//本文选择16M内部RC震荡。分频为1 即系统时钟为16M

void CLK_HSICmd(FunctionalState NewState)

{

    /* Check the parameters */

    assert_param(IS_FUNCTIONALSTATE_OK(NewState));

    if (NewState != DISABLE)

    {

        /* Set HSIEN bit */

        CLK->ICKR |= CLK_ICKR_HSIEN;

    }

    else

    {

        /* Reset HSIEN bit */

        CLK->ICKR &= (u8)(~CLK_ICKR_HSIEN);

    }

}

void CLK_HSIPrescalerConfig(CLK_Prescaler_TypeDef HSIPrescaler)

{

    /* check the parameters */

    assert_param(IS_CLK_HSIPRESCALER_OK(HSIPrescaler));

    /* Clear High speed internal clock prescaler */

    CLK->CKDIVR &= (u8)(~CLK_CKDIVR_HSIDIV);

    /* Set High speed internal clock prescaler */

    CLK->CKDIVR |= (u8)HSIPrescaler;

}

void CLK_Configuration(void)

{

   CLK_HSICmd(ENABLE);/* Set HSIEN bit */

  CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV1); /* Fmaster = 16MHz */

}

//初始化时，调用下面函数就可以：

CLK_Configuration();