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Project/STM32

STM32 NUCLEO-64 디지털 I/O 구현

by MachineJW 2026. 1. 8.

1. Cube MX (IO 설정)

GPIOIN/OUT용도
PA0OUTPUTLED - RED
PA1OUTPUTLED - YELLOW
PB5OUTPUT LED - GREEN
PB4OUTPUTLED - BLUE
PA4INPUTBUTTON - RED
PB6INPUT BUTTON  - YELLOW
PA6INPUT BUTTON  - GREEN
PA7INPUT BUTTON  - BLUE

2. Cube IDE (펌웨어 C 코드 작성)

/* USER CODE BEGIN Header */
/**
 ******************************************************************************
 * @file           : main.c
 * @brief          : Main program body
 ******************************************************************************
 * @attention
 *
 * Copyright (c) 2026 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"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* 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 ---------------------------------------------------------*/
UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
#define BTN_PRESSED GPIO_PIN_SET
/* 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_USART2_UART_Init();
	/* USER CODE BEGIN 2 */

	/* USER CODE END 2 */

	/* Infinite loop */
	/* USER CODE BEGIN WHILE */
	while (1) {
		/* OUTPUT */
		// PA0 : LED RED OUT
		// PA1 : LED YELLOW OUT
		// PB4 : LED BLUE OUT
		// PB5 : LED GREEN OUT
		/* INPUT */
		// PA4 : RED BTN IN
		// PB6 : YELLOW BTN IN
		// PA6 : GREEN BTN IN
		// PA7 : BLUE BTN IN
		/* USER CODE END WHILE */
		// RED
		if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_4) == BTN_PRESSED)
			HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_SET);
		else
			HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, GPIO_PIN_RESET);

		// YELLOW
		if (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6) == BTN_PRESSED)
			HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_SET);
		else
			HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, GPIO_PIN_RESET);

		// GREEN
		if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_6) == BTN_PRESSED)
			HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_SET);
		else
			HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_RESET);

		// BLUE
		if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_7) == BTN_PRESSED)
			HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, GPIO_PIN_SET);
		else
			HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, GPIO_PIN_RESET);

		HAL_Delay(10); // 간단 디바운스/CPU 점유 방지
		/* 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_HSI;
	RCC_OscInitStruct.HSIState = RCC_HSI_ON;
	RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
	RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
	RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
	RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
	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();
	}
}

/**
 * @brief USART2 Initialization Function
 * @param None
 * @retval None
 */
static void MX_USART2_UART_Init(void) {

	/* USER CODE BEGIN USART2_Init 0 */

	/* USER CODE END USART2_Init 0 */

	/* USER CODE BEGIN USART2_Init 1 */

	/* USER CODE END USART2_Init 1 */
	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();
	}
	/* USER CODE BEGIN USART2_Init 2 */

	/* USER CODE END USART2_Init 2 */

}

/**
 * @brief GPIO Initialization Function
 * @param None
 * @retval None
 */
static void MX_GPIO_Init(void) {
	GPIO_InitTypeDef GPIO_InitStruct = { 0 };
	/* USER CODE BEGIN MX_GPIO_Init_1 */

	/* USER CODE END MX_GPIO_Init_1 */

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

	/*Configure GPIO pin Output Level */
	HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0 | GPIO_PIN_1 | LD2_Pin, GPIO_PIN_RESET);

	/*Configure GPIO pin Output Level */
	HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4 | GPIO_PIN_5, GPIO_PIN_RESET);

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

	/*Configure GPIO pins : PA0 PA1 LD2_Pin */
	GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1 | LD2_Pin;
	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
	GPIO_InitStruct.Pull = GPIO_NOPULL;
	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

	/*Configure GPIO pins : PA4 PA6 PA7 */
	GPIO_InitStruct.Pin = GPIO_PIN_4 | GPIO_PIN_6 | GPIO_PIN_7;
	GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
	GPIO_InitStruct.Pull = GPIO_PULLDOWN;
	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

	/*Configure GPIO pins : PB4 PB5 */
	GPIO_InitStruct.Pin = GPIO_PIN_4 | GPIO_PIN_5;
	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
	GPIO_InitStruct.Pull = GPIO_NOPULL;
	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
	HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

	/*Configure GPIO pin : PB6 */
	GPIO_InitStruct.Pin = GPIO_PIN_6;
	GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
	GPIO_InitStruct.Pull = GPIO_PULLDOWN;
	HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

	/* EXTI interrupt init*/
	HAL_NVIC_SetPriority(EXTI15_10_IRQn, 0, 0);
	HAL_NVIC_EnableIRQ(EXTI15_10_IRQn);

	/* USER CODE BEGIN MX_GPIO_Init_2 */

	/* USER CODE END MX_GPIO_Init_2 */
}

/* 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 */

① 디지털 입력 (핀 상태 읽기)

GPIO_PinState HAL_GPIO_ReadPin(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin);

// 반환 값
// GPIO_PIN_SET = HIGH
// GPIO_PIN_RESET = LOW

② 디지털 출력

void HAL_GPIO_WritePin(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin, GPIO_PinState PinState);

// PinState:
// GPIO_PIN_SET = HIGH
// GPIO_PIN_RESET = LOW

③ 디지털 출력 (토글, 반전)

void HAL_GPIO_TogglePin(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin);

3. 플로팅 현상 발생

버튼 입력 핀에 풀업 풀다운이 되어 있지 않아 발생되는 플로팅 현상.

☞ 해결 : Cube MX에서 내부 풀 다운 설정 (3.3V 버튼 입력이므로)

  • 플로팅 현상은 입력 핀이 아무것도 연결되어 있지않아 (플로팅 현상) 인위적인 전압이 발생하는 현상임
  • 사실 하드웨어 회로에서 풀 다운 저항기를 연결해줘도 되지만 MCU 자체에 내부 풀업, 풀다운이 가능하기 때문에 Cube MX에서 조정하였다.

4. 동작 확인

☞ 버튼 1개 씩 눌렀을때

☞ 동시에 눌렀을때

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