硬件I2C读取SHT20温湿度传感器数据/HAL

SHT20 Command

Hold/No Hold Master Mode

Hold Master Mode : SHT20在测量完之前会拉低SCL，暂停通信。

NoHold Master mode ：测量未完成，SHT20 只回应 NACK

*数据最后两位是状态位，计算时置0

#include "S_SHT20.h"
#include "S_IIC.h"
#include "stdio.h"
/*
*  SHT20 地址：1000 000
*  hold master 模式
*  温度：1110 0011
   湿度：1110 0101
   no hold master 模式
*  温度：1111 0011
   湿度：1111 0101
   
   写寄存器：1110 0110
   读寄存器：1110 0111
   
   软重置：1111 1110
   
   
*/

#define SHT20_address 0x80
/*SHT20 command*/
#define CMD_T_Measure_Hold      0xe3
#define CMD_RH_Measure_Hold     0xe5
#define CMD_T_Measure_noHold    0xf3
#define CMD_RH_Measure_noHold   0xf5
#define CMD_Write_userRegister  0xe6
#define CMD_Read_userRegister   0xe7
#define CMD_SoftReset           0xfe

/*温度测量函数，返回温度值*/
float SHT20_Get_Temperature(void)
{
    uint8_t cmd = CMD_T_Measure_noHold;
    uint8_t DataBuff[3] = {0};
    uint16_t DataBuff_Link = 0;
    float  SHT20_Temperature = 0;
    
    HAL_I2C_Master_Transmit(&h_I2C_1,SHT20_address,&cmd,1,100);
    HAL_Delay(100);
    HAL_I2C_Master_Receive(&h_I2C_1,SHT20_address,DataBuff,3,100);
    
    DataBuff_Link =(uint16_t)DataBuff[0];
    DataBuff_Link=DataBuff_Link<<8;
    DataBuff_Link=DataBuff_Link + (DataBuff[1] & 0xfc);

    //printf("DataBuff_Link = %d\n",DataBuff_Link);
    
    
    SHT20_Temperature = -46.85+175.72*((float)DataBuff_Link/65536);
    return SHT20_Temperature;

}
/*湿度测量函数，返回湿度值*/
float SHT20_Get_RelativeHumidity(void)
{
    uint8_t cmd = CMD_RH_Measure_noHold;
    uint8_t DataBuff[3] = {0};
    uint16_t DataBuff_Link = 0;
    float  SHT20_Humidity = 0;
    
    HAL_I2C_Master_Transmit(&h_I2C_1,SHT20_address,&cmd,1,100);
    HAL_Delay(100);
    HAL_I2C_Master_Receive(&h_I2C_1,SHT20_address,DataBuff,3,100);
    
    DataBuff_Link =(uint16_t)DataBuff[0];
    DataBuff_Link=DataBuff_Link<<8;
    DataBuff_Link= DataBuff_Link + (DataBuff[1] & 0xfc);
    

    //printf("DataBuff_Link = %d\n",DataBuff_Link);
    
    
    SHT20_Humidity = -6+125*((float)DataBuff_Link/65536);
    return SHT20_Humidity;

}
/*使用串口打印温度和湿度值*/
void SHT20_test(void )
{

    printf("Temperature = %f\n",SHT20_Get_Temperature());
    HAL_Delay(20);
    printf("Humidity = %f\n",SHT20_Get_RelativeHumidity());


}