RTC_C Registers
739
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Real-Time Clock C (RTC_C)
29.4.3 RTCCTL1 Register
Real-Time Clock Control Register 1
(1)
The configuration of these bits is retained during LPMx.5 until LOCKLPM5 is cleared, but not the register bits themselves; therefore,
reconfiguration is required after wakeup from LPMx.5 before clearing LOCKLPM5.
Figure 29-6. RTCCTL1 Register
7
6
5
4
3
2
1
0
RTCBCD
RTCHOLD
(1)
RTCMODE
(1)
RTCRDY
RTCSSELx
(1)
RTCTEVx
(1)
rw-(0)
rw-(1)
rw-(1)
r-(1)
rw-(0)
rw-(0)
rw-(0)
rw-(0)
Table 29-7. RTCCTL1 Register Description
Bit
Field
Type
Reset
Description
7
RTCBCD
RW
0h
Real-time clock BCD select. Selects BCD counting for real-time clock. Applies to
calendar mode (RTCMODE = 1) only; setting is ignored in counter mode.
0b = Binary (hexadecimal) code selected
1b = Binary coded decimal (BCD) code selected
6
RTCHOLD
RW
1h
Real-time clock hold
0b = Real-time clock (32-bit counter or calendar mode) is operational.
1b = In counter mode (RTCMODE = 0), only the 32-bit counter is stopped. In
calendar mode (RTCMODE = 1), the calendar is stopped as well as the prescale
counters, RT0PS and RT1PS. RT0PSHOLD and RT1PSHOLD are don't care.
5
RTCMODE
RW
1h
Real-time clock mode. In RTC_C modules without counter mode support this bit
is read-only and always reads 1.
0b = 32-bit counter mode
1b = Calendar mode. Switching between counter and calendar mode does not
reset the real-time clock counter registers. These registers must be configured by
user software before use.
4
RTCRDY
R
1h
Real-time clock ready
0b = RTC time values in transition (calendar mode only)
1b = RTC time values safe for reading (calendar mode only). This bit indicates
when the real-time clock time values are safe for reading (calendar mode only).
In counter mode, RTCRDY remains cleared.
3-2
RTCSSELx
RW
0h
Real-time clock source select. In counter mode, selects clock input source to the
32-bit counter. In calendar mode, these bits are don't care. The clock input is
automatically set to the output of RT1PS.
00b = 32-kHz crystal oscillator clock
01b = 32-kHz crystal oscillator clock
10b = Output from RT1PS
11b = Output from RT1PS
1-0
RTCTEVx
RW
0h
Real-time clock time event
Calendar Mode (RTCMODE = 1)
00b = Minute changed
01b = Hour changed
10b = Every day at midnight (00:00)
11b = Every day at noon (12:00)
Counter Mode (RTCMODE = 0)
00b = 8-bit overflow
01b = 16-bit overflow
10b = 24-bit overflow
11b = 32-bit overflow