BV(COM1B0)) | _BV(COM1B1);
- }
- return 1;
-}
-
-void Servo::detach()
-{
- // muck with timer flags
- if (pin == 9) {
- attached9 = 0;
- TCCR1A = TCCR1A & ~_BV(COM1A0) & ~_BV(COM1A1);
- pinMode(pin, INPUT);
- }
-
- if (pin == 10) {
- attached10 = 0;
- TCCR1A = TCCR1A & ~_BV(COM1B0) & ~_BV(COM1B1);
- pinMode(pin, INPUT);
- }
-
- if (!attached9 && !attached10) releaseTimer1();
-}
-
-void Servo::write(int angleArg)
-{
- uint16_t p;
-
- if (angleArg < 0) angleArg = 0;
- if (angleArg > 180) angleArg = 180;
- angle = angleArg;
-
- // bleh, have to use longs to prevent overflow, could be tricky if always a 16MHz clock, but not true
- // That 8L on the end is the TCNT1 prescaler, it will need to change if the clock's prescaler changes,
- // but then there will likely be an overflow problem, so it will have to be handled by a human.
- p = (min16*16L*clockCyclesPerMicrosecond() + (max16-min16)*(16L*clockCyclesPerMicrosecond())*angle/180L)/8L;
- if (pin == 9) OCR1A = p;
- if (pin == 10) OCR1B = p;
-}
-
-uint8_t Servo::read()
-{
- return angle;
-}
-
-uint8_t Servo::attached()
-{
- if (pin == 9 && attached9) return 1;
- if (pin == 10 && attached10) return 1;
- return 0;
-}
+/*
+ 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 <WProgram.h>
+
+
+#include "Servo.h"
+
+#define TICKS_PER_uS (clockCyclesPerMicrosecond() / 8) // number of timer ticks per microsecond with prescale of 8
+
+#define SERVOS_PER_TIMER 12 // the maximum number of servos controlled by one timer
+#define TRIM_DURATION (SERVOS_PER_TIMER/2) // compensation ticks to trim adjust for digitalWrite delays
+
+#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_TIMERS]; // counter for the servo being pulsed for each timer (or -1 if refresh interval)
+#if defined(__AVR_ATmega1280__)
+typedef enum { _timer5, _timer1, _timer3, _timer4 } servoTimer_t; // this is the sequence for timer utilization on mega
+#else
+typedef enum { _timer1 } servoTimer_t; // this is the sequence for timer utilization on other controllers
+#endif
+
+uint8_t ServoCount = 0; // the total number of attached servos
+
+// convenience macros
+#define SERVO_INDEX_TO_TIMER(_servo_nbr) ((servoTimer_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(servoTimer_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 < (((unsigned int)REFRESH_INTERVAL * TICKS_PER_uS) + 4) ) // allow a few ticks to ensure the next OCR1A not missed
+ *OCRnA = (unsigned int)REFRESH_INTERVAL * TICKS_PER_uS;
+ 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
+ }
+}
+
+SIGNAL (TIMER1_COMPA_vect)
+{
+ handle_interrupts(_timer1, &TCNT1, &OCR1A);
+}
+
+#if defined(__AVR_ATmega1280__)
+SIGNAL (TIMER3_COMPA_vect)
+{
+ handle_interrupts(_timer3, &TCNT3, &OCR3A);
+}
+SIGNAL (TIMER4_COMPA_vect)
+{
+ handle_interrupts(_timer4, &TCNT4, &OCR4A);
+}
+SIGNAL (TIMER5_COMPA_vect)
+{
+ handle_interrupts(_timer5, &TCNT5, &OCR5A);
+}
+#endif
+
+static void initISR(servoTimer_t timer)
+{
+ 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__)
+ TIFR = _BV(OCF1A); // clear any pending interrupts;
+ TIMSK = _BV(OCIE1A) ; // enable the output compare interrupt
+#else
+ TIFR1 = _BV(OCF1A); // clear any pending interrupts;
+ TIMSK1 = _BV(OCIE1A) ; // enable the output compare interrupt
+#endif
+ }
+#if defined(__AVR_ATmega1280__)
+ else if(timer == _timer3) {
+ TCCR3A = 0; // normal counting mode
+ TCCR3B = _BV(CS31); // set prescaler of 8
+ TCNT3 = 0; // clear the timer count
+ TIFR3 = _BV(OCF3A); // clear any pending interrupts;
+ TIMSK3 = _BV(OCIE3A) ; // enable the output compare interrupt
+ }
+ else 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
+ }
+ else 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 boolean isTimerActive(servoTimer_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 = DEFAULT_PULSE_WIDTH * TICKS_PER_uS; // store default values
+ }
+ 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
+ servoTimer_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;
+
+#ifdef FREE_TIMERS
+ if(isTimerActive(SERVO_INDEX_TO_TIMER(servoIndex)) == false) {
+ ;// call to unimplimented function in wiring.c to re-init timer (set timer back to PWM mode) TODO?
