STM32 使用 SHT2x 温湿度传感器
简介
- 这TM的是个超级坑的通讯过程，虽然符合IIC通讯流程，但要是你直接用IIC通讯会发现完全不是这么回事。这个是在STM32F0系列单片机上使用的范例，可以正常读取温度和湿度，主机模式和轮询模式和寄存器配置都有实现。
- database.h 里面没啥东西，可以直接用
#include "stm32f0xx.h"代替 - 数据手册：点击查看
代码
SHT2x.h
#ifndef SHT2x_H
#define SHT2x_H
//---------- Includes ----------------------------------------------------------
#include "I2C_HAL.h"
#include "database.h"
//---------- Defines -----------------------------------------------------------
#define LITTLE_ENDIAN //一定要设置大小端，当设置错误会出现比较大的数据跳动
typedef union {
uint16_t u16; // element specifier for accessing whole u16
int16_t i16; // element specifier for accessing whole i16
struct {
#ifdef LITTLE_ENDIAN // Byte-order is little endian
uint8_t u8L; // element specifier for accessing low u8
uint8_t u8H; // element specifier for accessing high u8
#else // Byte-order is big endian
uint8_t u8H; // element specifier for accessing low u8
uint8_t u8L; // element specifier for accessing high u8
#endif
} s16; // element spec. for acc. struct with low or high u8
} nt16;
// Error codes
typedef enum{
ACK_ERROR = 0x01,
TIME_OUT_ERROR = 0x02,
CHECKSUM_ERROR = 0x04,
UNIT_ERROR = 0x08
}etError;
// CRC
#define SHT2xPOLYNOMIAL 0x131 //P(x)=x^8+x^5+x^4+1 = 100110001
// sensor command
typedef enum{
TRIG_T_MEASUREMENT_HM = 0xE3, // command trig. temp meas. hold master
TRIG_RH_MEASUREMENT_HM = 0xE5, // command trig. humidity meas. hold master
TRIG_T_MEASUREMENT_POLL = 0xF3, // command trig. temp meas. no hold master
TRIG_RH_MEASUREMENT_POLL = 0xF5, // command trig. humidity meas. no hold master
USER_REG_W = 0xE6, // command writing user register
USER_REG_R = 0xE7, // command reading user register
SOFT_RESET = 0xFE // command soft reset
}etSHT2xCommand;
typedef enum {
SHT2x_RES_12_14BIT = 0x00, // RH=12bit, T=14bit
SHT2x_RES_8_12BIT = 0x01, // RH= 8bit, T=12bit
SHT2x_RES_10_13BIT = 0x80, // RH=10bit, T=13bit
SHT2x_RES_11_11BIT = 0x81, // RH=11bit, T=11bit
SHT2x_RES_MASK = 0x81 // Mask for res. bits (7,0) in user reg.
} etSHT2xResolution;
typedef enum {
SHT2x_EOB_ON = 0x40, // end of battery
SHT2x_EOB_MASK = 0x40, // Mask for EOB bit(6) in user reg.
} etSHT2xEob;
typedef enum {
SHT2x_HEATER_ON = 0x04, // heater on
SHT2x_HEATER_OFF = 0x00, // heater off
SHT2x_HEATER_MASK = 0x04, // Mask for Heater bit(2) in user reg.
