STM32F103R6 UART1 And Character LCD Example

UART can be interfaced with some module such as GSM, Bluetooth, Nextion display, GPS module, etc. Communicating with a PC via an RS-232 interface or a USB to UART converter module is common.

In this example, I will use a UART terminal to input ASCII characters that will send to the STM32F103R6 micro-controller. Those characters will display on a 20x4 LCD.

Simulating Program

In the Code Configuration Tool, please set the following parameters.

GPIO Settings

On SYS tab select Serial Wire as Debug interface if you wish to use the ST-Link.

Debug Tool Selection

On USART1 tab select Asynchronous Mode to get UART.

UART Settings

Source code is very easy to write with the aid of code configuration tool in the STM32CubeIDE. LCD library is already written in previous post. 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "lcd4bits.h"
 
/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart1;
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);
 
/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART1_UART_Init();
 
  HAL_UART_Transmit(&huart1,"STM32F103R6 LCD And UART1 Example\r\n",35,100);
  lcdInit();
  lcdClear();
 
  lcdXY(2,1);
  lcdStr("STM32F103R6 HUART1");
 
  lcdXY(2,2);
  lcdStr("And Character LCD");
 
  lcdXY(2,3);
  lcdStr("Programming Example");
 
  lcdXY(5,4);
  lcdStr("STM32CubeIDE");
 
  HAL_Delay(2000);
  lcdClear();
  uint8_t rcvData=0,charNum=1,lineNum=1;
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
	  HAL_UART_Receive(&huart1,&rcvData,1,100);
 
	  if(rcvData!=0){
		    HAL_UART_Transmit(&huart1,&rcvData,1,100);
	      	if(rcvData==0x0D){
	      		if(lineNum<4) lineNum++;
	      		else { lcdClear(); lineNum=1;}
	      		charNum=1;
	      		lcdXY(charNum,lineNum);
	      	}else if(lineNum<=4&&charNum<=20){
	      		if(rcvData==0x08){
 
	      			if(charNum>0) charNum-=1;
	      			lcdXY(charNum,lineNum);
	      			lcdDat(' ');
	      			lcdXY(charNum,lineNum);
	      		}else{
	      			lcdDat(rcvData);
	      			charNum++;
	      		}
	      	}
 
	      	if(charNum>20&&lineNum<4){
	      		charNum=1;
	      	    lineNum++;
 
 
	      	    lcdXY(charNum,lineNum);
	      	}
	      	rcvData=0;
	  }
  }
  /* 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_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  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_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}
 
/**
  * @brief USART1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART1_UART_Init(void)
{
 
  /* USER CODE BEGIN USART1_Init 0 */
 
  /* USER CODE END USART1_Init 0 */
 
  /* USER CODE BEGIN USART1_Init 1 */
 
  /* USER CODE END USART1_Init 1 */
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART1_Init 2 */
 
  /* USER CODE END USART1_Init 2 */
 
}
 
/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
 
  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
                          |GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7
                          |GPIO_PIN_8, GPIO_PIN_RESET);
 
  /*Configure GPIO pins : PC0 PC1 PC2 PC3
                           PC4 PC5 PC6 PC7
                           PC8 */
  GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
                          |GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7
                          |GPIO_PIN_8;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
 
}
 
/* USER CODE BEGIN 4 */
 
/* 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 */
 
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
 

For more information about USART1 and 4-bit LCD Interfacing please see my previous posts. Click here to download its source file.