Temperature display on LCD

[hardeep]

Hello everyone,
I have interfaced 16×2 LCD and LM35 to atmega16….
The temperature value is not getting printed on the LCD…its a garbage value coming…some special and different symbols…
plz help me to convert hex value of adc to ascii to display on lcd…
i am attaching my code too…

#include<avr/io.h>

#include<util/delay.h>

 

#define LCD_DATA PORTB // LCD data port

#define ctrl PORTA

#define en PA7 // enable signal

#define rw PA6 // read/write signal

#define rs PA5 // register select signal

 

//

---

 

 

unsigned int ascii(unsigned char x)

{

            if (x<9)

x=x+0x30;

if (x>9)

x=x+0x37;

return (x);

}

unsigned int ADC_read(unsigned char ch)

{

ch= ch & 0b00000111; // channel must be b/w 0 to 7

ADMUX |= ch; // selecting channel

 

ADCSRA|=(1<<ADSC); // start conversion

while(!(ADCSRA & (1<<ADIF))); // waiting for ADIF, conversion complete

ADCSRA|=(1<<ADIF); // clearing of ADIF, it is done by writing 1 to it

 

return (ADC);

}

void ADC_init1(void) // Initialization of ADC

{

int intt=0b10000000;

SREG=SREG|intt;

ADMUX=(1<<REFS0); // For Aref=AVcc;

   ADCSRA=(1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0)|(1<<ADIE);

}

void LCD_cmd(unsigned char cmd)

{

LCD_DATA=cmd;

ctrl &=~ (1<<rs);

ctrl&=~(1<<rw);

ctrl|=(1<<en); // RS and RW as LOW and EN as HIGH

_delay_ms(1);

ctrl &=~ (1<<rs);

ctrl&=~(1<<rw);

ctrl&=~(1<<en); // RS, RW , LOW and EN as LOW

_delay_ms(50);

return;

}

 

void LCD_write(unsigned char data)

{

LCD_DATA= data;

ctrl |= (1<<rs);

ctrl&=~(1<<rw);

ctrl|=(1<<en); // RW as LOW and RS, EN as HIGH

_delay_ms(2);

ctrl |= (1<<rs);

ctrl&=~(1<<rw);

ctrl&=~(1<<en); // EN and RW as LOW and RS HIGH

_delay_ms(2); // delay to get things executed

return ;

}

void init_LCD(void)

{

LCD_cmd(0x38); // initialization of 16X2 LCD in 8bit mode

_delay_ms(1);

 

LCD_cmd(0x01); // clear LCD

_delay_ms(1);

 

LCD_cmd(0x0E); // cursor ON

_delay_ms(1);

 

LCD_cmd(0x80); // —8 go to first line and –0 is for 0th position

_delay_ms(1);

return;

}

  

 

//

---

int main(void)

{

unsigned int value_t;

DDRB=0xff;

PORTB=0x00;

DDRA=0xfc;

PORTA=0x02;

init_LCD();

_delay_ms(5);

int temp;

LCD_write(‘T’);

LCD_write(‘E’);

LCD_write(‘M’);

LCD_write(‘P’);

LCD_write(‘E’);

LCD_write(‘R’);

LCD_write(‘A’);

LCD_write(‘T’);

LCD_write(‘U’);

LCD_write(‘R’);

LCD_write(‘E’);

LCD_write(‘=’);

LCD_cmd(0xC0);

_delay_ms(1);

ADC_init1();

while(1)

{

value_t=ADC_read(0x01);

_delay_ms(1);

value_t=(5.00*value_t*100.00)/1023.00;

temp=value_t;

temp=temp&0xf0;

temp=temp>>4;

ascii(temp);

LCD_write(temp);

_delay_ms(10);

temp=value_t;

temp=temp&0x0f;

ascii(temp);

LCD_write(temp);

LCD_cmd(0xC0);

_delay_ms(1);

}

 

}

 

 

 

