Class _inta: external interrupt controller

A class _inta object is an external interrupt controller.

It is used in:

• ATtiny24/44/84 : int0
• ATtiny25/45/85 : int0
• ATmega48A/PA/88A/PA/168A/PA/328/P : int0, int1

Interrupts

Class _inta objects can trigger the following IRQs:

• int0

Interface

---

hw( configure, ... ) and hwa( configure, ... )

hw | hwa( configure,   int0,
 
          sense,       low_level             //  What does trigger the IRQ
                     | edge
                     | falling_edge
                     | rising_edge  );

Status

The IRQ mask and flag can be accessed through interrupt-related instructions:

if ( hw( read, (int0,irq) ) ) {         // Read IRQ flag
  hw( clear, (int0,irq) );              // Clear IRQ flag
  hw( disable, (int0,irq) );    // Disable IRQ
}

Internals

Class _inta objects hold the following hardware registers:

• sc: sense control
• ie: IRQ mask
• if: IRQ flag