Source file: /~heha/hsn/bl/cmsis4.zip/system_stm32f4xx.h

/*******************************************************************************
  * @file    system_stm32f4xx.h
  * @author  MCD Application Team
  * @brief   CMSIS Cortex-M4 Device System Source File for STM32F4xx devices.	    
  * <h2><center>&copy; COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
  *****************************************************************************/ 

#pragma once

#ifdef __cplusplus
 extern "C" {
#endif 

  /* This variable is updated in three ways:
      1) by calling CMSIS function SystemCoreClockUpdate()
      2) by calling HAL API function HAL_RCC_GetSysClockFreq()
      3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency 
	 Note: If you use this function to configure the system clock; then there
	       is no need to call the 2 first functions listed above, since SystemCoreClock
	       variable is updated automatically.
  */
extern uint32_t SystemCoreClock;	  // System Clock Frequency (Core Clock)

extern const uint8_t  AHBPrescTable[16];    // AHB prescalers table values
extern const uint8_t  APBPrescTable[8];	    // APB prescalers table values

extern void SystemInit(void);
extern void SystemCoreClockUpdate(void);

#ifdef __cplusplus
}
#endif