Interrupts are useful for making things happen automatically in microcontroller programs, and can help solve timing problems. Good tasks for using an interrupt may include reading a rotary encoder, or monitoring user input.
Assembly
Arduino.h
Summary
Methods
attachInterrupt
int attachInterrupt(PinName pin, Callback<void()> ISR, int mode);
Attach interrupt callback to digital pin.
Parameters
| Type | Name | Description |
| PinName | pin | Valid PinNames are: PA_4, PA_5, PA_10, PB_0, PB_2, PB_3, PB_6, PB_7, PB_8, PB_9, PB_13, PB_14, PB_15. |
| Callback<void()> | ISR | The callback function. |
| int | mode | Triggered event type, support CHANGE, RISING, FALLING now. |
Return value
| Type | Description |
| int | Result code, 0 in case of success, error code otherwise. |
detachInterrupt
int detachInterrupt(PinName pin);
Detach interrupt callback from digital pin.
Parameters
| Type | Name | Description |
| PinName | pin | Valid PinNames are: PA_4, PA_5, PA_10, PB_0, PB_2, PB_3, PB_6, PB_7, PB_8, PB_9, PB_13, PB_14, PB_15. |
Return value
| Type | Description |
| int | Result code, 0 in case of success, error code otherwise. |
Sample code
volatile byte led = LOW; volatile byte interruptOn = HIGH; void setup() { // Use USER_BUTTON_B to control USER_BUTTON_A attachInterrupt(USER_BUTTON_B, interruptSwitch, FALLING); // Use USER_BUTTON_A to control LED_USER if (interruptOn) { attachInterrupt(USER_BUTTON_A, blink, CHANGE); } } void loop() { digitalWrite(LED_USER, led); } void blink() { led = !led; } void interruptSwitch() { interruptOn = !interruptOn; if (interruptOn) { attachInterrupt(USER_BUTTON_A, blink, CHANGE); } else { detachInterrupt(USER_BUTTON_A); } }