DSPIC33FJ16GP101_13 Datasheet, PDF (241/386 Pages) Microchip Technology – 16-Bit Digital Signal Controllers up to 32-Kbyte Flash and 2-Kbyte SRAM

dsPIC33FJ16(GP/MC)101/102 AND dsPIC33FJ32(GP/MC)101/102/104
21.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
Note 1: This data sheet summarizes the features
of the dsPIC33FJ16(GP/MC)101/102
and dsPIC33FJ32(GP/MC)101/102/104
device families of devices. It is not
intended to be a comprehensive reference
source. To complement the information in
this data sheet, refer to Section 37.
“Real-Time Clock and Calendar
(RTCC)” (DS70310) in the
“dsPIC33F/PIC24H Family Reference
Manual”, which is available on the
Microchip web site (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
This chapter discusses the Real-Time Clock and
Calendar
(RTCC)
module,
available
on dsPIC33FJ16(GP/MC)101/102
and
dsPIC33FJ32(GP/MC)101/102/104 devices, and
its operation.
Some of the key features of the RTCC module are:
• Time: hours, minutes and seconds
• 24-hour format (military time)
• Calendar: weekday, date, month and year
• Alarm configurable
• Year range: 2000 to 2099
• Leap year correction
• BCD format for compact firmware
• Optimized for low-power operation
• User calibration with auto-adjust
• Calibration range: ±2.64 seconds error per month
• Requirements: external 32.768 kHz clock crystal
• Alarm pulse or seconds clock output on RTCC pin
The RTCC module is intended for applications where
accurate time must be maintained for extended periods
of time with minimum to no intervention from the CPU.
The RTCC module is optimized for low-power usage to
provide extended battery lifetime while keeping track of
time.
The RTCC module is a 100-year clock and calendar
with automatic 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.
The hours are available in 24-hour (military time)
format. The clock provides a granularity of one second
with half-second visibility to the user.
FIGURE 21-1:
RTCC BLOCK DIAGRAM
RTCC Clock Domain
32.768 kHz Input
from SOSC Oscillator
RTCC Prescalers
0.5s
Alarm
Event
RTCC Timer
Comparator
CPU Clock Domain
RCFGCAL
ALCFGRPT
RTCVAL
Compare Registers
with Masks
Repeat Counter
ALRMVAL
RTCC Interrupt Logic
RTCC Interrupt
Alarm Pulse
RTCC Pin
RTCOE
 2011-2012 Microchip Technology Inc.
DS70652E-page 241