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本示例将演示如何在Niobe Wifi IoT开发板上使用cmsis 2.0 接口进行定时器开发
/// Create and Initialize a timer.
/// \param[in] func function pointer to callback function.
/// \param[in] type \ref osTimerOnce for one-shot or \ref osTimerPeriodic for periodic behavior.
/// \param[in] argument argument to the timer callback function.
/// \param[in] attr timer attributes; NULL: default values.
/// \return timer ID for reference by other functions or NULL in case of error.
osTimerId_t osTimerNew (osTimerFunc_t func,osTimerType_t type,void *argument,const osTimerAttr_t *attr)
描述：
函数osTimerNew创建一个一次性或周期性计时器，并将其与一个带参数的回调函数相关联。计时器在osTimerStart启动之前一直处于停止状态。可以在RTOS启动(调用 osKernelStart)之前安全地调用该函数，但不能在内核初始化 (调用 osKernelInitialize)之前调用该函数。
注意 :不能在中断服务调用该函数 参数： |名字|描述| |:--|:------| | func | 函数指针指向回调函数. | | type | 定时器类型，osTimerOnce表示单次定时器，ostimer周期表示周期性定时器. | | argument |定时器回调函数的参数| | attr |计时器属性|
/// Start or restart a timer.
/// \param[in] timer_id timer ID obtained by \ref osTimerNew.
/// \param[in] ticks \ref CMSIS_RTOS_TimeOutValue "time ticks" value of the timer.
/// \return status code that indicates the execution status of the function.
osStatus_t osTimerStart(osTimerId_t timer_id, uint32_t ticks);
描述：
函数osTimerStart启动或重新启动指定参数timer_id的计时器。参数ticks指定计时器的计数值。
注意 :不能在中断服务调用该函数
参数：
| 名字 | 描述 |
|---|---|
| timer_id | 由osTimerNew获得的计时器ID. |
| ticks | 时间滴答计时器的值. |
主要代码分析
在OS_Timer_example函数中，通过osTimerNew()函数创建了回调函数为OS_Timer1_Callback的定时器1，并通过osTimerStart()函数将该定时器设置为100个tick,因为hi3861默认10ms为一个tick,所以100个tick正好为1S钟，1S计时到后会触发OS_Timer1_Callback()函数并打印日志。定时器2也同理为3S触发OS_Timer2_Callback()函数并打印日志.
static void OS_Timer_example(void)
{
osTimerId_t timerId1, timerId2;
uint32_t delay;
osStatus_t status;
timer1Exec = 1U;
/// Create and Initialize a timer.
/// \param[in] func function pointer to callback function.
/// \param[in] type \ref osTimerOnce for one-shot or \ref osTimerPeriodic for periodic behavior.
/// \param[in] argument argument to the timer callback function.
/// \param[in] attr timer attributes; NULL: default values.
/// \return timer ID for reference by other functions or NULL in case of error.
timerId1 = osTimerNew((osTimerFunc_t)OS_Timer1_Callback, osTimerPeriodic, &timer1Exec, NULL);
if (timerId1 != NULL)
{
delay = 100U;
/// Start or restart a timer.
/// \param[in] timer_id timer ID obtained by \ref osTimerNew.
/// \param[in] ticks \ref CMSIS_RTOS_TimeOutValue "time ticks" value of the timer.
/// \return status code that indicates the execution status of the function.
//osStatus_t osTimerStart(osTimerId_t timer_id, uint32_t ticks);
status = osTimerStart(timerId1, delay);
if (status != osOK)
{
printf("Falied to start timer1!\n");
}
}
timer2Exec = 100U;
timerId2 = osTimerNew((osTimerFunc_t)OS_Timer2_Callback, osTimerPeriodic, &timer2Exec, NULL);
if (timerId2 != NULL)
{
delay = 300U;
status = osTimerStart(timerId2, delay);
if (status != osOK)
{
printf("Falied to start timer2!\n");
}
}
}
修改 applications\app路径下 BUILD.gn 文件，指定 os_timer_example 参与编译。
#"TW001_OS_helloworld:helloworld_example",
#"TW002_OS_thread:os_thread_example",
"TW003_OS_timer:os_timer_example",
#"TW004_OS_event:os_event_example",
#"TW005_OS_mutex:os_mutex_example",
#"TW006_OS_semp:os_semaphore_example",
#"TW007_OS_message:os_message_example",
示例代码编译烧录代码后，按下开发板的RESET按键，通过串口助手查看日志，OS_Timer1_Callback会1S打印一次数据，OS_Timer2_Callback会3S打印一次数据。
This is Niebo Timer1_Callback:1!
This is Niebo Timer1_Callback:1!
This is Niebo Timer1_Callback:1!
This is Niebo Timer2_Callback:100!
This is Niebo Timer1_Callback:1!
This is Niebo Timer1_Callback:1!
This is Niebo Timer1_Callback:1!
This is Niebo Timer2_Callback:100!
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