Stm32 clock configuration method

Stm32 has three different clock types used to drive the system clock (sysclk)

(1) HSI (internal clock)

(2) HSE (external clock, provided by excellent vibration)

(3) PLL (PLL clock)

 

The reuse configuration is as follows:

Use HSE as the input source of the PLL, configure the PLL to 72 MHz, then use the PLL as the system clock, and finally configure other clocks as the system clock crossover output.

 

 

Note:

(1) When HSI is used as the input of the PLL clock, the maximum system clock can only reach 64 MHz;

(2) when using the USB function, HSE and PLL must be used simultaneously, and the CPU frequency must be 48 MHz or 72 MHz;

(3) When the ADC sampling time is 1 US, apb2 must be set to 14, 28, or 56 MHz;