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// Toggles the built-in LED when the built in button
// on the Maple is pushed in. This uses the attachInterrupt function to
// setup the interrupt handler for the button being pressed.
//
// This is similar to the exti-interrupt example, but shows the use of a class
// method to handle interrupts.
//
// More about attachInterrupt:
// http://leaflabs.com/docs/lang/api/attachinterrupt.html
//
#include <wirish/wirish.h>
class MyAwesomeClass
{
public:
// Setup the interrupt handler
void initialize()
{
// LED is off by default
this->isLEDOn = false;
// Attach interrupt to class method handler
attachInterrupt(BOARD_BUTTON_PIN, buttonInterruptHandler, this, RISING);
}
private:
bool isLEDOn;
// Static event handler takes a void * argument that was originally
// passed to the attachInterrupt call. If the argument in question is an
// instance of the class (MyAwesomeClass in this case), the static function
// get access to that instance's data (even private data).
//
// In other words, this setup allows the Maple to have class method
// interrupt handlers (albeit with a work around).
//
// However, as you might imagine, this argument can be anything (if you
// don't need instance data access).
//
static void buttonInterruptHandler(void *arg)
{
// Cast the "generic" void argument to the class instance.
MyAwesomeClass *instance = (MyAwesomeClass *)arg;
// Accessing private instance data
instance->isLEDOn = !(instance->isLEDOn);
// Set LED
digitalWrite(BOARD_LED_PIN, instance->isLEDOn);
// Delay slightly for switch de-bouncing
delay(20);
}
};
MyAwesomeClass myClass;
// Setup pin modes and the interrupt handler class
void setup() {
pinMode(BOARD_BUTTON_PIN, INPUT);
pinMode(BOARD_LED_PIN, OUTPUT);
// The initialize method sets up the event handler to the private method
// in MyAwesomeClass. There is however, nothing stopping you from setting
// up event handlers which are public methods in classes.
myClass.initialize();
}
// Loop. Does nothing in this example.
void loop() {
}
// Force init to be called *first*, i.e. before static object allocation.
// Otherwise, statically allocated objects that need libmaple may fail.
__attribute__((constructor)) void premain() {
init();
}
int main(void) {
setup();
while (true) {
loop();
}
return 0;
}
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