I2C 통신을 이용한 DAC 제어

HAL 함수를 통해 쉽게 I2C 통신을 할 수 있다.

나의 경우, 이상할 정도로 I2C를 쓰는 일은 없었다, 대부분 SPI나 UART...

작은 사이즈의 OLED 디스플레이나 EEPROM 정도로 기억한다.

인터넷을 찾아보면 대다수가 AT24C02 같은 메모리 예제가 많을 것이다.

 

오늘은 TI사의 8bit DAC IC인 DAC5571를 구동하는 예제를 작성해본다.

 

 

CubeIDE를 실행시키고 I2C1를 선택하면 다음과 같은 Configuration이 나타난다.

-Master Fearues는 MCU가 마스터 역할일 때의 설정.

-Slave Features는 MCU가 슬레이브 역할 일 때의 설정.

 

DAC5571의 데이터 시트를 확인 한뒤, 기본 설정인 Standard Mode로 선택했다.

그 이상 사실 I2C는 크게 세팅할 것은 없다.

 

 

DAC5571는 컨트롤 바이트가 16bit를 2개로 나눠서 받는다는 특징이 있다.

(데이터 시트 참조)

그래서 I2C Transmit을 할때 slave address를 제외하고 Ctrl데이터를 잘라서 버퍼에 담아 2bytes로 보낸다.

아래는 예제에 담긴 동작 코드.

void SetDacValue_8bit (uint8_t DacValue)
{
   //DacValue 범위: 0~255 -> 0V~5V

   DAC_MSByte = (DacValue & 0xf0) >> 4;
   DAC_LSByte = (DacValue & 0x0f) << 4;  
   DAC_TransmitBuffer[0] = DAC_MSByte;
   DAC_TransmitBuffer[1] = DAC_LSByte;

   HAL_I2C_Master_Transmit(&hi2c1, 0x98, &DAC_TransmitBuffer[0], 2, 100);
}

 

참고로 괜히 핀 설정에서 내부 Pull-up 했다고 풀업저항 달지 않는 바보같은 행위는 하지말자.

혹시나 했는데 역시 신호가 이상해서 저항 1Kohm 물렸다.

 

위 함수를 만들어서 10ms마다 비트 값을 올려 0~5V 전압이 반복 출력되도록 동작하였다.

스코프 상에서도 무리없이 잘 출력된다.

 

 

 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2021 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 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 ---------------------------------------------------------*/
I2C_HandleTypeDef hi2c1;
 
/* USER CODE BEGIN PV */
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_I2C1_Init(void);
/* USER CODE BEGIN PFP */
void SetDacValue_8bit (uint8_t DacValue);
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint8_t DAC_TransmitBuffer[2] = {0x00, 0x00};
uint8_t DAC_MSByte = 0x00;
uint8_t DAC_LSByte = 0x00;
uint8_t DACval = 0x00;
/* 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_I2C1_Init();
  /* USER CODE BEGIN 2 */
 
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
    SetDacValue_8bit(DACval);
    DACval++;
 
    HAL_Delay(10);
 
  }
  /* USER CODE END 3 */
}
 
/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
 
  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
  /** 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 I2C1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_I2C1_Init(void)
{
 
  /* USER CODE BEGIN I2C1_Init 0 */
 
  /* USER CODE END I2C1_Init 0 */
 
  /* USER CODE BEGIN I2C1_Init 1 */
 
  /* USER CODE END I2C1_Init 1 */
  hi2c1.Instance = I2C1;
  hi2c1.Init.ClockSpeed = 100000;
  hi2c1.Init.DutyCycle = I2C_DUTYCYCLE_2;
  hi2c1.Init.OwnAddress1 = 0;
  hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c1.Init.OwnAddress2 = 0;
  hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  if (HAL_I2C_Init(&hi2c1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN I2C1_Init 2 */
 
  /* USER CODE END I2C1_Init 2 */
 
}
 
/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
 
}
 
/* USER CODE BEGIN 4 */
void SetDacValue_8bit (uint8_t DacValue)
{
    //DacValue 범위: 0~255 -> 0V~5V
 
    DAC_MSByte = (DacValue & 0xf0) >> 4;
    DAC_LSByte = (DacValue & 0x0f) << 4;
    DAC_TransmitBuffer[0] = DAC_MSByte;
    DAC_TransmitBuffer[1] = DAC_LSByte;
 
    HAL_I2C_Master_Transmit(&hi2c1, 0x98, &DAC_TransmitBuffer[0], 2, 100);
}
 
/* 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****/