} etSHT2xHeater;
// measurement signal selection
typedef enum{
HUMIDITY,
TEMP
}etSHT2xMeasureType;
typedef enum{
I2C_ADR_W = 128, // sensor I2C address + write bit
I2C_ADR_R = 129 // sensor I2C address + read bit
}etI2cHeader;
uint8_t SHT2x_ReadUserRegister(uint8_t *pRegisterValue);
uint8_t SHT2x_WriteUserRegister(uint8_t *pRegisterValue);
void SHT2x_InitUserRegister(void);
uint8_t SHT2x_MeasureHM(etSHT2xMeasureType eSHT2xMeasureType, nt16 *pMeasurand);
float SHT2x_CalcRH(uint16_t u16sRH);
float SHT2x_CalcTemperatureC(uint16_t u16sT);
void SHT2x_Process();
#endif
SHT2x.c
//==============================================================================
// SH2x 温湿度采集程序
//==============================================================================
// File : SHT2x.c
// Author : MC
// Compiler : Keil 5
//==============================================================================
//---------- Includes ----------------------------------------------------------
#include "SHT2x.h"
#include I2C_HAL.h
#ifndef I2C_HAL_H
#define I2C_HAL_H
#ifndef I2C_HAL_H
#define I2C_HAL_H
//---------- Includes ----------------------------------------------------------
#include "database.h"
//---------- Defines -----------------------------------------------------------
//IO口操作宏定义
#define GPIOSCL GPIOA
#define PinSCL GPIO_Pin_2
#define GPIOSDA GPIOA
#define PinSDA GPIO_Pin_3
//IO方向设置
#define SDA_IN() {GPIOA->MODER&=0XFFFFFF3F;}
#define SDA_OUT() {uint32_t Temp=GPIOA->MODER;\
Temp&=0XFFFFFF3F;\
Temp|=0x00000040;\
GPIOA->MODER=Temp;}
#define SCL_IN() {GPIOA->MODER&=0XFFFFFFCF;}
#define SCL_OUT() {uint32_t Temp=GPIOA->MODER;\
Temp&=0XFFFFFFCF;\
Temp|=0x00000010;\
GPIOA->MODER=Temp;}
//IO操作函数
#define IIC_SCL1 GPIO_SetBits(GPIOSCL,PinSCL)
#define IIC_SCL0 GPIO_ResetBits(GPIOSCL,PinSCL) //SCL
#define IIC_SDAx(x) GPIO_WriteBit(GPIOSDA,PinSDA,x)
#define IIC_SDA1 GPIO_SetBits(GPIOSDA,PinSDA) //SDA
#define IIC_SDA0 GPIO_ResetBits(GPIOSDA,PinSDA) //SDA
#define READ_SDA GPIO_ReadInputDataBit(GPIOSDA,PinSDA) //输入SDA
#define READ_SCL GPIO_ReadInputDataBit(GPIOSDA,PinSCL) //输入SCL
//---------- Enumerations ------------------------------------------------------
// I2C level
typedef enum{
LOW = 0,
HIGH = 1,
}etI2cLevel;
// I2C acknowledge
typedef enum{
ACK = 0,
NO_ACK = 1,
}etI2cAck;
//==============================================================================
void I2c_Init ();
//==============================================================================
//Initializes the ports for I2C interface
//==============================================================================
void I2c_StartCondition ();
//==============================================================================
// writes a start condition on I2C-bus
// input : -
// output: -
// return: -
// note : timing (delay) may have to be changed for different microcontroller
// _____
// SDA: |_____
// _______
// SCL : |___
//==============================================================================
void I2c_StopCondition ();
//==============================================================================
// writes a stop condition on I2C-bus
// input : -
// output: -
// return: -
// note : timing (delay) may have to be changed for different microcontroller
// _____
// SDA: _____|
// _______
// SCL : ___|
//===========================================================================
uint8_t I2c_WriteByte (uint8_t txByte);
//===========================================================================
// writes a byte to I2C-bus and checks acknowledge
// input: txByte transmit byte
// output: -
// return: error
// note: timing (delay) may have to be changed for different microcontroller
//===========================================================================
uint8_t I2c_ReadByte (etI2cAck ack);
