Registers
1336
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Real-Time Clock (RTC)
27.3.14 Control Register (CTRL)
NOTE:
Out of reset, the control register (CTRL) is write-protected. To disable write protection,
correct keys must be written to the KICK
n
R registers (see
).
The control register (CTRL) is shown in
and described in
Figure 27-17. Control Register (CTRL)
31
8
Reserved
R-0
7
6
5
4
3
2
1
0
SPLITPOWER
RTCDISABLE
SET32COUNTER
Reserved
HOURMODE
AUTOCOMP
ROUNDMIN
RUN
W-0
R/W-0
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; W = Write only; -
n
= value after reset
Table 27-16. Control Register (CTRL) Field Descriptions
Bit
Field
Value
Description
31-8
Reserved
0
Reserved.
7
SPLITPOWER
Enable leakage-isolation circuitry used for isolated power schemes.
Write-only bit. Read-modify-
write updates to the control register may unintentionally clear the SPLITPOWER bit because
the bit always reads back 0.
0
Disable split power.
1
Enable split power.
6
RTCDISABLE
Disable RTC module and gate 32-kHz reference clock. RTC should only be disabled using this bit if
the module will never be used and saving power is desired.
0
RTC is functional.
1
RTC is disabled and 32-kHz reference clock is gated.
5
SET32COUNTER
Set the 32-kHz counter with the value stored in the compensation registers when the
SET32COUNTER bit is set. RTC does not run normally when the SET32COUNTER bit is high so
this bit should be toggled low-high-low when used.
0
No action.
1
Set 32-kHz counter with compensation register value.
4
Reserved
0
Reserved.
3
HOURMODE
Enable 12-hour mode for HOURS and ALARMHOURS registers.
0
24 Hour Mode (Valid hours 00-24).
1
12 Hour Mode (Valid hours 00-12; MERIDIEM bit in HOURS and ALARMHOURS must be used to
denote AM or PM).
2
AUTOCOMP
Enable oscillator compensation mode. Compensation takes place once every hour.
0
Auto compensation is disabled.
1
Auto compensation is enabled.
1
ROUNDMIN
Enable one-time rounding to nearest minute on next time register read.
0
Minute rounding disabled.
1
Rounding to nearest minute enabled.
0
RUN
Stop the RTC 32-kHz counter. RTC should be stopped using this bit for stopping and resuming the
counter.
0
Stop RTC counter.
1
Run RTC counter.