Systick函数
__STATIC_INLINE void CLK_SysTickDelay(uint32_t us)
{
SysTick->LOAD = us * CyclesPerUs;
SysTick->VAL = (0x00);
SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk;
...
}
CyclesPerUs是定义的12M/1000 000。这一步是不是可以认定systick的时钟源为HXT?
但是
SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk;//不是设定为72M,HCLK吗????
我该怎么理解??? |