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DigitalInOut

Use the DigitalInOut interface as a bidirectional digital pin:

  • Read the value of a digital pin when set as an input().
  • Write the value when set as an output().

You can use any of the numbered Arm Mbed pins as a DigitalInOut.

Note: Some platforms have a time delay when switching between input and output.

DigitalInOut class reference

Public Member Functions
 DigitalInOut (PinName pin)
 Create a DigitalInOut connected to the specified pin. More...
 DigitalInOut (PinName pin, PinDirection direction, PinMode mode, int value)
 Create a DigitalInOut connected to the specified pin. More...
void write (int value)
 Set the output, specified as 0 or 1 (int) More...
int read ()
 Return the output setting, represented as 0 or 1 (int) More...
void output ()
 Set as an output. More...
void input ()
 Set as an input. More...
void mode (PinMode pull)
 Set the input pin mode. More...
int is_connected ()
 Return the output setting, represented as 0 or 1 (int) More...
DigitalInOutoperator= (int value)
 A shorthand for write() More...
DigitalInOutoperator= (DigitalInOut &rhs)
 A shorthand for write() using the assignment operator which copies the state from the DigitalInOut argument. More...
 operator int ()
 A shorthand for read() More...

DigitalInOut hello, world

/* mbed Example Program
 * Copyright (c) 2006-2014 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "mbed.h"

DigitalInOut mypin(LED1);

int main()
{
    // check that mypin object is initialized and connected to a pin
    if(mypin.is_connected()) {
        printf("mypin is initialized and connected!\n\r");
    }

    // Optional: set mode as PullUp/PullDown/PullNone/OpenDrain
    mypin.mode(PullNone);

    while(1) {
        // write to pin as output
        mypin.output();
        mypin = !mypin; // toggle output
        wait(0.5);

        // read from pin as input
        mypin.input();
        printf("mypin.read() = %d \n\r",mypin.read());
        wait(0.5);
    }
}
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