2 Copyright 2011 Jun Wako <wakojun@gmail.com>
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #include <avr/interrupt.h>
20 #include <util/atomic.h>
22 #include "timer_avr.h"
26 // counter resolution 1ms
27 // NOTE: union { uint32_t timer32; struct { uint16_t dummy; uint16_t timer16; }}
28 volatile uint32_t timer_count;
32 #if TIMER_PRESCALER == 1
33 uint8_t prescaler = 0x01;
34 #elif TIMER_PRESCALER == 8
35 uint8_t prescaler = 0x02;
36 #elif TIMER_PRESCALER == 64
37 uint8_t prescaler = 0x03;
38 #elif TIMER_PRESCALER == 256
39 uint8_t prescaler = 0x04;
40 #elif TIMER_PRESCALER == 1024
41 uint8_t prescaler = 0x05;
43 # error "Timer prescaler value is NOT vaild."
46 #ifndef __AVR_ATmega32A__
52 OCR0A = TIMER_RAW_TOP;
56 TCCR0 = (1 << WGM01) | prescaler;
64 void timer_clear(void)
66 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
72 uint16_t timer_read(void)
76 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
84 uint32_t timer_read32(void)
88 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
96 uint16_t timer_elapsed(uint16_t last)
100 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
104 return TIMER_DIFF_16((t & 0xFFFF), last);
108 uint32_t timer_elapsed32(uint32_t last)
112 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
116 return TIMER_DIFF_32(t, last);
119 // excecuted once per 1ms.(excess for just timer count?)
120 #ifndef __AVR_ATmega32A__
121 #define TIMER_INTERRUPT_VECTOR TIMER0_COMPA_vect
123 #define TIMER_INTERRUPT_VECTOR TIMER0_COMP_vect
125 ISR(TIMER_INTERRUPT_VECTOR, ISR_NOBLOCK)