[SOLVED] interrupt in RTC, any possibility ?

[Raady Here]

PIC 30f5011
mplab 8.8
ds1307 rtc currently used.

hi,
In my project, I am updating system time using rtc every hour, i have to raise an interrupt 5 times a day at particular mentioned times as a shift entered by the user.
For this I am checking with my system time and shift time every second and then raising flag based on that doing the required function. for system time to run I have used timer for system time and to run the clock.

But I want to make it simpler way by using interrupts,
can there be any possibility that rtc can be configure to interrrupt the processor at predefined intervals or to interrrupt the processor when the rtc register reaches a specific value ?

Regards,
Raady

 

[FvM]

You are asking about DS1307, so the answer is: You can have a 1 Hz interrupt but no timer alarm. Other RTC chips like DS1337 provide the latter, too. You need to connect interrupt line(s). For details refer to the datasheets.

My personal opinion is that RTC interrupts are really helpful to wake a battery operated system from sleep, either periodical or at a predefined time. A processor that's running at regular speed doesn't take much advantage from RTC interrupts. It would be more a matter of confusion about reasonable interrupt usage to rely on it.

 

[andre_luis]

In case of systems which outputs current time at a display by updating its value every second, the 1Hz pin FvM mentioned also provide a visual "life-check" for RTC operation.


+++

 

[betwixt]

In a similar situation I use a software maintained real time clock and at 3:00am (when things are quiet) or when powered up it updates itself from a DS1302. The DS1302 has a built in battery/supercap charger which saves extenal backup circuitry. The software RTC increments a count of seconds since midnight which makes it very easy to compare with the numbers generated for timed events.

Brian.