SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
Any GPIO pin can be configured to be an external trigger for the ADC using the GPIO ADC Control (GPIOADCCTL) register. If any GPIO is configured as a non-masked interrupt pin (the appropriate bit of GPIOIM is set), and an interrupt for that port is generated, a trigger signal is sent to the ADC. If the ADC Event Multiplexer Select (ADCEMUX) register is configured to use the external trigger, an ADC conversion is initiated, see Section 10.5.6. Note that whether the GPIO is configured to trigger on edge events or level events, a single-clock ADC trigger pulse is created in either event. Thus, when a level event is selected, the ADC sample sequence will run only one time and multiple sample sequences will not be executed if the level remains the same. It is recommended that edge events be used as ADC trigger source.
Note that if the Port B GPIOADCCTL register is cleared, PB4 can still be used as an external trigger for the ADC. This is a legacy mode that allows code written for previous devices to operate on this microcontroller.