PIC24F08KA102-I Datasheet, PDF (155/278 Pages) Microchip Technology – 20/28-Pin General Purpose, 16-Bit Flash Microcontrollers with nanoWatt XLP Technology

PIC24F16KA102 FAMILY
19.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
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 on the
Real-Time Clock and Calendar, refer to the
“PIC24F Family Reference Manual”,
Section 29. “Real-Time Clock and
Calendar (RTCC)” (DS39696).
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:
• Operates in Deep Sleep mode
• Selectable clock source
• 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,
FIGURE 19-1:
RTCC BLOCK DIAGRAM
one day, one week, one month or one year
• 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
• User calibration of the 32.768 kHz clock
crystal/32K INTRC frequency with periodic
auto-adjust
19.1 RTCC Source Clock
The user can select between the SOSC crystal
oscillator or the LPRC internal oscillator as the clock
reference for the RTCC module. This is configured
using the RTCOSC (FDS<5>) Configuration bit. This
gives the user an option to trade off system cost,
accuracy and power consumption, based on the overall
system needs.
The RTCC will continue to run, along with its chosen
clock source, while the device is held in Reset with
MCLR and will continue running after MCLR is
released.
Input from
SOSC/LPRC
Oscillator
Alarm
Event
RTCC Clock Domain
RTCC Prescalers
0.5 Sec
RTCC Timer
Comparator
CPU Clock Domain
RCFGCAL
ALCFGRPT
RTCVAL
YEAR
MTHDY
WKDYHR
MINSEC
Alarm Registers with Masks
ALRMVAL
ALMTHDY
ALWDHR
ALMINSEC
Repeat Counter
RTCC Interrupt Logic
RTCC
Interrupt
Alarm Pulse
Clock Source
RTCOE
RTSECSEL<1:0>
1s
01
00
10
RTCC
Pin
 2008-2011 Microchip Technology Inc.
DS39927C-page 155