基于STM32的MLX90614(GY-906)人体红外测温

Posted 2022-04-13 文某9

先看实验现象

MLX90614 简介（资料来自商家文档）

MLX90614 存储器

RAM

测试所需硬件
MCU一块（主脑）
GY-906

OLED(0.96)

软件部分
mlx90614.c（代码来自网络）

/* Includes ------------------------------------------------------------------*/

#include "mlx90614.h"

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define ACK	 0 //应答
#define	NACK 1 //无应答
#define SA				0x00 //Slave address 单个MLX90614时地址为0x00,多个时地址默认为0x5a
#define RAM_ACCESS		0x00 //RAM access command RAM存取命令
#define EEPROM_ACCESS	0x20 //EEPROM access command EEPROM存取命令
#define RAM_TOBJ1		0x07 //To1 address in the eeprom 目标1温度,检测到的红外温度 -70.01 ~ 382.19度

#define SMBUS_PORT	GPIOA      //PB端口(端口和下面的两个针脚可自定义)
#define SMBUS_SCK		GPIO_Pin_5 //PB6：SCL
#define SMBUS_SDA		GPIO_Pin_4 //PB7：SDA

#define RCC_APB2Periph_SMBUS_PORT		RCC_APB2Periph_GPIOB

#define SMBUS_SCK_H()	    SMBUS_PORT->BSRR = SMBUS_SCK //置高电平
#define SMBUS_SCK_L()	    SMBUS_PORT->BRR = SMBUS_SCK  //置低电平
#define SMBUS_SDA_H()	    SMBUS_PORT->BSRR = SMBUS_SDA
#define SMBUS_SDA_L()	    SMBUS_PORT->BRR = SMBUS_SDA

#define SMBUS_SDA_PIN()	    SMBUS_PORT->IDR & SMBUS_SDA //读取引脚电平

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/

/*******************************************************************************
* Function Name  : SMBus_StartBit
* Description    : Generate START condition on SMBus
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_StartBit(void)

    SMBUS_SDA_H();		// Set SDA line
    SMBus_Delay(5);	    // Wait a few microseconds
    SMBUS_SCK_H();		// Set SCL line
    SMBus_Delay(5);	    // Generate bus free time between Stop
    SMBUS_SDA_L();		// Clear SDA line
    SMBus_Delay(5);	    // Hold time after (Repeated) Start
    // Condition. After this period, the first clock is generated.
    //(Thd:sta=4.0us min)在SCK=1时，检测到SDA由1到0表示通信开始（下降沿）
    SMBUS_SCK_L();	    // Clear SCL line
    SMBus_Delay(5);	    // Wait a few microseconds


/*******************************************************************************
* Function Name  : SMBus_StopBit
* Description    : Generate STOP condition on SMBus
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_StopBit(void)

    SMBUS_SCK_L();		// Clear SCL line
    SMBus_Delay(5);	    // Wait a few microseconds
    SMBUS_SDA_L();		// Clear SDA line
    SMBus_Delay(5);	    // Wait a few microseconds
    SMBUS_SCK_H();		// Set SCL line
    SMBus_Delay(5);	    // Stop condition setup time(Tsu:sto=4.0us min)
    SMBUS_SDA_H();		// Set SDA line在SCK=1时，检测到SDA由0到1表示通信结束（上升沿）


/*******************************************************************************
* Function Name  : SMBus_SendByte
* Description    : Send a byte on SMBus
* Input          : Tx_buffer
* Output         : None
* Return         : None
*******************************************************************************/
u8 SMBus_SendByte(u8 Tx_buffer)

    u8	Bit_counter;
    u8	Ack_bit;
    u8	bit_out;

    for(Bit_counter=8; Bit_counter; Bit_counter--)
    
        if (Tx_buffer&0x80)
        
            bit_out=1;   // If the current bit of Tx_buffer is 1 set bit_out
        
        else
        
            bit_out=0;  // else clear bit_out
        
        SMBus_SendBit(bit_out);		// Send the current bit on SDA
        Tx_buffer<<=1;				// Get next bit for checking
    

    Ack_bit=SMBus_ReceiveBit();		// Get acknowledgment bit
    return	Ack_bit;


/*******************************************************************************
* Function Name  : SMBus_SendBit
* Description    : Send a bit on SMBus 82.5kHz
* Input          : bit_out
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_SendBit(u8 bit_out)

    if(bit_out==0)
    
        SMBUS_SDA_L();
    
    else
    
        SMBUS_SDA_H();
    
