STM32F303 NUCLEO64开发板PWM无输出问题求助

我使用STM32F303 NUCLEO64开发板，通过CubeIDE自动生成代码，程序能正常运行（SWO可看到printf()输出持续更新）。在GPIO和TIM3初始化后添加1秒延时，再通过以下代码启动PWM：

HAL_Delay(1000);
HAL_TIMEx_PWMN_Start(&htim3, TIM_CHANNEL_3);

但PB0引脚始终没有输出PWM波形。完整代码如下：

#include "main.h"
#include "stdio.h"

TIM_HandleTypeDef htim3;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM3_Init(void);

uint8_t counter = 0;

int _write(int file, char *ptr, int len)
{
  int i=0;
  for(i=0 ; i<len ; i++)
    ITM_SendChar((*ptr++));
  return len;
}


int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_TIM3_Init();
  HAL_Delay(1000);
  HAL_TIMEx_PWMN_Start(&htim3, TIM_CHANNEL_3);
  while (1)
  {
    counter++;
    printf("counter = %d \n", counter);
    HAL_Delay(100);
  }
}


void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

  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;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  RCC_OscInitStruct.PLL.PREDIV = RCC_PREDIV_DIV1;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  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();
  }
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_TIM34;
  PeriphClkInit.Tim34ClockSelection = RCC_TIM34CLK_HCLK;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}


static void MX_TIM3_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};

  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 0;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 65535;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 26214;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
  HAL_TIM_MspPostInit(&htim3);

}


static void MX_GPIO_Init(void)
{
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

}


void Error_Handler(void)
{
  __disable_irq();
  while (1)
  {
  }
}

#ifdef  USE_FULL_ASSERT
void assert_failed(uint8_t *file, uint32_t line)
{

}
#endif

GPIO配置代码如下：

void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(htim->Instance==TIM3)
  {
    __HAL_RCC_GPIOB_CLK_ENABLE();
    GPIO_InitStruct.Pin = GPIO_PIN_0;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF2_TIM3;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
  }
}

问题原因与解决方法 #

核心问题 #

你调用的HAL_TIMEx_PWMN_Start(&htim3, TIM_CHANNEL_3)是用于启动TIM3_CH3的互补通道（CH3N），而该通道对应的引脚是PB1，并非你需要的PB0（PB0是TIM3_CH3的主通道引脚）。

修正方案 #

将启动PWM的代码替换为主通道启动函数：

HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_3);

额外验证点 #

1. 引脚映射确认：STM32F303的PB0确实是TIM3_CH3的复用功能引脚（复用功能AF2），你的GPIO配置完全正确。
2. 时钟与参数合理性：TIM3时钟来源为HCLK（72MHz），Prescaler=0，计数频率72MHz；Period=65535对应PWM周期约910µs（频率约1.1kHz），Pulse=26214对应约40%占空比，参数设置无问题。
3. 初始化流程：HAL_TIM_MspPostInit在MX_TIM3_Init末尾被正确调用，GPIO初始化流程正常。

内容的提问来源于stack exchange，提问作者Steven Wang