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Diffstat (limited to 'examples/exti-interrupt-callback.cpp')
-rw-r--r-- | examples/exti-interrupt-callback.cpp | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/examples/exti-interrupt-callback.cpp b/examples/exti-interrupt-callback.cpp new file mode 100644 index 0000000..c87c064 --- /dev/null +++ b/examples/exti-interrupt-callback.cpp @@ -0,0 +1,87 @@ +// 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; +} |