PWM output on PA8 (TIM1_CH1) does not reach 0V — waveform distorted

chachamaru · ‎2025-11-11

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 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"
#include "cmsis_os.h"
#include "usb_host.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 ---------------------------------------------------------*/
CRC_HandleTypeDef hcrc;

DCMI_HandleTypeDef hdcmi;

DMA2D_HandleTypeDef hdma2d;

I2C_HandleTypeDef hi2c1;

SPI_HandleTypeDef hspi5;

TIM_HandleTypeDef htim1;

UART_HandleTypeDef huart1;

SDRAM_HandleTypeDef hsdram1;

osThreadId defaultTaskHandle;
/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CRC_Init(void);
static void MX_DMA2D_Init(void);
static void MX_FMC_Init(void);
static void MX_SPI5_Init(void);
static void MX_TIM1_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_DCMI_Init(void);
static void MX_I2C1_Init(void);
void StartDefaultTask(void const * argument);

/* USER CODE BEGIN PFP */
void I2C_Scan(void);
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* 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_CRC_Init();
  MX_DMA2D_Init();
  MX_FMC_Init();
  MX_SPI5_Init();
  MX_TIM1_Init();
  MX_USART1_UART_Init();
  MX_DCMI_Init();
  MX_I2C1_Init();
  /* USER CODE BEGIN 2 */
  Start_XCLK(); //PWM開始
  I2C_Scan(); //I2C接続確認
  Read_MT9M001_ChipID(); //チップIDを読み取る
  /* USER CODE END 2 */

  /* USER CODE BEGIN RTOS_MUTEX */
  /* add mutexes, ... */
  /* USER CODE END RTOS_MUTEX */

  /* USER CODE BEGIN RTOS_SEMAPHORES */
  /* add semaphores, ... */
  /* USER CODE END RTOS_SEMAPHORES */

  /* USER CODE BEGIN RTOS_TIMERS */
  /* start timers, add new ones, ... */
  /* USER CODE END RTOS_TIMERS */

  /* USER CODE BEGIN RTOS_QUEUES */
  /* add queues, ... */
  /* USER CODE END RTOS_QUEUES */

  /* Create the thread(s) */
  /* definition and creation of defaultTask */
  osThreadDef(defaultTask, StartDefaultTask, osPriorityNormal, 0, 4096);
  defaultTaskHandle = osThreadCreate(osThread(defaultTask), NULL);

  /* USER CODE BEGIN RTOS_THREADS */
  /* add threads, ... */
  /* USER CODE END RTOS_THREADS */

  /* Start scheduler */
  osKernelStart();

  /* We should never get here as control is now taken by the scheduler */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* 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 = {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_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 8;
  RCC_OscInitStruct.PLL.PLLN = 360;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Activate the Over-Drive mode
  */
  if (HAL_PWREx_EnableOverDrive() != 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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief CRC Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_CRC_Init(void)
{

  /* USER CODE BEGIN CRC_Init 0 */

  /* USER CODE END CRC_Init 0 */

  /* USER CODE BEGIN CRC_Init 1 */

  /* USER CODE END CRC_Init 1 */
  hcrc.Instance = CRC;
  if (HAL_CRC_Init(&hcrc) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CRC_Init 2 */

  /* USER CODE END CRC_Init 2 */

}

/**
  * @brief DCMI Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_DCMI_Init(void)
{

  /* USER CODE BEGIN DCMI_Init 0 */

  /* USER CODE END DCMI_Init 0 */

  /* USER CODE BEGIN DCMI_Init 1 */

  /* USER CODE END DCMI_Init 1 */
  hdcmi.Instance = DCMI;
  hdcmi.Init.SynchroMode = DCMI_SYNCHRO_HARDWARE;
  hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_FALLING;
  hdcmi.Init.VSPolarity = DCMI_VSPOLARITY_LOW;
  hdcmi.Init.HSPolarity = DCMI_HSPOLARITY_LOW;
  hdcmi.Init.CaptureRate = DCMI_CR_ALL_FRAME;
  hdcmi.Init.ExtendedDataMode = DCMI_EXTEND_DATA_8B;
  hdcmi.Init.JPEGMode = DCMI_JPEG_DISABLE;
  if (HAL_DCMI_Init(&hdcmi) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN DCMI_Init 2 */

  /* USER CODE END DCMI_Init 2 */

}

/**
  * @brief DMA2D Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_DMA2D_Init(void)
{

