You can find a lot of relevant information on the Internet about usart serial port sending and receiving information, but most of them can only send limited characters. Some can send unlimited characters, but most of them cannot be used directly, which is not very friendly to novices. Just do the following, it’s actually very simple to achieve
1. Configure USART1, select asynchronous, and the software automatically configures the PA9 and PA10 pins.
2. Configure the clock tree, I use the default one, and then generate the code.
3. Modify the UASRT serial port program
Let me first declare:
volatile uint8_t rx_len = 0; //接收一帧数据的长度
volatile uint8_t recv_end_flag = 0; //一帧数据接收完成标志
uint8_t rx_buffer[200]={0}; //接收数据缓存
Modify static void MX_USART1_UART_Init(void) function
Just copy it directly, the code is as follows:
__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE); //使能IDLE中断
HAL_UART_Receive_DMA(&huart1,rx_buffer,BUFFER_SIZE);
3. Modify the serial port interrupt function (stm32f4xx_it.c).
void USART1_IRQHandler(void) //Serial port interrupt
{ uint32_t tmp_flag = 0; uint32_t temp;
HAL_UART_IRQHandler(&huart1);
if(USART1 == huart1.Instance)
{ tmp_flag =__HAL_UART_GET_FLAG(&huart1,UART_FLAG_IDLE); //Prepare IDLE setting
if((tmp_flag != RESET))//idle flag is set
{ recv_end_flag = 1; //Accept completion flag position 1 __HAL_UART_CLEAR_IDLEFLAG(&huart1);//Clear flag bit
HAL_UART_DMAStop(&huart1); //
temp = __HAL_DMA_GET_COUNTER(&hdma_usart1_rx); // Get the number of untransmitted data in DMA
rx_len = BUFFER_SIZE - temp; // Subtract the total count from the number of untransmitted data to get the number of received data number
HAL_UART_Receive_DMA(&huart1,rx_buffer,BUFFER_SIZE);//Re-open DMA reception
}
}
}
4. For the serial port interrupt processing function in the main function, add the following code to the main() function:
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
if(recv_end_flag ==1)
{ printf("rx_len=%d\r\n",rx_len);//Print the received length HAL_UART_Transmit(&huart1,rx_buffer, rx_len,200);// Print out the received data for(uint8_t i=0;i<rx_len;i++) { rx_buffer[i]=0;//Clear the receive buffer } rx_len=0;//Clear the count recv_end_flag=0;//Clear the receive end flag bit } HAL_UART_Receive_DMA(&huart1,rx_buffer,BUFFER_SIZE);//Re-open DMA reception
}
/* USER CODE END 3 */
