Welcome!

I've a M-Duino 21+ and I'm testing the digital input just with a button connected to 5Vdc (pin of M-DUINO) and I0_7 digital pin. In M-DUINO documentation says that digital input high voltage is 5-24V.

I've used this  simple program:

void setup() {
  pinMode(I0_7, INPUT);
  Serial.begin(9600);
}

void loop() {
 Serial.println(digitalRead(I0_7) ? "ON" : "OFF");   //print value on serial Monitor
 delay(2000); //wait 2 seconds
}

The problem is:

- If I press the button, the LED I0_7 brights as expected but the message remains "OFF"

I've changed button power supply to Vdc (in my case it is 12Vdc) the LED I0_7 brights and the message changes to "ON"

So, I've experienced that status LEDs for digital inputs don't show the actual value received by the arduino core.

Is ti my fault or something wrong? Is it just a design error?