SLAZ102AB October 2012 – May 2021 CC430F6137
RTC Module
Functional
the step size of the RTC frequency adjustment is twice the specified size.
In BCD mode of operation, the step size of the RTC frequency adjustment is =+8ppm/-4ppm. This is twice the size specified in the User's Guide.
In BCD mode, for up calibration this results in a step size per step of 8ppm (1024 cycles) instead of 4ppm (512 cycles). For down calibration this results in a step size per step of 4ppm (512 cycles) instead of 2ppm (256 cycles).
In Binary mode, the step size = +4ppm/-2ppm as per the spec.
In BCD mode of operation, half the calibration value could be written into RTCCAL register to compensate the doubled step size.