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Forum: µC & Digital Electronics Problem with atmega -8


von Ajay R. (ajay_r)


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Hey..I am trying my hands on lcd 16x2 and somehow i got it to work.I'm 
trying to display an output on 16x2 which is dependent on sum input on 
other pins but cant get it to work.Here is my code..
1
 #define F_CPU 1000000UL
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#include <avr/io.h>
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#include <util/delay.h>
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#define LCD_DATA PORTB                //LCD data port
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#define ctrl PORTD
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#define en PD2                         // enable signal
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#define rw PD1                       // read/write signal
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#define rs PD0                     // register select signal
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int main()
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{
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DDRB=0xff;                                  // setting the port B
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DDRD=0x07;                                // setting for port D
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DDRC=0;
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PORTC=0b0000000;
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init_LCD();                                 // initialization of LCD
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_delay_ms(50);                        // delay of 50 mili seconds
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LCD_write_string("“hello world”");                      // function to print string on LCD
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if(PINC==0b0000001){
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_delay_ms(50);
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LCD_cmd(0xc0);
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_delay_ms(1);
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LCD_write_string("THIS IS WORKING ");}
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return 0;
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}
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void init_LCD(void)
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{
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LCD_cmd(0x38);                            // initialization of 16X2 LCD in 8bit mode
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_delay_ms(1);
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LCD_cmd(0x01);                                 // clear LCD
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_delay_ms(1);
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LCD_cmd(0x0E);                        // cursor ON
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_delay_ms(1);
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LCD_cmd(0x80);                     // —8 go to first line and –0 is for 0th position
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_delay_ms(1);
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return;
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}
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void LCD_cmd(unsigned char cmd)
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{
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LCD_DATA=cmd;
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ctrl =(0<<rs)|(0<<rw)|(1<<en);
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_delay_ms(1);
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ctrl =(0<<rs)|(0<<rw)|(0<<en);
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_delay_ms(50);
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return;
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}
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void LCD_write(unsigned char data)
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{
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LCD_DATA= data;
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ctrl = (1<<rs)|(0<<rw)|(1<<en);
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_delay_ms(1);
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ctrl = (1<<rs)|(0<<rw)|(0<<en);
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_delay_ms(50);
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return ;
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}
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void LCD_write_string(unsigned char *str)             //store address value of the string in pointer *str
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{
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int i=0;
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while(str[i]!='\0')                               // loop will go on till the NULL character in the string
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{
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LCD_write(str[i]);                            // sending data on LCD byte by byte
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i++;
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}
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return;
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}
The first line ie HELLO WORLD is working fine but there is no display in 
the second line.

von Ralf (Guest)


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Ajay R. wrote:
> if(PINC==0b0000001){
> _delay_ms(50);
> LCD_cmd(0xc0);
> _delay_ms(1);
> LCD_write_string("THIS IS WORKING ");}

The program doesn't wait for PINC -> 1

von Ajay R. (ajay_r)


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Ralf wrote:
> Ajay R. wrote:
>> if(PINC==0b0000001){
>> _delay_ms(50);
>> LCD_cmd(0xc0);
>> _delay_ms(1);
>> LCD_write_string("THIS IS WORKING ");}
>
> The program doesn't wait for PINC -> 1

I didnt get can you elaborate a bit please.

von sepp1985 (Guest)


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1
#define F_CPU 1000000UL
2
3
#include <avr/io.h>
4
#include <util/delay.h>
5
6
#define LCD_DATA PORTB                //LCD data port
7
#define ctrl PORTD
8
#define en PD2                         // enable signal
9
#define rw PD1                       // read/write signal
10
#define rs PD0                     // register select signal
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int main()
15
{
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DDRB=0xff;                                  // setting the port B
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DDRD=0x07;                                // setting for port D
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DDRC=0;
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PORTC=0b0000001;  //Sink mode??? 
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init_LCD();                                 // initialization of LCD
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_delay_ms(50);                        // delay of 50 mili seconds
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LCD_write_string("“hello world”");                      // function to print string on LCD
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while(1) //do it ever and ever and ever
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{
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if(PINC==0b0000001){
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_delay_ms(50);
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LCD_cmd(0xc0);
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_delay_ms(1);
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LCD_write_string("THIS IS WORKING ");}
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}
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return 0;
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}
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void init_LCD(void)
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{
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LCD_cmd(0x38);                            // initialization of 16X2 LCD in 8bit mode
39
_delay_ms(1);
40
LCD_cmd(0x01);                                 // clear LCD
41
_delay_ms(1);
42
LCD_cmd(0x0E);                        // cursor ON
43
_delay_ms(1);
44
LCD_cmd(0x80);                     // —8 go to first line and –0 is for 0th position
45
_delay_ms(1);
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return;
47
}
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void LCD_cmd(unsigned char cmd)
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{
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LCD_DATA=cmd;
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ctrl =(0<<rs)|(0<<rw)|(1<<en);
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_delay_ms(1);
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ctrl =(0<<rs)|(0<<rw)|(0<<en);
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_delay_ms(50);
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return;
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}
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void LCD_write(unsigned char data)
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{
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LCD_DATA= data;
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ctrl = (1<<rs)|(0<<rw)|(1<<en);
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_delay_ms(1);
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ctrl = (1<<rs)|(0<<rw)|(0<<en);
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_delay_ms(50);
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return ;
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}
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void LCD_write_string(unsigned char *str)             //store address value of the string in pointer *str
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{
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int i=0;
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while(str[i]!='\0')                               // loop will go on till the NULL character in the string
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{
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LCD_write(str[i]);                            // sending data on LCD byte by byte
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i++;
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}
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return;
78
}

