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          專注電子技術學習與研究
          當前位置:單片機教程網 >> STM32 >> 瀏覽文章

          stm32使用內部RC晶振

          作者:佚名   來源:本站原創   點擊數:  更新時間:2014年03月28日   【字體:


          ///////////////////////////////////////////////////* Version            : V2.0////////////////////////////////////////////////////////

          #define RCC_SYSCLKSource_HSI             ((u32)0x00000000)
          /* AHB clock source */
          #define RCC_SYSCLK_Div1                  ((u32)0x00000000) // AHB 時鐘 = 系統時鐘 ;
          #define RCC_SYSCLK_Div2                  ((u32)0x00000080) // AHB 時鐘 = 系統時鐘/2 ;
          #define RCC_SYSCLK_Div4                  ((u32)0x00000090) // AHB 時鐘 = 系統時鐘/4 ;

          #define RCC_HCLK_Div4                    ((u32)0x00000500) // APBx 時鐘 = HCLK/4 ;

           
          /*******************************************************************************
          * Function Name  : RCC_Configuration
          * Description    : Configures the different system clocks.
          * Input          : None
          * Output         : None
          * Return         : None
          *******************************************************************************/
          void RCC_Configuration(void)

                 RCC_HSICmd(ENABLE);//使能內部高速晶振 ;
            RCC_SYSCLKConfig(RCC_SYSCLKSource_HSI);//選擇內部高速時鐘作為系統時鐘SYSCLOCK=8MHZ 
          RCC_HCLKConfig(RCC_SYSCLK_Div1);//選擇HCLK時鐘源為系統時鐘SYYSCLOCK
            RCC_PCLK1Config(RCC_HCLK_Div4);//APB1時鐘為2M
            RCC_PCLK2Config(RCC_HCLK_Div4);//APB2時鐘為2M
            RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB , ENABLE);//使能APB2外設GPIOB時鐘
          }

           


          /*******************************************************************************
          * Function Name  : RCC_HSICmd
          * Description    : Enables or disables the Internal High Speed oscillator (HSI).
          *                  HSI can not be stopped if it is used directly or through the
          *                  PLL as system clock.
          * Input          : - NewState: new state of the HSI.
          *                    This parameter can be: ENABLE or DISABLE.
          * Output         : None
          * Return         : None
          * 功能           : 使能或者失能內部高速晶振(HSI)
          *******************************************************************************/
          void RCC_HSICmd(FunctionalState NewState)
          {
            /* Check the parameters */
            assert_param(IS_FUNCTIONAL_STATE(NewState));

            *(vu32 *) CR_HSION_BB = (u32)NewState;
          }

          /*******************************************************************************
          * Function Name  : RCC_SYSCLKConfig
          * Description    : Configures the system clock (SYSCLK).
          * Input          : - RCC_SYSCLKSource: specifies the clock source used as system
          *                    clock. This parameter can be one of the following values:
          *                       - RCC_SYSCLKSource_HSI: HSI selected as system clock
          *                       - RCC_SYSCLKSource_HSE: HSE selected as system clock
          *                       - RCC_SYSCLKSource_PLLCLK: PLL selected as system clock
          * Output         : None
          * Return         : None
          * 功能           : 設置系統時鐘(SYSCLK);
          *******************************************************************************/
          void RCC_SYSCLKConfig(u32 RCC_SYSCLKSource)
          {
            u32 tmpreg = 0;

            /* Check the parameters */
            assert_param(IS_RCC_SYSCLK_SOURCE(RCC_SYSCLKSource));

            tmpreg = RCC->CFGR;

            /* Clear SW[1:0] bits */
            tmpreg &= CFGR_SW_Mask;

            /* Set SW[1:0] bits according to RCC_SYSCLKSource value */
            tmpreg |= RCC_SYSCLKSource;

            /* Store the new value */
            RCC->CFGR = tmpreg;
          }

          /*******************************************************************************
          * Function Name  : RCC_HCLKConfig
          * Description    : Configures the AHB clock (HCLK).
          * Input          : - RCC_SYSCLK: defines the AHB clock divider. This clock is
          *                    derived from the system clock (SYSCLK).
          *                    This parameter can be one of the following values:
          *                       - RCC_SYSCLK_Div1: AHB clock = SYSCLK
          *                       - RCC_SYSCLK_Div2: AHB clock = SYSCLK/2
          *                       - RCC_SYSCLK_Div4: AHB clock = SYSCLK/4
          *                       - RCC_SYSCLK_Div8: AHB clock = SYSCLK/8
          *                       - RCC_SYSCLK_Div16: AHB clock = SYSCLK/16
          *                       - RCC_SYSCLK_Div64: AHB clock = SYSCLK/64
          *                       - RCC_SYSCLK_Div128: AHB clock = SYSCLK/128
          *                       - RCC_SYSCLK_Div256: AHB clock = SYSCLK/256
          *                       - RCC_SYSCLK_Div512: AHB clock = SYSCLK/512
          * Output         : None
          * Return         : None
          * 功能           : 設置AHB時鐘(HCLK);
          *******************************************************************************/
          void RCC_HCLKConfig(u32 RCC_SYSCLK)
          {
            u32 tmpreg = 0;

