51单片机驱动sht20代码

以下是51单片机驱动SHT20温湿度传感器的基本代码：

#include<reg52.h>

sbit SHT20_SCL=P3^6;
sbit SHT20_SDA=P3^7;

void delay_us(unsigned int t)
{
    while(t--);
}

void delay_ms(unsigned int t)
{
    while(t--)
    {
        delay_us(1000);
    }
}

void IIC_Start(void)
{
    SHT20_SCL=1;
    SHT20_SDA=1;
    delay_us(4);
    SHT20_SDA=0;
    delay_us(4);
    SHT20_SCL=0;
}

void IIC_Stop(void)
{
    SHT20_SCL=0;
    SHT20_SDA=0;
    delay_us(4);
    SHT20_SCL=1;
    delay_us(4);
    SHT20_SDA=1;
}

unsigned char IIC_SendByte(unsigned char dat)
{
    unsigned char i;
    unsigned char ack_bit;
    for(i=0;i<8;i++)
    {
        SHT20_SCL=0;
        if(dat&0x80)
        {
            SHT20_SDA=1;
        }
        else
        {
            SHT20_SDA=0;
        }
        dat<<=1;
        delay_us(4);
        SHT20_SCL=1;
        delay_us(4);
    }
    SHT20_SCL=0;
    SHT20_SDA=1;
    delay_us(4);
    SHT20_SCL=1;
    ack_bit=SHT20_SDA;
    delay_us(4);
    SHT20_SCL=0;
    return ack_bit;
}

unsigned char IIC_ReadByte(unsigned char ack)
{
    unsigned char i;
    unsigned char dat=0;
    SHT20_SCL=0;
    SHT20_SDA=1;
    delay_us(4);
    for(i=0;i<8;i++)
    {
        SHT20_SCL=1;
        delay_us(4);
        dat<<=1;
        if(SHT20_SDA)
        {
            dat|=0x01;
        }
        SHT20_SCL=0;
        delay_us(4);
    }
    if(ack)
    {
        SHT20_SDA=0;
    }
    else
    {
        SHT20_SDA=1;
    }
    delay_us(4);
    SHT20_SCL=1;
    delay_us(4);
    SHT20_SCL=0;
    SHT20_SDA=1;
    return dat;
}

void SHT20_Reset(void)
{
    IIC_Start();
    IIC_SendByte(0x80);
    IIC_Stop();
    delay_ms(50);
}

unsigned char SHT20_CheckCRC(unsigned char *data,unsigned char len,unsigned char crc)
{
    unsigned char i,j;
    for(i=0;i<len;i++)
    {
        crc^=data[i];
        for(j=0;j<8;j++)
        {
            if(crc&0x80)
            {
                crc=(crc<<1)^0x31;
            }
            else
            {
                crc<<=1;
            }
        }
    }
    return crc;
}

void SHT20_StartMeasure(unsigned char mode)
{
    IIC_Start();
    IIC_SendByte(0x80);
    IIC_SendByte(mode);
}

unsigned char SHT20_ReadMeasure(unsigned char *data,unsigned char len)
{
    unsigned char i;
    unsigned char crc;
    for(i=0;i<len;i++)
    {
        data[i]=IIC_ReadByte(i==(len-1)?0:1);
    }
    crc=SHT20_CheckCRC(data,len-1,data[len-1]);
    return crc;
}

void main()
{
    unsigned char data[3];
    unsigned char crc;
    SHT20_Reset();
    SHT20_StartMeasure(0xF5);
    delay_ms(50);
    crc=SHT20_ReadMeasure(data,3);
    if(crc==data[2])
    {
        //温度值 data[0]
        //湿度值 data[1]
    }
}

注意，这只是基本的驱动代码，具体应用时还需要根据实际情况进行相应的修改和调整。