Настройка тактирования для BluePill (STM32F103C8)

Стандартная конфигурация тактирования STM32F103C8T6.
Подходит почти для всех случаев использования микропроцессора, включая возможность работы с USB.
Если понадобится тактировать внешние устройства, в этой конфигурации мы можем получить 8 MHz или 36 MHz на GPIOA.B8 (пин PA8)

  
    STM32F103C8
    
      15
      
        Internal high-speed clock enable
        internal 8 MHz RC oscillator OFF
      
      
        External high-speed clock enable
        HSE oscillator ON
      
      
        External high-speed clock bypass
        HSE oscillator not bypassed
      
      
        Clock security system enable
        Clock detector ON (Clock detector ON if the HSE oscillator is ready , OFF if not)
      
      
        PLL enable
        PLL ON
      
      
        System clock Switch
        PLL selected as system clock
      
      
        Set and cleared by software to control the division factor of the AHB clock
        SYSCLK not divided
      
      
        APB low-speed prescaler (APB1)
        HCLK divided by 2 
      
      
        APB high-speed prescaler (APB2)
        HCLK not divided 
      
      
        ADC prescaler
        PCLK2 divided by 2 
      
      
        PLL entry clock source
        Clock from PREDIV1 selected as the PLL input clock
      
      
        HSE divider for PLL entry
        HSE clock not divided
      
      
        PLL multiplication factor
        PLL input clock x 9
      
      
        USB prescaler
        PLL clock is divided by 1.5
      
      
        Microcontroller clock output
        HSE clock selected