PIC32MX440F256H-80I Datasheet, PDF (469/646 Pages) Microchip Technology – 64/100-Pin General Purpose and USB 32-Bit Flash Microcontrollers

21.0 REAL-TIME CLOCK AND
CALENDAR (RTCC)
Note:
This data sheet summarizes the features of
the PIC32MX3XX/4XX family of devices. It
is not intended to be a comprehensive refer-
ence source. Refer to the “PIC32MX Family
Reference Manual” (DS61132) for a
detailed description of this peripheral.
The PIC32MX Real-Time Clock and Calendar (RTCC)
module is intended for applications where accurate
time must be maintained for extended periods of time
with minimal or no CPU intervention. Low-power
optimization provides extended battery lifetime while
keeping track of time.
Following are some of the key features of this module:
• Time: Hours, Minutes and Seconds
• 24-Hour Format (Military Time)
• Visibility of One-Half-Second Period
• Provides Calendar: Weekday, Date, Month and
Year
FIGURE 21-1:
RTCC BLOCK DIAGRAM
PIC32MX3XX/4XX
• Alarm Intervals are configurable for Half of a
Second, One Second, 10 Seconds, One Minute,
10 Minutes, One Hour, One Day, One Week, One
Month and One Year
• Alarm Repeat with Decrementing Counter
• Alarm with Indefinite Repeat: Chime
• Year Range: 2000 to 2099
• Leap Year Correction
• BCD Format for Smaller Firmware Overhead
• Optimized for Long-Term Battery Operation
• Fractional Second Synchronization
• User Calibration of the Clock Crystal Frequency
with Auto-Adjust
• Calibration Range: ±0.66 Seconds Error per
Month
• Calibrates up to 260 ppm of Crystal Error
• Requirements: External 32.768 kHz Clock Crystal
• Alarm Pulse or Seconds Clock Output on RTCC
pin
32.768 kHz Input
from SOSC Oscillator
RTCC Prescalers
0.5s
Alarm
Event
RTCC Timer
Comparator
Compare Registers
with Masks
Repeat Counter
RTCVAL
ALRMVAL
RTCC Interrupt Logic
YEAR, MTH, DAY
WKDAY
HR, MIN, SEC
MTH, DAY
WKDAY
HR, MIN, SEC
RTCC Interrupt
Alarm Pulse
Seconds Pulse
RTCOE
RTCC Pin
© 2008 Microchip Technology Inc.
Preliminary
DS61143E-page 467