基于STC89c52cpu，以MLX90615传感器测温，无法读出温度数据
我要做以STC89C52单片机为基础，MLX90615为测温传感器的一个测温仪，我下载了网上的程序，一开始连接硬件，拷入程序后可以直接测温，但是有一天程序突然测不了温了，做了很多尝试，找了其他人写的程序，但是接上温度传感器单片机还是没有反应，原来能测温的程序最后lcd分别显示-273.150,727.970,77.730，67.490数值，然后就不动了
做过改动有改变SDA，SCL的上拉电阻，修改延时程序，使用其他的STC89C52开发板，更换传感器，重新焊接面包板连电路。
只能求助大家了。以下是我找的程序，做了些修改，先只粘上有关MLX90615的程序：
#include "LCD1602.h"
#include "reg52.h"
#include "MLX90615.h"
#include "delay.h"
#include "stdio.h"
sbit KEY=P3^2; // 定义按键
unsigned char s[20]; // 待显示的字符串
float temp; // 温度值
void main()
{
unsigned char RunStatus=0; // 是否测量标志
unsigned char SlaveAddress; // Contains device address
unsigned char command; // Contains the access command
unsigned int tdata; // Contains data value
SlaveAddress=SA<<1; // Set device address
command=RAM_Access|RAM_To; // Form RAM access command + RAM address
MLX90615_init();
LCD1602_init();
write_string(0,0,"Press the KEY");
write_string(1,0,"to start");
while(1)
{
if(RunStatus)
{
tdata=MemRead(SlaveAddress,command); //Read memory
temp = (float)tdata*0.02-273.15;
clean_screen();
write_string(0,0,"Measuring");
sprintf(s,"%.3f C");
s[6]=0xDF;
write_string(1,0,s);
delay_ms(400);
}
if(!KEY)
{
delay_ms(20);
if(!KEY)
{
if(RunStatus)
{
RunStatus=0;
clean_screen();
write_string(0,0,"Press the KEY");
write_string(1,0,"to start");
}
else
{
RunStatus=1;
clean_screen();
write_string(0,0,"Measuring");
}
while(!KEY);
}
}
}
}
#include "MLX90615.h"
#include "intrins.h"
#include "delay.h"
#include "UART.h"
#define _NOP() _nop_()
// 5us
void delay_Tbuf()
{
unsigned char a,b;
for(b=1;b>0;b--)
for(a=1;a>0;a--);
}
void delay_Thd()
{
_nop_();
}
void MLX90615_init(void)
{
mSDA_OUT; // Set SDA as Output
mSCL_OUT; // Set SCL as Output
mSDA_HIGH(); // bus free
mSCL_HIGH();
}
void START_bit(void)
{
mSDA_OUT;
mSDA_HIGH(); // Set SDA line
delay_Tbuf(); // Wait a few microseconds
mSCL_HIGH(); // Set SCL line
delay_Tbuf(); // Generate bus free time between Stop
// and Start condition (Tbuf=4.7us min)
mSDA_LOW(); // Clear SDA line
delay_Tbuf(); // Hold time after (Repeated) Start
// Condition. After this period, the first clock is generated.
//(Thd:sta=4.0us min)
mSCL_LOW(); // Clear SCL line
delay_Tbuf(); // Wait a few microseconds
}
void STOP_bit(void)
{
mSDA_OUT;
mSCL_LOW(); // Clear SCL line
delay_Tbuf(); // Wait a few microseconds
mSDA_LOW(); // Clear SDA line
delay_Tbuf(); // Wait a few microseconds
mSCL_HIGH(); // Set SCL line
delay_Tbuf(); // Stop condition setup time(Tsu:sto=4.0us min)
mSDA_HIGH(); // Set SDA line
}
unsigned char TX_byte(unsigned char Tx_buffer)
{
unsigned char Bit_counter;
unsigned char Ack_bit;
unsigned char 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
send_bit(bit_out); // Send the current bit on SDA
Tx_buffer<<=1; // Get next bit for checking
}
Ack_bit=Receive_bit(); // Get acknowledgment bit
return Ack_bit;
}// End of TX_bite()
unsigned char RX_byte(unsigned char ack_nack)
{
unsigned char RX_buffer;
unsigned char Bit_Counter;
for(Bit_Counter=8; Bit_Counter; Bit_Counter--)
{
if(Receive_bit()) // 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;
}
}
send_bit(ack_nack); // Sends acknowledgment bit
return RX_buffer;
}
//---------------------------------------------------------------------------------------------
void send_bit(unsigned char bit_out)
{
mSDA_OUT;
if(bit_out)
mSDA_HIGH();
else
mSDA_LOW();
delay_Thd(); // Tsu:dat = 250ns minimum
mSCL_HIGH(); // Set SCL line
delay_Tbuf(); // High Level of Clock Pulse------------------
mSCL_LOW(); // Clear SCL line
delay_Tbuf(); // Low Level of Clock Pulse----------------------
// mSDA_HIGH(); // Master release SDA line ,
return;
}//End of send_bit()
//---------------------------------------------------------------------------------------------
