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Chapter 32
Real Time Clock (RTC)
32.1 Chip-specific RTC information
32.1.1 RTC Instantiation Information
RTC prescaler is clocked by ERCLK32K.
RTC is reset on POR Only.
RTC_CR[OSCE] can override the configuration of the System OSC, configuring the
OSC for 32 kHz crystal operation in all power modes except VLLS0, and through any
System Reset. When OSCE is enabled, the RTC also overrides the capacitor
configurations. So make sure to use low-range crystal (30KHz - 40KHz) when using
RTC_CR to configure the OSC.
32.1.2 RTC_CLKOUT options
RTC_CLKOUT pin can be driven either with the RTC 1 Hz output or with the
OSCERCLK on-chip clock source. Control for this option is through
SIM_SOPT2[RTCCLKOUTSEL].
When SIM_SOPT2[RTCCLKOUTSEL] = 0, the RTC 1 Hz clock is output on the
RTC_CLKOUT pin. When SIM_SOPT2[RTCCLKOUTSEL] = 1, OSCERCLK clock is
output on the RTC_CLKOUT pin.
32.2 Introduction
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
Freescale Semiconductor, Inc.
513
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