我用的是stm32f103zet6，利用cubeide控制pwm输出使得PB5端口的led灯的亮度从亮到暗再从暗到亮循环往复地改变，生成一个这样的代码

好的，以下是基于STM32CubeIDE的PWM输出控制代码，可以实现你所需要的功能：

#include "main.h"

/* TIM handler declaration */
TIM_HandleTypeDef htim2;

/* PWM duty cycle */
uint32_t dutyCycle = 0;
/* PWM direction */
uint8_t dir = 1;

/* TIM2 init function */
static void MX_TIM2_Init(void)
{
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};

  /* Peripheral clock enable */
  __HAL_RCC_TIM2_CLK_ENABLE();

  /* TIM2 interrupt Init */
  HAL_NVIC_SetPriority(TIM2_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(TIM2_IRQn);

  /* TIM2 configuration */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 71;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 999;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }

  /* TIM2 PWM mode configuration */
  if (HAL_TIM_PWM_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 0;
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }

  /* TIM2 interrupt enable */
  __HAL_TIM_ENABLE_IT(&htim2, TIM_IT_UPDATE);

  /* TIM2 master configuration */
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
}

/* TIM2 interrupt callback */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Instance == TIM2)
  {
    /* Update PWM duty cycle */
    if (dir == 1)
    {
      dutyCycle += 10;
      if (dutyCycle >= 1000)
      {
        dutyCycle = 1000;
        dir = 0;
      }
    }
    else
    {
      dutyCycle -= 10;
      if (dutyCycle <= 0)
      {
        dutyCycle = 0;
        dir = 1;
      }
    }
    /* Set PWM duty cycle */
    TIM_OC_InitTypeDef sConfigOC = {0};
    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = dutyCycle;
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
    {
      Error_Handler();
    }
    HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1);
  }
}

/* System Clock Configuration */
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_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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();
  }
}

/* GPIO initialization */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO clock enable */
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /* GPIO configuration */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF2_TIM2;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}

/* Main function */
int main(void)
{
  /* MCU Configuration */
  HAL_Init();

  /* System Clock Configuration */
  SystemClock_Config();

  /* GPIO initialization */
  MX_GPIO_Init();

  /* TIM2 initialization */
  MX_TIM2_Init();

  /* Start TIM2 PWM */
  HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1);

  /* Infinite loop */
  while (1)
  {
  }
}

/* Error handler */
void Error_Handler(void)
{
  while (1)
  {
  }
}

/* IRQ handler for TIM2 */
void TIM2_IRQHandler(void)
{
  HAL_TIM_IRQHandler(&htim2);
}

这个代码中使用了 TIM2 定时器的 PWM 输出功能，通过改变占空比来实现 LED 亮度的变化。在 TIM2 的定时中断回调函数中，不断更新占空比并重新配置 PWM 占空比，从而实现 LED 亮度的循环变化。

其中，TIM2 的初始化配置如下：

- 预分频器 Prescaler = 71，即定时器时钟频率为 72 MHz / (71 + 1) = 1 MHz；
- 自动重装载寄存器 ARR = 999，即定时器溢出时间为 1 ms；
- PWM 模式下占空比寄存器 CCR1 初值为 0。

你可以将以上代码复制到 CubeIDE 的 main.c 文件中，并在 CubeMX 中配置 TIM2 为 PWM 输出模式，GPIOB5 为复用输出模式，然后编译烧录到 STM32F103ZET6 开发板上，即可看到 LED 的亮度按照你所需要的方式循环变化。