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
811
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
Real-Time Clock (RTC_C)
Figure 20-2. RTC_C Offset Error Calibration and Temperature Compensation
20.2.8.3 Temperature Measurement and Updates to RTC
The application may need to perform temperature measurement once every few seconds or once every
minute or once in several minutes. Writing to the RTCTCMP register for temperature compensation is
effective once per one minute. This means that if the user performs temperature measurement every
minute and updates RTCTCMP register with the frequency error, compensation would immediately apply.
But if software performs temperature measurement more frequently than once per minute (for example
once every 5 seconds), then the application should 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 the application must 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.