基于HAL库，写一段STM32G030芯片的低功耗STOP模式的例程

好的，以下是基于HAL库的STM32G030芯片低功耗STOP模式的例程：

/* Includes --------------------------------------------------------------*/
#include "main.h"
#include "stm32g0xx_hal.h"

/* Private function prototypes --------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);

/* Private user code -------------------------------------------------------*/
void EnterStopMode(void)
{
  // 关闭所有外设时钟
  HAL_RCC_DeInit();

  // 配置唤醒源为PA0引脚上的外部中断
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  // 配置外部中断
  HAL_NVIC_SetPriority(EXTI0_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI0_IRQn);

  // 进入低功耗STOP模式
  HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
}

/* External interrupt callback function */
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
  // 禁用外部中断
  HAL_NVIC_DisableIRQ(EXTI0_IRQn);

  // 停止进入低功耗STOP模式
  HAL_PWR_DisableSleepOnExit();
}

/* System initialization function */
int main(void)
{
  // 初始化HAL库
  HAL_Init();

  // 初始化系统时钟
  SystemClock_Config();

  // 初始化GPIO
  MX_GPIO_Init();

  // 进入低功耗STOP模式
  EnterStopMode();

  while (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_HSI|RCC_OSCILLATORTYPE_HSI48;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSI48State = RCC_HSI48_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();
  }
}

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

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /* Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);

  /* Configure GPIO pin : PA0 */
  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* Configure GPIO pin : PA5 */
  GPIO_InitStruct.Pin = 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(GPIOA, &GPIO_InitStruct);
}

该例程的作用是进入低功耗STOP模式，并在PA0引脚上等待外部中断唤醒，同时PA5引脚会输出一个低电平以表示STM32芯片已经进入低功耗STOP模式。当PA0引脚上出现下降沿时，外部中断会触发，程序会退出低功耗STOP模式并停止PA5引脚的输出。