STM32F103R6 and Common Anode Seven-Segment Display Interfacing STM32CubeIDE

Overview

Seven-Segment Display is a conventional electronics display device that is very easy to interface and control using any digital circuit, micro-processor parallel port or even manual setting. It's very widely used in low-end electronics control system. It's very low cost, rich in color and size. 

A 6-Inch Common Cathode Display - Front

I one 6-Inch Common Cathode 7-Segment Display left from a previous project.

A 6-Inch Common Cathode Display - Back

 

In this programming example, I will use a single common anode 7-Segment display with an STM32F103R6 controller to show a free running numbers range between 0 and F. I use the HAL_GPIO_WritePin function to process the output data.

Running Program in Proteus VSM

 

The STM32 device operate in 3.3VDC only even some of its I/O pins could withstands with +5.0VDC tolerance voltage. So to avoid I/O pins burning we have to use 3.3VDC I/O devices. Interfacing with the 7-Segment display we need to add some 330/220 Ohm resistors to cut down current and voltage since each segment forward voltage is around 2VDC. 

 

STM32CubeIDE HAL Programming 

I use Pinout and Configuration to configure the output pins. After configuring all requirements, click on save button. The HAL source code will automatically generates in C main file.

 

STM32CubeIDE IOC

 

The output pins are between PC0 and PC7. We can use other I/O pins on this MCU. However some pins have their alternative functions such as wake up, SPI, I2C, USB, etc. We need to consider this functionalities in a large project.

 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2022 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"
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
/* USER CODE BEGIN PFP */
 
const unsigned char dAnode[16]   = {0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,
		0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E};
char temp=0,gpioNum=0x0001,cnt=0;
 
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();
  /* USER CODE BEGIN WHILE */
  while (1)
  {
 
	  gpioNum=0x01;
	  temp=0x01;
	  for(int i=0;i<8;i++){
		  HAL_GPIO_WritePin(GPIOC,gpioNum,dAnode[cnt]&temp);
		  gpioNum<<=1;
		  temp<<=1;
	  }
 
	  cnt+=1;
	  if(cnt>15) cnt=0;
	  HAL_Delay(200);
  }
  /* 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 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_RESET);
 
  /*Configure GPIO pins : PC0 PC1 PC2 PC3
                           PC4 PC5 PC6 PC7 */
  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_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****/
 

 

In the STM32CubeIDE and STM32 HAL we can use direct I/O interface to send data to the output port rather than HAL function. It's fast and effective. 

Click here to download its source file.