Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

how to make a seven segment based count down timer for traffic signal using atmega 16

Status
Not open for further replies.

prashanttyagi85

Advanced Member level 4
Joined
May 5, 2011
Messages
106
Helped
33
Reputation
66
Reaction score
33
Trophy points
1,308
Location
india
Activity points
1,982
dear all
i am working on traffic signal's countdown timer.
as everyone know that timer shows the remaining stop time for that road.
it starts from final value & reduce upto 0 till the signal is changed.
i have to read the red signal first of all then calculate the time then convert it into seconds then send it to 7 segments then reduce it by 1 second & change it on 7 segment.
am i write?
if yes then how to convert time into second & send it to 7 segment?

- - - Updated - - -

is nobody interested to tell me about it?
 

Er.abdulrehman

Member level 2
Joined
Jul 18, 2011
Messages
51
Helped
6
Reputation
12
Reaction score
6
Trophy points
1,288
Location
India
Activity points
1,517
You need to load the timer register first with the HEX value of your time count.
Timer Count=1/((1/12)*Crystal Frequency)
 

BradtheRad

Super Moderator
Staff member
Joined
Apr 1, 2011
Messages
14,240
Helped
2,817
Reputation
5,642
Reaction score
2,757
Trophy points
1,393
Location
Minneapolis, Minnesota, USA
Activity points
106,225
This is a system consisting of several circuits. It is hard to visualize the entire layout from your verbal description.

i have to read the red signal first of all then calculate the time then convert it into seconds then send it to 7 segments then reduce it by 1 second & change it on 7 segment.

The method I'm used to seeing, is to load a desired value into the seconds timer, then start it counting down.
 

prashanttyagi85

Advanced Member level 4
Joined
May 5, 2011
Messages
106
Helped
33
Reputation
66
Reaction score
33
Trophy points
1,308
Location
india
Activity points
1,982
actually we are not having any desired value here.
we have to detect the red signal then read it in first cycle
after that wait for next cycle
in next next cycle again read the red signal
then compare the first red signals time with second one
if both time are same then display it on 7 segment in next cycle with count down
now we have to read it in each cycle that the red value is same or not
 

ALERTLINKS

Advanced Member level 4
Joined
Dec 13, 2003
Messages
1,259
Helped
396
Reputation
786
Reaction score
380
Trophy points
1,363
Location
Pakistan
Activity points
7,263
actually we are not having any desired value here.
we have to detect the red signal then read it in first cycle
after that wait for next cycle
in next next cycle again read the red signal
then compare the first red signals time with second one
if both time are same then display it on 7 segment in next cycle with count down
now we have to read it in each cycle that the red value is same or not

It as a clever approach for automatic time lapse calculation. You dont have to feed any value for time but by calculating time taken for red signal, seconds count value is updated accordingly making setup real easy.
 

prashanttyagi85

Advanced Member level 4
Joined
May 5, 2011
Messages
106
Helped
33
Reputation
66
Reaction score
33
Trophy points
1,308
Location
india
Activity points
1,982
dear all after a long time i worked on this count down timer.
i am posting the code here please help me in this code as i want to use here timer interrupt.

- - - Updated - - -

Code:
#include<avr/io.h>
#include<util/delay.h>
#include<avr/interrupt.h>
#define F_CPU 16000000UL 

char digit[] = {0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6};

char count=0,sec=0,tensec=0, halfsec=0;
char i=0,j=0,one=0,ten1=0,one1=0,ten=0,hun=0,sec1=0,k=0,track=0;


//char greencount=0,greensec1=0,greentensec=0, greenhalfsec=0;

void main()
{
	DDRD=0xFF;
	DDRB=0x00;
	DDRA=0xFF;
//	sei();	// set intrupt enable

	while(1)
	{
	//	PORTA=0xff;	
	//	PORTD=0xff;
		if(PINB & 0b00010000)
		{
		
			_delay_ms(5);
			read();			//function to read the i/p.
			
