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| 接收函数 uint8_t Reception_buff[RX_SIZE] attribute((aligned(4)));
 uint8_t USART_flag=0;
 void USART1_IRQHandler(void)
 {
 if(USART1 ->ISR & USART_FLAG_IDLE){
 Reception_buff[RX_SIZE-1] = USART1->RDR & 0x1ff; //读取一次数据清除标志
 USART_flag = 0xff;
 DMA1_Channel3->CCR &= (uint16_t)(~DMA_CCR_EN);
 DMA1_Channel3->CNDTR = RX_SIZE;
 DMA1_Channel3->CCR |= DMA_CCR_EN;
 }
 USART1->ICR = (uint32_t)USART_FLAG_IDLE;
 }
 发送函数
 void Scan_data(uint8_t *p,uint8_t num)
 {
 GPIOB->BRR |= GPIO_Pin_1;
 while(num--){
 while((USART1->ISR & 0x40)==0);
 USART1->TDR = *p++;
 }
 while((USART1->ISR & 0x40)==0);
 delay_ms(2);
 GPIOB->BSRR |= GPIO_Pin_1;
 }
 串口配置
 void USART1_Init(uint32_t baud)
 {
 char usart_isr;
 GPIO_InitTypeDef GPIO_InitStructure;
 USART_InitTypeDef USART_InitStructure;
 NVIC_InitTypeDef NVIC_InitStruct;
 
 USART1_DMA_Init();
 
 USART_DeInit(USART1);
 
 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB, ENABLE);  //使能GPIOA的时钟
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);//使能USART的时钟
 /* USART1的端口配置 */
 GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);        //配置PA9成第二功能引脚        TX
 GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);        //配置PA10成第二功能引脚  RX
 //485流向控制
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
 GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
 GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
 GPIO_Init(GPIOB, &GPIO_InitStructure);
 
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_Init(GPIOA, &GPIO_InitStructure);
 
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
 GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
 GPIO_Init(GPIOA, &GPIO_InitStructure);
 /* USART1的基本配置 */
 USART_InitStructure.USART_BaudRate = baud;              //波特率
 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(USART1, &USART_InitStructure);
 USART_ITConfig(USART1,USART_IT_IDLE,ENABLE); //使能空闲中断
 USART_Cmd(USART1,ENABLE);                             //使能USART1
 USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
 /* USART1的NVIC中断配置 */
 NVIC_InitStruct.NVIC_IRQChannel = USART1_IRQn;
 NVIC_InitStruct.NVIC_IRQChannelPriority = 0x0;
 NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
 NVIC_Init(&NVIC_InitStruct);
 usart_isr = USART1->ISR ;
 GPIOB->BSRR |= GPIO_Pin_1;
 }
 
 int fputc(int c, FILE stream)
 {
 / 将Printf内容发往串口 */
 GPIOB->BRR |= GPIO_Pin_1;
 USART1->TDR = (uint8_t)c;
 while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET){}
 delay_ms(1);
 GPIOB->BSRR |= GPIO_Pin_1;
 return (c);
 }
 
 extern uint8_t Reception_buff[RX_SIZE] attribute((aligned(4)));
 
 static void USART1_DMA_Init(void)
 {
 NVIC_InitTypeDef NVIC_InitStruct;
 DMA_InitTypeDef DMA_InitMode;
 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);
 
 DMA_DeInit(DMA1_Channel3);
 DMA_InitMode.DMA_BufferSize = RX_SIZE;
 DMA_InitMode.DMA_DIR = DMA_DIR_PeripheralSRC;
 DMA_InitMode.DMA_M2M = DMA_M2M_Disable;
 DMA_InitMode.DMA_MemoryBaseAddr = (uint32_t)Reception_buff;
 DMA_InitMode.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
 DMA_InitMode.DMA_Mode = DMA_Mode_Circular;
 DMA_InitMode.DMA_PeripheralBaseAddr = (uint32_t)&USART1->RDR;
 DMA_InitMode.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
 DMA_InitMode.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
 DMA_InitMode.DMA_Priority = DMA_Priority_High;
 DMA_InitMode.DMA_MemoryInc = DMA_MemoryInc_Enable;
 
 DMA_Init(DMA1_Channel3,&DMA_InitMode);
 
 DMA_Cmd(DMA1_Channel3,ENABLE);
 }
 
 屏幕截图 2024-08-24 162613.png屏幕截图 2024-08-24 162253.png
 芯片是stm32f030f4,程序运行到发送函数的GPIOB->BRR |= GPIO_Pin_1;然后会发送00。但我没给从机发数据,他自动回传的00,这是为什么。
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