    SMBus_Delay(2);					// Tsu:dat = 250ns minimum
    SMBUS_SCK_H();					// Set SCL line
    SMBus_Delay(6);					// High Level of Clock Pulse
    SMBUS_SCK_L();					// Clear SCL line
    SMBus_Delay(3);					// Low Level of Clock Pulse
//	SMBUS_SDA_H();				    // Master release SDA line ,
    return;


/*******************************************************************************
* Function Name  : SMBus_ReceiveBit
* Description    : Receive a bit on SMBus
* Input          : None
* Output         : None
* Return         : Ack_bit
*******************************************************************************/
u8 SMBus_ReceiveBit(void)

    u8 Ack_bit;

    SMBUS_SDA_H();          //引脚靠外部电阻上拉，当作输入
	SMBus_Delay(2);			// High Level of Clock Pulse
    SMBUS_SCK_H();			// Set SCL line
    SMBus_Delay(5);			// High Level of Clock Pulse
    if (SMBUS_SDA_PIN())
    
        Ack_bit=1;
    
    else
    
        Ack_bit=0;
    
    SMBUS_SCK_L();			// Clear SCL line
    SMBus_Delay(3);			// Low Level of Clock Pulse

    return	Ack_bit;


/*******************************************************************************
* Function Name  : SMBus_ReceiveByte
* Description    : Receive a byte on SMBus
* Input          : ack_nack
* Output         : None
* Return         : RX_buffer
*******************************************************************************/
u8 SMBus_ReceiveByte(u8 ack_nack)

    u8 	RX_buffer;
    u8	Bit_Counter;

    for(Bit_Counter=8; Bit_Counter; Bit_Counter--)
    
        if(SMBus_ReceiveBit())			// Get a bit from the SDA line
        
            RX_buffer <<= 1;			// If the bit is HIGH save 1  in RX_buffer
            RX_buffer |=0x01;
        
        else
        
            RX_buffer <<= 1;			// If the bit is LOW save 0 in RX_buffer
            RX_buffer &=0xfe;
        
    
    SMBus_SendBit(ack_nack);			// Sends acknowledgment bit
    return RX_buffer;


/*******************************************************************************
* Function Name  : SMBus_Delay
* Description    : 延时  一次循环约1us
* Input          : time
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_Delay(u16 time)

    u16 i, j;
    for (i=0; i<4; i++)
    
        for (j=0; j<time; j++);
    


/*******************************************************************************
* Function Name  : SMBus_Init
* Description    : SMBus初始化
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_Init()

    GPIO_InitTypeDef    GPIO_InitStructure;

	/* Enable SMBUS_PORT clocks */
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SMBUS_PORT, ENABLE);

    /*配置SMBUS_SCK、SMBUS_SDA为集电极开漏输出*/
    GPIO_InitStructure.GPIO_Pin = SMBUS_SCK | SMBUS_SDA;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(SMBUS_PORT, &GPIO_InitStructure);

    SMBUS_SCK_H();
    SMBUS_SDA_H();


/*******************************************************************************
 * Function Name  : SMBus_ReadMemory
 * Description    : READ DATA FROM RAM/EEPROM
 * Input          : slaveAddress, command
 * Output         : None
 * Return         : Data
*******************************************************************************/
u16 SMBus_ReadMemory(u8 slaveAddress, u8 command)

    u16 data;			// Data storage (DataH:DataL)
    u8 Pec;				// PEC byte storage
    u8 DataL=0;			// Low data byte storage
    u8 DataH=0;			// High data byte storage
    u8 arr[6];			// Buffer for the sent bytes
    u8 PecReg;			// Calculated PEC byte storage
    u8 ErrorCounter;	// Defines the number of the attempts for communication with MLX90614

    ErrorCounter=0x00;				// Initialising of ErrorCounter
	slaveAddress <<= 1;	//2-7位表示从机地址
	
    do
    
repeat:
        SMBus_StopBit();			    //If slave send NACK stop comunication
        --ErrorCounter;				    //Pre-decrement ErrorCounter
        if(!ErrorCounter) 			    //ErrorCounter=0?
        
