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DigitalOut

Table of Contents

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

/media/uploads/mbedofficial/digitalout_interfaces.png

The DigitalOut interface is used to configure and control a digital output pin.

Hello World!

Flash an LED

#include "mbed.h"

DigitalOut myled(LED1);

int main() {
    while(1) {
        myled = 1;
        wait(0.25);
        myled = 0;
        wait(0.25);
    }
}

API

API summary

Import library
mbed - DigitalOut Class Reference

Public Member Functions

DigitalOut (PinName pin, const char *name=NULL)
Create a DigitalOut connected to the specified pin.
void write (int value)
Set the output, specified as 0 or 1 (int)
int read ()
Return the output setting, represented as 0 or 1 (int)
DigitalOut & operator= (int value)
A shorthand for write()
operator int ()
A shorthand for read()
virtual struct rpc_method * get_rpc_methods ()
Returns a pointer to an array describing the rpc methods supported by this object, terminated by either RPC_METHOD_END or RPC_METHOD_SUPER(Superclass).
void register_object (const char *name)
Registers this object with the given name, so that it can be looked up with lookup.
const char * name ()
Returns the name of the object.
virtual bool rpc (const char *method, const char *arguments, char *result)
Call the given method with the given arguments, and write the result into the string pointed to by result.

Static Public Member Functions

static bool rpc (const char *name, const char *method, const char *arguments, char *result)
Use the lookup function to lookup an object and, if successful, call its rpc method.
static Base * lookup (const char *name, unsigned int len)
Lookup and return the object that has the given name.
template<class C >
static void add_rpc_class ()
Add the class to the list of classes which can have static methods called via rpc (the static methods which can be called are defined by that class' get_rpc_class() static method).

Interface

The DigitalOut Interface can be used on mbed pins p5-p30, and also on-board LED1-LED4

The DigitalOut Interface can be used to set the state of the output pin, and also read back the current output state. Set the DigitalOut to zero to turn it off, or 1 to turn it on.

Details

The pin output is 0v and 3.3v (0 and 1), and can source or sink a maximum of 40mA.

Examples

Alternative flashing

#include "mbed.h"

DigitalOut myled(LED1);

int main() {
    while(1) {
        myled = !myled;
        wait(0.25);
    }
}

Alternative flashing

#include "mbed.h"

DigitalOut red(p5);
DigitalOut green(p6);
DigitalOut blue(p7);

int main() {
    // red
    red = 1;
    green = blue = 0;
    wait(1);
    
    // green
    green = 1;
    red = blue = 0;
    wait(1);

    // white
    red = green = blue = 1;
}
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