Microchip Technology DM183037 Data Sheet

 2012 Microchip Technology Inc.

DS30575A-page 297

The key features of the Real-Time Clock and Calendar
(RTCC) module are:
• Hardware Real-Time Clock and Calendar (RTCC)
• Provides hours, minutes and seconds using 

24- hour format

• Visibility of one-half second period
• Provides calendar – weekday, date, month and 

year

• Alarm configurable for half a second, one second, 

10 seconds, one minute, 10 minutes, one hour, 
one day, one week or one month

• Alarm repeat with decrementing counter
• Alarm with indefinite repeat – chime
• Year 2000 to 2099 leap year correction
• BCD format for smaller software overhead
• Optimized for long term battery operation
• Fractional second synchronization

• Multiple clock sources

- SOSC
- LPRC
- 50  Hz
- 60  Hz

• User calibration of the 32.768 kHz clock crystal 

frequency with periodic auto-adjust

• Calibration to within ±2.64 seconds error per 

month

• Calibrates up to 260 ppm of crystal error
The RTCC module is intended for applications where
accurate time must be maintained for an extended
period with minimum to no intervention from the CPU.
The module is optimized for low-power usage in order
to provide extended battery life, while keeping track of
time.
The module is a 100-year clock and calendar with auto-
matic leap year detection. The range of the clock is
from 00:00:00 (midnight) on January 1, 2000 to
23:59:59 on December 31, 2099.
Hours are measured in 24-hour (military time) format.
The clock provides a granularity of one second with
half-second visibility to the user.

RTCC Prescalers

RTCC Timer

Comparator

Compare Registers

Repeat Counter

YEAR

MTHDY

WKDYHR

MINSEC

ALMTHDY

ALWDHR

ALMINSEC

with Masks

RTCC Interrupt Logic

RTCCON1

ALRMRPT

Alarm
Event

0.5s

Alarm Pulse

RTCC Interrupt

RTCVALx

ALRMVALx

RTCC Pin

RTCOE

32.768 kHz Input

from SOSC Oscillator

Internal RC

(LF-INTOSC)