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84 lines
2.4 KiB
84 lines
2.4 KiB
5 years ago
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/*
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|| @author Paul Stoffregen (paul at pjrc dot com)
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|| @contribution Brett Hagman <bhagman@wiring.org.co>
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|| @url http://wiring.org.co/
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|| @description
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|| | A Software PWM Library
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|| | Simple timer abstractions.
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|| #
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|| @license Please see the accompanying LICENSE.txt file for this project.
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|| @name Software PWM Library support
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|| @type Library support
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|| @target Atmel AVR 8 Bit
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|| @version 1.0.1
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*/
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#include <avr/io.h>
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#include <avr/interrupt.h>
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// allow certain chips to use different timers
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#if defined(__AVR_ATmega32U4__)
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#define USE_TIMER4_HS // Teensy 2.0 lacks timer2, but has high speed timer4 :-)
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#elif defined(__arm__) && defined(TEENSYDUINO)
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#define USE_INTERVALTIMER // Teensy 3.x has special interval timers :-)
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#else
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#define USE_TIMER1
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#endif
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// for each timer, these macros define how to actually use it
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#if defined(USE_TIMER1)
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#define SOFTPWM_TIMER_INTERRUPT TIMER1_COMPA_vect
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#define SOFTPWM_TIMER_SET(val) (TCNT1 = (val))
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#define SOFTPWM_TIMER_INIT(ocr) ({\
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cli(); \
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TCCR1A = 0; \
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TCCR1B = (1 << WGM12); \
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TCCR1B |= ((1 << CS10) | (1 << CS12)); \
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TIMSK1 = (1 << OCIE1A); \
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OCR1A = 15624; \
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sei(); \
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})
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#elif defined(USE_TIMER2)
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#define SOFTPWM_TIMER_INTERRUPT TIMER2_COMPA_vect
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#define SOFTPWM_TIMER_SET(val) (TCNT2 = (val))
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#define SOFTPWM_TIMER_INIT(ocr) ({\
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TIFR2 = (1 << TOV2); /* clear interrupt flag */ \
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TCCR2B = (1 << CS21); /* start timer (ck/8 prescalar) */ \
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TCCR2A = (1 << WGM21); /* CTC mode */ \
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OCR2A = (15624); /* We want to have at least 30Hz or else it gets choppy */ \
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TIMSK2 = (1 << OCIE2A); /* enable timer2 output compare match interrupt */ \
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})
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#elif defined(USE_TIMER4_HS)
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#define SOFTPWM_TIMER_INTERRUPT TIMER4_COMPA_vect
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#define SOFTPWM_TIMER_SET(val) (TCNT4 = (val))
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#define SOFTPWM_TIMER_INIT(ocr) ({\
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TCCR4A = 0; \
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TCCR4B = 0x04; /* CTC Mode */\
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TCCR4C = 0; \
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TCCR4D = 0; \
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TCCR4E = 0; \
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OCR4C = 0; \
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OCR4C = (ocr); \
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TIMSK4 = (1 << OCIE4A); \
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})
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#elif defined(USE_INTERVALTIMER)
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#define SOFTPWM_TIMER_INTERRUPT softpwm_interval_timer
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#ifdef ISR
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#undef ISR
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#endif
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#define ISR(f) void f(void)
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#define SOFTPWM_TIMER_SET(val)
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#define SOFTPWM_TIMER_INIT(ocr) ({\
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IntervalTimer *t = new IntervalTimer(); \
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t->begin(softpwm_interval_timer, 1000000.0 / (float)(SOFTPWM_FREQ * 256)); \
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})
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#endif
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