system_stm32f10x.h头文件的代码

以下是 `system_stm32f10x.h` 头文件的代码：

/**
  ******************************************************************************
  * @file    system_stm32f10x.h
  * @author  MCD Application Team
  * @version V3.6.1
  * @date    22-April-2016
  * @brief   CMSIS Cortex-M3 Device Peripheral Access Layer System Header File.
  *          This file contains the system clock configuration for STM32F10x devices,
  *          and is customized for use with STM32F103 devices.
  ******************************************************************************
  * @copyright (c) 2016 STMicroelectronics
  * @author MCD
  * @brief Header for system_stm32f10x.c module
  ******************************************************************************
  */

#ifndef __SYSTEM_STM32F10X_H
#define __SYSTEM_STM32F10X_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

extern uint32_t SystemCoreClock;

/**
  * @brief  Setup the microcontroller system
  *         Initialize the Embedded Flash Interface, the PLL and update the
  *         SystemCoreClock variable.
  * @note   This function should be used only after reset.
  * @param  None
  * @retval None
  */
void SystemInit(void);

/**
  * @brief  Update SystemCoreClock variable according to Clock Register Values.
  *         The SystemCoreClock variable contains the core clock (HCLK), it can
  *         be used by the user application to setup the SysTick timer or configure
  *         other parameters.
  * @note   None
  * @param  None
  * @retval None
  */
void SystemCoreClockUpdate(void);

#ifdef __cplusplus
}
#endif

#endif /* __SYSTEM_STM32F10X_H */

该文件定义了 `SystemInit()` 和 `SystemCoreClockUpdate()` 函数，并声明了一个名为 `SystemCoreClock` 的全局变量。这些函数和变量用于设置和更新系统时钟。