Interfacing LM35 and avr controller with use of internal ADC of ATMEGA32

[Dhruwank Vankawala]

Hey, frds i m doing interfacing of LM35 with AVR controller(ATMEGA32). I got output on software bt still i dint get it on hardware following is the code for it……………can u plz help me…………….

 

#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 char val,t;
LCD_init();
while(1)
{
LCD_gotoxy(1,1);
LCD_print(“Temp “);
LCD_gotoxy(1,2);
val=adc_conv();
t=round(val*0.48876);
char buffer[10];
itoa(val,buffer,10);
LCD_print(buffer);
delay_ms(1000);
}
return 0;
}

[Tuhin]

 hey, Dhruwank you just forget to diable jtag interface Port. I have modified your program a little and it is working on hardware and 

wysiwyg_imageupload:3465:

I have checked it. You have done a great job.

 

 

 

 

 

#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

#define LS_NULL 0B00000000

 

 

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)

{

MCUCSR|= (1<<JTD);      //disaleb JTAG

MCUCSR|= (1<<JTD); 

 

unsigned char val,t;

LCD_init(LS_NULL);

LCD_gotoxy(1,1);

LCD_print(“Temperature “);

LCD_gotoxy(10,2);

LCD_print(“*c”);

while(1)

{

 

LCD_gotoxy(8,2);

val=adc_conv();

t=round(val*0.48876);

char buffer[10];

itoa(val,buffer,10);

LCD_print(buffer);

 

 

delay_ms(100);

}

return 0;

}

 

[Dhruwank Vankawala]

i have tried the code that u have sent bt i dint work on hardware….

i m using ATMEGA 32 development board provided by NEX ROBOTICS….

Which development board u have used?????

And tell me another manufacturer that provide ATMEGA 32 development board………

[Tuhin]

I connected it on BreadBoard. I have a developement board from Extreme Electronics But in my Developement board JTAG is already disabled by fuse byte settings from the time of buying. So I tried this on BreadBoard and it worked.

[jinay]

well i assume that there’s no problem with your LCD CODE…so you are getting output on LCD but you have a problem in ADC CODE and Interfacing

 

Interfacing is quite simple : Simply Connect LM35 to your ADC PIN

 

CODE ERROR:

 

I have found in your code that you are returning ADCH in adc_conv() function but my friend ADCH carries only upper bits of the resulting step as ATMEGA16/32 supports 10bit resolution ADC

 

ADCH :- 9:8

ADCL :-  7:0

 

thus whole ADCL and ADCH combine gives the result of ADC

 

and for that you only need to change ADC instead of ADCH

 

where ADC register is 10 bit register and it combines ADCL and ADCH

 

and don’t forget to change the return type of your function to unsigned short int adc_conv() for 10bit return

 

 

Try this i am sure this will surely clears your problem….

 

and still you find problem try to refer DATASHEET.. it will explain you very well…

[abhijit]

t=round(val/2);

char buffer[10];

d1=t/2;

itoa(d1,buffer,10);

LCD_print(buffer);

 

only adjust this in main for temperature show

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