/*

SLdt 190323
SLdt 221001           Disclaimer: none. Sue me.

ATmega88.Timer2 asynchron 32 KiHz

*/

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

#define	DDR_LED		DDRB
#define	PIN_LED		PINB
#define LED			PB0

int main()
{
 DDR_LED	|= (1<<LED);
 ASSR		= (1<<AS2);							// Timer2 asynchron
 TCCR2A		= (1<<WGM21);						// CTC (auf OCR2A)
 OCR2A		= 1 * 32768/1024  -1;				// 1 s
 TCCR2B		= (1<<CS22)|(1<<CS21)|(1<<CS20);	// /1024
 TIMSK2		= (1<<OCIE2A);
 SMCR		= (1<<SE)|(1<<SM1)|(1<<SM0);		// power-save (s.u.)
 sei();
 while(1) {
    while (ASSR & ((1<<OCR2BUB)|(1<<TCR2BUB)));	// sonst evtl. Mehrfachinterrupts
   sleep_mode();
    OCR2B	= 0;								// &OCR2BUB: warten auf asynchron-update, s.o. ASSR
   
    PIN_LED	|= (1<<LED);						// Aktionen
   
 };
}

ISR (TIMER2_COMPA_vect)
{
}

// set_sleep_mode(SLEEP_MODE_PWR_SAVE);			geht auch, s.o.


// ISR (TIMER2_COMPA_vect, ISR__NAKED)
// {
//  reti();
// }