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niamsterniamster
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imported TimerOne library
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‎libraries/TimerOne/TimerOne.cpp

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/*
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* Interrupt and PWM utilities for 16 bit Timer1 on ATmega168/328
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* Original code by Jesse Tane for http://labs.ideo.com August 2008
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* Modified March 2009 by Jérôme Despatis and Jesse Tane for ATmega328 support
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* Modified June 2009 by Michael Polli and Jesse Tane to fix a bug in setPeriod() which caused the timer to stop
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* Modified June 2011 by Lex Talionis to add a function to read the timer
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*
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* This is free software. You can redistribute it and/or modify it under
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* the terms of Creative Commons Attribution 3.0 United States License.
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* To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/us/
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* or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.
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*
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* See Google Code project http://code.google.com/p/arduino-timerone/ for latest
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*/
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#ifndef TIMERONE_cpp
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#define TIMERONE_cpp
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#include "TimerOne.h"
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TimerOne Timer1; // preinstatiate
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ISR(TIMER1_OVF_vect) // interrupt service routine that wraps a user defined function supplied by attachInterrupt
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{
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Timer1.isrCallback();
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}
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void TimerOne::initialize(long microseconds)
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{
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TCCR1A = 0; // clear control register A
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TCCR1B = _BV(WGM13); // set mode 8: phase and frequency correct pwm, stop the timer
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setPeriod(microseconds);
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}
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void TimerOne::setPeriod(long microseconds)
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{
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long cycles = (F_CPU / 2000000) * microseconds; // the counter runs backwards after TOP, interrupt is at BOTTOM so divide microseconds by 2
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if(cycles < RESOLUTION) clockSelectBits = _BV(CS10); // no prescale, full xtal
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else if((cycles >>= 3) < RESOLUTION) clockSelectBits = _BV(CS11); // prescale by /8
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else if((cycles >>= 3) < RESOLUTION) clockSelectBits = _BV(CS11) | _BV(CS10); // prescale by /64
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else if((cycles >>= 2) < RESOLUTION) clockSelectBits = _BV(CS12); // prescale by /256
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else if((cycles >>= 2) < RESOLUTION) clockSelectBits = _BV(CS12) | _BV(CS10); // prescale by /1024
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else cycles = RESOLUTION - 1, clockSelectBits = _BV(CS12) | _BV(CS10); // request was out of bounds, set as maximum
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ICR1 = pwmPeriod = cycles; // ICR1 is TOP in p & f correct pwm mode
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TCCR1B &= ~(_BV(CS10) | _BV(CS11) | _BV(CS12));
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TCCR1B |= clockSelectBits; // reset clock select register
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}
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void TimerOne::setPwmDuty(char pin, int duty)
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{
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unsigned long dutyCycle = pwmPeriod;
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dutyCycle *= duty;
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dutyCycle >>= 10;
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if(pin == 1 || pin == 9) OCR1A = dutyCycle;
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else if(pin == 2 || pin == 10) OCR1B = dutyCycle;
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}
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void TimerOne::pwm(char pin, int duty, long microseconds) // expects duty cycle to be 10 bit (1024)
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{
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if(microseconds > 0) setPeriod(microseconds);
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if(pin == 1 || pin == 9) {
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DDRB |= _BV(PORTB1); // sets data direction register for pwm output pin
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TCCR1A |= _BV(COM1A1); // activates the output pin
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}
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else if(pin == 2 || pin == 10) {
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DDRB |= _BV(PORTB2);
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TCCR1A |= _BV(COM1B1);
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}
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setPwmDuty(pin, duty);
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start();
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}
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void TimerOne::disablePwm(char pin)
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{
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if(pin == 1 || pin == 9) TCCR1A &= ~_BV(COM1A1); // clear the bit that enables pwm on PB1
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else if(pin == 2 || pin == 10) TCCR1A &= ~_BV(COM1B1); // clear the bit that enables pwm on PB2
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}
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void TimerOne::attachInterrupt(void (*isr)(), long microseconds)
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{
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if(microseconds > 0) setPeriod(microseconds);
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isrCallback = isr; // register the user's callback with the real ISR
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TIMSK1 = _BV(TOIE1); // sets the timer overflow interrupt enable bit
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sei(); // ensures that interrupts are globally enabled
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start();
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}
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void TimerOne::detachInterrupt()
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{
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TIMSK1 &= ~_BV(TOIE1); // clears the timer overflow interrupt enable bit
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}
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void TimerOne::start()
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{
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TCCR1B |= clockSelectBits;
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}
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void TimerOne::stop()
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{
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TCCR1B &= ~(_BV(CS10) | _BV(CS11) | _BV(CS12)); // clears all clock selects bits
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}
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void TimerOne::restart()
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{
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TCNT1 = 0;
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}
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unsigned long TimerOne::read() //returns the value of the timer in microseconds
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{ //rember! phase and freq correct mode counts up to then down again
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unsigned int tmp=TCNT1;
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char scale=0;
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switch (clockSelectBits)
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{
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case 1:// no prescalse
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scale=0;
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break;
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case 2:// x8 prescale
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scale=3;
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break;
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case 3:// x64
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scale=6;
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break;
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case 4:// x256
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scale=8;
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break;
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case 5:// x1024
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scale=10;
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break;
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}
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while (TCNT1==tmp) //if the timer has not ticked yet
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{
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//do nothing -- max delay here is ~1023 cycles
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}
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tmp = ( (TCNT1>tmp) ? (tmp) : (ICR1-TCNT1)+ICR1 );//if we are counting down add the top value to how far we have counted down
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return ((tmp*1000L)/(F_CPU /1000L))<<scale;
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}
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#endif

