Interrupts : Interrupt vs. Polling

int main()
{
    while(1){
        . . .
    }
}

OnSwitch_ISR{
    getData()
}

Interrupt

int main()
{
    while(1){
        if(switch = on ){
            getData();
        }
        . . .
    }
}

Polling

Interrupts NVIC

• Interrupts from the processor core are know as exceptions.
• Interrupts from outside the processor core are known as hardware exceptions or Interrupt Requests.

Interrupts: The Vector Table

The vector table contains the addresses of the Interrupt Handlers and Exception Handlers.

Interrupts: External Interrupt (EXTI) Lines

• GPIO pins are connected to EXTI lines
• It possible to enable interrupt for any GPIO pin
• Multiple pins share the same EXTI line
• Pin 0 of every Port is connected EXTI0_IRQ
• Pin 1 of every Port is connected EXTI1_IRQ
• Pin 2 of every Port is connected EXTI2_IRQ