SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
To use the RTC mode, the timer must have a 32.768-KHz input signal on an even CCP input. To enable the RTC feature, follow these steps:
When the timer count equals the value in the GPTMTnMATCHR register, the GPTM asserts the RTCRIS bit in the GPTMRIS register and continues counting until Timer A is disabled or a hardware reset. The interrupt is cleared by writing the RTCCINT bit in the GPTMICR register. If the GPTMTnILR register is loaded with a new value, the timer begins counting at this new value and continues until it reaches 0xFFFF.FFFF, at which point it rolls over.