SLAU893B October 2023 – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1
To use VREF to generate an internal voltage reference, the user must first enable the power to the module using the ENABLE control bit in the PWREN register and then enable the reference buffer using the ENABLE control bit in the CTL0 register. The VREF module generates voltage references based on the factory trimmed bandgap coming from the PMU. The bandgap reference is buffered through a noninverting amplifier to generate one of two internal reference voltages (1.4V or 2.5V). Only one voltage can be selected at a time using the BUFCONFIG control bit in CTL0.
After it is enabled and settled, the internal reference can be used as an accurate and stable voltage reference for the on-board ADC. Refer to the the ADC chapter for more info on how can leverage this reference voltage.
The VREF provides a READY indication bit in the CTL1 register. The first time the VREF is enabled, the READY bit will remain cleared until the VREF is started and settled, after which the READY bit will be set by hardware. If the VREF is disabled, the READY bit will be cleared back to zero by hardware. If the VREF is re-enabled later, the READY bit will not be set, and application software must manage the VREF startup time.