+ }
+#endif
+}
+
+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 >= 0) && (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) * TICKS_PER_uS; // convert to ticks after compensating for interrupt overhead
+ 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 = (servos[this->servoIndex].ticks / TICKS_PER_uS) + TRIM_DURATION ;
+ else
+ pulsewidth = 0;
+
+ return pulsewidth;
+}
+
+bool Servo::attached()
+{
+ return servos[this->servoIndex].Pin.isActive ;
+}
diff --git a/libraries/Servo/Servo.h b/libraries/Servo/Servo.h
index 0b0e8db..9a25c65 100755
--- a/libraries/Servo/Servo.h
+++ b/libraries/Servo/Servo.h
@@ -1,10 +1,6 @@
-#ifndef Servo_h
-#define Servo_h
-
/*
- Servo.h - Hardware Servo Timer Library
- Author: Jim Studt, jim@federated.com
- Copyright (c) 2007 David A. Mellis. All right reserved.
+ Servo.h - 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
@@ -21,32 +17,76 @@
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 siezed 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.
+ */
+
+#ifndef Servo_h
+#define Servo_h
+
#include <inttypes.h>
+#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
+
+#if defined(__AVR_ATmega1280__)
+#define MAX_SERVOS 48 // the maximum number of servos (valid range is from 1 to 48)
+#else
+#define MAX_SERVOS 12 // this library supports up to 12 on a standard Arduino
+#endif
+
+#define INVALID_SERVO 255 // flag indicating an invalid servo index
+
+typedef struct {
+ uint8_t nbr :6 ; // a pin number from 0 to 63
+ 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 Servo
{
- private:
- uint8_t pin;
- uint8_t angle; // in degrees
- uint8_t min16; // minimum pulse, 16uS units (default is 34)
- uint8_t max16; // maximum pulse, 16uS units, 0-4ms range (default is 150)
- static void seizeTimer1();
- static void releaseTimer1();
- static uint8_t attached9;
- static uint8_t attached10;
- public:
- Servo();
- uint8_t attach(int);
- // pulse length for 0 degrees in microseconds, 544uS default
- // pulse length for 180 degrees in microseconds, 2400uS default
- uint8_t attach(int, int, int);
- // attach to a pin, sets pinMode, returns 0 on failure, won't
- // position the servo until a subsequent write() happens
- // Only works for 9 and 10.
- void detach();
- void write(int); // specify the angle in degrees, 0 to 180
- uint8_t read();
- uint8_t attached();
+public:
+ Servo();
+ 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.
+ 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
+ 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
+#endif \ No newline at end of file
diff --git a/libraries/Servo/keywords.txt b/libraries/Servo/keywords.txt
index 918c46a..ca5ba79 100755
--- a/libraries/Servo/keywords.txt
+++ b/libraries/Servo/keywords.txt
@@ -6,16 +6,18 @@
# Datatypes (KEYWORD1)
#######################################
-Servo KEYWORD1
+Servo KEYWORD1
#######################################
# Methods and Functions (KEYWORD2)
#######################################
-attach KEYWORD2
-detach KEYWORD2
-write KEYWORD2
-read KEYWORD2
-attached KEYWORD2
+attach KEYWORD2
+detach KEYWORD2
+write KEYWORD2
+read KEYWORD2
+attached KEYWORD2
+writeMicroseconds KEYWORD2
+readMicroseconds KEYWORD2
#######################################
# Constants (LITERAL1)