 

 

 

 

 

[Amit Joshi]

as you get digital value you have to extract unit, decade and hundred position values. by dividing and taking remainder . for example

for(i=0;i<2;i++)
{
ar=value%10;
value=value/10;
}
for example if you get 123 you will found following values-
when i=0;
ar[0];
value=12;

when i=1
ar[1]=2
value=1

when i=2
ar[2]=1
value=0

add 0x30 in ar values and print it one by one.

hope this method will work

[hardeep]

Thanks a lot buddy…
bt when i use this

for(i=0;i<2;i++)

{

ar=(value_t)%10;

(value_t)=(value_t)/10;

}

LCD_write(0x30+ar[2]);

LCD_write(0x30+ar[1]);

LCD_write(‘.’);

LCD_write(0x30+ar[0]);

LCD_write(‘d’);

LCD_write(‘C’);

 

_delay_ms(100);

the first digit is not getting printed…plz help…!!! 

[dagakshay]

for(i=0;value_t<=10;i++)
{
ar=(value_t)%10;
(value_t)=(value_t)/10;
}
LCD_write(value_t);
for(int j=i; j>=0;j–)
{
LCD_write(ar[j]);
}
_delay_ms(100);

try this out and let me know the result….

[hardeep]

Nothng is getting printed buddy …!!!

[dagakshay]

sorry mistake in first line
for(i=0;value_t>=10;i++)
{
ar=(value_t)%10;
(value_t)=(value_t)/10;
}
LCD_write(value_t);
for(int j=i; j>=0;j–)
{
LCD_write(ar[j]);
}
_delay_ms(100);

NOW try this out and let me know….

[hardeep]

Still not working…

[dagakshay]

sorry for misconceptions you just need to do +48 in the values here i am sending the complete i my self compiled and checked it….

/*
LCD data transfer through 8 bit mode

jsut writing a single letter 137 on LCD

LCD DATA port—-PORT A
signal port

---

PORT B
rs

---

PB0
rw

---

PB1
en

---

PB2

usidng internal clock frequency 1MHz

*/
#include
#include

#define LCD_DATA PORTA //LCD data port

#define signal PORTB
#define en PB2 //enable signal
#define rw PB1 //read/write signal
#define rs PB0 //resister select signal

void LCD_cmd(unsigned char cmd);
void init_LCD(void);
void LCD_write(unsigned char data);
void character();

int main()
{
DDRA=0xff; //making LCD_DATA port as out put port
DDRB=0x07; //making signal as out put
init_LCD(); //initialization of LCD
_delay_ms(50); // delay of 50 mili seconds
LCD_cmd(0xC0); // —8 go to first line and –0 is for 0th position
_delay_ms(1);
unsigned char value_t=137,i,j;
unsigned char ar[4];
for(i=0;value_t>=10;i++)
{
ar=(value_t)%10;
(value_t)=(value_t)/10;
}
LCD_write(value_t+48);
for(j=2;j>0 ;j–)
{
LCD_write(ar[j-1]+48);
}
_delay_ms(100);
}

void init_LCD(void)
{

LCD_cmd(0x38); //initializtion of 16X2 LCD in 8bit mode
_delay_ms(1);

LCD_cmd(0x01); //clear LCD
_delay_ms(1);

LCD_cmd(0x0E); //cursor ON
_delay_ms(1);

LCD_cmd(0x80); // —8 go to first line and –0 is for 0th position
_delay_ms(1);
return;
}

void LCD_cmd(unsigned char cmd)
{
LCD_DATA=cmd;
signal =(0< _delay_ms(1);
signal =(0< _delay_ms(50);
return;
}

void LCD_write(unsigned char data)
{
LCD_DATA= data;
signal = (1< _delay_ms(1);
signal = (1< _delay_ms(50); // give a 10 milli second delay to get thigs executed
return ;
}

[dagakshay]

wysiwyg_imageupload:918:

[muhammad]

