在STM32F103上使用TD301D485H模块通过USB转485/422串口线与电脑通信

• TXD (TD301D485H) -> PA2 (STM32F103)
• RXD (TD301D485H) -> PA3 (STM32F103)
• CON (TD301D485H) -> PA1 (STM32F103)

由于485是半双工通信，需要在发送和接收时控制方向引脚（CON）。

• CON = 0：发送模式
• CON = 1：接收模式

参考教程：

【【工作STM32】第10集 STM32串口DMA模式与收发不定长数据 | keysking的stm32教程】 【工作STM32】第10集 STM32串口DMA模式与收发不定长数据 | keysking的stm32教程_哔哩哔哩_bilibili

rs485和教程中的串口使用时候的区别就是多了CON控制方向引脚

使用cubemx配置

代码：

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** Copyright (c) 2025 STMicroelectronics.* All rights reserved.** This software is licensed under terms that can be found in the LICENSE file* in the root directory of this software component.* If no LICENSE file comes with this software, it is provided AS-IS.********************************************************************************/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "dma.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stm32f1xx_hal.h"
#include "OLED.h"
#include "led.h"
#include "OLED_Data.h"
#include "ch452a.h"
#include "key.h"
#include "oled_show.h"
#include "input_system.h"
#include "Rotary.h"
#include "at24c32.h"
#include "soft_i2c.h"
#include "delay.h"
#include "function.h"
#include "string.h"/* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD *//* USER CODE END PTD *//* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD *//* USER CODE END PD *//* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM *//* USER CODE END PM *//* Private variables ---------------------------------------------------------*//* USER CODE BEGIN PV */
unsigned char EEDATA;uint8_t rxBuffer[50];volatile uint8_t usart2_tx_complete = 0; // 发送完成标志
/* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP *//* USER CODE END PFP *//* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */ȫ�ֱ���
//volatile uint8_t ch452_key_event = 0;//���ڲ��Ի�����
extern uint8_t OLED_DisplayBuf[64][128];// �жϻص�
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {if(GPIO_Pin == CH452_DOUT_PIN) {ch452_key_event = 1;}
}//extern DMA_HandleTypeDef hdma_usart2_rx；
extern DMA_HandleTypeDef hdma_usart2_rx;
void RS485_Send(uint8_t *data, uint16_t size) {HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_RESET); // 发送模式usart2_tx_complete = 0;HAL_UART_Transmit_DMA(&huart2, data, size); // 非阻塞发送
}void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart) {if (huart == &huart2) {HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_SET); // 发送完成后切接收模式usart2_tx_complete = 1;}
}void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) {if (huart == &huart2) {RS485_Send(rxBuffer, 3); // 回传数据HAL_UART_Receive_DMA(&huart2, rxBuffer, 3); // 重启接收}
}	void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size){if (huart == &huart2) {RS485_Send(rxBuffer, Size); // 回传数据HAL_UARTEx_ReceiveToIdle_DMA(&huart2, rxBuffer, sizeof(rxBuffer));__HAL_DMA_DISABLE_IT(&hdma_usart2_rx,DMA_IT_HT);}
}/* USER CODE END 0 *//*** @brief  The application entry point.* @retval int*/
int main(void)
{/* USER CODE BEGIN 1 *//* USER CODE END 1 *//* MCU Configuration--------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* USER CODE BEGIN Init *//* USER CODE END Init *//* Configure the system clock */SystemClock_Config();/* USER CODE BEGIN SysInit *//* USER CODE END SysInit *//* Initialize all configured peripherals */MX_GPIO_Init();MX_DMA_Init();MX_TIM4_Init();MX_USART2_UART_Init();/* USER CODE BEGIN 2 */led_init();OLED_Init();CH452_Init();Input_Init();  Encoder_Init() ;Storage_Init();char message[]="Hello World";
uint8_t test_data[] = "Hello, PC!\r\n";OLED_ShowGrayImage(epd_bitmap_simplecolor6464, 0, 0, 64, 64);//	OLED_ShowGrayImage(epd_bitmap_HWL6464, 65, 0, 64, 64);OLED_ShowGrayImage(epd_bitmap_momo6464, 129, 0, 64, 64);HAL_Delay(500);
//Buffer_DrawString(40, 0, "AAAAAA",0x0f, 16,0);Buffer_DrawString(40, 0, "DGL",0x0f, 16,1);
//Buffer_DrawTest(20, 21, 'A', 0x0f);
Buffer_DrawTest(1,1, '1', 0x0f,0);//Buffer_DrawPixel(0, 0, 0x0f);Buffer_Swap(); // ��ʾHAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_SET); // 接收模式//   HAL_UART_Receive_DMA(&huart2, rxBuffer, 3);		HAL_UARTEx_ReceiveToIdle_DMA(&huart2, rxBuffer, sizeof(rxBuffer));__HAL_DMA_DISABLE_IT(&hdma_usart2_rx,DMA_IT_HT);/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){//  HAL_UART_Receive(&huart2, rxBuffer, 3, HAL_MAX_DELAY);//    HAL_Delay(1000);//     Keyval_Scan();//         __WFI(); // �͹��ĵȴ�/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;RCC_OscInitStruct.HSIState = RCC_HSI_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks*/RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK){Error_Handler();}
}/* USER CODE BEGIN 4 */
// EXTI2�жϴ�������ʵ�֣�
void EXTI2_IRQHandler(void) {HAL_GPIO_EXTI_IRQHandler(CH452_DOUT_PIN);
}/* USER CODE END 4 *//*** @brief  This function is executed in case of error occurrence.* @retval None*/
void Error_Handler(void)
{/* USER CODE BEGIN Error_Handler_Debug *//* User can add his own implementation to report the HAL error return state */__disable_irq();while (1){}/* USER CODE END Error_Handler_Debug */
}#ifdef  USE_FULL_ASSERT
/*** @brief  Reports the name of the source file and the source line number*         where the assert_param error has occurred.* @param  file: pointer to the source file name* @param  line: assert_param error line source number* @retval None*/
void assert_failed(uint8_t *file, uint32_t line)
{/* USER CODE BEGIN 6 *//* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

结果：

波特律动 串口助手