[SOLVED] LCD problem for display the second part

jackrude · Mar 28, 2012

Hello all, I'm have trouble for displaying the second part of the message on to the LCD, it only display "temp controller, cur temp degree", it's not showing "temp =, deg C", please help me, i dont know it's the code problem or it's the hardware issue, this code is working on my demo board XL400, but is not working on my prototype,

Code C - [expand]
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#include<reg51.h>
#define data P0
#define UPTEMP 45
#define DOWNTEMP 35
#define AL 50
 
sbit rs=P2^0;
sbit rw=P2^1;
sbit en=P2^2;
sbit adc_read=P3^4;
sbit adc_write=P3^3;
sbit adc_intr=P3^5;
sbit output=P3^7;
sbit alam=P3^6;
bit loadon=0;
 
void delay(int time)
    {   
        int i, j;   
            for(i=0;i<127;i++)  
                {
                    for (j=0;j<time;j++);
                }       
    }
 
void lcd_data(unsigned char a)
    {
        rs =1;
        data=a;
        en =1;
        delay(5);
        en = 0;
        delay(5);
    }
 
void lcd_cmd(unsigned char a)
    {
        rs=0;
        data=a;
        en=1;
        delay(1);
        en=0;
        delay(1);
 
    }
void lcd_string (char * s)
    {
        while(*s)
            
            {
                lcd_data(*s);
                s++;
            }
    }
 
void lcd_init()
{
    lcd_cmd(0x38);
    lcd_cmd(0x0e);
    lcd_cmd(0x01);
    lcd_cmd(0x0c);
    lcd_cmd(0x80);
}
 
void pwmm(int i)
{  int j,k;
   output=1;    
   for(j=0;j<i;j++)
    delay(5);
   k=10-i;
   output=0;
   for(j=0;j<k;j++)
    delay(5);
}
 
void main()
{
    unsigned char val=0, temp=0;
    unsigned int x=0;
    float temp1;
    output=0;
    alam=1;
    rw=0;
    lcd_init();
    lcd_string (" Temp controller" );
    lcd_cmd(0xC0);
    lcd_string( "Cur temp degree");
    adc_read = 1;
    adc_write = 1;
    delay(1000);
    lcd_cmd(0x01);
 
    while (1)
        {
            delay(100);
            adc_read=1;
            adc_write=0;
            delay(1);
 
            adc_write=1;
            while(adc_intr==1);
 
            adc_read=0;
            val=P1;
 
            temp=((float)val/255)*100.00;
 
            x+=(int)temp1;
            delay(10);
 
            delay (100);
 
            adc_read=1;
            adc_write=0;
            delay(1);
 
            adc_write=1;
            while(adc_intr==1);
 
            adc_read=0;
            val=P1;
            temp=((float)val/255)*100;
            x+=(int)temp1;
            delay(10);
            delay(100);
 
            adc_read=1;
            adc_write=0;
            delay(1);
            adc_write=1;
            while(adc_intr==1);
            adc_read=0;
            val=P1;
            temp=((float)val/255)*100;
            x+=(int)temp1;
 
            temp=x/3;
            x=0;
 
            if(temp>UPTEMP&&loadon==0)
                {
                    output=1;
                    loadon=1;
                }
            if(temp<=DOWNTEMP&&loadon==1)
                {
                    pwmm(10);
                    loadon=0;
                }
            if(temp>=AL)
                {
                    alam=0;
                }
                                        
            lcd_cmd(0x80);
            lcd_string("TEMP=");
            lcd_data((temp/10)%10+48);
            lcd_data(temp%10+48);
            lcd_string(" DEG. C");
            lcd_cmd(0xc0);
 
            if(loadon==1)
                {
                    lcd_string("COOLER ON ");
                }
            else
                {
                    lcd_string("COOLER OFF");
                }
            lcd_cmd(0x80);
        }
}

:pH · Mar 28, 2012

Firstly please provide some details regarding your hardware , i can see 8051 series , what ADC are you using ? what temp. sensor ?

