请问：TIM1 input clock、TIM1 counter clock、TIM1 output clock什么关系呀？

请问：TIM1 input clock、TIM1 counter clock、TIM1 output clock什么关系呀？
TIM1 input clock (TIM1CLK) is set to APB1 clock (PCLK1),since APB1 prescaler is equal to 1.
TIM1CLK = PCLK1
PCLK1 = HCLK
=> TIM1CLK = HCLK = SystemCoreClock =80MHz

To get TIM1 counter clock at 16 MHz, the prescaler is computed as follows:
Prescaler = (TIM1CLK / TIM1 counter clock) - 1
Prescaler = ((SystemCoreClock) /16 MHz) - 1

To get TIM1 output clock at 24 KHz, the period (ARR)) is computed as follows:
ARR = (TIM1 counter clock / TIM1 output clock) - 1
= 665

TIM1 input clock不就是直接从端口输出了吗？为什么还有TIM1 counter clock、TIM1 output clock？

TIM1 input clock，任何外设都是需要时钟才能运行的，你可以把这个输入时钟看成是使TM1运行的心脏。这个时钟是挂在APB总线上的。属于直接从APB总线上获取到的时钟。
TIM1 counter clock 在可以理解为定时器的实际时钟，这个一般是通过TIM1CLK分频达到的。
TIM1 output clock是定时器的实际定时时间。