NXP Semiconductors KE1xF Series, Reference Manual, Page: 1187 / 1483

RTC_CR field descriptions (continued)
Field Description
13–10
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
9
CLKO
Clock Output
0 The 32 kHz clock is allowed to output on RTC_CLKOUT.
1 The 32 kHz clock is not allowed to output on RTC_CLKOUT.
8
OSCE
Oscillator Enable
0 32.768 kHz oscillator is disabled.
1 32.768 kHz oscillator is enabled. After setting this bit, wait the oscillator startup time before enabling
the time counter to allow the 32.768 kHz clock time to stabilize.
7
LPOS
LPO Select
When set, the RTC prescaler increments using the LPO clock and not the RTC 32 kHz clock. The LPO
increments the prescaler from bit TPR[5] (TPR[4:0] are ignored), supporting close to 1 second increment
of the seconds register. Although compensation is supported when clocked from the LPO, TCR[4:0] of the
compensation register are also ignored and only TCR[7:5] set the compensation value (can overflow after
1020 to 1027 cycles).
0 RTC prescaler increments using 32 kHz clock.
1 RTC prescaler increments using LPO, bits [4:0] of the prescaler are bypassed.
6
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
5
CPS
Clock Pin Select
0 The prescaler output clock (as configured by TSIC) is output on RTC_CLKOUT.
1 The RTC 32kHz clock is output on RTC_CLKOUT.
4
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
3
UM
Update Mode
Allows SR[TCE] to be written even when the Status Register is locked. When set, the SR[TCE] can always
be 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.
2
SUP
Supervisor Access
0 Non-supervisor mode write accesses are not supported and generate a bus error.
1 Non-supervisor mode write accesses are supported.
1
WPE
Wakeup Pin Enable
The 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 is
turned on.
0
SWR
Software Reset
Table continues on the next page...
Chapter 45 Real Time Clock (RTC)
Kinetis KE1xF Sub-Family Reference Manual, Rev. 4, 06/2019
NXP Semiconductors 1187