STM32的三种延时方法的代码实现_纯软件延时, 系统定时器延时, 定时器延时

/* 外部调用:

    delay_init(72);    //系统主频, 单位为MHZ, 仅对 SYSTICK_DELAY 有效

    delay_ms(1000);

*/

#include 'stm32f10x.h'

//#define SOFT_DELAY        //纯软件延时

//#define SYSTICK_DELAY    //系统定时器延时

#define TIMER_DELAY            //定时器延时

#ifdef TIMER_DELAY

#define TIMER_DELAY                                    TIM4

#define TIMER_DELAY_PERIOD                    1000

#define TIMER_DELAY_PRESCALER                72

#define TIMER_DELAY_CLOCK                        RCC_APB1Periph_TIM4

#define TIMER_DELAY_IRQ_HANDLER            TIM4_IRQHandler

#define TIMER_DELAY_PREEMPTION_PRIORITY        2

#define TIMER_DELAY_SUB_PRIORITY                    2

#define TIMER_DELAY_IRQ_CHANNEL                        TIM4_IRQn

static __IO u16    counter_delay_ms;

#endif

//-----------------------------------------------------------------

#ifdef SOFT_DELAY

void delay_init(u8 SYSCLK)

{}

#if 1

void delay_us(u32 Number)

{

    u32 i=0;

     while(Number--){

      i=12; while(i--);

     }

}

void delay_ms(u16 Number)

{

    u32 i;

     while(Number--){

      i=12000; while(i--);

    }

}

#else

unsigned char MULTIPLE8M = 9;

void delay_us(u32 usNum)

{

  unsigned short kk, i;

  for(i=usNum; i>0; i--)

  {

    kk = 2*MULTIPLE8M - 1; //0x080003AA 4C06 LDR r4,[pc,#24] ; @0x080003C4 2clk

    do

    { //0x080003AC BF00 NOP 1clk

      kk--; //0x080003AE 1E64 SUBS r4,r4,#1 1clk

    } while(kk); //0x080003B0 2C00 CMP r4,#0x00 1clk

                    //0x080003B2 D1FC BNE 0x080003AE jump:2clk, no jump:1clk

  }

}

void delay_ms(u16 usNum)

{

  unsigned short kk, i;

  for(i=usNum; i>0; i--)

  {

    if (i % 100 == 0) {

        //FEEDDOG;

    }

    kk = 2000*MULTIPLE8M - 1; //0x080003AA 4C06 LDR r4,[pc,#24] ; @0x080003C4 2clk

    do

    { //0x080003AC BF00 NOP 1clk

      kk--; //0x080003AE 1E64 SUBS r4,r4,#1 1clk

    } while(kk); //0x080003B0 2C00 CMP r4,#0x00 1clk

                    //0x080003B2 D1FC BNE 0x080003AE jump:2clk, no jump:1clk

  }

}

#endif

#endif

//---------------------------------------------------------------------------

#ifdef SYSTICK_DELAY

//参考原子的代码. 修正了中断中调用出现死循环的错误, 防止延时不准确,采用do

static u8 fac_us = 0;    //us延时倍乘数

static u16 fac_ms = 0;    //ms延时倍乘数

//初始化延迟函数, SYSTICK的时钟固定为HCLK时钟的1/8, SYSCLK:系统时钟, 单位为MHZ

void delay_init(u8 SYSCLK)

{

    SysTick->CTRL &= 0xfffffffb;    //bit2清空,选择外部时钟 HCLK/8

    fac_us = SYSCLK/8;

    fac_ms = (u16)fac_us*1000;

}

//延时nms, 注意nms的范围

//SysTick->LOAD为24位寄存器,所以,最大延时为:nms<=0xffffff*8*1000/SYSCLK

//SYSCLK单位为Hz,nms单位为ms, 对72M条件下,nms<=1864

void delay_ms(u16 nms)

{

    u32 temp;

    SysTick->LOAD = (u32)nms*fac_ms;//时间加载(SysTick->LOAD为24bit)

    SysTick->VAL = 0x00; //清空计数器

    SysTick->CTRL = 0x01 ; //开始倒数

    do {

        temp = SysTick->CTRL;

    }while(temp&0x01 && !(temp&(1<<16)));//等待时间到达

    SysTick->CTRL = 0x00; //关闭计数器

    SysTick->VAL = 0X00; //清空计数器

}

//延时nus, nus为要延时的us数.

void delay_us(u32 nus)

{

    u32 temp;

    SysTick->LOAD = nus*fac_us; //时间加载

    SysTick->VAL = 0x00; //清空计数器

    SysTick->CTRL = 0x01 ; //开始倒数

    do{

        temp = SysTick->CTRL;

    }while(temp&0x01 && !(temp&(1<<16)));//等待时间到达

    SysTick->CTRL = 0x00; //关闭计数器

    SysTick->VAL = 0X00; //清空计数器

}

#endif

//-------------------------------------------------------------------

#ifdef TIMER_DELAY

void decrement_delay(void)

{

    if(counter_delay_ms != 0)

    {

        /* Decrement the counter */

        counter_delay_ms--;

    }

}

void delay_init(u8 SYSCLK)

{

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(TIMER_DELAY_CLOCK, ENABLE);

    TIM_TimeBaseStructure.TIM_Period                 = TIMER_DELAY_PERIOD;

    TIM_TimeBaseStructure.TIM_Prescaler         = TIMER_DELAY_PRESCALER;

    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;

    TIM_TimeBaseStructure.TIM_CounterMode     = TIM_CounterMode_Up;

    TIM_TimeBaseInit(TIMER_DELAY, &TIM_TimeBaseStructure);

    TIM_UpdateRequestConfig(TIMER_DELAY, TIM_UpdateSource_Global);

    TIM_ClearITPendingBit(TIMER_DELAY, TIM_IT_Update);

    /* Enable TIMER Update interrupt */

    TIM_ITConfig(TIMER_DELAY, TIM_IT_Update, ENABLE);

    // Disable timers

    TIM_Cmd(TIMER_DELAY, DISABLE);

    /* Enable and set TIMER IRQ used for delays */

    NVIC_InitStructure.NVIC_IRQChannel                                          = TIMER_DELAY_IRQ_CHANNEL;

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority     = TIMER_DELAY_PREEMPTION_PRIORITY;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority                  = TIMER_DELAY_SUB_PRIORITY;

    NVIC_InitStructure.NVIC_IRQChannelCmd                                 = ENABLE;

    NVIC_Init(&NVIC_InitStructure);

}

void delay_ms(uint16_t delay)

{

    counter_delay_ms = delay;

    TIM_SetCounter(TIMER_DELAY, 0);

    /* TIM4 enable counter */

  TIM_Cmd(TIMER_DELAY, ENABLE);

    /* Wait for 'delay' milliseconds */

    while(counter_delay_ms != 0);

    /* TIM4 disable counter */

    TIM_Cmd(TIMER_DELAY, DISABLE);

}

void TIMER_DELAY_IRQ_HANDLER(void)

{

    /* Clear TIMER update interrupt flag */

    TIM_ClearITPendingBit(TIMER_DELAY, TIM_IT_Update);

    decrement_delay();

}

#endif

当然运行RTOS时, 一般系统定时器延时就不能用了.