RTC_CR field descriptions (continued)Field Description11SC8POscillator 8pF Load Configure0 Disable the load.1 Enable the additional load.10SC16POscillator 16pF Load Configure0 Disable the load.1 Enable the additional load.9CLKOClock Output0 The 32 kHz clock is output to other peripherals.1 The 32 kHz clock is not output to other peripherals.8OSCEOscillator Enable0 32.768 kHz oscillator is disabled.1 32.768 kHz oscillator is enabled. After setting this bit, wait the oscillator startup time before enablingthe time counter to allow the 32.768 kHz clock time to stabilize.7–5ReservedThis field is reserved.This read-only field is reserved and always has the value 0.4WPSWakeup Pin SelectThe wakeup pin is optional and not available on all devices.0 Wakeup pin asserts (active low, open drain) if the RTC interrupt asserts or the wakeup pin is turnedon.1 Wakeup pin instead outputs the RTC 32kHz clock, provided the wakeup pin is turned on and the32kHz clock is output to other peripherals.3UMUpdate ModeAllows SR[TCE] to be written even when the Status Register is locked. When set, the SR[TCE] can alwaysbe written if the SR[TIF] or SR[TOF] are set or if the SR[TCE] is clear.0 Registers cannot be written when locked.1 Registers can be written when locked under limited conditions.2SUPSupervisor Access0 Non-supervisor mode write accesses are not supported and generate a bus error.1 Non-supervisor mode write accesses are supported.1WPEWakeup Pin EnableThe wakeup pin is optional and not available on all devices.0 Wakeup pin is disabled.1 Wakeup pin is enabled and wakeup pin asserts if the RTC interrupt asserts or the wakeup pin isturned on.0SWRSoftware Reset0 No effect.1 Resets all RTC registers except for the SWR bit . The SWR bit is cleared by POR and by softwareexplicitly clearing it.Chapter 32 Real Time Clock (RTC)KL27 Sub-Family Reference Manual , Rev. 5, 01/2016Freescale Semiconductor, Inc. 519
