STM32F103中USART2的使用

USART1程序很多，看看USART2程序。注意红色部分，首先要使能相关端口的时钟。

因为USART2可以映射成不同的端口，所以要端口映射。

结合你自己的开发板，设置正确的映射口.(正点原子的是PA03PA02.)

STM32F103ZE默认的USART2就是PA03PA02，如果配置映射，USART2端口是PD05PD06了。

程序在正点原子开发板SRAM中调试通过，开发环境IAR5.30.

void USART2_Initialise( u32 bound )

{

    GPIO_InitTypeDef GPIO_InitStructure;//I/O¿ú3õê¼»ˉ½á11ìå

    NVIC_InitTypeDef NVIC_InitStructure;//ÖD¶Ï3õê¼»ˉ½á11ìå

    USART_InitTypeDef USART_InitStructure;//′®¿ú3õê¼»ˉ½á11ìå  

    /* Enable the USART2 Pins Software Remapping */

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE); 

    /* Configure USART2 Rx (PA.03) as input floating */

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;    

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* Configure USART2 Tx (PA.02) as alternate function push-pull */

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* Enable the USART2 Interrupt */

    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStructure);    

    USART_InitStructure.USART_BaudRate = bound;                //ò»°ãéèÖÃÎa9600;

    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö3¤Îa8λêy¾Y¸ñê½

    USART_InitStructure.USART_StopBits = USART_StopBits_1;     //ò»¸öí￡Ö1λ

    USART_InitStructure.USART_Parity = USART_Parity_No;        //ÎTÆæżD￡Ñéλ

    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//Yá÷¿ØÖÆ

    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//êÕ·￠Ä￡ê½   

    USART_Init(USART2, &USART_InitStructure);

    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    //USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

    /* Enable USART2 */

    USART_Cmd(USART2, ENABLE);

}

void USART2_IRQHandler(void)  

{  

     if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET)  

      {       

              USART_SendData(USART2, USART_ReceiveData(USART2));             

      }

}

该程序功能是返回你发送到串口的数据。

如果你的USART2接到PD端口上面了，要修改程序如下，这里就需要端口映射了，映射寄存器是AFIO控制的，它接在APB2时钟区域，所以下面的红色代码必须要有，蓝色代码对端口进行初始化。

void USART2_Initialise( u32 bound )

{

    GPIO_InitTypeDef GPIO_InitStructure;//I/O¿ú3õê¼»ˉ½á11ìå

    NVIC_InitTypeDef NVIC_InitStructure;//ÖD¶Ï3õê¼»ˉ½á11ìå

    USART_InitTypeDef USART_InitStructure;//′®¿ú3õê¼»ˉ½á11ìå  

    /* Enable the USART2 Pins Software Remapping */

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD ,ENABLE);

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);    

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

    GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE);    

    /* Configure USART2 Rx (PD.06) as input floating */

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;    

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

    GPIO_Init(GPIOD, &GPIO_InitStructure);

    /* Configure USART2 Tx (PD.05) as alternate function push-pull */

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

    GPIO_Init(GPIOD, &GPIO_InitStructure);

    /* Enable the USART2 Interrupt */

    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStructure);    

    USART_InitStructure.USART_BaudRate = bound;//ò»°ãéèÖÃÎa9600;

    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö3¤Îa8λêy¾Y¸ñê½

    USART_InitStructure.USART_StopBits = USART_StopBits_1;//ò»¸öí￡Ö1λ

    USART_InitStructure.USART_Parity = USART_Parity_No;//ÎTÆæżD￡Ñéλ

    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//¾Yá÷¿ØÖÆ

    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//êÕ·￠Ä￡ê½   

    USART_Init(USART2, &USART_InitStructure);

    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    //USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

    /* Enable USART2 */

    USART_Cmd(USART2, ENABLE);

}

void USART2_IRQHandler(void)  

{  

     if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET)  

      {       

              USART_SendData(USART2, USART_ReceiveData(USART2));             

      }

}