/* Copyright 2011 Jun Wako <wakojun@gmail.com> 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 #ifndef __AVR_ATmega32A__ // Timer0 CTC mode TCCR0A = _BV(WGM01); TCCR0B = prescaler; OCR0A = TIMER_RAW_TOP; TIMSK0 = _BV(OCIE0A); #else // Timer0 CTC mode TCCR0 = _BV(WGM01) | prescaler; OCR0 = TIMER_RAW_TOP; TIMSK = _BV(OCIE0); #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++; }