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1 | /* | |
2 | * (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de> | |
3 | * | |
4 | * SPDX-License-Identifier: GPL-2.0 | |
5 | */ | |
6 | ||
7 | #include "timer.h" | |
8 | #include <avr/interrupt.h> | |
9 | #include <util/atomic.h> | |
10 | #include "time.h" | |
11 | ||
12 | /* timer interrupt/overflow counter */ | |
13 | /* counts up every ms. */ | |
14 | static volatile | |
15 | uint32_t timestamp; | |
16 | ||
17 | /* | |
18 | * 1000Hz timer interrupt generated by OC4A | |
19 | */ | |
20 | ISR(TIMER4_COMPA_vect) | |
21 | { | |
22 | static int_fast8_t tick_10ms; | |
23 | static int_fast8_t tick_1s; | |
24 | int_fast8_t i, j; | |
25 | ||
26 | extern void disk_timerproc(void); | |
27 | ||
28 | OCR4A += F_CPU / 1000; /* 1000Hz interval */ | |
29 | ||
30 | timestamp++; | |
31 | ||
32 | i = tick_10ms + 1; | |
33 | if (i == 10) { | |
34 | Stat |= S_10MS_TO; | |
35 | ||
36 | /* Drive timer procedure of low level disk I/O module */ | |
37 | disk_timerproc(); | |
38 | ||
39 | j = tick_1s - 1; | |
40 | if (j == 0) { | |
41 | system_tick(); | |
42 | j = 100; | |
43 | } | |
44 | tick_1s = j; | |
45 | i = 0; | |
46 | } | |
47 | tick_10ms = i; | |
48 | } | |
49 | ||
50 | ||
51 | /*--------------------------------------------------------------------------*/ | |
52 | ||
53 | uint32_t get_timer(uint32_t base) | |
54 | { | |
55 | uint32_t ret; | |
56 | ATOMIC_BLOCK(ATOMIC_FORCEON) | |
57 | { | |
58 | ret = timestamp; | |
59 | } | |
60 | return ret - base; | |
61 | } |