PIC24HJ32GP302_11 Datasheet, PDF (237/368 Pages) Microchip Technology – High-Performance, 16-bit Microcontrollers

PIC24HJ32GP302/304, PIC24HJ64GPX02/X04 AND PIC24HJ128GPX02/X04
22.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
Note 1: This data sheet summarizes the features
of
the
PIC24HJ32GP302/304,
PIC24HJ64GPX02/X04
and
PIC24HJ128GPX02/X04 families of
devices. It is not intended to be a compre-
hensive reference source. To comple-
ment the information in this data sheet,
refer to Section 37. “Real-Time Clock
and Calendar (RTCC)” (DS70301) of
the “dsPIC33F/PIC24H Family Refer-
ence Manual”, which is available from the
Microchip website (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
PIC24HJ32GP302/304, PIC24HJ64GPX02/X04 and
PIC24HJ128GPX02/X04 devices, and its operation.
The following are some of the key features of this
module:
• 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 22-1:
RTCC BLOCK DIAGRAM
RTCC Clock Domain
32.768 kHz Input
from SOSC Oscillator
RTCC Prescalers
0.5s
Alarm
Event
RTCC Timer
Comparator
Compare Registers
with Masks
Repeat Counter
CPU Clock Domain
RCFGCAL
ALCFGRPT
RTCVAL
ALRMVAL
RTCC Interrupt Logic
RTCC Interrupt
Alarm Pulse
RTCOE
RTCC Pin
© 2011 Microchip Technology Inc.
DS70293E-page 237