		}
		sec=sec1;		
		breake(sec);		//function to break sec into ones, tens
		display(one, ten);	// to display on 7 segment
	}
}
read()
{
	if(PINB & 0b00010000)
	{
		
	_delay_ms(20);
	while(PINB & 0b00010000)
	{
		count++;
		_delay_ms(5);
		if(count==20)
		{
			tensec++;
			count=0;
			if(!(PINB & 0b00010000))
				break;
		}
		if(tensec==5)
		{
			halfsec++;
			tensec=0;
			if(!(PINB & 0b00010000))
				break;
		}
		if(halfsec==2)
		{
			sec1++;
			halfsec=0;
			if(!(PINB & 0b00010000))
				break;
		}				
	}
	}
}

breake(sec)
{
	if(sec<=99)
	{
		hun=0;
		one=sec%10;
		one1=one;
		ten=sec/10;
		ten1=ten;
	}
	else
	{
		hun=1;
		one=sec%100;
		sec=sec/10;
		ten=sec%10;
	}
}

display(one, ten)
{
	for(i=ten;i>0;i--)
	{
		PORTD=~digit[i];
		for(j=one;j>0;j--)
		{
			PORTA=~digit[j];
			_delay_ms(1000);
		}
		if(j==0)
		{
			PORTA=~digit[j];
			_delay_ms(1000);
			one=9;	
		}
	}
	if(i==0)
	{
		PORTD=~digit[i];
		for(j=one;j>0;j--)
		{
			PORTA=~digit[j];
			_delay_ms(1000);
		}
	}
	if(i==0&j==0)
	{
		PORTD=~digit[i];
		PORTA=~digit[j];
		_delay_ms(1000);
		one=one1;
		ten=ten1;
	}
		
}

- - - Updated - - -

the basic funda behind my project is
i have to read a +ve signal which i am reading using PB4 pin of atmega16.
when signal on, i have to detect it, count the time upto which it remains on, & display it on 7 segment.
so i used here function read() to read it
function breake() to convert it for display
Function display() for display it
i am doing here polling
but it is not an efficient method so please any body arrange my code with the help of timer interrupt.
thanks
 

prashanttyagi85

Advanced Member level 4
Joined
May 5, 2011
Messages
106
Helped
33
Reputation
66
Reaction score
33
Trophy points
1,308
Location
india
Activity points
1,982
dear all
please send any suggestion or correction in my code for removal of my problem
thanks to all for reply
 

Joined
Dec 4, 2012
Messages
4,294
Helped
822
Reputation
1,654
Reaction score
793
Trophy points
1,393
Location
Bangalore, India
Activity points
0
When PB4 becomes high, start the timer and when PB4 becomes low then stop the timer. In the timer interrupt routine increment ms, sec, hour counters. The values of ms, sec, hour counters will give you the time for which PB4 was on. If you want more precision then incluse a timer interrupt for one us. Then increment the ms, sec, and hour counters depending upon the value of counter used for us.



Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
//Timer0 Prescaler = 0; Preload = 16; Actual Interrupt Time = 1 us
 
//Place/Copy this part in declaration section
void InitTimer0(){
  SREG_I_bit = 1; 
  OCR0 = 16; 
  TCCR0 = 0x28;
  TCCR0 |= 0x01;
  OCIE0_bit = 1; 
}
 
void Timer0Overflow_ISR() org IVT_ADDR_TIMER0_COMP {
  //Enter your code here
  OCR0 = 16;
  us++
  if(us == 1000){ms++; us = 0;}
  if(ms == 1000){sec++; ms = 0;}
  if(sec == 60){min++; sec = 0;}
  if(min == 60){hour++; min = 0;}
  if(hour == 24){day++; hour = 0;}
    
 
}
 
 
//Display day:hour:min:sec:ms:us

 
Last edited:

prashanttyagi85

Advanced Member level 4
Joined
May 5, 2011
Messages
106
Helped
33
Reputation
66
Reaction score
33
Trophy points
1,308
Location
india
Activity points
1,982
thanks for reply & sorry for responding so much late.
please also tell that in your code line no. 13 said that "enter your code here" it means that should i write the code for displaying the data at 7 segment? or else.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top