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.