            break;					    //Yes,go out from do-while
        

        SMBus_StartBit();				//Start condition
        if(SMBus_SendByte(slaveAddress))//Send SlaveAddress 最低位Wr=0表示接下来写命令
        
            goto	repeat;			    //Repeat comunication again
        
        if(SMBus_SendByte(command))	    //Send command
        
            goto	repeat;		    	//Repeat comunication again
        

        SMBus_StartBit();					//Repeated Start condition
        if(SMBus_SendByte(slaveAddress+1))	//Send SlaveAddress 最低位Rd=1表示接下来读数据
        
            goto	repeat;             	//Repeat comunication again
        

        DataL = SMBus_ReceiveByte(ACK);	//Read low data,master must send ACK
        DataH = SMBus_ReceiveByte(ACK); //Read high data,master must send ACK
        Pec = SMBus_ReceiveByte(NACK);	//Read PEC byte, master must send NACK
        SMBus_StopBit();				//Stop condition

        arr[5] = slaveAddress;		//
        arr[4] = command;			//
        arr[3] = slaveAddress+1;	//Load array arr
        arr[2] = DataL;				//
        arr[1] = DataH;				//
        arr[0] = 0;					//
        PecReg=PEC_Calculation(arr);//Calculate CRC
    
    while(PecReg != Pec);		//If received and calculated CRC are equal go out from do-while

	data = (DataH<<8) | DataL;	//data=DataH:DataL
    return data;


/*******************************************************************************
* Function Name  : PEC_calculation
* Description    : Calculates the PEC of received bytes
* Input          : pec[]
* Output         : None
* Return         : pec[0]-this byte contains calculated crc value
*******************************************************************************/
u8 PEC_Calculation(u8 pec[])

    u8 	crc[6];
    u8	BitPosition=47;
    u8	shift;
    u8	i;
    u8	j;
    u8	temp;

    do
    
        /*Load pattern value 0x000000000107*/
        crc[5]=0;
        crc[4]=0;
        crc[3]=0;
        crc[2]=0;
        crc[1]=0x01;
        crc[0]=0x07;

        /*Set maximum bit position at 47 ( six bytes byte5...byte0,MSbit=47)*/
        BitPosition=47;

        /*Set shift position at 0*/
        shift=0;

        /*Find first "1" in the transmited message beginning from the MSByte byte5*/
        i=5;
        j=0;
        while((pec[i]&(0x80>>j))==0 && i>0)
        
            BitPosition--;
            if(j<7)
            
                j++;
            
            else
            
                j=0x00;
                i--;
            
        /*End of while */

        /*Get shift value for pattern value*/
        shift=BitPosition-8;

        /*Shift pattern value */
        while(shift)
        
            for(i=5; i<0xFF; i--)
            
                if((crc[i-1]&0x80) && (i>0))
                
                    temp=1;
                
                else
                
                    temp=0;
                
                crc[i]<<=1;
                crc[i]+=temp;
            /*End of for*/
            shift--;
        /*End of while*/

        /*Exclusive OR between pec and crc*/
        for(i=0; i<=5; i++)
        
            pec[i] ^=crc[i];
        /*End of for*/
    
    while(BitPosition>8); /*End of do-while*/

    return pec[0];


 /*******************************************************************************
 * Function Name  : SMBus_ReadTemp
 * Description    : Calculate and return the temperature
 * Input          : None
 * Output         : None
 * Return         : SMBus_ReadMemory(0x00, 0x07)*0.02-273.15
*******************************************************************************/
float SMBus_ReadTemp(void)
   
	float temp;
	temp = SMBus_ReadMemory(SA, RAM_ACCESS|RAM_TOBJ1)*0.02-273.15;
	return temp;


/*********************************END OF FILE*********************************/

mlx90614.h

/*******************************************************************************
* 文件名		: mlx90614.h
* 作  者	: 
* 版  本	: 
* 日  期	: 2013-08-07
* 描  述	: mlx90614函数
*******************************************************************************/

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __MLX90614_H
#define __MLX90614_H

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x.h"
/* Exported types ------------------------------------------------------------*/
/* Exported variables --------------------------------------------------------*/
/* Exported constants --------------------------------------------------------*/
/* Exported macro ------------------------------------------------------------*/
/* Exported functions ------------------------------------------------------- */
void SMBus_StartBit(void);
void SMBus_StopBit(void);
void SMBus_SendBit(u8);
u8 SMBus_SendByte(u8);
u8 SMBus_ReceiveBit(void);
u8 SMBus_ReceiveByte(u8);
void SMBus_Delay(u16);
void SMBus_Init(void);
u16 SMBus_ReadMemory(u8, u8);
u8 PEC_Calculation(u8*);
float SMBus_ReadTemp(void); //获取温度值

#endif

/*********************************END OF FILE*********************************/

总结
个人觉得数据不太准确，网上找过很多驱动程序要么是付费，要么是文件发一半，几个能用的这个驱动相对稳定。

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