  /* USER CODE BEGIN DMA2D_Init 0 */

  /* USER CODE END DMA2D_Init 0 */

  /* USER CODE BEGIN DMA2D_Init 1 */

  /* USER CODE END DMA2D_Init 1 */
  hdma2d.Instance = DMA2D;
  hdma2d.Init.Mode = DMA2D_M2M;
  hdma2d.Init.ColorMode = DMA2D_OUTPUT_ARGB8888;
  hdma2d.Init.OutputOffset = 0;
  hdma2d.LayerCfg[1].InputOffset = 0;
  hdma2d.LayerCfg[1].InputColorMode = DMA2D_INPUT_ARGB8888;
  hdma2d.LayerCfg[1].AlphaMode = DMA2D_NO_MODIF_ALPHA;
  hdma2d.LayerCfg[1].InputAlpha = 0;
  if (HAL_DMA2D_Init(&hdma2d) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DMA2D_ConfigLayer(&hdma2d, 1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN DMA2D_Init 2 */

  /* USER CODE END DMA2D_Init 2 */

}

/**
  * @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();
  }

  /** Configure Analogue filter
  */
  if (HAL_I2CEx_ConfigAnalogFilter(&hi2c1, I2C_ANALOGFILTER_ENABLE) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Digital filter
  */
  if (HAL_I2CEx_ConfigDigitalFilter(&hi2c1, 0) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN I2C1_Init 2 */

  /* USER CODE END I2C1_Init 2 */

}

/**
  * @brief SPI5 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_SPI5_Init(void)
{

  /* USER CODE BEGIN SPI5_Init 0 */

  /* USER CODE END SPI5_Init 0 */

  /* USER CODE BEGIN SPI5_Init 1 */

  /* USER CODE END SPI5_Init 1 */
  /* SPI5 parameter configuration*/
  hspi5.Instance = SPI5;
  hspi5.Init.Mode = SPI_MODE_MASTER;
  hspi5.Init.Direction = SPI_DIRECTION_2LINES;
  hspi5.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi5.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi5.Init.CLKPhase = SPI_PHASE_1EDGE;
  hspi5.Init.NSS = SPI_NSS_SOFT;
  hspi5.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;
  hspi5.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi5.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi5.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi5.Init.CRCPolynomial = 10;
  if (HAL_SPI_Init(&hspi5) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI5_Init 2 */

  /* USER CODE END SPI5_Init 2 */

}

/**
  * @brief TIM1 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_TIM1_Init(void)
{

  /* USER CODE BEGIN TIM1_Init 0 */

  /* USER CODE END TIM1_Init 0 */

  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};
  TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};

  /* USER CODE BEGIN TIM1_Init 1 */

  /* USER CODE END TIM1_Init 1 */
  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 0;
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 7;
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.RepetitionCounter = 0;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 4;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
  sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
  if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
  sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
  sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
  sBreakDeadTimeConfig.DeadTime = 0;
  sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
  sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
  sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
  if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM1_Init 2 */
  __HAL_TIM_MOE_ENABLE(&htim1);  // ★ Advanced-timerの出力許可
  /* USER CODE END TIM1_Init 2 */
  HAL_TIM_MspPostInit(&htim1);

}

/**
  * @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 */

}

/* FMC initialization function */
static void MX_FMC_Init(void)
{

  /* USER CODE BEGIN FMC_Init 0 */

  /* USER CODE END FMC_Init 0 */

  FMC_SDRAM_TimingTypeDef SdramTiming = {0};

  /* USER CODE BEGIN FMC_Init 1 */

  /* USER CODE END FMC_Init 1 */

  /** Perform the SDRAM1 memory initialization sequence
  */
  hsdram1.Instance = FMC_SDRAM_DEVICE;
  /* hsdram1.Init */
  hsdram1.Init.SDBank = FMC_SDRAM_BANK2;
  hsdram1.Init.ColumnBitsNumber = FMC_SDRAM_COLUMN_BITS_NUM_8;
  hsdram1.Init.RowBitsNumber = FMC_SDRAM_ROW_BITS_NUM_12;
  hsdram1.Init.MemoryDataWidth = FMC_SDRAM_MEM_BUS_WIDTH_16;
  hsdram1.Init.InternalBankNumber = FMC_SDRAM_INTERN_BANKS_NUM_4;
  hsdram1.Init.CASLatency = FMC_SDRAM_CAS_LATENCY_3;
  hsdram1.Init.WriteProtection = FMC_SDRAM_WRITE_PROTECTION_DISABLE;
  hsdram1.Init.SDClockPeriod = FMC_SDRAM_CLOCK_PERIOD_2;
  hsdram1.Init.ReadBurst = FMC_SDRAM_RBURST_DISABLE;
  hsdram1.Init.ReadPipeDelay = FMC_SDRAM_RPIPE_DELAY_1;
  /* SdramTiming */
  SdramTiming.LoadToActiveDelay = 2;
  SdramTiming.ExitSelfRefreshDelay = 7;
  SdramTiming.SelfRefreshTime = 4;
  SdramTiming.RowCycleDelay = 7;
  SdramTiming.WriteRecoveryTime = 3;
  SdramTiming.RPDelay = 2;
  SdramTiming.RCDDelay = 2;

  if (HAL_SDRAM_Init(&hsdram1, &SdramTiming) != HAL_OK)
  {
    Error_Handler( );
  }

