Arduino入門：デジタル入出力関数

Arduinoのデジタル入出力関数について解説します。

pinMode

pinModeは、ピンをINPUT(入力)かOUTPUT(出力)に設定します。 Arduino 1.0.1以降は、INPUT_PULLUP(内部プルアップ抵抗を有効化した入力)もできる様になりました。ただのINPUTの場合、内部プルアップは無効です。

//Arduino Sketch Example: pinMode
//Date: 2015.1.12
//Edited and Modified by: easy labo
//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax
pinMode(pin, mode)

//pin: the number of the pin whose mode you wish to set
//mode: INPUT, OUTPUT, or INPUT_PULLUP.

//Example
int ledPin = 13;                 // LED connected to digital pin 13

void setup()
{
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output
}

void loop()
{
  digitalWrite(ledPin, HIGH);   // sets the LED on
  delay(1000);                  // waits for a second
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(1000);                  // waits for a second
}

//Arduino Sketch Example: pinMode

//Date: 2015.1.12

//Edited and Modified by: easy labo

//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax

pinMode(pin, mode)

//pin: the number of the pin whose mode you wish to set

//mode: INPUT, OUTPUT, or INPUT_PULLUP.

//Example

int ledPin = 13; // LED connected to digital pin 13

void setup()

{

pinMode(ledPin, OUTPUT); // sets the digital pin as output

}

void loop()

{

digitalWrite(ledPin, HIGH); // sets the LED on

delay(1000); // waits for a second

digitalWrite(ledPin, LOW); // sets the LED off

delay(1000); // waits for a second

}

Creative Commons Attribution-ShareAlike 3.0 License (CC BY-SA 3.0)
“Arduino Reference:pinMode()” by Arduino Team, used under CC BY-SA 3.0/ easy labo made some changes and comments to the original

上の例では、13番ピンを出力に設定し、HIGHとLOWの切り替えを1秒間隔で行っています。このピンにLEDをつないでおけば、点滅させる事ができます。

digitalWire

digitalWireは、指定pin(ピン)にHIGHまたはLOWを出力しますが、pinModeの設定により動作が異なります。

指定ピンがpinMode()関数でOUTPUTに設定されている場合
HIGH: 5V出力 (ボードの電源電圧。製品によっては、3.3Vの場合もある)
LOW: 0V(GND)出力

指定ピンがpinMode()関数でINPUTに設定されている場合
HIGH: 20kΩの内部プルアップ抵抗が有効
LOW: 20kΩの内部プルアップ抵抗は無効

//Arduino Sketch Example: digitalWrite
//Date: 2015.1.12
//Edited and Modified by: easy labo
//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax
digitalWrite(pin, value)

//pin: the pin number
//value: HIGH or LOW

//Example
int ledPin = 13;                 // LED connected to digital pin 13

void setup()
{
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output
}

void loop()
{
  digitalWrite(ledPin, HIGH);   // sets the LED on
  delay(1000);                  // waits for a second
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(1000);                  // waits for a second
}

//Arduino Sketch Example: digitalWrite

//Date: 2015.1.12

//Edited and Modified by: easy labo

//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax

digitalWrite(pin, value)

//pin: the pin number

//value: HIGH or LOW

//Example

int ledPin = 13; // LED connected to digital pin 13

void setup()

{

pinMode(ledPin, OUTPUT); // sets the digital pin as output

}

void loop()

{

digitalWrite(ledPin, HIGH); // sets the LED on

delay(1000); // waits for a second

digitalWrite(ledPin, LOW); // sets the LED off

delay(1000); // waits for a second

}

Creative Commons Attribution-ShareAlike 3.0 License (CC BY-SA 3.0)
“Arduino Reference:digitalWrite()” by Arduino Team, used under CC BY-SA 3.0/ easy labo made some changes and comments to the original

上の例は、先ほどのpinModeの例と内容は同じです。13番ピンの状態をdigitalWriteを使用してHIGHとLOWを交互に切り替えています。

digitalRead

digitalReadは、指定したピンの状態をを読み取ります。戻り値は、HIGHまたはLOWになります。

//Arduino Sketch Example: digitalRead
//Date: 2015.1.12
//Edited and Modified by: easy labo
//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax
digitalRead(pin)

//pin: the number of the digital pin you want to read (int)
//Returns: HIGH or LOW

//Example
//Sets pin 13 to the same value as pin 7, declared as an input.
int ledPin = 13; // LED connected to digital pin 13
int inPin = 7;   // pushbutton connected to digital pin 7
int val = 0;     // variable to store the read value

void setup()
{
  pinMode(ledPin, OUTPUT);      // sets the digital pin 13 as output
  pinMode(inPin, INPUT);      // sets the digital pin 7 as input
}

void loop()
{
  val = digitalRead(inPin);   // read the input pin
  digitalWrite(ledPin, val);    // sets the LED to the button's value
}

//Arduino Sketch Example: digitalRead

//Date: 2015.1.12

//Edited and Modified by: easy labo

//Original Source: Arduino Reference (http://arduino.cc/en/Reference/HomePage)

//Syntax

digitalRead(pin)

//pin: the number of the digital pin you want to read (int)

//Returns: HIGH or LOW

//Example

//Sets pin 13 to the same value as pin 7, declared as an input.

int ledPin = 13; // LED connected to digital pin 13

int inPin = 7; // pushbutton connected to digital pin 7

int val = 0; // variable to store the read value

void setup()

{

pinMode(ledPin, OUTPUT); // sets the digital pin 13 as output

pinMode(inPin, INPUT); // sets the digital pin 7 as input

}

void loop()

{

val = digitalRead(inPin); // read the input pin

digitalWrite(ledPin, val); // sets the LED to the button's value

}

Creative Commons Attribution-ShareAlike 3.0 License (CC BY-SA 3.0)
“Arduino Reference:digitalRead()” by Arduino Team, used under CC BY-SA 3.0/ easy labo made some changes and comments to the original

上の例では、7番ピンの入力状態を読み取って、変数valに格納しています。

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