Atmel Button Debounce not working

Question

I am trying to make a button debounce software by the help of an led toggle function that returns a different boolean each time which i got by asking the question before but that never worked :

#include <avr/io.h>

bool ledToggle();

int main(void)
{   
    DDRB |= (1 << 0); 
    DDRB &= ~(1 << 0); 

    while(1)
    {   
        //TODO:: Please write your application code                 

        if (ledToggle() == true)
        {       
            //led on
            PORTB |= (1 << 0);          
        }else{          
            //led off
            PORTB &= ~(1 << 0);         
        }       
    }
}

bool ledToggle()
{
    static bool state = false;  
    if(bit_is_clear(PINB, 1)){
        state = !state;
    }

    return state;   
}

EDIT

I get no errors or anything when I try to compile it just doesn't work...

Are you getting any errors, getting unexpected output? Are you stuck?Can you form a clear question please? — Tim, Apr 17 '14 at 14:20
What do you expect it to do ? What does it do ? Explain better your problem, please. — blue112, Apr 17 '14 at 14:28
the led just keeps off whatever I try to do and never turns on — user3407319, Apr 17 '14 at 14:29
@blue112 it is a button debounce software it is supposed to turn on the led when I press the button and turn it off when I press it again — user3407319, Apr 17 '14 at 14:30

score 0 · Answer 1 · 2020-02-10T02:24:42.903

0

In the second line of main () you are mistakenly setting the LED port instead of the BUTTON port as an input.

I suggest using defines as a way of making this kind of mistakes less likely:

#define LED    0
#define BUTTON 1

DDRB |= (1 << LED);
DDRB &= ~(1 << BUTTON);

edited Feb 10 '20 at 02:24

answered Apr 17 '14 at 14:58

2

Needs explanation of why / what the change actually does to be a quality answer. – nobody Apr 17 '14 at 15:17

score 0 · Answer 2 · answered May 28 '14 at 12:30

I don't recognize in which way this code would debounce a switch connected to Port B / 1. Debouncing means to

check and store the key logic state
wait a certain amount of time (depending on hardware, 5 - 50 ms)
compare the (now) logic state with what was read before
if equal the (now) logic state is the debounced key state

Provided the program is functioning well, the LED would bounce at the same pace as the switch.

In your bool ledToggle() I suggest you declare static volatile bool state; to ensure the variable is created in RAM (rather than a CPU register)

Atmel Button Debounce not working

2 Answers2