Just provide little briefing so that we can help you !!!

jackrude · Mar 29, 2012

I am using AT89s52 as the MCU, and the converter is ADC0804, and LM35 for the sensor

papunblg · Apr 2, 2012

jackrude said:

Hello all, I'm have trouble for displaying the second part of the message on to the LCD, it only display "temp controller, cur temp degree", it's not showing "temp =, deg C", please help me, i dont know it's the code problem or it's the hardware issue, this code is working on my demo board XL400, but is not working on my prototype,

Code C - [expand]
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#include<reg51.h>
#define data P0
#define UPTEMP 45
#define DOWNTEMP 35
#define AL 50
 
sbit rs=P2^0;
sbit rw=P2^1;
sbit en=P2^2;
sbit adc_read=P3^4;
sbit adc_write=P3^3;
sbit adc_intr=P3^5;
sbit output=P3^7;
sbit alam=P3^6;
bit loadon=0;
 
void delay(int time)
    {   
        int i, j;   
            for(i=0;i<127;i++)  
                {
                    for (j=0;j<time;j++);
                }       
    }
 
void lcd_data(unsigned char a)
    {
        rs =1;
        data=a;
        en =1;
        delay(5);
        en = 0;
        delay(5);
    }
 
void lcd_cmd(unsigned char a)
    {
        rs=0;
        data=a;
        en=1;
        delay(1);
        en=0;
        delay(1);
 
    }
void lcd_string (char * s)
    {
        while(*s)
            
            {
                lcd_data(*s);
                s++;
            }
    }
 
void lcd_init()
{
    lcd_cmd(0x38);
    lcd_cmd(0x0e);
    lcd_cmd(0x01);
    lcd_cmd(0x0c);
    lcd_cmd(0x80);
}
 
void pwmm(int i)
{  int j,k;
   output=1;    
   for(j=0;j<i;j++)
    delay(5);
   k=10-i;
   output=0;
   for(j=0;j<k;j++)
    delay(5);
}
 
void main()
{
    unsigned char val=0, temp=0;
    unsigned int x=0;
    float temp1;
    output=0;
    alam=1;
    rw=0;
    lcd_init();
    lcd_string (" Temp controller" );
    lcd_cmd(0xC0);
    lcd_string( "Cur temp degree");
    adc_read = 1;
    adc_write = 1;
    delay(1000);
    lcd_cmd(0x01);
 
    while (1)
        {
            delay(100);
            adc_read=1;
            adc_write=0;
            delay(1);
 
            adc_write=1;
            while(adc_intr==1);
 
            adc_read=0;
            val=P1;
 
            temp=((float)val/255)*100.00;
 
            x+=(int)temp1;
            delay(10);
 
            delay (100);
 
            adc_read=1;
            adc_write=0;
            delay(1);
 
            adc_write=1;
            while(adc_intr==1);
 
            adc_read=0;
            val=P1;
            temp=((float)val/255)*100;
            x+=(int)temp1;
            delay(10);
            delay(100);
 
            adc_read=1;
            adc_write=0;
            delay(1);
            adc_write=1;
            while(adc_intr==1);
            adc_read=0;
            val=P1;
            temp=((float)val/255)*100;
            x+=(int)temp1;
 
            temp=x/3;
            x=0;
 
            if(temp>UPTEMP&&loadon==0)
                {
                    output=1;
                    loadon=1;
                }
            if(temp<=DOWNTEMP&&loadon==1)
                {
                    pwmm(10);
                    loadon=0;
                }
            if(temp>=AL)
                {
                    alam=0;
                }
                                        
            lcd_cmd(0x80);
            lcd_string("TEMP=");
            lcd_data((temp/10)%10+48);
            lcd_data(temp%10+48);
            lcd_string(" DEG. C");
            lcd_cmd(0xc0);
 
            if(loadon==1)
                {
                    lcd_string("COOLER ON ");
                }
            else
                {
                    lcd_string("COOLER OFF");
                }
            lcd_cmd(0x80);
        }
}

Port P1 is connected to D0-D7 of the ADC.
Make the port as input at the start of the main().
like, P1=0xFF;

And, also make INTR, RD, WR pin high before that infinite while loop like:-

adc_read=1;
adc_write=1;
adc_intr=1;

After that in the while loop before conversion,

Code C - [expand]
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........................
............
while (1)
        {
            adc_write=0;
            adc_write=1;
            while(adc_intr==1);
            adc_read=0;
            val=P1;
            adc_read=1;
            temp=((float)val/255)*100.00;
.................................................
}

