STM32 - reset and clock control (cubemx for clock configuration)

1.RCC peripherals

RCC peripherals , It is the English abbreviation of reset and in-process control ,RCC Peripheral management is right STM32 The reset and clock control of the chip are managed

2.STM32 The reset function of

System reset ： System reset will reset except Clock control register CSR Reset flag in and Registers in the backup area All registers except for are their reset values

  The system reset circuit is shown in the figure , Press the button ,NRST The pin is pulled to the low level

Power reset ： Power reset resets all registers except the backup area

Backup domain reset ： The backup area has two dedicated resets , Only the backup area is affected

 3. The clock

Clock can be simply understood as heartbeat , For electronic devices , The clock is its heartbeat ,STM32 chip , It will work according to the beat specified by the program ,72Mhz,480Mhz Wait STM32 Master clock （ The system clock ） The frequency of ,STM32 The chip is at this frequency , In the chip, various devices are synchronized

STM32 How to configure the clock on , According to the demand , The higher the clock frequency is selected , Power consumption will also be higher , Besides , Also consider the working conditions of the chip , Select the clock frequency according to the working conditions .

Clock source ：

Three different clock sources can be used to drive the system clock （SYSCLK）

HSI Oscillator clock （ High speed internal clock ）

HSE Oscillator clock （ High speed external clock ） Need external clock circuit , Or external crystal oscillator

PLL The clock （ PLL frequency doubling clock ）

Secondary clock source

40kHz Vulgar interior RC（LSI RC） oscillator

32.768kHz Low speed external crystal （LSE Crystal ）, You can give RTC Provide clock source

Clock tree

Use CumeMX Configure clock

  When setting the frequency, be careful not to exceed the maximum frequency range given in the data manual