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118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
#ifndef CONTIKI_CLOCK_AVR_H
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#define CONTIKI_CLOCK_AVR_H
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#if defined (__AVR_ATmega128__)
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#define AVR_OUTPUT_COMPARE_INT TIMER0_COMP_vect
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#define OCRSetup() \
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/* Select internal clock */ \
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ASSR = 0x00; \
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\
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/* Set counter to zero */ \
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TCNT0 = 0; \
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\
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/* \
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* Set comparison register: \
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* Crystal freq. is 16000000,\
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* pre-scale factor is 1024, i.e. we have 125 "ticks" / sec: \
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* 16000000 = 1024 * 125 * 125 \
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*/ \
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OCR0 = 125; \
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\
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/* \
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* Set timer control register: \
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* - prescale: 1024 (CS00 - CS02) \
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* - counter reset via comparison register (WGM01) \
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*/ \
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TCCR0 = _BV(CS00) | _BV(CS01) | _BV(CS02) | _BV(WGM01); \
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\
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/* Clear interrupt flag register */ \
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TIFR = 0x00; \
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\
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/* \
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* Raise interrupt when value in OCR0 is reached. Note that the \
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* counter value in TCNT0 is cleared automatically. \
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*/ \
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TIMSK = _BV (OCIE0);
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#elif defined (__AVR_ATmega1284P__) || (__AVR_AT90USB1287__) || (__AVR_ATmega1281__)
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/*
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The Raven has a 32768Hz watch crystal that can be used to clock the timer
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while the 1284p is sleeping. The Jackdaw has pads for a crystal. The crystal
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can be used to clock the 8 bit timer2.
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*/
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#if AVR_CONF_USE32KCRYSTAL
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#define AVR_OUTPUT_COMPARE_INT TIMER2_COMPA_vect
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#define OCRSetup() \
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/* Clock from crystal on TOSC0-1 */ \
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ASSR = _BV(AS2); \
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\
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/* Set counter to zero */ \
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TCNT2 = 0; \
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\
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/* \
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* Set comparison register: \
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* Crystal freq. is 32768,\
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* pre-scale factor is 8, we want 125 ticks / sec: \
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* 32768 = 8 * 124.1 * 33, less 1 for CTC mode\
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*/ \
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OCR2A = 32; \
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\
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/* \
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* Set timer control register: \
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* - prescale: 8 (CS21) \
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* - counter reset via comparison register (WGM21) \
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*/ \
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TCCR2A = _BV(WGM21); \
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TCCR2B = _BV(CS21); \
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\
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/* Clear interrupt flag register */ \
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TIFR2 = TIFR2; \
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\
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/* \
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* Raise interrupt when value in OCR2 is reached. Note that the \
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* counter value in TCNT2 is cleared automatically. \
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*/ \
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TIMSK2 = _BV (OCIE2A);
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#else
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#define AVR_OUTPUT_COMPARE_INT TIMER0_COMPA_vect
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#define OCRSetup() \
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/* Select internal clock */ \
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ASSR = 0x00; \
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\
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/* Set counter to zero */ \
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TCNT0 = 0; \
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\
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/* \
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* Set comparison register: \
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* Crystal freq. is 8000000,\
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* pre-scale factor is 1024, we want 125 ticks / sec: \
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* 8000000 = 1024 * 126.01 * 62, less 1 for CTC mode \
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*/ \
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OCR0A = 61; \
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\
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/* \
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* Set timer control register: \
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* - prescale: 1024 (CS00 - CS02) \
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* - counter reset via comparison register (WGM01) \
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*/ \
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TCCR0A = _BV(WGM01); \
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TCCR0B = _BV(CS00) | _BV(CS02); \
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\
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/* Clear interrupt flag register */ \
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TIFR0 = TIFR0; \
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\
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/* \
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* Raise interrupt when value in OCR0 is reached. Note that the \
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* counter value in TCNT0 is cleared automatically. \
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*/ \
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TIMSK0 = _BV (OCIE0A);
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#endif /* AVR_CONF_USE32KCRYSTAL */
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#else
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#error "Setup CPU in clock-avr.h"
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#endif
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#endif //CONTIKI_CLOCK_AVR_H
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