Datasheet

Real Time Clock (RTC)
Data Sheet MC68HC908LJ24/LK24 — Rev. 2.1
230 Real Time Clock (RTC) Freescale Semiconductor
12.9.2 Stop Mode
For continuous RTC operation in stop mode, the oscillator stop mode
enable bit (STOP_XCLKEN in CONFIG2 register) must be set before
executing the STOP instruction. When STOP_XCLKEN is set,
CGMXCLK continues to drive the RTC module, and any enabled CPU
interrupt request from the RTC can bring the MCU out of stop mode.
If STOP_XCLKEN bit is cleared, the RTC module is inactive after the
execution of a STOP instruction. The STOP instruction does not affect
RTC register states. RTC module operation resumes after an external
interrupt. To further reduce power consumption, the RTC module should
be powered-down by clearing the RTCE bit before executing the STOP
instruction.
12.10 RTC Registers
The RTC module has fifteen memory-mapped registers:
• RTC calibration control register (RTCCOMR)
• RTC calibration data register (RTCCDAT)
• RTC control register 1 (RTCCR1)
• RTC control register 2 (RTCCR2)
• RTC status register (RTCSR)
• Alarm minute and hour registers (ALMR and ALHR)
• Second register (SECR)
• Minute register (MINR)
• Hour register (HRR)
• Day register (DAY)
• Month register (MTHR)
• Year register (YRR)
• Day of the week register (DOWR)
• Chronograph data register (CHRR)