SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
The MSP432E4 microcontroller provides a main oscillator verification circuit that generates an error condition if the oscillator is running too fast or too slow. If the main oscillator verification circuit is enabled and a failure occurs, either a POR is generated and control is transferred to the NMI handler, or an interrupt is generated. The MOSCIM bit in the MOSCCTL register determines which action occurs. In either case, the system clock source is automatically switched to the PIOSC. If a MOSC failure reset occurs, the NMI handler is used to address the main oscillator verification failure, because the necessary code can be removed from the general reset handler, speeding up reset processing. The detection circuit is enabled by setting the CVAL bit in the Main Oscillator Control (MOSCCTL) register. The main oscillator verification error is indicated in the main oscillator fail status (MOSCFAIL) bit in the RESC register. The main oscillator verification circuit action is described in more detail in Section 4.1.5.4.1.