leds-buttons.md

LEDS/Buttons

There are several LEDs and Buttons on the processor board of the Macchina M2. These are user programmable and can be used for many applications.

LEDs

M2 has 5 single-color LEDs and 1 RGB LED. Each LED is active LOW - the processor needs to pull the pin LOW to turn on the LED.

The following table shows what LEDs correspond to what Pin name.

LED	Mapped Pin Name
DS2 (RED)	DS2
DS3 (YELLOW)	DS3
DS4 (YELLOW)	DS4
DS5 (YELLOW)	DS5
DS6 (GREEN)	DS6
RGB RED	DS7_RED / RGB_RED
RGB GREEN	DS7_GREEN / RGB_GREEN
RGB BLUE	DS7_BLUE / RGB_BLUE

For example, if you want the Green LED to blink, this sketch will do that for you:

void setup() {
  // initialize digital pin DS6 as an output.
  pinMode(DS6, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(DS6, LOW);   // turn the LED on (LOW is the voltage level)
  delay(1000);              // wait for a second
  digitalWrite(DS6, HIGH);  // turn the LED off by making the voltage HIGH
  delay(1000);              // wait for a second
}

Buttons

M2 has 4 buttons on the Processor board.

2 of these buttons (Button1 and Button2) are user-programmable. Use these for triggering something in your program. For example, this code turns on the Red LED when Button 1 is pressed:

const int buttonPin = Button1;     // the number of the pushbutton pin
const int ledPin =  DS2;      // the number of the LED pin

int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);
}

void loop() {
  buttonState = digitalRead(buttonPin);

  if (buttonState == LOW) {   // If button is pressed
    digitalWrite(ledPin, LOW);  // Turn the Red LED on
  } else {
    digitalWrite(ledPin, HIGH);  // Turn the Red LED off
  }
}

RESET button will reset the processor.

ERASE button is used in conjunction with the RESET button. In the event your program hangs or there is some other issue, power up M2, hold down ERASE and then press and release RESET. This will erase the flash on the processor.