Digital I/O

This library is to input/output a digital signal (0 or 1).

pinMode

Description: Configures the specified pin to behave either as an input or an output.
Syntax: pinMode(pin, mode)
Parameters: pin: The number of the pin whose mode you wish to set
mode: INPUT, OUTPUT, or INPUT_PULLUP
Returns: None
Remark: Analog pins A0 to A5 (14 to 21) have no internal pull-up registers. Do not specify INPUT_PULLUP for these pins.

digitalWrite

Description: Write a HIGH or a LOW value to a digital pin. If the pin is configured as an INPUT, writing a HIGH value with digitalWrite() will enable an internal pullup resistor. Writing LOW will disable the pullup.
Syntax: digitalWrite(pin, value)
Parameters: pin: The pin number
value: HIGH or LOW
Returns: none

digitalRead

Description: Reads the value from a specified digital pin, either HIGH or LOW.
Syntax: digitaRead(pin)
Parameters: pin: The number of the digital pin you want to read
Returns: HIGH or LOW

Example

　

LED 13 is lit periodically.


#include <Arduino.h>
void setup()
{
    pinMode(13, OUTPUT);
}
    
void loop()
{
    digitalWrite(13, HIGH);
    delay(100);
    digitalWrite(13, LOW);
    delay(100);
}