If I select internal clock source to run my TIM3 in TM32F103 (TIMxCLK from RCC) as shown in the attached picture:


Then how to find out what is the freq of this clock?

I am using External Crystal 8MHz to get 72MHz as my SYSCLK. Clock tree



1 Answer 1


TIM3 is on APB1 (see RCC_APB1RSTR).

This means in your configuration the TIM3 clock is 72 MHz, since it's derived from PCLK1 x2.


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