  /* USER CODE BEGIN FMC_Init 2 */

  /* USER CODE END FMC_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_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOG_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, NCS_MEMS_SPI_Pin|CSX_Pin|OTG_FS_PSO_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(ACP_RST_GPIO_Port, ACP_RST_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOD, RDX_Pin|WRX_DCX_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOG, LD3_Pin|LD4_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin : ENABLE_Pin */
  GPIO_InitStruct.Pin = ENABLE_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(ENABLE_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : NCS_MEMS_SPI_Pin CSX_Pin OTG_FS_PSO_Pin */
  GPIO_InitStruct.Pin = NCS_MEMS_SPI_Pin|CSX_Pin|OTG_FS_PSO_Pin;
  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);

  /*Configure GPIO pins : B1_Pin MEMS_INT1_Pin MEMS_INT2_Pin TP_INT1_Pin */
  GPIO_InitStruct.Pin = B1_Pin|MEMS_INT1_Pin|MEMS_INT2_Pin|TP_INT1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_EVT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pins : B5_Pin R4_Pin R5_Pin */
  GPIO_InitStruct.Pin = B5_Pin|R4_Pin|R5_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pin : ACP_RST_Pin */
  GPIO_InitStruct.Pin = ACP_RST_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(ACP_RST_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : OTG_FS_OC_Pin */
  GPIO_InitStruct.Pin = OTG_FS_OC_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_EVT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(OTG_FS_OC_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : R3_Pin R6_Pin */
  GPIO_InitStruct.Pin = R3_Pin|R6_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF9_LTDC;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : BOOT1_Pin */
  GPIO_InitStruct.Pin = BOOT1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(BOOT1_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : G4_Pin G5_Pin */
  GPIO_InitStruct.Pin = G4_Pin|G5_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : TE_Pin */
  GPIO_InitStruct.Pin = TE_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(TE_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : RDX_Pin WRX_DCX_Pin */
  GPIO_InitStruct.Pin = RDX_Pin|WRX_DCX_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

  /*Configure GPIO pins : R7_Pin DOTCLK_Pin B3_Pin */
  GPIO_InitStruct.Pin = R7_Pin|DOTCLK_Pin|B3_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

  /*Configure GPIO pin : R2_Pin */
  GPIO_InitStruct.Pin = R2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(R2_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : B2_Pin */
  GPIO_InitStruct.Pin = B2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF14_LTDC;
  HAL_GPIO_Init(B2_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pins : G3_Pin B4_Pin */
  GPIO_InitStruct.Pin = G3_Pin|B4_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF9_LTDC;
  HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

  /*Configure GPIO pins : LD3_Pin LD4_Pin */
  GPIO_InitStruct.Pin = LD3_Pin|LD4_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

  /* USER CODE BEGIN MX_GPIO_Init_2 */
  // GPIO設定：PA8をTIM1_CH1として出力
  	__HAL_RCC_GPIOA_CLK_ENABLE();
  	GPIO_InitStruct.Pin = GPIO_PIN_8;
  	GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  	GPIO_InitStruct.Pull = GPIO_NOPULL;
  	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  	GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
  	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  /* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */
void Start_XCLK(void)
{
	HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1); //PWM出力開始
}

// I2C スキャナ関数
void I2C_Scan(void)
{
    char msg[64]; //文字列を一時的に格納するためのバッファ（UART通信）
    HAL_UART_Transmit(&huart1, (uint8_t*)"\r\n[I2C Scan Start]\r\n", 19, HAL_MAX_DELAY); //UART１で文字列を送信

    for (uint8_t addr = 1; addr < 128; addr++) //I²C の 7bit アドレス範囲（1～127）を総当たりでチェック
    	{
    	if (HAL_I2C_IsDeviceReady(&hi2c1, addr << 1, 1, 100) == HAL_OK) //HAL_I2C_IsDeviceReady() =指定アドレスの I²C デバイスに問い合わせて応答があるか確認する関数
    		{
    		sprintf(msg, "Found device at 7bit address 0x%02X\r\n", addr); //応答があった場合，そのアドレスをメッセージに整形，msgに入れる．
            HAL_UART_Transmit(&huart1, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY); //UART1経由で送信
            }
    	}
    HAL_UART_Transmit(&huart1, (uint8_t*)"[I2C Scan End]\r\n", 16, HAL_MAX_DELAY);
}


