t1614_timerB.cpp

/*
 * t1614_timerB.cpp
 *
 * Created: 2018/10/25
 * Author : chromia <chromia@outlook.jp>
 */

#include <avr/io.h>
#include <avr/interrupt.h>

/* PIN Assign
 * 5.PA7  : LED
 */

#define PIN_LED_bp 7 // PA7
#define PIN_LED_bm (1 << PIN_LED_bp)

/* 1sec-interval LED blinking by TCB(Periodic Interrupt Mode)
 * Attiny1614's default clock is 20MHz(RC)
 * CLK_PER is 3.333MHz ( default prescaler rate is 6, then 20/6 == 3.3 )
 *
 * interrupt interval = 1ms ( 3333 / 3.333MHz = 0.001sec )
 * 500ms ON -> 500ms OFF
 *
 * If you want to write more smart code,
 * please use TCA which has an internal prescaler.
 */
#define COMPARE 3333
#define LOOP 500

int main(void)
{
    // LED
    PORTA.DIRSET = PIN_LED_bm;

    // TCB0
    TCB0.CCMP = COMPARE;
    TCB0.INTCTRL = TCB_CAPT_bm;
    TCB0.CTRLA = TCB_ENABLE_bm;

    sei();

    while (1)
    {
    }
}

volatile uint16_t count = 0;
ISR(TCB0_INT_vect)
{
    count++;
    if(count == LOOP){
        count = 0;
        if(PORTA.OUT & PIN_LED_bm){
            PORTA.OUTCLR = PIN_LED_bm;
        }else{
            PORTA.OUTSET = PIN_LED_bm;
        }
    }
    TCB0.INTFLAGS |= TCB_CAPT_bm; //clear the interrupt flag(to reset TCB0.CNT)
}