how to make a daily time organizer using P16F84A?

need help on how to make a 24 hr or 12 hr clock which you can set a time for alarm...any idea will be appreciated..thanks

Use an RTC (Real Time Clock) chip, and use the 16F84 (or preferably it's higher spec and cheaper replacement, the 16F628) to set and read the chip.

You could use an interrupt timer to do it all in the PIC, but the 16F84 isn't a good choice for this! (although there are 'work arounds' at MicroChip) - the 16F628 has better timers, and is a much better choice (use TMR2).