71 lines
3 KiB
C++
71 lines
3 KiB
C++
/*
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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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* Modified Oct 2011 by Andrew Richards to avoid certain problems:
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* - Add (long) assignments and casts to TimerOne::read() to ensure calculations involving tmp, ICR1 and TCNT1 aren't truncated
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* - Ensure 16 bit registers accesses are atomic - run with interrupts disabled when accessing
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* - Remove global enable of interrupts (sei())- could be running within an interrupt routine)
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* - Disable interrupts whilst TCTN1 == 0. Datasheet vague on this, but experiment shows that overflow interrupt
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* flag gets set whilst TCNT1 == 0, resulting in a phantom interrupt. Could just set to 1, but gets inaccurate
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* at very short durations
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* - startBottom() added to start counter at 0 and handle all interrupt enabling.
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* - start() amended to enable interrupts
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* - restart() amended to point at startBottom()
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* Modiied 7:26 PM Sunday, October 09, 2011 by Lex Talionis
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* - renamed start() to resume() to reflect it's actual role
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* - renamed startBottom() to start(). This breaks some old code that expects start to continue counting where it left off
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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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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char oldSREG; // To hold Status Register while ints disabled
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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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void resume();
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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
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