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DigitalIn

Table of Contents

  1. Hello World!
  2. API
  3. Details
  4. Examples
  5. Related

/media/uploads/mbedofficial/digitalin_interfaces.png

The DigitalIn interface is used to read the value of a digital input pin.

Any of the numbered mbed pins can be used as a DigitalIn.

Hello World!

Flash an LED while a DigitalIn is true

#include "mbed.h"

DigitalIn enable(p5);
DigitalOut led(LED1);

int main() {
    while(1) {
        if(enable) {
            led = !led;
        }
        wait(0.25);
    }
}

API

API summary

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Details

The pin input is logic '0' for any voltage on the pin below 0.8v, and '1' for any voltage above 2.0v. By default, the DigitalIn is setup with an internal pull-down resistor.

Examples

Boolean logic - NOT, AND, OR, XOR

#include "mbed.h"

DigitalIn a(p5);
DigitalIn b(p6);
DigitalOut z_not(LED1);
DigitalOut z_and(LED2);
DigitalOut z_or(LED3);
DigitalOut z_xor(LED4);

int main() {
    while(1) {
        z_not = !a;
        z_and = a && b;
        z_or = a || b;
        z_xor = a ^ b;
    }
}

Flash a LED while a pin is true, then exit

#include "mbed.h"

DigitalIn (p5);
DigitalOut led(LED1);

int main() {
    while(p5) {
        led = !led;
        wait(0.25);
    }
}

To handle an interrupt, see InterruptIn

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