Example for TI MSP40 board. Will blink button on specific frequency depending on button presses.

buttonBlink.ino

#define hz_to_ms(hz) (1000 / (hz))  // T = 1 / f

// constants won't change. Used here to 
// set pin numbers:
const int ledPin =  RED_LED;      // the number of the LED pin
const int buttonPin = PUSH2;     // the number of the pushbutton pin

// Variables will change:
int ledState = LOW;             // ledState used to set the LED
long previousMillis = 0;        // will store last time LED was updated
int buttonStateAccumulator = 1; // holds how many times the button has changed state.

// interval at which to blink (milliseconds)
long interval = hz_to_ms(30);   // (30 Hz) 

void setup() {
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  attachInterrupt(buttonPin, onButtonUp, RISING);
}

void loop()
{
  if (buttonStateAccumulator % 2 == 0)
  {  
    blink(interval);
  }
  else
  {
    digitalWrite(ledPin, LOW);
  }
}

void onButtonUp()
{
  buttonStateAccumulator++;
}

void blink(int intervalMillis)
{
  unsigned long currentMillis = millis();

  if(currentMillis - previousMillis > intervalMillis) {
    // save the last time you blinked the LED 
    previousMillis = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW)
      ledState = HIGH;
    else
      ledState = LOW;

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);
  }
}

It would be great if I can be notified when the state of the pin (button) changes, but I couldn't find how to do it.

You can try this!
http://energia.nu/reference/attachinterrupt/