Information

Chapter 39
Real Time Clock (RTC)
39.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration chapter.
39.1.1 Features
The RTC module features include:
• Independent power supply, POR and 32 kHz crystal oscillator
• 32-bit seconds counter with roll-over protection and 32-bit alarm
• 16-bit prescaler with compensation that can correct errors between 0.12 ppm and
3906 ppm
• Register write protection
• Lock register requires VBAT POR or software reset to enable write access
• Access control registers require system reset to enable read and/or write access
• 1 Hz square wave output
39.1.2 Modes of operation
The RTC operates in one of two modes of operation, chip power-up and chip power-
down.
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 865