帮我写一份基于STM32的例程，并且包含进入睡眠模式

以下是基于STM32的FXAS21002例程，包含了进入低功耗睡眠模式：

#include "stm32f4xx.h"
#include "stm32f4xx_hal.h"
#include <stdio.h>
#include "FXAS21002C.h"

FXAS21002C gyro;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI1_Init(void);

int main(void) {
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_SPI1_Init();

  if (!gyro.begin()) { // 初始化传感器
    printf("Could not find a valid FXAS21002C sensor, check wiring!\n");
    while (1);
  }

  gyro.setRange(FXAS21002_RANGE_250DPS); // 设置测量范围

  while (1) {
    sensors_event_t event;
    gyro.getEvent(&event); // 读取传感器数据

    printf("X: %f dps\tY: %f dps\tZ: %f dps\n", event.gyro.x, event.gyro.y, event.gyro.z);

    HAL_Delay(1000); // 等待一段时间后再次读取数据

    // 进入低功耗睡眠模式
    HAL_PWR_EnterSLEEPMode(PWR_MAINREGULATOR_ON, PWR_SLEEPENTRY_WFI);
  }
}

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

  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  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 = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK) {
    Error_Handler();
  }
}

static void MX_SPI1_Init(void) {
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* SPI1 clock enable */
  __HAL_RCC_SPI1_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /**SPI1 GPIO Configuration
  PA5     ------> SPI1_SCK
  PA6     ------> SPI1_MISO
  PA7     ------> SPI1_MOSI
  */
  GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

static void MX_GPIO_Init(void) {
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  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);
}

在main函数中，初始化传感器并设置测量范围，然后在一个无限循环中读取传感器数据并输出到串口。每次读取数据后，调用HAL_Delay函数等待一段时间后再次读取数据。当微控制器进入循环时，它将进入低功耗睡眠模式。当传感器数据准备好时，微控制器将自动唤醒并继续执行代码。