stm32读取GY39光照强度

在STM32上读取GY39光照强度，也需要使用I2C进行通信。以下是一个使用HAL库读取GY39光照传感器数据的示例代码：

#include "main.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"

I2C_HandleTypeDef hi2c1;
UART_HandleTypeDef huart2;

#define GY39_ADDR 0x5C // GY39 I2C地址

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_I2C1_Init(void);

int main(void) {
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_USART2_UART_Init();
  MX_I2C1_Init();

  uint8_t cmd[1] = {0x01}; // 发送读取光照强度的命令
  uint8_t illuminance[2];

  while (1) {
    HAL_I2C_Master_Transmit(&hi2c1, GY39_ADDR<<1, cmd, 1, 100);
    HAL_I2C_Master_Receive(&hi2c1, GY39_ADDR<<1, illuminance, 2, 100);

    int illuminance_value = (illuminance[0] << 8) | illuminance[1]; // 拼接数据

    char buffer[50];
    sprintf(buffer, "光照强度：%d lux\r\n", illuminance_value);
    HAL_UART_Transmit(&huart2, (uint8_t*)buffer, strlen(buffer), 1000);

    HAL_Delay(1000);
  }
}

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_OscInitStruct.HSIState = RCC_HSI_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();
  }
}

static void MX_I2C1_Init(void) {
  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();
  }
}

static void MX_USART2_UART_Init(void) {
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK) {
    Error_Handler();
  }
}

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

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

代码中使用了HAL库进行I2C通信，通过发送命令和读取数据来获取GY39光照传感器的数据。注意，GY39的I2C地址为0x5C，读取光照强度的命令为0x01。最后，将读取到的光照强度数据拼接起来，单位为lux。同时，使用UART串口将数据输出到电脑上进行查看。