Digital output

  const int outPin=3; 
  
  void setup(){ 
  pinMode (outPin, OUTPUT); 
  Serial.begin (9600); 
  Serial.printlin ("Enter 1 or 0");} 
  
  
  void loop(){ 
  if (Serial.avaiable()>0)} 
  char ch=Serial.read 
  if (ch='1'){  
  digitalWrite (outPin, HIGH);}
  else if (ch= ='0'){ 
  digitalWrite (outPin, LOW);}
  }}
  

Digital input

   const int inputPin=5;
  
  void setup(){
  pinMode (inputtPin, INPUT);
  Serial.begin (9600);

  
  void loop(){
  int reading= digitalRead (inputPin)}
  Serial.println (reading);
  delay (1000);}
  
  
  

Analog output

   const int outPin=3;
  
  void setup(){
  pinMode (outPin, OUTPUT;
  Serial.begin (9600);
  Serial.println ("Entre Volts: 0-5");}

  
  void loop(){
  if (Serial.avaiable > 0){
  float volts = Serial.parseFloat();
  int pwmValue = volts *255.0/5.0;
  analogWrite (outputPin, pwmValue);}}
  

Analog input

   const int analogPin=A0;
  
  void setup(){
  Serial.begin (9600);}

  
  void loop(){
  int reading= analogRead (analogPin);
  float voltage = reading/204.6;
  Serial.println ("Reading");
  Serial.print (reading);
  Serial.print ("\t\tVolt=");
  Serial.println (voltage);
  delay (500);}