使用STM32CubeMX HAL库驱动SHT40温湿度传感器的硬件I2C接口

STM32cubemx配置硬件IIC如图所示

 SHT40的驱动代码

#include "SHT40.h"


#include "i2c.h"

#include <rtthread.h>
#include <rtdbg.h>

#define SHT40_ADDR_WRITE    0x44<<1         //10001000
#define SHT40_ADDR_READ     (0x44<<1)+1     //10001011

#define CRC8_POLYNOMIAL 0x31

uint8_t SHT40_CheckCrc8(uint8_t* const message, uint8_t initial_value)
{
    uint8_t  remainder;     //余数
    uint8_t  i = 0, j = 0;  //循环变量

    /* 初始化 */
    remainder = initial_value;

    for(j = 0; j < 2;j++)
    {
        remainder ^= message[j];

        /* 从最高位开始依次计算  */
        for (i = 0; i < 8; i++)
        {
            if (remainder & 0x80)
            {
                remainder = (remainder << 1)^CRC8_POLYNOMIAL;
            }
            else
            {
                remainder = (remainder << 1);
            }
        }
    }

    /* 返回计算的CRC码 */
    return remainder;
}
/**
 * @brief   向SHT40发送一条指令(16bit)
 * @param   cmd —— SHT40指令（在etCommands中枚举定义）
 * @retval  成功返回HAL_OK
*/
static uint8_t  SHT40_Send_Cmd(SHT40Command cmd)
{
    uint8_t cmd_buffer = 0;
    cmd_buffer = cmd ;
    return HAL_I2C_Master_Transmit(&hi2c1, SHT40_ADDR_WRITE, (uint8_t*)&cmd_buffer, 1, 0x00FF);
}
/**
 * @brief   复位SHT40
 * @param   none
 * @retval  none
*/
void SHT40_reset(void)
{
    SHT40_Send_Cmd(SHT4X_CMD_SOFT_RESET);
//    HAL_Delay(20);
		rt_thread_mdelay(20);
}
/**
 * @brief   初始化SHT40
 * @param   none
 * @retval  成功返回HAL_OK
 * @note    周期测量模式
*/
uint8_t SHT40_Init(void)
{
    return SHT40_Send_Cmd(SHT4X_CMD_MEASURE_HPM);
}
/**
 * @brief   从SHT40读取一次数据
 * @param   dat —— 存储读取数据的地址（6个字节数组）
 * @retval  成功 —— 返回HAL_OK
*/
uint8_t SHT40_Read_Dat(uint8_t* dat)
{
    SHT40_Send_Cmd(SHT4X_CMD_MEASURE_HPM);
		rt_thread_mdelay(10);
    return HAL_I2C_Master_Receive(&hi2c1, SHT40_ADDR_READ, dat, 6, 0xFFFF);
}
/**
 * @brief   将SHT40接收的6个字节数据进行CRC校验，并转换为温度值和湿度值
 * @param   dat  —— 存储接收数据的地址（6个字节数组）
 * @retval  校验成功  —— 返回0
 *          校验失败  —— 返回1，并设置温度值和湿度值为0
*/
uint8_t SHT40_Dat_To_Float(uint8_t* const dat, float* temperature, float* humidity)
{
    uint16_t recv_temperature = 0;
    uint16_t recv_humidity = 0;

    /* 校验温度数据和湿度数据是否接收正确 */
    if(SHT40_CheckCrc8(dat, 0xFF) != dat[2] || SHT40_CheckCrc8(&dat[3], 0xFF) != dat[5])
        return 1;

    /* 转换温度数据 */
    recv_temperature = ((uint16_t)dat[0]<<8)|dat[1];
    *temperature = -45 + 175*((float)recv_temperature/65535);

    /* 转换湿度数据 */
    recv_humidity = ((uint16_t)dat[3]<<8)|dat[4];
    *humidity = -6 + 125 * ((float)recv_humidity / 65535);
		if(*humidity>=100)   //根据数据手册编写
				*humidity=100;
		else if(*humidity<=0)
				*humidity=0;
    return 0;
}

#ifndef   __SHT40_H__
#define   __SHT40_H__

#include "main.h"

// Sensor Commands
typedef enum {
		SHT4X_CMD_MEASURE_HPM = 0xFD,   //measure T & RH with high precision (high repeatability)
		SHT4X_CMD_MEASURE_MPM = 0xF6,   //measure T & RH with medium precision (medium repeatability)
		SHT4X_CMD_MEASURE_LPM = 0xE0,   //measure T & RH with lowest precision (low repeatability)
		SHT4X_CMD_READ_SERIAL = 0x89,   //read serial number
		SHT4X_CMD_SOFT_RESET  = 0x94,   //soft reset
		SHT4X_CMD_200W_1S = 0x39,       //activate heater with 200mW for 1s, including a high precision measurement just before deactivation
		SHT4X_CMD_200W_01S = 0x32,      //activate heater with 200mW for 0.1s including a high precision measurement just before deactivation
	  SHT4X_CMD_110W_1S = 0x2F,       //activate heater with 110mW for 1s including a high precision measurement just before deactivation
		SHT4X_CMD_110W_01S = 0x24,      //activate heater with 110mW for 0.1s including a high precision measurement just before deactivation
		SHT4X_CMD_20W_1S = 0x1E,        //activate heater with 20mW for 1s including a high precision measurement just before deactivation
		SHT4X_CMD_20W_01S = 0x15,       //activate heater with 20mW for 0.1s including a high precision measurement just before deactivation
}SHT40Command; 




uint8_t SHT40_CheckCrc8(uint8_t* const message, uint8_t initial_value);
	

uint8_t SHT40_Init(void);
void SHT40_reset(void);
uint8_t SHT40_Read_Dat(uint8_t* dat);
uint8_t SHT40_Dat_To_Float(uint8_t* const dat, float* temperature, float* humidity);





















#endif

注意：在读sht40的寄存器之后一定要加10几个ms的延时