Make these changes to get reading from ADC.
It would be good if you pass the value of "val" to a seperate function and process there. The main() will look good. Also take average of multiple(>1000) readings.
Use loop.
At a quick glance these are the changes you need.

jackrude · Apr 3, 2012

thank you for help, we had initial the input P1= 0xff, all the message is displaying on the LCD, but the temperature is changing, look like the sensor is detecting any heat source, we had check over and over again of the circuit, but still not working, plz help

:pH · Apr 3, 2012

You are using LM35 so check the output pin of LM35 i.e. pin2 , it should be like :

for 35 C - 0.35 V
for 40 C - 0.4 V

check if it remains constant for 5 sec and then tell me

papunblg · Apr 3, 2012

This generally happens if you do not take average of multiple readings. Take average of 2000 readings. The output will be stable.
For Idea:-

Code C - [expand]
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void read_adc(void)
{
unsigned short i;
unsigned long result_temp=0;
      for(i=2000;i>0;i-=1) //looping 2000 times for getting average value
      {
            adc_write=0;
            adc_write=1;
            while(adc_intr==1);
            adc_read=0;
            val=P1;
            adc_read=1;
           result_temp+=val;
      }
result = result_temp/2000; //getting average value result declared as global
}

Call the function from main and then continue with the value stored in result. [check data types]
This is the idea.

Arch Zone · Apr 3, 2012

Reading sensor very often can make it's temperature up. it will sense his own temperature rather than environment.

:pH · Apr 3, 2012

But thats not the case with lm35 because one of its key features is minimal self heating , so dont worry about that problem !

jackrude · Apr 5, 2012

hi there, we did measure the output voltage from the LM35 on the output, it keep increase on the voltage from 0.338......

:pH · Apr 5, 2012

So it increases from 0.338 upto what ? if it changes a lot then there is some problem wit your lm35 coz generally they are stable output transducers

---------- Post added at 09:10 ---------- Previous post was at 09:07 ----------

Still as it shows some readings near room temp i will say its alright , so now just take an average of some 500 readings and show at the output , more readings avg u take less would be the fluctuations . . .

hope it helped !

jackrude · Apr 9, 2012

the output voltage seems find, and we reconnect the diagram, and measure all the pin to pin voltage, it look find, I am wondering can it be code problem?

papunblg · Apr 9, 2012

Publish the final code

mgate · Apr 11, 2012

papunblg said:
Publish the final code

I agree... We can't just guess...

One little suggestion about temperatures and averages, control and stuff... keep in mind that a user don't need to get real time info on the lcd... we probably will never note if the info comes a fraction of a second later.. my suggestion is: use timed display info refreshing, according to what is reasonable... avoid the flashing unreadable numbers... you should separate what is working actions from report actions in time domain

jackrude · Apr 12, 2012

Code:

#include <REGX51.H>
#define data P0
#define input P1
#define UPTEMP 45
#define DOWNTEMP 35
#define AL 50

sbit rs=P2^0;
sbit rw=P2^1;
sbit en=P2^2;
sbit adc_read=P3^4;
sbit adc_write=P3^3;
sbit adc_intr=P3^5;
sbit output=P3^7;
sbit alam=P3^6;
bit loadon=0;

void delay(int time)
	{	
		int i,j;	
			for(i=0;i<127;i++)	
				{
					for (j=0;j<time;j++);
				}		
	}

void lcd_data(unsigned char a)
	{
		rs=1;
		data=a;
		en=1;
		delay(1);
		en=0;
		delay(1);
	}

void lcd_cmd(unsigned char a)
	{
		rs=0;
		data=a;
		en=1;
		delay(1);
		en=0;
		delay(1);

	}

void lcd_string(char*s)
	{
		while(*s)
			
