SLAZ290AC October 2012 – May 2021 MSP430F5438A , MSP430F5438A-EP
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.