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Diffstat (limited to 'docs/source/lang/api/attachinterrupt.rst')
| -rw-r--r-- | docs/source/lang/api/attachinterrupt.rst | 57 |
1 files changed, 18 insertions, 39 deletions
diff --git a/docs/source/lang/api/attachinterrupt.rst b/docs/source/lang/api/attachinterrupt.rst index 7c5a6c7..39902ac 100644 --- a/docs/source/lang/api/attachinterrupt.rst +++ b/docs/source/lang/api/attachinterrupt.rst @@ -5,9 +5,8 @@ attachInterrupt() ================= -Used to specify a function to call when an external interrupt (like an -GPIO changing from LOW to HIGH, a button getting pressed, etc.) -occurs. +Used to specify a function to call when an :ref:`external interrupt +<external-interrupts>` occurs. .. contents:: Contents :local: @@ -15,9 +14,9 @@ occurs. Library Documentation --------------------- -.. FIXME once breathe knows how to get the correct attachInterupt -.. (right now it's copying from HardwareTimer), replace with a -.. doxygenfunction directive +.. FIXME [doxygenfunction] once Breathe knows how to get the correct +.. attachInterupt (right now it's copying from HardwareTimer), replace +.. with a doxygenfunction directive .. cpp:function:: void attachInterrupt(uint8 pin, voidFuncPtr handler, ExtIntTriggerMode mode) @@ -47,49 +46,29 @@ Discussion Because the function will run in interrupt context, inside of it, :ref:`lang-delay` won't work, and the value returned by -:ref:`lang-millis` will not increment. Serial data received while -in the function may be lost. You should declare as ``volatile`` any +:ref:`lang-millis` will not increment. Serial data received while in +the function may be lost. You should declare as ``volatile`` any global variables that you modify within the attached function. -There are a few constraints you should be aware of if you're using -more than one interrupt at a time; the :ref:`external-interrupts` page -has the details. - -Using Interrupts ----------------- - -Interrupts are useful for making things happen automatically in -microcontroller programs, and can help solve timing problems. A -good task for using an interrupt might be reading a rotary encoder, -or monitoring user input. - -If you wanted to insure that a program always caught the pulses -from a rotary encoder, never missing a pulse, it would make it very -tricky to write a program to do anything else, because the program -would need to constantly poll the sensor lines for the encoder, in -order to catch pulses when they occurred. Other sensors have a -similar interface dynamic too, such as trying to read a sound -sensor that is trying to catch a click, or an infrared slot sensor -(photo-interrupter) trying to catch a coin drop. In all of these -situations, using an interrupt can free the microcontroller to get -some other work done while not missing the doorbell. +There are a few limits you should be aware of if you're using more +than one interrupt at a time; the :ref:`External Interrupts +<external-interrupts-exti-line>` page has more information. Example ------- -:: + :: - int maple_led_pin = 13; volatile int state = LOW; // must declare volatile, since it's - // modified within the blink handler + // modified within the blink() handler void setup() { - pinMode(maple_led_pin, OUTPUT); + pinMode(BOARD_LED_PIN, OUTPUT); attachInterrupt(0, blink, CHANGE); } void loop() { - digitalWrite(maple_led_pin, state); + digitalWrite(BOARD_LED_PIN, state); } void blink() { @@ -106,10 +85,10 @@ additional four: numbers 2 (pin 21), 3 (pin 20), 4 (pin 19), and 5 number goes with which pin -- just tell ``attachInterrupt()`` the pin you want. -See also +See Also -------- -- :ref:`detachInterrupt <lang-detachinterrupt>` -- :ref:`external-interrupts` +- :ref:`lang-detachinterrupt` +- :ref:`external-interrupts` -.. include:: cc-attribution.txt +.. include:: /arduino-cc-attribution.txt |