STM32学习笔记之SysTick-EDA365

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STM32学习笔记之SysTick

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STM32
笔记

#define SYSTICK_COUNTFLAG 16

//初始化延迟函数
void delay_init(void)
{
uint32_t ticks;

ticks = SystemFrequency/1000;
if (ticks > SYSTICK_MAXCOUNT)while (1);

SysTick->LOAD=(ticks & SYSTICK_MAXCOUNT) - 1;
NVIC_SetPriority (SysTick_IRQn, (1<<__nvic_prio_bits>
SysTick->VAL=(0x00);
SysTick->CTRL = (1 << SYSTICK_CLKSOURCE);//选择内核时钟
}

//ms延时
void delay_nms(__IO uint32_t nms)
{
u32 temp;

if(nms == 0)return;
SysTick->VAL = 0x00;//清空计数器

SysTick->CTRL |= (1 << SYSTICK_ENABLE);

while(nms--)
{
do
{
temp=SysTick->CTRL;
}
while(temp&0x01&&!(temp&(1<<16)));//等待时间到达
}