Question

stm32在keil mdk中system_stm32f10x.c这个文件是什么作用呢？跪求解释 ，一定采纳。。。文件代码如下

/**
******************************************************************************
* @file system_stm32f10x.c
* @author MCD Application Team
* @version V3.5.0
* @date 11-March-2011
* @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
*
* 1. This file provides two functions and one global variable to be called from
* user application:
* - SystemInit(): Setups the system clock (System clock source, PLL Multiplier
* factors, AHB/APBx prescalers and Flash settings).
* This function is called at startup just after reset and
* before branch to main program. This call is made inside
* the "startup_stm32f10x_xx.s" file.
*
* - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
* by the user application to setup the SysTick
* timer or configure other parameters.
*
* - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
* be called whenever the core clock is changed
* during program execution.
*
* 2. After each device reset the HSI (8 MHz) is used as system clock source.
* Then SystemInit() function is called, in "startup_stm32f10x_xx.s" file, to
* configure the system clock before to branch to main program.
*
* 3. If the system clock source selected by user fails to startup, the SystemInit()
* function will do nothing and HSI still used as system clock source. User can

Answer 1

初始化MCU，设置RCC

Answer 2

设置晶振频率啊