使用定时器代替Systick延时，不使用中断，不改变原子的接口

只看该作者 · 2017-6-21 08:42

C++ Code

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static u32 fac_us = 0;  //us延时倍乘数

void delay_init(u8 SYSCLK)
{
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14, ENABLE);

TIM_TimeBaseStructure.TIM_Period = 65535 - 1;
TIM_TimeBaseStructure.TIM_Prescaler = 1 - 1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;
TIM_TimeBaseInit(TIM14, &TIM_TimeBaseStructure);

fac_us = SYSCLK;

TIM_SetCounter(TIM14, 0);
TIM_Cmd(TIM14, ENABLE);

}

void delay_us(u32 nus)
{
u32 ticks;
u32 told, tnow, tcnt = 0;
u32 reload = 65535 - 1;
ticks = nus * fac_us;
told = TIM14->CNT;
while(1)
{
      tnow = TIM14->CNT;
      if(tnow != told)
      {
         if(tnow > told)tcnt += tnow - told;
         else tcnt += reload - told + tnow;
         told = tnow;
         if(tcnt >= ticks)break;
      }
};
}

void delay_ms(u32 nms)
{
u32 i;
for(i = 0; i < nms; i++) delay_us(1000);
}