Internal Timers of Arduino

In this tutorial I will explain how to use the TIMER0 of Arduino

May 30, 2018

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105840 views

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31 respects

embedded

clocks

Components and supplies

Resistor 220 ohm

LED (generic)

Arduino UNO

Project description

Code

Internal timer

arduino

1/*
2This program turns on and off a LED on pin 13 each 1 second using  an internal timer
3*/
4
5int timer=0;
6bool state=0;
7void setup() {
8  pinMode(13,OUTPUT);
9    
10  TCCR0A=(1<<WGM01);    //Set the CTC mode   
11  OCR0A=0xF9; //Value for ORC0A for 1ms 
12  
13  TIMSK0|=(1<<OCIE0A);   //Set  the interrupt request
14  sei(); //Enable interrupt
15  
16  TCCR0B|=(1<<CS01);    //Set the prescale 1/64 clock
17  TCCR0B|=(1<<CS00);
18
19 
20    
21}
22
23void  loop() {
24  //in this way you can count 1 second because the nterrupt request  is each 1ms
25  if(timer>=1000){
26    state=!state;
27    timer=0;
28  }
29  
30  digitalWrite(13,state);
31  
32}
33
34ISR(TIMER0_COMPA_vect){    //This  is the interrupt request
35  timer++;
36}
37
38

/*
This program turns on and off a LED on pin 13 each 1 second using  an internal timer
*/

int timer=0;
bool state=0;
void setup() {
  pinMode(13,OUTPUT);
    
  TCCR0A=(1<<WGM01);    //Set the CTC mode   
  OCR0A=0xF9; //Value for ORC0A for 1ms 
  
  TIMSK0|=(1<<OCIE0A);   //Set  the interrupt request
  sei(); //Enable interrupt
  
  TCCR0B|=(1<<CS01);    //Set the prescale 1/64 clock
  TCCR0B|=(1<<CS00);

 
    
}

void  loop() {
  //in this way you can count 1 second because the nterrupt request  is each 1ms
  if(timer>=1000){
    state=!state;
    timer=0;
  }
  
  digitalWrite(13,state);
  
}

ISR(TIMER0_COMPA_vect){    //This  is the interrupt request
  timer++;
}

Downloadable files

schema_jlNkRtLRSE.jpg

Comments

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Pahan_Bhagya

2 years ago

Nice tutorial

Anonymous user

2 years ago

There seems to be a typo in the line: "In this case, we activate an interrupt request each 0.1 seconds." I see from the code that follow that you meant 1ms not 0.1 s.

Marcazzan_M

2 years ago

you're right, thanks

Anonymous user

2 years ago

For some reason, once in five ON times is 0.76ms. The other four ON times are 1ms. This is according to my o-scope. Has anyone noticed this? Is there a way to make the ON time consist?

Anonymous user

2 years ago

great tutorial .i made 100 USD from this tutorial thanks my boss.

Anonymous user

2 years ago

Great tutorial, thanks

Anonymous user

2 years ago

Yes, nothing earth shattering, I made a count up timer that counts from 1 second to days, for timing whatever.

Pahan_Bhagya

2 years ago

Did you try this?

shrijanunbound

2 years ago

Kindly share tutorial of other timers in arduino Uno .

Anonymous user

2 years ago

Good intro to interrupts, thanks

Ardu-Fan

2 years ago

Great project. I shall use the idea with one dedicated Arduino board for my gadget related timers. Keep on exciting us.

Anonymous user

2 years ago

Excellent! Great job! :)

Anonymous user

3 years ago

For some reason, once in five ON times is 0.76ms. The other four ON times are 1ms. This is according to my o-scope. Has anyone noticed this? Is there a way to make the ON time consist?

shrijanunbound

4 years ago

Kindly share tutorial of other timers in arduino Uno .

Anonymous user

4 years ago

great tutorial .i made 100 USD from this tutorial thanks my boss.

Anonymous user

7 years ago

Excellent! Great job! :)

Ardu-Fan

7 years ago

Great project. I shall use the idea with one dedicated Arduino board for my gadget related timers. Keep on exciting us.

Anonymous user

7 years ago

There seems to be a typo in the line: "In this case, we activate an interrupt request each 0.1 seconds." I see from the code that follow that you meant 1ms not 0.1 s.

Marcazzan_M

2 years ago

you're right, thanks

stevenbennett

7 years ago

Good intro to interrupts, thanks

Pahan_Bhagya

7 years ago

Nice tutorial, thank you

Pahan_Bhagya

7 years ago

Nice tutorial

Anonymous user

7 years ago

Great tutorial, thanks

Anonymous user

2 years ago

Yes, nothing earth shattering, I made a count up timer that counts from 1 second to days, for timing whatever.

Pahan_Bhagya

2 years ago

Did you try this?

Marcazzan_M

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