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a074364c | 1 | /* |
2 | Copyright 2011 Jun Wako <wakojun@gmail.com> | |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
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/>. | |
16 | */ | |
17 | ||
18 | #include <avr/io.h> | |
19 | #include <avr/interrupt.h> | |
be4e7542 | 20 | #include <util/atomic.h> |
a074364c | 21 | #include <stdint.h> |
22 | #include "timer_avr.h" | |
23 | #include "timer.h" | |
24 | ||
25 | ||
26 | // counter resolution 1ms | |
27 | // NOTE: union { uint32_t timer32; struct { uint16_t dummy; uint16_t timer16; }} | |
be4e7542 | 28 | volatile uint32_t timer_count; |
a074364c | 29 | |
7c9d5ace | 30 | /** \brief timer initialization |
31 | * | |
32 | * FIXME: needs doc | |
33 | */ | |
a074364c | 34 | void timer_init(void) |
35 | { | |
a074364c | 36 | #if TIMER_PRESCALER == 1 |
f7462aaa | 37 | uint8_t prescaler = 0x01; |
a074364c | 38 | #elif TIMER_PRESCALER == 8 |
f7462aaa | 39 | uint8_t prescaler = 0x02; |
a074364c | 40 | #elif TIMER_PRESCALER == 64 |
f7462aaa | 41 | uint8_t prescaler = 0x03; |
a074364c | 42 | #elif TIMER_PRESCALER == 256 |
f7462aaa | 43 | uint8_t prescaler = 0x04; |
a074364c | 44 | #elif TIMER_PRESCALER == 1024 |
f7462aaa | 45 | uint8_t prescaler = 0x05; |
a074364c | 46 | #else |
47 | # error "Timer prescaler value is NOT vaild." | |
48 | #endif | |
49 | ||
f7462aaa LR |
50 | #ifndef __AVR_ATmega32A__ |
51 | // Timer0 CTC mode | |
52 | TCCR0A = 0x02; | |
53 | ||
54 | TCCR0B = prescaler; | |
55 | ||
a074364c | 56 | OCR0A = TIMER_RAW_TOP; |
57 | TIMSK0 = (1<<OCIE0A); | |
f7462aaa LR |
58 | #else |
59 | // Timer0 CTC mode | |
60 | TCCR0 = (1 << WGM01) | prescaler; | |
61 | ||
62 | OCR0 = TIMER_RAW_TOP; | |
63 | TIMSK = (1 << OCIE0); | |
64 | #endif | |
a074364c | 65 | } |
66 | ||
7c9d5ace | 67 | /** \brief timer clear |
68 | * | |
69 | * FIXME: needs doc | |
70 | */ | |
a074364c | 71 | inline |
72 | void timer_clear(void) | |
73 | { | |
be4e7542 | 74 | ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { |
a074364c | 75 | timer_count = 0; |
be4e7542 | 76 | } |
a074364c | 77 | } |
78 | ||
7c9d5ace | 79 | /** \brief timer read |
80 | * | |
81 | * FIXME: needs doc | |
82 | */ | |
a074364c | 83 | inline |
84 | uint16_t timer_read(void) | |
85 | { | |
86 | uint32_t t; | |
87 | ||
be4e7542 WF |
88 | ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { |
89 | t = timer_count; | |
90 | } | |
a074364c | 91 | |
92 | return (t & 0xFFFF); | |
93 | } | |
94 | ||
7c9d5ace | 95 | /** \brief timer read32 |
96 | * | |
97 | * FIXME: needs doc | |
98 | */ | |
a074364c | 99 | inline |
100 | uint32_t timer_read32(void) | |
101 | { | |
102 | uint32_t t; | |
103 | ||
be4e7542 WF |
104 | ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { |
105 | t = timer_count; | |
106 | } | |
a074364c | 107 | |
108 | return t; | |
109 | } | |
110 | ||
7c9d5ace | 111 | /** \brief timer elapsed |
112 | * | |
113 | * FIXME: needs doc | |
114 | */ | |
a074364c | 115 | inline |
116 | uint16_t timer_elapsed(uint16_t last) | |
117 | { | |
118 | uint32_t t; | |
119 | ||
be4e7542 WF |
120 | ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { |
121 | t = timer_count; | |
122 | } | |
a074364c | 123 | |
124 | return TIMER_DIFF_16((t & 0xFFFF), last); | |
125 | } | |
126 | ||
7c9d5ace | 127 | /** \brief timer elapsed32 |
128 | * | |
129 | * FIXME: needs doc | |
130 | */ | |
a074364c | 131 | inline |
132 | uint32_t timer_elapsed32(uint32_t last) | |
133 | { | |
134 | uint32_t t; | |
135 | ||
be4e7542 WF |
136 | ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { |
137 | t = timer_count; | |
138 | } | |
a074364c | 139 | |
140 | return TIMER_DIFF_32(t, last); | |
141 | } | |
142 | ||
143 | // excecuted once per 1ms.(excess for just timer count?) | |
f7462aaa LR |
144 | #ifndef __AVR_ATmega32A__ |
145 | #define TIMER_INTERRUPT_VECTOR TIMER0_COMPA_vect | |
146 | #else | |
147 | #define TIMER_INTERRUPT_VECTOR TIMER0_COMP_vect | |
148 | #endif | |
149 | ISR(TIMER_INTERRUPT_VECTOR, ISR_NOBLOCK) | |
a074364c | 150 | { |
151 | timer_count++; | |
152 | } |