SHT3X 高精度温湿度传感器驱动

#include "SHTxx.h" #include "delay.h" #include <math.h> //Keil library #include <stdio.h> //Keil library //******************************************************************** //产生IIC起始信号 static void IIC_Start(void) { SDA_OUT(); //sda线输出 IIC_SDA=1; IIC_SCL=1; delay_us(4); IIC_SDA=0;//START:when CLK is high,DATA change form high to low delay_us(4); IIC_SCL=0;//钳住I2C总线，准备发送或接收数据 } //产生IIC停止信号 static void IIC_Stop(void) { SDA_OUT();//sda线输出 IIC_SCL=0; IIC_SDA=0;//STOP:when CLK is high DATA change form low to high delay_us(4); IIC_SCL=1; IIC_SDA=1;//发送I2C总线结束信号 delay_us(4); } //等待应答信号到来 //返回值：1，接收应答失败 // 0，接收应答成功 static u8 IIC_Wait_Ack(void) { u16 ucErrTime=0; SDA_IN(); //SDA设置为输入 IIC_SDA=1;delay_us(1); IIC_SCL=1;delay_us(1); while(READ_SDA) { ucErrTime++; if(ucErrTime>60000) { IIC_Stop(); return 1; } } IIC_SCL=0;//时钟输出0 return 0; } //产生ACK应答 static void IIC_Ack(void) { IIC_SCL=0; SDA_OUT(); IIC_SDA=0; delay_us(2); IIC_SCL=1; delay_us(2); IIC_SCL=0; } //不产生ACK应答 static void IIC_NAck(void) { IIC_SCL=0; SDA_OUT(); IIC_SDA=1; delay_us(2); IIC_SCL=1; delay_us(2); IIC_SCL=0; } //IIC发送一个字节 //返回从机有无应答 //1，有应答 //0，无应答 static void IIC_Send_Byte(u8 txd) { u8 t; SDA_OUT(); IIC_SCL=0;//拉低时钟开始数据传输 for(t=0;t<8;t++) { IIC_SDA=(txd&0x80)>>7; txd<<=1; delay_us(2); //对TEA5767这三个延时都是必须的 IIC_SCL=1; delay_us(2); IIC_SCL=0; delay_us(2); } } //读1个字节，ack=1时，发送ACK，ack=0，发送nACK static u8 IIC_Read_Byte(u8 ack) { u8 i,receive=0; SDA_IN();//SDA设置为输入 for(i=0;i<8;i++ ) { IIC_SCL=0; delay_us(2); IIC_SCL=1; receive<<=1; if(READ_SDA)receive++; delay_us(1); } if (!ack) IIC_NAck();//发送nACK else IIC_Ack(); //发送ACK return receive; } //********************************************************************** void SHT3x_Init(void) { RCC->APB2ENR|=1<<6; //使能PORTE时钟 GPIOE->CRL&=0XFF00FFFF; //PE4,PE5 GPIOE->CRL|=0X00330000; GPIOE->ODR|=3<<4; } static etError SHT3x_StartWriteAccess(void) { u8 err; IIC_Start(); IIC_Send_Byte(DevAddr<<1); err=IIC_Wait_Ack(); return err; } static etError SHT3x_StartReadAccess(void) { u8 err; IIC_Start(); IIC_Send_Byte((DevAddr<<1)|0x01); err=IIC_Wait_Ack(); return err; } static etError SHT3x_StopAccess(void) { IIC_Stop(); return NO_ERROR; } //返回正确:0, 错误:非0 static etError SHT3x_WriteCmd(u16 cmd) { u8 err; IIC_Send_Byte(cmd>>8); //写高字节 err=IIC_Wait_Ack(); if(err) return ACK_ERROR; IIC_Send_Byte(cmd&0xff); //写低字节 err=IIC_Wait_Ack(); if(err) return ACK_ERROR; else return NO_ERROR; } static u8 SHT3X_CalcCrc(u8 data[], u8 nbrOfBytes) { u8 bit; // bit mask u8 crc = 0xFF; // calculated checksum u8 byteCtr; // byte counter // calculates 8-Bit checksum with given polynomial for(byteCtr = 0; byteCtr < nbrOfBytes; byteCtr++) { crc ^= (data[byteCtr]); for(bit = 8; bit > 0; --bit) { if(crc & 0x80) crc = (crc << 1) ^ POLYNOMIAL; else crc = (crc << 1); } } return crc; } static etError SHT3X_CheckCrc(u8 data[], u8 nbrOfBytes, u8 checksum) { u8 crc; // calculated checksum // calculates 8-Bit checksum crc = SHT3X_CalcCrc(data, nbrOfBytes); // verify checksum if(crc != checksum) return CHECKSUM_ERROR; else return NO_ERROR; } float SHT3X_CalcTemperature(u16 rawValue) { // calculate temperature [°C] // T = -45 + 175 * rawValue / (2^16-1) return 175.0f * (float)rawValue / 65535.0f - 45.0f; } //----------------------------------------------------------------------------- float SHT3X_CalcHumidity(u16 rawValue) { // calculate relative humidity [%RH] // RH = rawValue / (2^16-1) * 100 return 100.0f * (float)rawValue / 65535.0f; } etError SHT3x_Read2ByteAndCrc(u16 *Res,u8 ack) { u8 Byte[2]; u8 checksum; Byte[0]=IIC_Read_Byte(ACK); Byte[1]=IIC_Read_Byte(ACK); checksum=IIC_Read_Byte(ack); //读取crc checksum=SHT3X_CheckCrc(Byte, 2,checksum); *Res=(Byte[0]<<8)+Byte[1]; return checksum; } u8 SHT3x_ReadTempAndHumi(float *Temp,float* Humi) { u8 err; u16 rawTemp,rawHumi; err = SHT3x_StartWriteAccess(); err<<=2; err+=SHT3x_WriteCmd(CMD_MEAS_CLOCKSTR_H); SHT3x_StopAccess(); delay_ms(500); err=SHT3x_StartReadAccess(); if(err) SHT3x_StartReadAccess(); SHT3x_Read2ByteAndCrc(&rawTemp,ACK); SHT3x_Read2ByteAndCrc(&rawHumi,NACK); SHT3x_StopAccess(); *Temp=SHT3X_CalcTemperature(rawTemp); *Humi=SHT3X_CalcHumidity(rawHumi); return err; }