一、硬件连接配置
1.1 引脚连接方案
SHT31 STM32F103C8T6 VCC3.3V GND GND SCLPB6(I2C1_SCL)SDAPB7(I2C1_SDA)ADDR 悬空（地址0x44）1.2 硬件设计要点
- 需添加4.7kΩ上拉电阻到SCL/SDA线
- 电源引脚建议添加0.1μF去耦电容
- 通信速率建议配置为400kHz
二、I2C通信协议实现
2.1 HAL库配置代码
// I2C初始化函数voidMX_I2C1_Init(void){hi2c1.Instance=I2C1;hi2c1.Init.ClockSpeed=400000;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();}}2.2 传感器指令集
#defineSHT31_ADDR0x44#defineSHT31_MEASURE_HIGH0x2400#defineSHT31_MEASURE_LOW0x2400#defineSHT31_READ0xE000#defineSHT31_SOFT_RESET0x30A2// 发送命令函数HAL_StatusTypeDefSHT31_SendCommand(uint16_tcmd){uint8_ttx_data[2]={cmd>>8,cmd&0xFF};returnHAL_I2C_Master_Transmit(&hi2c1,SHT31_ADDR<<1,tx_data,2,100);}三、数据采集与处理
3.1 测量流程实现
floattemperature;floathumidity;voidSHT31_Read_Data(){uint8_trx_data[6]={0};// 发送测量命令SHT31_SendCommand(SHT31_MEASURE_HIGH);HAL_Delay(20);// 等待测量完成// 读取数据HAL_I2C_Master_Receive(&hi2c1,SHT31_ADDR<<1,rx_data,6,100);// CRC校验if(CRC8_Check(rx_data,2)!=rx_data[2]||CRC8_Check(rx_data+3,2)!=rx_data[5]){Error_Handler();// 数据校验失败}// 数据转换uint16_traw_temp=(rx_data[0]<<8)|rx_data[1];uint16_traw_humi=(rx_data[3]<<8)|rx_data[4];temperature=-45+175*(float)raw_temp/65535.0;humidity=100*(float)raw_humi/65535.0;}3.2 CRC校验算法
uint8_tCRC8_Check(uint8_t*data,uint8_tlen){constuint8_tpolynomial=0x31;uint8_tcrc=0xFF;for(uint8_ti=0;i<len;i++){crc^=data[i];for(uint8_tj=0;j<8;j++){if(crc&0x80)crc=(crc<<1)^polynomial;elsecrc<<=1;}}returncrc;}四、完整工程框架
4.1 主程序流程
intmain(void){HAL_Init();SystemClock_Config();MX_I2C1_Init();while(1){SHT31_Read_Data();// 显示数据（通过USART或LCD）printf("T:%.2fC H:%.2fRH\r\n",temperature,humidity);HAL_Delay(1000);}}4.2 系统初始化
voidSystemClock_Config(void){RCC_OscInitTypeDef RCC_OscInitStruct={0};RCC_ClkInitTypeDef RCC_ClkInitStruct={0};RCC_OscInitStruct.OscillatorType=RCC_OSCILLATORTYPE_HSI;RCC_OscInitStruct.HSIState=RCC_HSI_ON;RCC_OscInitStruct.PLL.PLLState=RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource=RCC_PLLSOURCE_HSI;RCC_OscInitStruct.PLL.PLLMUL=RCC_PLL_MUL12;HAL_RCC_OscConfig(&RCC_OscInitStruct);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;HAL_RCC_ClockConfig(&RCC_ClkInitStruct,FLASH_LATENCY_1);}参考代码 STM32+SHT31温湿度传感器程序www.3dddown.com/csa/56446.html
五、完整代码结构
// main.c#include"main.h"#include"sht31.h"floattemperature,humidity;intmain(void){HAL_Init();SystemClock_Config();MX_I2C1_Init();MX_USART1_UART_Init();while(1){SHT31_Read_Data();Data_Filter();Check_Alert();printf("T:%.1fC H:%.1fRH\r\n",temperature,humidity);Save_Data();HAL_Delay(1000);}}六、注意事项
- 电源稳定性：建议使用LDO稳压芯片提供3.3V电源
- PCB布局：SCL/SDA走线长度应小于20mm，避免直角转弯
- 固件升级：可通过SWD接口更新CRC校验算法版本
- 环境干扰：在工业现场建议添加金属屏蔽罩