            /* Check the parameters */
            assert_param(IS_RCC_HCLK(RCC_SYSCLK));

            tmpreg = RCC->CFGR;

            /* Clear HPRE[3:0] bits */
            tmpreg &= CFGR_HPRE_Reset_Mask;

            /* Set HPRE[3:0] bits according to RCC_SYSCLK value */
            tmpreg |= RCC_SYSCLK;

            /* Store the new value */
            RCC->CFGR = tmpreg;
          }
          /*******************************************************************************
          * Function Name  : RCC_PCLK1Config
          * Description    : Configures the Low Speed APB clock (PCLK1).
          * Input          : - RCC_HCLK: defines the APB1 clock divider. This clock is
          *                    derived from the AHB clock (HCLK).
          *                    This parameter can be one of the following values:
          *                       - RCC_HCLK_Div1: APB1 clock = HCLK
          *                       - RCC_HCLK_Div2: APB1 clock = HCLK/2
          *                       - RCC_HCLK_Div4: APB1 clock = HCLK/4
          *                       - RCC_HCLK_Div8: APB1 clock = HCLK/8
          *                       - RCC_HCLK_Div16: APB1 clock = HCLK/16
          * Output         : None
          * Return         : None
          * 功能           : 設置低速AHB時鐘(PCLK1) ;
          *******************************************************************************/
          void RCC_PCLK1Config(u32 RCC_HCLK)
          {
            u32 tmpreg = 0;

            /* Check the parameters */
            assert_param(IS_RCC_PCLK(RCC_HCLK));

            tmpreg = RCC->CFGR;

            /* Clear PPRE1[2:0] bits */
            tmpreg &= CFGR_PPRE1_Reset_Mask;

            /* Set PPRE1[2:0] bits according to RCC_HCLK value */
            tmpreg |= RCC_HCLK;

            /* Store the new value */
            RCC->CFGR = tmpreg;
          }

          /*******************************************************************************
          * Function Name  : RCC_PCLK2Config
          * Description    : Configures the High Speed APB clock (PCLK2).
          * Input          : - RCC_HCLK: defines the APB2 clock divider. This clock is
          *                    derived from the AHB clock (HCLK).
          *                    This parameter can be one of the following values:
          *                       - RCC_HCLK_Div1: APB2 clock = HCLK
          *                       - RCC_HCLK_Div2: APB2 clock = HCLK/2
          *                       - RCC_HCLK_Div4: APB2 clock = HCLK/4
          *                       - RCC_HCLK_Div8: APB2 clock = HCLK/8
          *                       - RCC_HCLK_Div16: APB2 clock = HCLK/16
          * Output         : None
          * Return         : None
          * 功能           : 設置高速AHB時鐘(PCLK2);
          *******************************************************************************/
          void RCC_PCLK2Config(u32 RCC_HCLK)
          {
            u32 tmpreg = 0;

            /* Check the parameters */
            assert_param(IS_RCC_PCLK(RCC_HCLK));

            tmpreg = RCC->CFGR;

            /* Clear PPRE2[2:0] bits */
            tmpreg &= CFGR_PPRE2_Reset_Mask;

            /* Set PPRE2[2:0] bits according to RCC_HCLK value */
            tmpreg |= RCC_HCLK << 3;

            /* Store the new value */
            RCC->CFGR = tmpreg;
          }
           /*******************************************************************************
          * Function Name  : RCC_APB2PeriphClockCmd
          * Description    : Enables or disables the High Speed APB (APB2) peripheral clock.
          * Input          : - RCC_APB2Periph: specifies the APB2 peripheral to gates its
          *                    clock.
          *                    This parameter can be any combination of the following values:
          *                       - RCC_APB2Periph_AFIO, RCC_APB2Periph_GPIOA, RCC_APB2Periph_GPIOB,
          *                         RCC_APB2Periph_GPIOC, RCC_APB2Periph_GPIOD, RCC_APB2Periph_GPIOE,
          *                         RCC_APB2Periph_GPIOF, RCC_APB2Periph_GPIOG, RCC_APB2Periph_ADC1,
          *                         RCC_APB2Periph_ADC2, RCC_APB2Periph_TIM1, RCC_APB2Periph_SPI1,
          *                         RCC_APB2Periph_TIM8, RCC_APB2Periph_USART1, RCC_APB2Periph_ADC3,
          *                         RCC_APB2Periph_ALL
          *                  - NewState: new state of the specified peripheral clock.
          *                    This parameter can be: ENABLE or DISABLE.
          * Output         : None
          * Return         : None
          * 功能           : 使能或者失能APB2外設時鐘 ;
          *******************************************************************************/
          void RCC_APB2PeriphClockCmd(u32 RCC_APB2Periph, FunctionalState NewState)
          {
            /* Check the parameters */
            assert_param(IS_RCC_APB2_PERIPH(RCC_APB2Periph));
            assert_param(IS_FUNCTIONAL_STATE(NewState));

            if (NewState != DISABLE)
            {
              RCC->APB2ENR |= RCC_APB2Periph;
            }
            else
            {
              RCC->APB2ENR &= ~RCC_APB2Periph;
            }
          }
           

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