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/ ************************************************* ****************************** 
* Function name: USART1_Init 
* Function function: USART1 initialization function 
* Input: bound: Baud rate 
* Output: None 
************************************************ ********************************* / 
void USART1_Init (u32 bound) 
{ 
   // GPIO port setting 
    GPIO_InitTypeDef GPIO_InitStructure; 
    USART_InitTypeDef USART_InitStructure; 
    NVIC_InitTypeDef NVIC_InitStructure; 
    
    RCC_AHB1PeriphClockCmd (RCC_AHB1Periph_GPIOA, ENABLE); // Enable GPIOA clock 
    RCC_APB2PeriphClockCmd (RCC_APB2Periph_USART1, ENABLE);
  
    /
    GPIO_PinAFConfig (GPIOA, GPIO_PinSource9, GPIO_AF_USART1); // GPIOA9 is multiplexed as USART1 
    GPIO_PinAFConfig (GPIOA, GPIO_PinSource10, GPIO_AF_USART1); // GPIOA10 is multiplexed as USART1 
    
    // USART1 port configuration 
    GPIO_InitStructure9GPIO_GP_IO_GP_IO_GP_IO 
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; // Multiplexing function 
    GPIO_InitStructure.GPIO_Speed ​​= GPIO_Speed_50MHz; // Speed ​​50MHz 
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; // Push-pull multiplexing output 
    GPIO_InitStructure.GPIO_PuPd = GPIO_Pu = dp_upp = 
    GPIO_Init (GPIOA, & GPIO_InitStructure); // initialize PA9, PA10 
    

   // the USART1 Initialize settings
    USART_InitStructure.USART_BaudRate = bound; // Baud rate setting 
    USART_InitStructure.USART_WordLength = USART_WordLength_8b; // Word length is 8-bit data format 
    USART_InitStructure.USART_StopBits = USART_StopBits_1; // One stop bit 
    USART_InitParity. Bit 
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; // No hardware data flow control 
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; // Transmit and receive mode 
    USART_Init (USART1, & USART_InitStructure); // 
    
    Enable serial port 1 USART_USART_1 1
    
    
    USART_ClearFlag (USART1, USART_FLAG_TC); 
        
    USART_ITConfig (USART1, USART_IT_RXNE, ENABLE); // Turn on related interrupts 

    // Usart1 NVIC configuration 
    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; // Serial port 1 interrupt channel 
    priority NVIC_InitStructure3Preemption3VPreemption3 
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; // 
    Subpriority 3 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; // IRQ channel enable 
    NVIC_Init (& NVIC_InitStructure); // Initialize the VIC register according to the specified parameters,     

}