Hello Hardeep.can you share the circuit schematic diagram..it might help me..TQ

 

[Dhruwank Vankawala]

Try this code for displaying temperature on LCD

 

#include <avr/io.h>
#include<util/delay.h>
#include<math.h>
#include<stdlib.h>
#define LCD_PRT PORTC
#define LCD_PIN PINC
#define LCD_DDR DDRC
#define LCD_RS 0
#define LCD_RW 1
#define LCD_EN 2

void delay_us(int d)
{
_delay_us(d);
}

void delay_ms(int d)
{
_delay_ms(d);
}

void lcdcommand(unsigned char cmnd)
{
LCD_PRT = (LCD_PRT & 0x0F)| (cmnd & 0xF0);
LCD_PRT &=~(1<<LCD_RS);
LCD_PRT &=~(1<<LCD_RW);
LCD_PRT |=(1<<LCD_EN);
delay_us(1);
LCD_PRT &=~(1<<LCD_EN);
delay_us(20);
LCD_PRT = (LCD_PRT & 0x0F) | (cmnd<<4);
LCD_PRT |= (1<<LCD_EN);
delay_us(1);
LCD_PRT &=~ (1<<LCD_EN);
}

void lcddata(unsigned char data)
{
LCD_PRT = (LCD_PRT & 0x0F) | (data & 0xF0);
LCD_PRT |= (1<<LCD_RS);
LCD_PRT &=~ (1<<LCD_RW);
LCD_PRT |= (1<<LCD_EN);
delay_us(1);
LCD_PRT &=~ (1<<LCD_EN);
delay_us(20);
LCD_PRT = (LCD_PRT & 0x0F) | (data << 4);
LCD_PRT |= (1<<LCD_EN);
delay_us(1);
LCD_PRT &=~ (1<<LCD_EN);
}

void LCD_init()
{
LCD_DDR = 0xFF;
LCD_PRT &=~(1<<LCD_EN);
delay_us(2000);
lcdcommand(0x33);
delay_us(100);
lcdcommand(0x32);
delay_us(100);
lcdcommand(0x28);
delay_us(100);
lcdcommand(0x0E);
delay_us(100);
lcdcommand(0x01);
delay_us(2000);
lcdcommand(0x06);
delay_us(100);
}

unsigned int adc_conv(void)
{
DDRA=0;
ADCSRA=0x87;
ADMUX=0xE0;
ADCSRA|=(1<<ADSC);
while((ADCSRA&(1<<ADIF))==0);
return ADCH;
}

void LCD_gotoxy(unsigned char x, unsigned char y)
{
unsigned char firstcharadr[]={0x80, 0x85};
lcdcommand(firstcharadr[y-1] + x – 1);
delay_us(100);
}

void LCD_print(char * str)
{
unsigned char i=0;
while(str!=0)
{
lcddata(str);
i++;
}
}

int main(void)
{
    unsigned int val;
    LCD_init();
    while(1)
    {
    LCD_gotoxy(1,1);
    LCD_print(“Temp “);
    LCD_gotoxy(1,2);
    val=adc_conv();
    char buffer[10];
    itoa(val,buffer,10);
    LCD_print(buffer);
    delay_ms(1000);
}
return 0;
}

[hazrat ali]

dear sir! 

         i have problem to interface external ADC0804 to atmega16 for temperature sensor…plz help me out obout this problem….Also their is problem to show value of temperature on lcd….how its value can be converted to decimal values…..

 

 

[hazrat ali]

Dear sir!

how ADC080 can be interface with atmega16…..???? i am not using inbuilt adc of atmaga16..

[AJISH ALFRED]

Hi Hazrat Ali,

Connect 8 digital output to any of the port of atmega16. Make sure that you’ve made all the pins of the port as input. Now simply read the port as a whole and you will get the value.

Regarding the decimal conversion, all you need is a function which can convert integer to string. C library already has such a function. Use printf with %d option.

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