diff options
Diffstat (limited to 'platforms/avr/timer.c')
| -rw-r--r-- | platforms/avr/timer.c | 133 | 
1 files changed, 133 insertions, 0 deletions
| diff --git a/platforms/avr/timer.c b/platforms/avr/timer.c new file mode 100644 index 0000000000..c2e6c6e081 --- /dev/null +++ b/platforms/avr/timer.c @@ -0,0 +1,133 @@ +/* +Copyright 2011 Jun Wako <[email protected]> + +This program is free software: you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation, either version 2 of the License, or +(at your option) any later version. + +This program 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 General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program.  If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <avr/io.h> +#include <avr/interrupt.h> +#include <util/atomic.h> +#include <stdint.h> +#include "timer_avr.h" +#include "timer.h" + +// counter resolution 1ms +// NOTE: union { uint32_t timer32; struct { uint16_t dummy; uint16_t timer16; }} +volatile uint32_t timer_count; + +/** \brief timer initialization + * + * FIXME: needs doc + */ +void timer_init(void) { +#if TIMER_PRESCALER == 1 +    uint8_t prescaler = _BV(CS00); +#elif TIMER_PRESCALER == 8 +    uint8_t prescaler = _BV(CS01); +#elif TIMER_PRESCALER == 64 +    uint8_t prescaler = _BV(CS00) | _BV(CS01); +#elif TIMER_PRESCALER == 256 +    uint8_t prescaler = _BV(CS02); +#elif TIMER_PRESCALER == 1024 +    uint8_t prescaler = _BV(CS00) | _BV(CS02); +#else +#    error "Timer prescaler value is not valid" +#endif + +#if defined(__AVR_ATmega32A__) +    // Timer0 CTC mode +    TCCR0 = _BV(WGM01) | prescaler; + +    OCR0  = TIMER_RAW_TOP; +    TIMSK = _BV(OCIE0); +#elif defined(__AVR_ATtiny85__) +    // Timer0 CTC mode +    TCCR0A = _BV(WGM01); +    TCCR0B = prescaler; + +    OCR0A = TIMER_RAW_TOP; +    TIMSK = _BV(OCIE0A); +#else +    // Timer0 CTC mode +    TCCR0A = _BV(WGM01); +    TCCR0B = prescaler; + +    OCR0A  = TIMER_RAW_TOP; +    TIMSK0 = _BV(OCIE0A); +#endif +} + +/** \brief timer clear + * + * FIXME: needs doc + */ +inline void timer_clear(void) { +    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { timer_count = 0; } +} + +/** \brief timer read + * + * FIXME: needs doc + */ +inline uint16_t timer_read(void) { +    uint32_t t; + +    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { t = timer_count; } + +    return (t & 0xFFFF); +} + +/** \brief timer read32 + * + * FIXME: needs doc + */ +inline uint32_t timer_read32(void) { +    uint32_t t; + +    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { t = timer_count; } + +    return t; +} + +/** \brief timer elapsed + * + * FIXME: needs doc + */ +inline uint16_t timer_elapsed(uint16_t last) { +    uint32_t t; + +    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { t = timer_count; } + +    return TIMER_DIFF_16((t & 0xFFFF), last); +} + +/** \brief timer elapsed32 + * + * FIXME: needs doc + */ +inline uint32_t timer_elapsed32(uint32_t last) { +    uint32_t t; + +    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { t = timer_count; } + +    return TIMER_DIFF_32(t, last); +} + +// excecuted once per 1ms.(excess for just timer count?) +#ifndef __AVR_ATmega32A__ +#    define TIMER_INTERRUPT_VECTOR TIMER0_COMPA_vect +#else +#    define TIMER_INTERRUPT_VECTOR TIMER0_COMP_vect +#endif +ISR(TIMER_INTERRUPT_VECTOR, ISR_NOBLOCK) { timer_count++; } | 
