DS3231 led ansteuern im realen zeit

// during an alarm the INT pin of the RTC is pulled low

//

// this is handy for minimizing power consumption for sensor-like devices, 

// since they can be started up by this pin on given time intervals.

#include <Wire.h>

#include "ds3231.h"

#define BUFF_MAX 256

// time when to wake up

uint8_t wake_HOUR = 15;

uint8_t wake_MINUTE = 49;

uint8_t wake_SECOND = 9;

// how often to refresh the info on stdout (ms)

unsigned long prev = 5000, interval = 5000;

void set_alarm(void)

{

    // flags define what calendar component to be checked against the current time in order

    // to trigger the alarm - see datasheet

    // A1M1 (seconds) (0 to enable, 1 to disable)

    // A1M2 (minutes) (0 to enable, 1 to disable)

    // A1M3 (hour)    (0 to enable, 1 to disable) 

    // A1M4 (day)     (0 to enable, 1 to disable)

    // DY/DT          (dayofweek == 1/dayofmonth == 0)

    uint8_t flags[5] = { 0, 0, 0, 1, 1 };

    // set Alarm1

    DS3231_set_a1(wake_SECOND, wake_MINUTE, wake_HOUR, 0, flags);

    // activate Alarm1

    DS3231_set_creg(DS3231_INTCN | DS3231_A1IE);

}

void setup()

{

    Serial.begin(9600);

    Wire.begin();

    DS3231_init(DS3231_INTCN);

    DS3231_clear_a1f();

    set_alarm();

}

void loop()

{

    char buff[BUFF_MAX];

    unsigned long now = millis();

    struct ts t;

    // once a while show what is going on

    if ((now - prev > interval) && (Serial.available() <= 0)) {

        DS3231_get(&t);

        // display current time

        snprintf(buff, BUFF_MAX, "%d.%02d.%02d %02d:%02d:%02d", t.year,

             t.mon, t.mday, t.hour, t.min, t.sec);

        Serial.println(buff);

        // display a1 debug info

        DS3231_get_a1(&buff[0], 59);

        Serial.println(buff);

        if (DS3231_triggered_a1()) {

            // INT has been pulled low

            Serial.println(" -> alarm1 has been triggered");

            // clear a1 alarm flag and let INT go into hi-z

            DS3231_clear_a1f();

        }

        prev = now;

    }

}