Humidity Display on LCD

[proteek basu]

I have compiled the code for humidity display posted in engineers garage site using KEIL 4, I got zero errors and zero warnings, but when I run the controller I get garbage characters on the LCD first line the second line displats two single digit numbers with some gap in between, has anybody done this project? please help.

 

Proteek

[AJISH ALFRED]

Hi Proteek,

Please share the location from where you’ve find the code.

[proteek basu]

The code has been taken from Engineers Garage only under 8051 projects titled:

 

How to interface Humidity Sensor with 8051 Microcontroller (AT89C51)

 

// Program to Interface Humidity sensor with 8051 Microcontroller

#include<reg51.h>

sfr lcd_data_pin=0x80;//p0 port

sbit rs=P3^0;

sbit rw=P3^1;

sbit en=P3^2;

sbit wr= P3^3;

sbit rd= P3^4;

sbit intr= P3^5;

sfr input_port=0x90; //p1 port

unsigned int number=0;

unsigned char humidity,lcd,key=0;

 

void delay(unsigned char count)

{

unsigned char i;

unsigned int j;

for(i=0;i<count;i++)

for(j=0;j<1275;j++);

}

 

void lcd_command(unsigned char comm)

{

lcd_data_pin=comm;

en=1;

rs=0;

rw=0;

delay(1);

en=0;

}

 

void lcd_data(unsigned char disp)

{

lcd_data_pin=disp;

en=1;

rs=1;

rw=0;

delay(1);

en=0;

}

 

lcd_dataa(unsigned char *disp)

{

unsigned char x;

for(x=0;disp[x]!=0;x++)

{

lcd_data(disp[x]); 

}

}

 

void lcd_ini()

{

lcd_command(0x38);  // for using 8-bit 2 row LCD 

delay(50);

lcd_command(0x0F);        // for display on cursor blinking

delay(50);

lcd_command(0x0C);

delay(50);

lcd_command(0x80);

delay(50);

}

 

void lcd_display(unsigned int val)

{  

unsigned char flg=0;

lcd_command(0xC7);

if(val==0)

lcd_data(‘0’);

while(val>0)

{  

lcd=val%10;

val=val/10;

lcd_command(0xC7-flg);

lcd_data(lcd+’0′);

flg++;  

}

  

}

 

void display()

{

key++;

number=number+input_port;

if(key==11)

{

number=number/key;

number=number*10;

number=number/25;

humidity=number-3;

lcd_display(humidity);

key=0;

number=0;

}

}

 

void adc()

{

rd=1;

wr=0;

delay(2);

wr=1;

while(intr==1);

rd=0;

display();

delay(2);

intr=1;

}

 

void main()

{

lcd_ini();

lcd_dataa(“%Rel.Humidity:”);

while(1)

{

adc();

}

}

[proteek basu]

The characters displayed on the LCD are as follows:

 

$Pd1,Hthdht*8                               -1st line

        4   3                                       – 2nd line

[proteek basu]

I have checked the code using Proteus 8 simulator the display goes blank with the backlight only comming on

[AJISH ALFRED]

Hi Proteek,

Have you made exactly the same circuit as you find along with the code? The LCD should be connected in 8 bit mode. Please check your connections, especially the data lines.

[proteek basu]

Alfred Sir,

 

I have wired up the whole thing as per the circuit and rechecked everything several times, in fact there is a minor mistake in the circuit pin 34 is printed for a second time instead of 35 of the microcontroller, still then I am getting the same error.

[proteek basu]

Alfred Sir,

 

I have rechecked everything several times and things are just according to the circuit, LCD is in 8 bit mode only, still I am getting errors.

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