/****************************************************************************

    * Function Name : RCC_Configuration

    * Description : Sets System clock frequency to 72MHz and configure HCLK, PCLK2

    * and PCLK1 prescalers.

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    void RCC_Configuration(void)

    {

        /* Deinitialize the RCC registers */

        RCC_DeInit();

        /* Enable the HSE */

        RCC_HSEConfig(RCC_HSE_ON);

        /* Wait till HSE is ready and if Time out is reached exit */

        HSEStartUpStatus = RCC_WaitForHSEStartUp();

        if(HSEStartUpStatus == SUCCESS)

        {

            /* Add here PLL ans system clock config */

            /* Enable The Prefetch Buffer */

            FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

            /* Configure Tthe Latency cycle: Set 0 Latency cycles */

            FLASH_SetLatency(FLASH_Latency_2);

            /* Configure HCLK such as HCLK = SYSCLK */

            RCC_HCLKConfig(RCC_SYSCLK_Div1);

            /* PCLK2 = HCLK */

            RCC_PCLK2Config(RCC_HCLK_Div1);

            /* PCLK1 = HCLK/2 */

            RCC_PCLK1Config(RCC_HCLK_Div2);

            /* ADCCLK = PCLK2/4 */

            RCC_ADCCLKConfig(RCC_PCLK2_Div4);

            /* PLLCLK = 8MHz * 9 = 72MHz */

            RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

            /* Enable PLL */

            RCC_PLLCmd(ENABLE);

            /* Wait till PLL is ready */

            while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);

            /* Select PLL as system clock source */

            RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); /* Wait till HSE is used as system clock source */

            while(RCC_GetSYSCLKSource() != 0x08)

            {

            }

        }

    }

     /****************************************************************************

    * Function Name : GPIO_Configuration

    * Description :

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    void GPIO_Configuration(void)

    {

        RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO | RCC_APB2Periph_USART1, ENABLE);

        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

        GPIO_Init(GPIOA, &GPIO_InitStructure);

        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

        GPIO_Init(GPIOA, &GPIO_InitStructure);

        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;

        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

        GPIO_Init(GPIOB, &GPIO_InitStructure);

    }

     /*******************************************************************************

    * Function Name : USART_Configure

    * Description : Configures the USART

    * Input : None

    * Output : None

    * Return : None

    *******************************************************************************/

    void USART_Configuration(void)

    {

        USART_InitStructure.USART_BaudRate = ;                            //设置波特率

        USART_InitStructure.USART_WordLength = USART_WordLength_8b;             //设置为8位

        USART_InitStructure.USART_StopBits = USART_StopBits_1;                  //停止为1位

        USART_InitStructure.USART_Parity = USART_Parity_No;                     //没有校验位

        USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;          //没有流控

        USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;         //设置RX和TX模式

        USART_Init(USART1, &USART_InitStructure);                               //初始化结构体

        USART_Cmd(USART1, ENABLE);                                              //开启串口

    }

     /*******************************************************************************

    * Function Name : DMA_Configure

    * Description : Configures the DMA

    * Input : None

    * Output : None

    * Return : None

    *******************************************************************************/

    void DMA_Configuration(void)

    {

        DMA_InitTypeDef DMA_InitStructure;                                         //定义DMA结构体

        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);                         //开启DMA的RCC

        DMA_InitStructure.DMA_PeripheralBaseAddr = APB2PERIPH_BASE + 0X3804;       //设置DMA外设基地址：串口1的地址+串口1的数据寄存器偏移量

        DMA_InitStructure.DMA_MemoryBaseAddr = (u32)SendBuff;                      //要发送的内容地址

        DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;                         //设置外设作为数据传输的目的地

        DMA_InitStructure.DMA_BufferSize = SENDBUFF_SIZE;                          //指定DMA缓存大小

        DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;           //设置外设地址寄存器不递增

        DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;                    //内存地址寄存器递增

        DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;    //数据宽度为8位

        DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;            //数据宽度为8位

        DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;                              //工作在正常缓存模式

        DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;                      //设置DMA为中优先级

        DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;                               //不设置为内存到内存传输

        DMA_Init(DMA1_Channel4, &DMA_InitStructure);                               //初始化DMA结构体

        DMA_Cmd(DMA1_Channel4, ENABLE);                                            //开启DMA

        DMA_ITConfig(DMA1_Channel4, DMA_IT_TC, ENABLE);                            //使能DMA1_Channel4作为中断通道，传输完成后中断屏蔽，使能

    }

     /****************************************************************************

    * Function Name : NVIC_Configuration

    * Description : Configures Vector Table base location.

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    void NVIC_Configuration(void)

    {

        NVIC_InitTypeDef NVIC_InitStructure;

    #ifdef VET_TAB_RAM

        /* Set the Vector Table base location at 0x2000 0000 */

        NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

    #else

        /* Set the Vector Table base location at 0x8000 0000 */

        NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

    #endif

        NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);                           //设置为组1

        NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;                  //设置DMA1_Channel4为中断源

        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;                 //优先级1

        NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;                        //子优先级1

        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                           //使能

        NVIC_Init(&NVIC_InitStructure);                                           //初始化

    }

     void DMA1_Channel4_IRQHandler(void)

    {

        if(DMA_GetFlagStatus(DMA1_FLAG_TC4) == SET)          //如果中断源是设置了

        {

            DMA_ClearFlag(DMA1_FLAG_TC4);                    //清除中断

        }

    }

     /****************************************************************************

    * Function Name : main

    * Description : Main program.

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    int main(void)

    {

        RCC_Configuration();

        NVIC_Configuration();

        GPIO_Configuration();

        USART_Configuration();

        DMA_Configuration();

        while()

        {

            GPIO_WriteBit(GPIOB, GPIO_Pin_8, (BitAction)( - GPIO_ReadOutputDataBit(GPIOB, GPIO_Pin_8)));

            fPutString("Hello World!", );

            Delay(0xffffff);

        }

    }

    /****************************************************************************

    * Function Name : fPutString

    * Description : Send a string.

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    void fPutString(u8 *buf, u8 len)

    {

        u8 i;

        for(i=;i<len;i++)

        {

            fPutChar(*buf++);

        }

    }

    /****************************************************************************

    * Function Name : fPutChar

    * Description : Send a byte

    * Input : None

    * Output : None

    * Return : None

    ****************************************************************************/

    u8 fPutChar(u8 ch)

    {

        USART_SendData(USART1, (u8) ch);

        while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)

        {

        }

        return ch;

    }

• /*******************************************************************************
• * Function Name : USART_Configure
• * Description : Configures the USART
• * Input : None
• * Output : None
• * Return : None
• *******************************************************************************/
• void USART_Configuration(void)
• {
• USART_InitStructure.USART_BaudRate = 115200;
• USART_InitStructure.USART_WordLength = USART_WordLength_8b;
• USART_InitStructure.USART_StopBits = USART_StopBits_1;
• USART_InitStructure.USART_Parity = USART_Parity_No;
• USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
• USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
• USART_Init(USART1, &USART_InitStructure);
• USART_Cmd(USART1, ENABLE);
• }