//===========================================================================
// reads a byte on I2C-bus
// input: rxByte receive byte
// output: rxByte
// note: timing (delay) may have to be changed for different microcontroller
u8 IIC_Wait_Ack(void);
uint8_t I2c_SHT21WithSCLReadByte(etI2cAck ack);
#endif
I2C_HAL.c
//---------- Includes ----------------------------------------------------------
#include "I2C_HAL.h"
//==============================================================================
void I2c_Init ()
//==============================================================================
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA , ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
IIC_SDA0; // Set port as output for configuration
IIC_SCL0; // Set port as output for configuration
SDA_OUT(); // Set SDA level as low for output mode
SCL_OUT();
IIC_SDA1; // I2C-bus idle mode SDA released (input)
IIC_SCL1; // I2C-bus idle mode SCL released (input)
}
//==============================================================================
void I2c_StartCondition ()
//==============================================================================
{
SDA_OUT();
SCL_OUT();
IIC_SDA1;
IIC_SCL1;
delay_us(20); // hold time start condition (t_HD;STA)
IIC_SDA0;
delay_us(20); // hold time start condition (t_HD;STA)
IIC_SCL0;
delay_us(20);
}
//==============================================================================
void I2c_StopCondition ()
//==============================================================================
{
SDA_OUT();
SCL_OUT();
IIC_SDA0;
IIC_SCL0;
delay_us(20); // set-up time stop condition (t_SU;STO)
IIC_SCL1;
delay_us(20); // set-up time stop condition (t_SU;STO)
IIC_SDA1;
delay_us(20);
}
//不产生ACK应答
void IIC_NAck(void)
{
SCL_OUT();
SDA_OUT();
IIC_SCL0;
IIC_SDA1;
delay_us(10);
IIC_SCL1;
delay_us(10);
IIC_SCL0;
}
//产生ACK应答
void IIC_Ack(void)
{
SCL_OUT();
SDA_OUT();
IIC_SCL0;
IIC_SDA0;
delay_us(10);
IIC_SCL1;
delay_us(10);
IIC_SCL0;
}
//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
u8 IIC_Wait_Ack(void)
{
u8 ucErrTime=0;
SDA_IN(); //SDA设置为输入
IIC_SCL1;delay_us(5);
while(READ_SDA)
{
ucErrTime++;
if(ucErrTime>250)
{
//I2c_StopCondition();
return 1;
}
delay_us(100);
}
IIC_SCL0;//时钟输出0
return 0;
}
//==============================================================================
uint8_t I2c_WriteByte (uint8_t txByte)
//==============================================================================
{
uint8_t mask,error=0;
u8 t;
SCL_OUT();
SDA_OUT();
IIC_SCL0;//拉低时钟开始数据传输
for(t=0;t<8;t++)
{
IIC_SDAx((txByte&0x80)>>7);
txByte<<=1;
delay_us(10); //对TEA5767这三个延时都是必须的
IIC_SCL1;
delay_us(10);
IIC_SCL0;
delay_us(10);
}
return error; //return error code
}
//==============================================================================
uint8_t I2c_ReadByte (etI2cAck ack)
//==============================================================================
{
unsigned char i,receive=0;
SCL_OUT();
SDA_IN();//SDA设置为输入
for(i=0;i<8;i++ )
{
IIC_SCL0;
delay_us(5);
IIC_SCL1;
receive<<=1;
if(READ_SDA)receive++;
delay_us(5);
}
if (ack==ACK)
IIC_Ack(); //发送ACK
else
IIC_NAck();//发送nACK
return receive;
}
//==============================================================================
uint8_t I2c_SHT21WithSCLReadByte(etI2cAck ack)
//==============================================================================
{
uint16_t i;
unsigned char receive=0;
SCL_IN(); // set SCL I/O port as input
SDA_IN();
for(i=0; i<10000; i++) // wait until master hold is released or
{ delay_us(10); // a timeout (~1s) is reached
if (READ_SCL==1){
if(READ_SDA)receive++;
break;
}
}
SCL_OUT();
SDA_IN();//SDA设置为输入
for(i=0;i<7;i++ )
{
IIC_SCL0;
delay_us(5);
IIC_SCL1;
receive<<=1;
if(READ_SDA)receive++;
delay_us(5);
}
if (ack==ACK)
IIC_Ack(); //发送ACK
else
IIC_NAck();//发送nACK
return receive;
}