Internal RTC - Based segment Clock

A simple clock made by using an STM32F446RE and a 7-segment display.

IntermediateProtip4 hours1,642

Things used in this project

Hardware components

SparkFun 7-Segment Serial Display - Red

STMicroelectronics STM32 Nucleo-64 Board

Software apps and online services

Arm Keil microvision

STMicroelectronics STM32 QubeMx

Story

STM32

The STM32 family of 32-bit microcontrollers based on the Arm Cortex-M processor is designed to offer new degrees of freedom to MCU users. It offers products combining very high performance, real-time capabilities, digital signal processing, and low-power and low-voltage operation, and connectivity, while maintaining full integration and ease of development.

I chose the STM32 because of some reasons below:

1. Latest ARM microcontrollers

2. Industrial grade

3. High hardware configurations

Schematic Diagram:

Schematic Diagram

Nucleo Board connection

Internal RTC

A real-time clock (RTC) is a computer clock that keeps track of the current time. Although the RTCs are often used in personal computers, servers and embedded systems, they are also present in almost any electronic device that requires an accurate time keeping. The microcontrollers supporting the RTC can be used for chronometers, alarm clocks, watches, small electronic agendas, and many other devices.

Video

It's a very simple 7-segment clock Demo Video

Working Demo

Code

Source code

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stm32f4xx_hal.h"

#define mypins GPIO_PIN_4|GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_11|GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_10|GPIO_PIN_12|GPIO_PIN_5|GPIO_PIN_6;
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private variables ---------------------------------------------------------*/
RTC_HandleTypeDef hrtc;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_RTC_Init(void);



char aRxBuffer[] = "";
/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  *
  * @retval None
  */
int main(void)
{
  HAL_Init();



  /* Configure the system clock */
  SystemClock_Config();

  

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART2_UART_Init();
  MX_RTC_Init();

RTC_TimeTypeDef gtime;
char data[] = "data";
	int s;
	
HAL_UART_Transmit(&huart2,(uint8_t*)data,sizeof(data),1000);
		HAL_Delay(1000);
  uint16_t numbers[] = {5135,6,1067,47,4134,4141,5165,7,5167,4143};
  while (1)
  {
		for(int count = 0;count<125;count++){
	HAL_RTC_GetTime(&hrtc,&gtime,FORMAT_BIN);
		//sprintf(data,"%d%d%d dates",gtime.Hours,gtime.Minutes,gtime.Seconds);
	//HAL_UART_Transmit(&huart2,(uint8_t*)data,sizeof(data),10000);
		//HAL_UART_Transmit(&huart2,(uint8_t*)"\r\n",2,1000);
		s = gtime.Hours/10;
		GPIOC ->ODR = 0x0000;
		GPIOC ->ODR = ~((numbers[s])<<0)|1<<4;
		GPIOC ->ODR &= ~(1<<8|1<<9|1<<11);
		HAL_Delay(1);
	s = gtime.Hours%10;
		GPIOC ->ODR = 0x0000;
		GPIOC ->ODR = ~((numbers[s]+64)<<0)|1<<8;
		GPIOC ->ODR &= ~(1<<4|1<<9|1<<11);
		HAL_Delay(1);
			
	 s = gtime.Minutes/10;
		GPIOC ->ODR = 0x0000;
		GPIOC ->ODR = ~((numbers[s])<<0)|1<<9;
		GPIOC ->ODR &= ~(1<<8|1<<4|1<<11);
		HAL_Delay(1);
	s = gtime.Minutes%10;
		GPIOC ->ODR = 0x0000;
		GPIOC ->ODR = ~((numbers[s])<<0)|1<<11;
		GPIOC ->ODR &= ~(1<<4|1<<9|1<<8);
		HAL_Delay(1);
	 
	}
		GPIOC ->ODR = 0x0000;
		HAL_Delay(999);
		
		//GPIOC ->BSRR = ~(numbers[h]<<0);
		//GPIOC ->BSRR = ~(numbers[h]<<0);
		//GPIOC ->BSRR = ~(numbers[h]<<0);
		
		//HAL_Delay(1000);
		
  /* 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;
  RCC_ClkInitTypeDef RCC_ClkInitStruct;
  RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;

    /**Configure the main internal regulator output voltage 
    */
  __HAL_RCC_PWR_CLK_ENABLE();

  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);

    /**Initializes the CPU, AHB and APB busses clocks 
    */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI;
  RCC_OscInitStruct.LSEState = RCC_LSE_ON;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = 16;
  RCC_OscInitStruct.LSIState = RCC_LSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLM = 16;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  RCC_OscInitStruct.PLL.PLLR = 2;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**Initializes the CPU, AHB and APB busses 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(__FILE__, __LINE__);
  }

  PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;
  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**Configure the Systick interrupt time 
    */
  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

    /**Configure the Systick 
    */
  HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

  /* SysTick_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}

/* RTC init function */
static void MX_RTC_Init(void)
{

    /**Initialize RTC Only 
    */
	RTC_TimeTypeDef stime;
  hrtc.Instance = RTC;
  hrtc.Init.HourFormat = RTC_HOURFORMAT_12;
  hrtc.Init.AsynchPrediv = 127;
  hrtc.Init.SynchPrediv = 255;
  hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
  hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
  hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
	stime.Hours = 0x06;
	stime.Minutes = 0x20;
	stime.Seconds= 0x50;
	
  if (HAL_RTC_Init(&hrtc) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
	HAL_RTC_SetTime(&hrtc,&stime,RTC_FORMAT_BIN);
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR1,0x32F2);
}

/* USART2 init function */
static void MX_USART2_UART_Init(void)
{

  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

}

/** Configure pins as 
        * Analog 
        * Input 
        * Output
        * EVENT_OUT
        * EXTI
*/
static void MX_GPIO_Init(void)
{

  GPIO_InitTypeDef GPIO_InitStruct;

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  //HAL_GPIO_WritePin(LD2_GPIO_Port, LD2_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin : B1_Pin */
 /* GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);
	

  
  GPIO_InitStruct.Pin = LD2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LD2_GPIO_Port, &GPIO_InitStruct);
	*/
	GPIO_InitStruct.Pin = mypins;
  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);

}




void _Error_Handler(char *file, int line)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  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,
     tex: 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****/