: Edited by Admin
von Route_66 (Guest)


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Ralf wrote:
> The program doesn't wait for PINC -> 1

What is connected to PORT C, especialli at bit 0 of it?

von Route_66 (Guest)


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sorry, bit 1 of port C.

von B.A. (Guest)


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This linie is possiply wrong.
> if(PINC==0b0000001){

You want to do something if PC0 (Pin0 from Port C) is high?

try this:
if(PINC & 0b0000001){

von Route_66 (Guest)


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Route_66 wrote:
> sorry, bit 0 of port C.

von Ajay R. (ajay_r)


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Route_66 wrote:
> Ralf wrote:
>> The program doesn't wait for PINC -> 1
>
> What is connected to PORT C, especialli at bit 0 of it?

just a constant voltage source. I was trying to test thats why

von Ajay R. (ajay_r)


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I tried this code and it worked fine for a simple led
1
#define F_CPU 1000000UL
2
3
 #include <avr/io.h>
4
 #include <util/delay.h>
5
6
7
int main(void) {
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DDRB=0;
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DDRC=0b11111111;
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PORTC=0b00000000;
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PORTB=0b00000000;
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if(PINB==0b00000001)
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{PORTC=0b11111111;}
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return 0;
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}
but when i interchanged PORTC AND PORTB ie interchanged their function 
it didnt worked.So i guess there in something wrong with input pins at 
PORTC.By the way im using proteus for simulating

von Ralf (Guest)


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sepp1985 wrote:
> while(1) //do it ever and ever and ever
> {
> if(PINC==0b0000001){
> _delay_ms(50);
> LCD_cmd(0xc0);
> _delay_ms(1);
> LCD_write_string("THIS IS WORKING ");}
> }

thereabouts.

But what changes the bit? I think, you would better wait (e.g. if it is 
a button)

von Ralf (Guest)


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Ralf wrote:
> But what changes the bit?

Sorry, to slow.

von Ajay R. (ajay_r)


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Ralf wrote:
> sepp1985 wrote:
>> while(1) //do it ever and ever and ever
>> {
>> if(PINC==0b0000001){
>> _delay_ms(50);
>> LCD_cmd(0xc0);
>> _delay_ms(1);
>> LCD_write_string("THIS IS WORKING ");}
>> }
>
> thereabouts.
>
> But what changes the bit? I think, you would better wait (e.g. if it is
> a button)

I understand what you are saying but im not using a switch pinc is 
connected to vcc from the beginning no switch is there

von B.A. (Guest)


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Ajay R. wrote:
> I understand what you are saying but im not using a switch pinc is
> connected to vcc from the beginning no switch is there

>> if(PINC==0b0000001){
PC0 = high
PC1 ... PC7 = low

Do you have connect the other Pins (Pin 1 to Pin 7) from Port C to 
Ground?

von Ajay R. (ajay_r)


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B.A. wrote:
> Ajay R. wrote:
>> I understand what you are saying but im not using a switch pinc is
>> connected to vcc from the beginning no switch is there
>
>>> if(PINC==0b0000001){
> PC0 = high
> PC1 ... PC7 = low
>
> Do you have connect the other Pins (Pin 1 to Pin 7) from Port C to
> Ground?

Yes...Done that

von Ajay R. (ajay_r)


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TAKE A LOOK AT THIS

I tried this code and it worked fine for a simple led

#define F_CPU 1000000UL

 #include <avr/io.h>
 #include <util/delay.h>


int main(void) {

DDRB=0;
DDRC=0b11111111;
PORTC=0b00000000;
PORTB=0b00000000;
if(PINB==0b00000001)
{PORTC=0b11111111;}
return 0;
}

but when i interchanged PORTC AND PORTB ie interchanged their function
it didnt worked.So i guess there in something wrong with input pins at
PORTC.By the way im using proteus for simulating

von B.A. (Guest)


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Ajay R. wrote:
>> Do you have connect the other Pins (Pin 1 to Pin 7) from Port C to
>> Ground?
>
> Yes...Done that

Realy?

PC6 is the Reset-Pin of the ISP-Port ... this Pin must be high, if it is 
Low the AVR is in Programming-Mode.

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