Wulin teaches you how to use PIC32 (10) Real-time Clock (RTC)

Real-Time Clock and Calendar (RTCC) available on PIC32MX devices

Hardware modules and their operation. Some of the main features of this module are listed below:

• Time: hours, minutes and seconds

• 24 hour format (military time)

• Ability to resolve half-second durations

• Provides calendar: week, day, month and year

• Configurable alarm intervals of 0.5 seconds, 1 second, 10 seconds, 1 minute, 10 minutes, 1 hour, 1 day, 1 week, 1 month or 1 year

• Alarm repeats using a down counter

• Infinitely repeatable alarm: chime

• Year range: 2000 to 2099

• Leap year correction

• BCD format to reduce firmware overhead

• Optimized for long battery life

• Fractional second synchronization

• User can use the auto-tune function to calibrate the clock crystal frequency

• Calibration range: ±0.66 seconds error per month

• Calibrates up to 260 ppm of crystal error

• Requirement: External 32.768 kHz clock crystal (there is no crystal on the board, you need to solder it in, and the capacitor needs to be larger, as described below)

• Alarm pulse or seconds clock output on RTCC pin

This module provides real-time clock and calendar functions. RTCC is designed for applications that need to maintain accurate time for a long time without or with

Minimal CPU intervention is required. The module is optimized for low power use to extend battery life while tracking time. The RTCC module features a 100-year clock and calendar with automatic leap year detection. The clock range is from 00:00:00 (midnight) January 1, 2000 to 23:59:59 December 31, 2099. Hours are provided in 24-hour (military time) format. The clock provides one-second time granularity, with half-second time intervals visible to the user.

As shown in the picture, I use a ceramic capacitor of 20pF soldered at both ends of C14. 20pF added to the original 12, that is, 30pF, can cause vibration.

The function we implement is that the serial port prints the current time every second, and LED1 flashes.

The following library functions are used:

RtccInit(); Clock initialization

RtccSetTimeDate(tm.l, dt.l);Set time

RtccGetTime(); Get time