DigitalRead__

int digitalRead (uint8_t pin)

读数字引脚

读数字引脚, 返回引脚的高低电平. 在读引脚之前, 需要将引脚设置为INPUT模式.

参数:

• pin 引脚编号

返回: HIGH或LOW

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
}

注解:

   如果引脚没有链接到任何地方, 那么将随机返回 HIGH 或 LOW.