今天在使用STM32F1芯片的USART3接口調(diào)試創(chuàng)樂博WIFI模塊時(shí)發(fā)下接收的數(shù)據(jù)全是0，檢查接線沒有問題籽御，USART3管角配置沒錯(cuò)（復(fù)用推挽輸出和浮空輸入）、WIfi波特率等參數(shù)沒錯(cuò)配置時(shí)沒有發(fā)現(xiàn)什么問題。在網(wǎng)上找了同類問題的答案榴徐，都沒能解決問題守问，于是懷疑是USART RX端口配置問題，于是將其設(shè)置為GPIO_Mode_IPU后接收正確坑资。

下面是USART正確配置后的代碼：

void usart3_init(u32 bound)
{  
    NVIC_InitTypeDef NVIC_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

    USART_DeInit(USART3);  //復(fù)位串口3
    //USART3_TX   PB10
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PB10
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復(fù)用推挽輸出
    GPIO_Init(GPIOB, &GPIO_InitStructure); //初始化PB10
    //USART3_RX   PB11
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU ;//上拉輸入(創(chuàng)樂博WIFI模塊需要設(shè)置為上拉輸入耗帕，其它的可能是下拉或浮空輸入)
    GPIO_Init(GPIOB, &GPIO_InitStructure);  //初始化PB11
            
    //設(shè)置中斷優(yōu)先級(jí)
    NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;//搶占優(yōu)先級(jí)3
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;      //子優(yōu)先級(jí)3
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;         //IRQ通道使能
    NVIC_Init(&NVIC_InitStructure); //根據(jù)指定的參數(shù)初始化VIC寄存器
    
    USART_InitStructure.USART_BaudRate = bound;//波特率一般設(shè)置為9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字長為8位數(shù)據(jù)格式
    USART_InitStructure.USART_StopBits = USART_StopBits_1;//一個(gè)停止位
    USART_InitStructure.USART_Parity = USART_Parity_No;//無奇偶校驗(yàn)位
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//無硬件數(shù)據(jù)流控制
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收發(fā)模式
    USART_Init(USART3, &USART_InitStructure); //初始化串口3
    
       USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);//開啟中斷   

    USART_Cmd(USART3, ENABLE);                    //使能串口 

    USART3_RX_STA = 0;
}

void USART3_IRQHandler(void)  {
    u8 Res;
    char i = 0;
    if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET) 
    {
        Res = USART_ReceiveData(USART3);    //讀取接收到的數(shù)據(jù)
        
        USART3_RX_BUF[USART3_RX_STA++]=Res ;

                // 串口1輸出收到的內(nèi)容
        printf("USERT3 Recv: ");
        for (i = 0; i < USART3_RX_STA; i++){
            printf(" %x[%c]", USART3_RX_BUF[i], USART3_RX_BUF[i]);
        }   
        printf("\r\n");     
     } 
}