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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)
 DigitalInOut (PinName pin, PinDirection direction, PinMode mode, int value)
void write (int value)
int read ()
void output ()
void input ()
void mode (PinMode pull)
int is_connected ()
DigitalInOutoperator= (int value)
DigitalInOutoperator= (DigitalInOut &rhs)
 operator int ()
Protected Attributes
gpio_t gpio

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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