PIC24FJ64GA104 FAMILY
• Alarm-configurable for half a second, one second,
10 seconds, one minute, 10 minutes, one hour,
one day, one week, one month or one year
19.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
• Alarm repeat with decrementing counter
• Alarm with indefinite repeat chime
Note:
This data sheet summarizes the features
of this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. For more information, refer to the
“PIC24F Family Reference Manual”,
Section 29. “Real-Time Clock and
Calendar (RTCC)” (DS39696).
• Year 2000 to 2099 leap year correction
• BCD format for smaller software overhead
• Optimized for long-term battery operation
• User calibration of the 32.768 kHz clock
crystal/32K INTRC frequency with periodic
auto-adjust
The RTCC provides the user with a Real-Time Clock
and Calendar (RTCC) function that can be calibrated.
Key features of the RTCC module are:
19.1 RTCC Source Clock
• Operates in Deep Sleep mode
• Selectable clock source
The user can select between the SOSC crystal
oscillator or the LPRC Low-Power Internal Oscillator as
the clock reference for the RTCC module. This is con-
figured using the RTCOSC (CW4<5>) Configuration
bit. This gives the user an option to trade off system
cost, accuracy and power consumption, based on the
overall system needs.
• Provides hours, minutes and seconds using
24-hour format
• Visibility of one half second period
• Provides calendar – weekday, date, month and
year
The SOSC and RTCC will both remain running while
the device is held in Reset with MCLR and will continue
running after MCLR is released.
FIGURE 19-1:
RTCC BLOCK DIAGRAM
RTCC Clock Domain
CPU Clock Domain
RCFGCAL
Input from
SOSC/LPRC
Oscillator
RTCC Prescalers
0.5 Sec
ALCFGRPT
YEAR
MTHDY
WKDYHR
MINSEC
RTCC Timer
1 Sec
RTCVAL
Alarm
Event
Comparator
Alarm Registers with Masks
Repeat Counter
ALMTHDY
ALRMVAL
ALWDHR
ALMINSEC
RTSECSEL<1:0>
01
RTCC
Interrupt
RTCC Interrupt Logic
Alarm Pulse
00
10
RTCC
Pin
Clock Source
RTCOE
2010 Microchip Technology Inc.
DS39951C-page 201
MICROCHIP [ MICROCHIP ]
