Arduino GPIO LED Blink

                                           Solving Approach

How do you plan to solve it?

I will use my brain to think, then I will write some stuff and think some more. After a lot of thinking, writing and making dumb mispeling, I will have the answer! Of course some resources from internet :D

Used Ohms law to calculate the resistor value. 

 U=IR     ==      U/I=R 

Where U = voltage, I=current, R=resistance

I assume the LED is red and its forward voltage is 2.2V. (The forward voltage can be found in datasheets or by googl-ing red LED forward voltage)

To find the voltage that needs to be "restricted" to get the desired current I did the first part in (). Total voltage - voltage used to drive LED.

(5-2.2)/0.01=280 Ohm

I chose to turn on pin D2 for Arduino UNO board.

                                                  Code

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

#define LED_PIN 			PORTD2

#define LED_PIN_ON()		PORTD |=  (1 << LED_PIN)
#define LED_PIN_OFF()		PORTD &= ~(1 << LED_PIN)

void LED_PIN_INIT();

int main()
{
    LED_PIN_INIT();
    while (1)
    {
        LED_PIN_ON();
        _delay_ms(400);
        
        LED_PIN_OFF();
        _delay_ms(800);
    }    
    return 0;
}

void LED_PIN_INIT(){
	DDRD |= (1 << LED_PIN);
}

                                                  Output

Video....

You will have to believe me on this one.

Photo of Output

Add a photo of your hardware showing the output.

                                                 P.S.

Thanks for the tasks, quizzes! I will try to write code not specifically for Arduino IDE but more generically and with more register usage.

Best regards,

Rodrigo