基于小熊派Hi3861鸿蒙开发的IoT物联网学习【三】

软件定时器:是基于系统Tick时钟中断且由软件来模拟的定时器，当经过设定的Tick时钟计数值后会触发用户定义的回调函数。定时精度与系统Tick时钟的周期有关。

定时器运行机制：

cmsis_os2的API软件定时器接口:

⚫ 静态裁剪：能通过宏关闭软件定时器功能。
⚫ 软件定时器创建:osTimerNew (osTimerFunc_t func, osTimerType_t type, void *argument, const osTimerAttr_t *attr);
⚫ 软件定时器启动:osTimerStart (osTimerId_t timer_id, uint32_t ticks);
⚫ 软件定时器停止:osTimerStop (osTimerId_t timer_id);
⚫ 软件定时器删除:osTimerDelete (osTimerId_t timer_id);
⚫ 软件定时器剩余Tick数获取:

#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "ohos_init.h"
#include "cmsis_os2.h"

uint32_t exec1, exec2;//typedef unsigned int    uint32_t;

/***** 定时器1 回调函数 *****/
////arg 是一个void的指针变量，指向一个地址
void Timer1_Callback(void *arg)
{
    (void)arg;
    printf("This is BearPi Harmony Timer1_Callback!
");
}

/***** 定时器2 回调函数 *****/
void Timer2_Callback(void *arg)
{
    (void)arg;
    printf("This is BearPi Harmony Timer2_Callback!
");
}

/***** 定时器创建 *****/
static void Timer_example(void)
{
    osTimerId_t id1, id2;
    uint32_t timerDelay; //延迟时间  unsigned int 类型
    osStatus_t status; //状态是枚举值

    exec1 = 1U;
    id1 = osTimerNew(Timer1_Callback, osTimerPeriodic, &exec1, NULL);
    if (id1 != NULL)
    {
        // Hi3861 1U=10ms,100U=1S
        timerDelay = 100U;//延迟1s

        status = osTimerStart(id1, timerDelay);
        if (status != osOK)
        {
            // Timer could not be started
        }
    }

    exec2 = 1U;
    id2 = osTimerNew(Timer2_Callback, osTimerPeriodic, &exec2, NULL);
    if (id2 != NULL)
    {

        // Hi3861 1U=10ms,300U=3S
        timerDelay = 300U;

        status = osTimerStart(id2, timerDelay);
        if (status != osOK)
        {
            // Timer could not be started
        }
    }
}

APP_FEATURE_INIT(Timer_example);

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