‎libraries/TimerOne/TimerOne.h

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/*
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* Interrupt and PWM utilities for 16 bit Timer1 on ATmega168/328
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* Original code by Jesse Tane for http://labs.ideo.com August 2008
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* Modified March 2009 by Jérôme Despatis and Jesse Tane for ATmega328 support
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* Modified June 2009 by Michael Polli and Jesse Tane to fix a bug in setPeriod() which caused the timer to stop
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* Modified June 2011 by Lex Talionis to add a function to read the timer
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*
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* This is free software. You can redistribute it and/or modify it under
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* the terms of Creative Commons Attribution 3.0 United States License.
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* To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/us/
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* or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.
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*
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* See Google Code project http://code.google.com/p/arduino-timerone/ for latest
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*/
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#ifndef TIMERONE_h
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#define TIMERONE_h
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#define RESOLUTION 65536 // Timer1 is 16 bit
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class TimerOne
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{
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public:
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// properties
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unsigned int pwmPeriod;
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unsigned char clockSelectBits;
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// methods
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void initialize(long microseconds=1000000);
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void start();
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void stop();
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void restart();
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unsigned long read();
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void pwm(char pin, int duty, long microseconds=-1);
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void disablePwm(char pin);
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void attachInterrupt(void (*isr)(), long microseconds=-1);
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void detachInterrupt();
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void setPeriod(long microseconds);
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void setPwmDuty(char pin, int duty);
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void (*isrCallback)();
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};
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extern TimerOne Timer1;
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#endif

‎libraries/TimerOne/examples/timer_one/timer_one.pde

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/*
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* Timer1 library example
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* June 2008 | jesse dot tane at gmail dot com
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*/
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#include "TimerOne.h"
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void setup()
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{
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pinMode(10, OUTPUT);
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Timer1.initialize(500000); // initialize timer1, and set a 1/2 second period
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Timer1.pwm(9, 512); // setup pwm on pin 9, 50% duty cycle
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Timer1.attachInterrupt(callback); // attaches callback() as a timer overflow interrupt
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}
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void callback()
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{
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digitalWrite(10, digitalRead(10) ^ 1);
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}
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void loop()
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{
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// your program here...
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}
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