//Chip ID読み取り関数
void Read_MT9M001_ChipID(void)
{
	uint8_t buf[2]; //I²Cで受け取った2バイト（上位+下位）を一時保存
	uint16_t chip_id; //MSB+LSBして得られる16bitのチップID
	char msg[64]; //UARTで出力するメッセージを一時格納

	HAL_UART_Transmit(&huart1, (uint8_t*)"\r\n[Read MT9M001 CHIP ID]\r\n", 26, HAL_MAX_DELAY);

	uint8_t devAddr = 0xBA; //MT9M001の8bitアドレス：0xBA(write)

	if(HAL_I2C_Mem_Read(&hi2c1, devAddr, 0x00, I2C_MEMADD_SIZE_8BIT, buf, 2, 100) == HAL_OK)
	{
		chip_id = (buf[0] << 8) | buf[1]; //MSB→LSB
		sprintf(msg, "CHIP_VERSION = 0x%04X\r\n", chip_id);
		HAL_UART_Transmit(&huart1, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY);
	}
	else
	{
        HAL_UART_Transmit(&huart1, (uint8_t*)"I2C read error!\r\n", 17, HAL_MAX_DELAY);
	}
}

/* USER CODE END 4 */

/* USER CODE BEGIN Header_StartDefaultTask */
/**
  * @brief  Function implementing the defaultTask thread.
  * @PAram  argument: Not used
  * @retval None
  */
/* USER CODE END Header_StartDefaultTask */
void StartDefaultTask(void const * argument)
{
  /* init code for USB_HOST */
  MX_USB_HOST_Init();
  /* USER CODE BEGIN 5 */
  /* Infinite loop */
  for(;;)
  {
    osDelay(1);
  }
  /* USER CODE END 5 */
}

/**
  * @brief  Period elapsed callback in non blocking mode
  * @note   This function is called  when TIM6 interrupt took place, inside
  * HAL_TIM_IRQHandler(). It makes a direct call to HAL_IncTick() to increment
  * a global variable "uwTick" used as application time base.
  * @PAram  htim : TIM handle
  * @retval None
  */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  /* USER CODE BEGIN Callback 0 */

  /* USER CODE END Callback 0 */
  if (htim->Instance == TIM6)
  {
    HAL_IncTick();
  }
  /* USER CODE BEGIN Callback 1 */

  /* USER CODE END Callback 1 */
}

/**
  * @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 */

Hello,
I’m using the STM32F429I-Discovery board.
I’m trying to generate an external clock (XCLK, about 24 MHz) for a camera module from TIM1 CH1 (PA8), but the PWM waveform doesn’t look correct on the oscilloscope.
A square wave appears, but the voltage never drops to 0 V and the waveform is distorted.

Here are my settings and environment:

Board: STM32F429I-Discovery
IDE: STM32CubeIDE 1.19.0
Clock config: PLL = HSE (8 MHz) × 360 / 2 = 180 MHz
TIM1: Prescaler = 0, Period = 7 (≈ 22.5 MHz output)
PWM mode: PWM1, Duty = 50 %
GPIO: PA8 (AF1, Push-Pull, Very High Speed)
__HAL_TIM_MOE_ENABLE(&htim1); is called
Observation: square wave visible, but it does not go down to 0 V

Could anyone suggest possible causes or points to check?
I suspect a GPIO AF conflict or initialization order issue, but I’m not sure.

Thank you in advance for your help.

MGogr.1 · ‎2025-11-11

If it does not goes to 0v then can you please tell how much it remains??

chachamaru · ‎2025-11-11

Thank you for replying.

My PWM signal doesn’t drop to 0 V.
The oscilloscope reads: max 2.72 V, min 1.60 V, average 2.192 V.
I’ve attached the scope screenshot for reference—could you please take a look?

TDK · ‎2025-11-12

The scope plot show a square wave which has been smoothed out due to excess capacitance on the line. The line may only be this way when you have a probe attached. Some thing you can do:

Ensure pin speed is set to VERY HIGH.
Ensure scope probes are in 10x mode to reduce capacitance on line.
Is anything else connected to that pin? Disconnect it.
Measure the signal directly at the pin and using a nearby ground.

Looks like the signal is roughly 20 MHz, which the STM32 can drive without issue and much cleaner than what is shown.

If you feel a post has answered your question, please click "Accept as Solution".

Tesla DeLorean · ‎2025-11-12

PA8 has a 4K7 pull and is connected too the STMPE811QTR, across the board, and to multiple headers

Try and find a pin that's less conflicted.

Use scope probe in 10X mode, and appropriate settings.

Does it look better at lower frequencies?

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