unsigned char Receive_bit(void)
{
unsigned char Ack_bit;
mSDA_IN; // SDA-input
_NOP();_NOP();_NOP();
mSCL_HIGH(); // Set SCL line
delay_Tbuf(); // High Level of Clock Pulse
// if(P2Input(BIT2))
SDA=1;
if(SDA)
Ack_bit=1; // \ Read acknowledgment bit, save it in Ack_bit
else
Ack_bit=0; // /
mSCL_LOW(); // Clear SCL line
delay_Tbuf(); // Low Level of Clock Pulse
return Ack_bit;
}//End of Receive_bit
unsigned int MemRead(unsigned char SlaveAddress,unsigned char command)
{
unsigned int tdata; // Data storage (DataH:DataL)
unsigned char Pec; // PEC byte storage
unsigned char DataL; // Low data byte storage
unsigned char DataH; // High data byte storage
unsigned char arr[6]; // Buffer for the sent bytes
unsigned char PecReg; // Calculated PEC byte storage
unsigned char ErrorCounter; // Defines the number of the attempts for communication with MLX90614
ErrorCounter=0x00; // Initialising of ErrorCounter
do{
repeat:
STOP_bit(); //If slave send NACK stop comunication
--ErrorCounter; //Pre-decrement ErrorCounter
if(!ErrorCounter){ //ErrorCounter=0?
break; //Yes,go out from do-while{}
}
START_bit(); //Start condition
if(TX_byte(SlaveAddress)){ //Send SlaveAddress
goto repeat; //Repeat comunication again
}
if(TX_byte(command)){ //Send command
goto repeat; //Repeat comunication again
}
START_bit(); //Repeated Start condition
if(TX_byte(SlaveAddress)){ //Send SlaveAddress-------------------???
goto repeat; //Repeat comunication again
}
DataL=RX_byte(ACK); //Read low data,master must send ACK
DataH=RX_byte(ACK); //Read high data,master must send ACK
Pec=RX_byte(NACK); //Read PEC byte, master must send NACK
STOP_bit(); //Stop condition
arr[5]=SlaveAddress; //
arr[4]=command; //
arr[3]=SlaveAddress; //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{}
*((unsigned char *)(&tdata))=DataH; //
*((unsigned char *)(&tdata)+1)=DataL; //data=DataH:DataL
return tdata;
}
unsigned char PEC_calculation(unsigned char pec[])
{
unsigned char crc[6];
unsigned char BitPosition=47;
unsigned char shift;
unsigned char i;
unsigned char j;
unsigned char temp;
do{
crc[5]=0; /* Load CRC value 0x000000000107 */
crc[4]=0;
crc[3]=0;
crc[2]=0;
crc[1]=0x01;
crc[0]=0x07;
BitPosition=47; /* Set maximum bit position at 47 */
shift=0;
//Find first 1 in the transmited message
i=5; /* Set highest index */
j=0;
while((pec[i]&(0x80>>j))==0 && i>0){
BitPosition--;
if(j<7){
j++;
}
else{
j=0x00;
i--;
}
}/*End of while */
shift=BitPosition-8; /*Get shift value for crc value*/
//Shift crc 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];
}/*End of PEC_calculation*/
#ifndef __MLX90615_H
#define __MLX90615_H
#include "reg52.h"
sbit SDA = P2^0;
sbit SCL = P2^1;
#define mSDA_IN do{} while(0)
#define mSDA_OUT do{} while(0)
#define mSCL_IN do{} while(0)
#define mSCL_OUT do{} while(0)
#define ACK 0
#define NACK 1
//MLX90614 constants
#define SA 0x00 // Slave address
#define DEFAULT_SA 0x5B // Default Slave address
#define RAM_Access 0x20 // RAM access command
#define EEPROM_Access 0x10 // EEPROM access command
#define RAM_Ta 0x06 // Ta address in the ram
#define RAM_To 0x07 // To address in the ram
//*PROTOTYPES**********************************************************************************
void start_bit(void);
void STOP_bit(void);
void TX_byte(unsigned char Tx_buffer);
unsigned char RX_byte(unsigned char ack_nack);
void send_bit(unsigned char bit_out);
unsigned char Receive_bit(void);
void MLX90615_init(void);
unsigned int MEM_READ(unsigned char slave_addR, unsigned char cmdR);
void SendRequest(void);
void DummyCommand(unsigned char byte);
unsigned int *CALTEMP(unsigned long int TEMP);
unsigned char PEC_cal(unsigned char pec[],int n);
void Delay(unsigned int N);
#endif