Issue regarding waveform generation

[lokesh tiwari]

I have used !Mhz internal clock with prescale as 64…after each 60 seconds i have to generate waveform at 4 differnt pins….with that wave i have to drive minute’s niddle of aa watch….

i am posting 2 codes here….1st one is working while 2nd is not….but the second code is more accurate….

 

1st code is:—

 

#include <avr/io.h>

#define F_CPU 1000000UL

#include <util/delay.h>

#include <avr/interrupt.h>

int counter;

void timer_init()

{

TCCR1B |= (1 << WGM12)|(1 << CS10)|(1 << CS11);

TIMSK |= (1 << OCIE1A);

TCNT1 = 0;

}

void timer_set()

{

OCR1A = 15624;

sei();

}

 

ISR(TIMER1_COMPA_vect)

{

counter++;

if(counter == 60)

{

counter=0;

cli();

PORTD = 0x80; 

_delay_ms(125); 

PORTD = 0x00; 

_delay_ms(125); 

PORTC=0x01; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x02; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x80; 

_delay_ms(125); 

PORTC = 0x00;

TCNT1=0;

counter=1;

sei();

}

}

 

int main()

{

DDRC = 0xFF; 

DDRD = 0xFF; 

timer_init(); 

timer_set();

while(1);

}

 

 

2nd code is

---

 

 

#include <avr/io.h>

#define F_CPU 1000000UL

#include <util/delay.h>

#include <avr/interrupt.h>

int counter,flag;

void timer_init()

{

TCCR1B |= (1 << WGM12)|(1 << CS10)|(1 << CS11);

TIMSK |= (1 << OCIE1A);

TCNT1 = 0;

}

void timer_set()

{

OCR1A = 15624;

sei();

}

 

ISR(TIMER1_COMPA_vect)

{

counter++;

if(counter == 60)

{

counter=0;

flag=1;

}

else

counter++;

}

 

int main()

{

DDRC = 0xFF; 

DDRD = 0xFF; 

timer_init(); 

timer_set();

while(1)

{

while(flag)

{

PORTD = 0x80; 

_delay_ms(125); 

PORTD = 0x00; 

_delay_ms(125); 

PORTC=0x01; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x02; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x80; 

_delay_ms(125); 

PORTC = 0x00;

}

}

}

 

 

The only differnece is in the ISR…..but 2nd code is compiling well,generating Hex code also but does not provide the waveform at particular pins as mentiones……both codes are 99% same……

 

[AJISH ALFRED]

Hi Lokesh,

 

Try these modifications.

 

#include <avr/io.h>

#define F_CPU 1000000UL

#include <util/delay.h>

#include <avr/interrupt.h>

//int counter,flag;

int counter = 0, flag = 0;                               //modification

void timer_init()

{

TCCR1B |= (1 << WGM12)|(1 << CS10)|(1 << CS11);

TIMSK |= (1 << OCIE1A);

TCNT1 = 0;

}

void timer_set()

{

OCR1A = 15624;

sei();

}

 

ISR(TIMER1_COMPA_vect)

{

//counter++;                                                //modification

if(counter == 60)

{

counter=0;

flag=1;

}

else

counter++;

}

 

int main()

{

DDRC = 0xFF; 

DDRD = 0xFF; 

timer_init(); 

timer_set();

while(1)

{

if(flag)                            //modification

{

PORTD = 0x80; 

_delay_ms(125); 

PORTD = 0x00; 

_delay_ms(125); 

PORTC=0x01; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x02; 

_delay_ms(125); 

PORTC = 0x00; 

_delay_ms(125); 

PORTC=0x80; 

_delay_ms(125); 

PORTC = 0x00;

_delay_ms(125);             //modification

flag = 0;                          //modification

}

}

}

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