stm32之10.系统定时器

delay_s()延时秒= delay_ms()毫秒*1000= delay_us()微秒*1000000

微秒定时器代码

void delay_us(uint32_t n)

{

SysTick->CTRL = 0; // Disable SysTick，关闭系统定时器

SysTick->LOAD = SystemCoreClock/1000000*n-1; // 就是nus

SysTick->LOAD = SystemCoreClock/1000*n-1; // 就是ms

SysTick->LOAD = SystemCoreClock/1*n-1; // 就是s

SysTick->VAL = 0; // Clear current value as well as count flag，清空当前计数值且清零count flag

SysTick->CTRL = 5; // Enable SysTick timer with processor clock，启动系统定时器，其时钟源为处理器时钟168MHz

while ((SysTick->CTRL & 0x10000)==0);// Wait until count flag is set

SysTick->CTRL = 0; // Disable SysTick，关闭系统定时器

}