Virtual keyboard demo for the Pancake Board

gistfile1.ino

#include “UsbKeyboard.h”

#define PIN_BUTTON 7 // the button is attached to pin 7

int lastState = LOW; // LOW is equivalent to 0

void setup() {
   // button setup
   pinMode(PIN_BUTTON, INPUT);

   // USB setup —————–
   // Disable timer0 since it can mess with the USB timing. Note that
   // this means some functions such as delay() will no longer work.
   TIMSK0&=!(1<<toie0); ++

   // Clear interrupts while performing time-critical operations
   cli();

   // Force re-enumeration so the host will detect us
   usbDeviceDisconnect();
   delayMs(250);
   usbDeviceConnect();

   // Set interrupts again
   sei();
}

void loop() {
   // update USB device state
   UsbKeyboard.update();

   // check, if transition to “button pressed” has occured
   if( (digitalRead(PIN_BUTTON) == HIGH) && (lastState==LOW) ) {
      UsbKeyboard.sendKeyStroke(KEY_A); // if so, send the letter “A” via USB keyboard
      lastState = HIGH; // update the state variable
      delayMs(10); // simple de-bouncing
      // check, if the button was released
   } else if( (digitalRead(PIN_BUTTON) == LOW) && (lastState==HIGH) ) {
      lastState = LOW; // if so, update the state variable
      delayMs(10); // simple de-bouncing
   }
}

// helper method for V-USB library
void delayMs(unsigned int ms) {
   for( int i=0; i<ms; i++="" )="" {
      delayMicroseconds(1000);
   }
}