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作為一個(gè)搞電子嵌入式的你來(lái)說(shuō)，定時(shí)器相信絕對(duì)不會(huì)陌生，去翻看STM32的官方數(shù)據(jù)手冊(cè)，可能有四分之一的篇幅都在講定時(shí)器，可見定時(shí)器的重要性，定時(shí)器定時(shí)器嘛，最重要的功能還是定時(shí)。之前經(jīng)常有師弟跟我抱怨，哎呀，這個(gè)單片機(jī)怎么只有2個(gè)定時(shí)器，我都不夠用了，怎么辦呀，然后一頭霧水，其實(shí)，只要有一個(gè)硬件定時(shí)器，在實(shí)際不是要求特別特別精準(zhǔn)的場(chǎng)合，我們可以模擬很多個(gè)軟件定時(shí)器出來(lái)，今天，群主給大家分享一個(gè)完全由C語(yǔ)言編寫，高度可移植，超級(jí)牛逼的軟件定時(shí)器！

/*
* main.c
*
* Created on: 20161229
* @Author : 曉宇
* @version ：V1.0.0
*
* ,%%%%%%%%,
* ,%%/\%%%%/\%%
* ,%%%\c''''J/%%%
* %. %%%%/ o o \%%%
* `%%. %%%% |%%%
* `%% `%%%%(__Y__)%%'
* // ;%%%%`\-/%%%'
* (( / `%%%%%%%'
* \\ .' |
* \\ / \ | |
* \\/ ) | |
* \ /_ | |__
* (____________))))))) 攻城獅
*
*/
#include "multi_timer.h"
struct Timer timer1;
struct Timer timer2;
void timer1_callback()
{
printf("timer1 timeout!\r\n");
}
void timer2_callback()
{
printf("timer2 timeout!\r\n");
}
int main()
{
timer_init(&timer1, timer1_callback, 1000, 1000); //1s loop
timer_start(&timer1);
timer_init(&timer2, timer2_callback, 50, 0); //50ms delay
timer_start(&timer2);
while(1) {
timer_loop();
}
}
void HAL_SYSTICK_Callback(void)
{
timer_ticks(); //1ms ticks
}

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struct Timer timer1;

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timer_init(struct Timer* handle, void(*timeout_cb)(), uint32_t timeout, uint32_t repeat);

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timer_start(&timer1);

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上面，我們定義了兩個(gè)定時(shí)器，第一個(gè)以每1秒一次進(jìn)行循環(huán)執(zhí)行，第二個(gè)定時(shí)器50ms之后只執(zhí)行一次，執(zhí)行之后，可以通過(guò)相應(yīng)的回調(diào)函數(shù)打印出來(lái)，里面就可以添加我們的定時(shí)任務(wù)了。怎么樣，是不是很簡(jiǎn)單，只需要設(shè)置好定時(shí)基準(zhǔn)，申請(qǐng)好定時(shí)器，初始化完畢，你想要的效果，是定時(shí)一次還是進(jìn)行循環(huán)，都沒(méi)問(wèn)題，多個(gè)定時(shí)器之間使用鏈表來(lái)實(shí)現(xiàn)，可以啟動(dòng)暫停每個(gè)定時(shí)器，用起來(lái)之后，是不是很爽？具體的代碼，需要大家仔細(xì)去推敲其中的原理，當(dāng)然直接用也是可以的。

/*
* multi_timer.h
*
* Created on: 20161229
* @Author : 曉宇
* @version ：V1.0.0
*/
#ifndef _MULTI_TIMER_H_
#define _MULTI_TIMER_H_
#include "stdint.h"
typedef struct Timer {
uint32_t timeout;
uint32_t repeat;
void (*timeout_cb)(void);
struct Timer* next;
}Timer;
#ifdef __cplusplus
extern "C" {
#endif
void timer_init(struct Timer* handle, void(*timeout_cb)(), uint32_t timeout, uint32_t repeat);
int timer_start(struct Timer* handle);
void timer_stop(struct Timer* handle);
void timer_ticks(void);
void timer_loop(void);
// void timer_again(struct Timer* handle);
// void timer_set_repeat(struct Timer* handle, uint32_t repeat);
#ifdef __cplusplus
}
#endif
#endif/*
* multi_timer.c
*
* Created on: 20161229
* @Author : 曉宇
* @version ：V1.0.0
*/
#include "multi_timer.h"
//timer handle list head.
static struct Timer* head_handle = NULL;
//Timer ticks
static uint32_t _timer_ticks = 0;
/**
* @brief Initializes the timer struct handle.
* @param handle: the timer handle strcut.
* @param timeout_cb: timeout callback.
* @param repeat: repeat interval time.
* @retval None
*/
void timer_init(struct Timer* handle, void(*timeout_cb)(), uint32_t timeout, uint32_t repeat)
{
// memset(handle, sizeof(struct Timer), 0);
handle->timeout_cb = timeout_cb;
handle->timeout = _timer_ticks + timeout;
handle->repeat = repeat;
}
/**
* @brief Start the timer work, add the handle into work list.
* @param btn: target handle strcut.
* @retval 0: succeed. -1: already exist.
*/
int timer_start(struct Timer* handle)
{
struct Timer* target = head_handle;
while(target) {
if(target == handle) return -1; //already exist.
target = target->next;
}
handle->next = head_handle;
head_handle = handle;
return 0;
}
/**
* @brief Stop the timer work, remove the handle off work list.
* @param handle: target handle strcut.
* @retval None
*/
void timer_stop(struct Timer* handle)
{
struct Timer** curr;
for(curr = &head_handle; *curr; ) {
struct Timer* entry = *curr;
if (entry == handle) {
*curr = entry->next;
// free(entry);
} else
curr = &entry->next;
}
}
/**
* @brief main loop.
* @param None.
* @retval None
*/
void timer_loop()
{
struct Timer* target;
for(target=head_handle; target; target=target->next) {
if(_timer_ticks >= target->timeout) {
if(target->repeat == 0) {
timer_stop(target);
} else {
target->timeout = _timer_ticks + target->repeat;
}
target->timeout_cb();
}
}
}
/**
* @brief background ticks, timer repeat invoking interval 1ms.
* @param None.
* @retval None.
*/
void timer_ticks()
{
_timer_ticks++;
}

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