在写PA9(TX),PA10作为USART1串口程序时。上位机发送一个字符,stm32接收到后,还回去一个字符。现在遇到如下问题,如图:
主程序如下:
void RCC_Configuration(void) //RC初始化
{
SystemInit();
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE); //打开管脚复用时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);//打开A组端口时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);//打开USART1时钟
}
GPIO_Configuration_GPIOA_GPIO_Pin_9(void) //PA_9 TX
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA,&GPIO_InitStructure);
}
GPIO_Configuration_GPIOA_GPIO_Pin_10(void) //PA_10 RX
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA,&GPIO_InitStructure);
}
void USART1_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
USART_InitStructure.USART_BaudRate = 9600; //波特率9600
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_Tx|USART_Mode_Rx;
USART_Init(USART1,&USART_InitStructure);
USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
USART_Cmd(USART1,ENABLE);
USART_ClearFlag(USART1,USART_FLAG_TC);
}
void NVIC_Configuration_USART1_IRQn(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
int main(void)
{
RCC_Configuration();
GPIO_Configuration_GPIOA_GPIO_Pin_9();
GPIO_Configuration_GPIOA_GPIO_Pin_10();
USART1_Configuration();
NVIC_Configuration_USART1_IRQn();
while(1);
}
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