This content relates to a deprecated version of Mbed

Mbed 2 is now deprecated. For the latest version please see the Mbed OS documentation.

For the latest DigitalIn API, please see DigitalIn.

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!

Import program

00001 #include "mbed.h"
00003 DigitalIn enable(p5);
00004 DigitalOut led(LED1);
00006 int main() {
00007     while(1) {
00008         if(enable) {
00009             led = !led;
00010         }
00011         wait(0.25);
00012     }
00013 }

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API summary

Import librarymbed

No documentation found.


The DigitalIn Interface can be used on any pin with a blue label.

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.

See the Pinout page for more details

To handle an interrupt, see InterruptIn

Examples of logical functions

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;

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