SW
Temperature
Sensor
Parameters
SW
Temperature
Sensor
Readings
SW
Temperature
Estimation
SW
Parabolic
Calculations
SW
Crystal Offset
Error
Calculation
HW
Write to
RTCOCAL
HW
Write to
RTCTCMP
HW
Calibration
Logic
Uncalibrated
32-kHz Clock
Uncalibrated
16-kHz Clock
Calibrated
16-kHz Clock
Calibrated
128-Hz Clock
Calibrated
1-Hz Clock
HW RT0PS - Q0
HW
HW
HW
RT0PS - Q1 to Q7
RT1PS - Q0 to Q6
RTC Counters
RTC_C Operation
727
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Real-Time Clock C (RTC_C)
Figure 29-2. RTC_C Offset Error Calibration and Temperature Compensation Scheme
29.2.8.3 Temperature Measurement and Updates to RTC_C
The user may wish to perform temperature measurement once every few seconds or once every minute
or once in several minutes. Writing to RTCTCMP register for temperature compensation is effective
always once in one minute. This means that if the user performs temperature measurement every minute
and updates RTCTCMP register with the frequency error, compensation would immediately work fine. But
if software performs temperature measurement more frequently than once per minute (for example once
every 5 seconds) then it needs to average the error over one minute and update RTCTCMP register once
per minute. If the software performs temperature measurement less frequently than once per minute (for
example, once every 5 minutes) then it needs to calculate the frequency error for the measured
temperature and write into RTCTCMP register. The value written into RTCTCMP in this case would be
effective until it is updated again by software.