STM32用SysTick來做定時(shí)器

1 硬件電路配置

這里還是借用前面LED電路我就不貼圖片。

2 時(shí)鐘說明

SysTick和HCK的時(shí)鐘頻率是一樣的庫函數(shù)代碼如下

/**

*@briefInitializeandstarttheSysTickcounteranditsinterrupt.

*

*@paramticksnumberofticksbetweentwointerrupts

*@return1=failed,0=successful

*

*Initialisethesystemticktimeranditsinterruptandstartthe

*systemticktimer/counterinfreerunningmodetogenerate

*periodicalinterrupts.

*/

static__INLINEuint32_tSysTick_Config(uint32_tticks)

{

if(ticks>SysTick_LOAD_RELOAD_Msk)return(1);/*Reloadvalueimpossible*/

SysTick->LOAD=(ticks&SysTick_LOAD_RELOAD_Msk)-1;/*setreloadregister*/

NVIC_SetPriority(SysTick_IRQn,(1<<__NVIC_PRIO_BITS)-1);/*setPriorityforCortex-M0SystemInterrupts*/

SysTick->VAL=0;/*LoadtheSysTickCounterValue*/

SysTick->CTRL=SysTick_CTRL_CLKSOURCE_Msk|

SysTick_CTRL_TICKINT_Msk|

SysTick_CTRL_ENABLE_Msk;/*EnableSysTickIRQandSysTickTimer*/

return(0);/*Functionsuccessful*/

}

由庫函數(shù)可知道沒有進(jìn)行分頻動(dòng)作所以時(shí)鐘和主時(shí)鐘一樣

配置時(shí)鐘中斷的時(shí)間間隔

voidSysTick_Init(void)

{

/*SystemFrequency/10001ms中斷一次

*SystemFrequency/10000010us中斷一次

*SystemFrequency/10000001us中斷一次

*/

//if(SysTick_Config(SystemFrequency/100000))//ST3.0.0庫版本

if(SysTick_Config(SystemCoreClock/1000))//ST3.5.0庫版本

{

/*Captureerror*/

while(1);

}

//我需要不斷的開啟中斷所以這句話屏蔽起來

//SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;

}

用中斷模式所以需要在中斷文件中做定時(shí)標(biāo)志。一下這個(gè)函數(shù)在中斷文件中

/**

*@briefThisfunctionhandlesSysTickHandler.

*@paramNone

*@retval:None

*/

voidSysTick_Handler(void)

{

TimingDelay_Decrement();

}

中斷函數(shù)在調(diào)用一個(gè)計(jì)數(shù)函數(shù)，計(jì)數(shù)函數(shù)應(yīng)該放在外面一個(gè)公共文件中方便各個(gè)文件中數(shù)據(jù)傳遞。

/*

*函數(shù)名：TimingDelay_Decrement

*描述獲取節(jié)拍程序

*輸入無

*輸出無

*調(diào)用在SysTick中斷函數(shù)SysTick_Handler()調(diào)用

*/

voidTimingDelay_Decrement(void)

{

if(TimingDelay!=0x00)

{

TimingDelay--;

}

}