F405为什么UART4配置好之后，PA11脚就一直是低呢？

只看该作者 · 2014-7-24 20:57

//USART2µÄIOÅäÖÃ PA0->4T PA1->4R
            RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
            RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4,ENABLE);
            GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_UART4);
            GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_UART4);
            GPIO_Init(GPIOA,&GPIO_InitStructure);//就是在这里发生的，一使用之后PA11就一直是低，无法拉高了，谁能告诉我原因啊？:'(
            GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
            GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
            GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
            GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
            GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
            GPIO_Init(GPIOA,&GPIO_InitStructure);

            GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
            GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
            GPIO_Init(GPIOA,&GPIO_InitStructure);


//USARTµÄ´®¿ÚÅäÖÃ


            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(UART4,&USART_InitStructure);
            USART_ITConfig(UART4,USART_IT_RXNE,ENABLE);
            USART_Cmd(UART4,ENABLE);
            USART_ClearFlag(UART4, USART_FLAG_TC);
//NVICÅäÖÃ
            NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
      NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;
            NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
            NVIC_InitStructure.NVIC_IRQChannelSubPriority = 4;
            NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
            NVIC_Init(&NVIC_InitStructure);

第五句一加上，引脚复用之后PA11就无法拉高了，为什么呐？