STM32F429I - USART2怎么Rx/Tx对接也不通呢

void NVIC2_Config()

{

    NVIC_InitTypeDef NVIC_InitStructure;

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

    

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x03;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;

    NVIC_InitStructure.NVIC_IRQChannel  = USART2_IRQn;

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

        

    NVIC_Init(&NVIC_InitStructure);

}

void USART2_Gpio_Config(void)

{

    GPIO_InitTypeDef GPIO_InitStructure;

    

    RCC_AHB1PeriphClockCmd( RCC_AHB1Periph_GPIOA, ENABLE);

    

    //PA2->TX  PA3->Rx

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

    GPIO_Init(GPIOA, &GPIO_InitStructure);

    

    GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2);

    GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2);

}



void USART2_Config(void)

{

    USART2_Gpio_Config();

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);

    USART_InitTypeDef USART_InitStructure;



    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(USART2,&USART_InitStructure);   

    USART_ITConfig(USART2,USART_IT_RXNE,ENABLE);

    

    USART_Cmd(USART2,ENABLE);   

}



void USART2_IRQHandler(void)

{

    char c;

    if(USART_GetFlagStatus(USART2,USART_FLAG_RXNE)!= RESET)

    {

        c = USART_ReceiveData(USART2);

        USART_SendData(USART2,c);

    }

}



void USART2_Send(void)

{

     while(1)

    {

        USART_SendData(USART2,0x55);

        while(RESET == USART_GetFlagStatus(USART2,USART_FLAG_TC));



        USART_SendData(USART2,0xAA);

        while(RESET == USART_GetFlagStatus(USART2,USART_FLAG_TC));



        Delay_us(1000);

    }

}