			{
				lcd_data(*s);
				s++;
			}
	}

void lcd_init()
{
	lcd_cmd(0x38);
	lcd_cmd(0x0e);
	lcd_cmd(0x01);
	lcd_cmd(0x0c);
	lcd_cmd(0x80);
}

void pwmm(int i)
{  
	int j,k;
   	output=1;	
   	for(j=0;j<i;j++);
	delay(5);
   	k=10-i;
   	output=0;
   	for(j=0;j<k;j++);
	delay(5);
}

void main()
{
	unsigned char val=0, temp=0;
	unsigned int x=0;
	float temp1;
	output=0;
	alam=1;
	rw=0;
	lcd_init();
	lcd_string (" Temp controller" );
	lcd_cmd(0xC0);
	lcd_string( "Cur temp degree");
	adc_read=1;
	adc_write=1;
	delay(1000);
	lcd_cmd(0x01);
	input=0xff;

	while (1)
		{
			delay(100);
			adc_read=1;
			adc_write=0;
			delay(1);

			adc_write=1;
			while(adc_intr==1);

			adc_read=0;
			val=input;

			temp=((float)val/255)*100.00;

			x+=(int)temp1;
			delay(10);
			delay (100);

			adc_read=1;
			adc_write=0;
			delay(1);

			adc_write=1;
			while(adc_intr==1);

			adc_read=0;
			val=input;
			temp=((float)val/255)*100.00;
			x+=(int)temp1;
			delay(10);
			delay(100);

			adc_read=1;
			adc_write=0;
			delay(1);
			adc_write=1;
			while(adc_intr==1);
			adc_read=0;
			val=input;
			temp=((float)val/255)*100.00;
			x+=(int)temp1;

			temp=x/3;
			x=0;

			if(temp>=UPTEMP&&loadon==0)
				{
					pwmm(10);
					loadon=1;
				}
			if(temp<=DOWNTEMP&&loadon==1)
				{
					
					output=0;
					loadon=0;
				}
			if(temp>=AL)
				{
					alam=0;
				}
									    
			lcd_cmd(0x80);
			lcd_string("TEMP= ");
			lcd_data((temp/10)%10+48);
			lcd_data(temp%10+48);
			lcd_string("DEG.C");

			lcd_cmd(0xc0);
			if(loadon==1)
				{
					lcd_string("Fast running");
				}
			else
				{
					lcd_string("Slow running");
				}
			lcd_cmd(0x80);
		}
}

mgate · Apr 12, 2012

Well.. you are actually displaying garbage....
float temp 1 is never defined

also I don't understand why is temp and x is integer.. probably you have dead code mixed with new code

Code:

float temp1; 

.....

val=input;

temp=((float)val/255)*100.00;

x+=(int)temp1;  // you are adding garbage to you sum... with out any temperature info at all

then you do it again ....

val=input;
temp=((float)val/255)*100.00;
x+=(int)temp1;

and again...

val=input;
temp=((float)val/255)*100.00;
x+=(int)temp1;

until you  get the mean value of a variable with garbage
temp=x/3;
x=0;

And finally you print the mean of garbage

lcd_string("TEMP= ");
lcd_data((temp/10)%10+48);
lcd_data(temp%10+48);

jackrude · Apr 17, 2012

yeh, we also recognized it too, and we had change the temp1 to temp, now is give some value, but the degree is not accuracy, wondering for the calculation, any suggestion, thank you for reply

mgate · Apr 17, 2012

well.. your calculation is not so bright

LM35 --> 10mV/ºC
0.5°C accuracy guaranteeable (at +25°C) --> 5mV

ADC0804, using REF/2= 2.500 V

1LSB = 5000mV/256 =19.53 mV --> 2 degrees aprox. note you have a +/- 1LSB error with this setup, meaning you have +/- 2 ºC error on the measuring... this without considering noise..

conclusion... you have a a bad overall temperature accuracy, and also a bad signal to noise relationship..
advice... figure out the max temp your system will be dealing with, then make the higher temp lm35 output match the adc max input voltage (5V) using an OPAMP to introduce the desired gain on the LM35 signal..

xpress_embedo · Apr 17, 2012

Hmmm... You are not able to display reading on second line...
This mainly occurs when your lcd is not properly initialized..

I had also faced this problem... few months back...

So just give some delay after initialization command

Code:

void lcd_init()
{
	lcd_cmd(0x38);
        //Give Some Delay Here
	lcd_cmd(0x0e);
        //Give Some Delay Here
	lcd_cmd(0x01);
        //Give Some Delay Here
	lcd_cmd(0x0c);
        //Give Some Delay Here
	lcd_cmd(0x80);
        //Give Some Delay Here
}

OKay, if this works then great, otherwise write a test code to check your lcd display to display some string on first and second line.

Hope this helps

jackrude · May 13, 2012

thank you to everyone, I had found the issues, thank you again

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[SOLVED] LCD problem for display the second part

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