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- /*
- 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 <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 = 0;
-
- void timer_init(void)
- {
- // Timer0 CTC mode
- TCCR0A = 0x02;
-
- #if TIMER_PRESCALER == 1
- TCCR0B = 0x01;
- #elif TIMER_PRESCALER == 8
- TCCR0B = 0x02;
- #elif TIMER_PRESCALER == 64
- TCCR0B = 0x03;
- #elif TIMER_PRESCALER == 256
- TCCR0B = 0x04;
- #elif TIMER_PRESCALER == 1024
- TCCR0B = 0x05;
- #else
- # error "Timer prescaler value is NOT vaild."
- #endif
-
- OCR0A = TIMER_RAW_TOP;
- TIMSK0 = (1<<OCIE0A);
- }
-
- inline
- void timer_clear(void)
- {
- uint8_t sreg = SREG;
- cli();
- timer_count = 0;
- SREG = sreg;
- }
-
- inline
- uint16_t timer_read(void)
- {
- uint32_t t;
-
- uint8_t sreg = SREG;
- cli();
- t = timer_count;
- SREG = sreg;
-
- return (t & 0xFFFF);
- }
-
- inline
- uint32_t timer_read32(void)
- {
- uint32_t t;
-
- uint8_t sreg = SREG;
- cli();
- t = timer_count;
- SREG = sreg;
-
- return t;
- }
-
- inline
- uint16_t timer_elapsed(uint16_t last)
- {
- uint32_t t;
-
- uint8_t sreg = SREG;
- cli();
- t = timer_count;
- SREG = sreg;
-
- return TIMER_DIFF_16((t & 0xFFFF), last);
- }
-
- inline
- uint32_t timer_elapsed32(uint32_t last)
- {
- uint32_t t;
-
- uint8_t sreg = SREG;
- cli();
- t = timer_count;
- SREG = sreg;
-
- return TIMER_DIFF_32(t, last);
- }
-
- // excecuted once per 1ms.(excess for just timer count?)
- ISR(TIMER0_COMPA_vect)
- {
- timer_count++;
- }
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