5.10.1 Power Management Module (PMM) and On-Chip Reference Voltages

The PMM includes an integrated voltage regulator that supplies the core voltage to the device. The PMM also includes supply voltage supervisor (SVS) and brownout protection. The brownout reset circuit (BOR) is implemented to provide the proper internal reset signal to the device during power-on and power-off. The SVS circuitry detects if the supply voltage drops below a user-selectable safe level. SVS circuitry is available on the primary supply.

The device contains three on-chip references:

• Internal shared reference (1.5 V, 2.0 V, or 2.5 V)
• 1.2 V for external reference (VREF pin)
• 1.2 V low-power reference for eCOMP

The internal shared reference is controlled by PMM settings to select 1.5 V, 2.0 V, or 2.5 V. This reference is internally connected to ADC channel 13. DVCC is internally connected to ADC channel 15. When DVCC is set as the reference voltage for ADC conversion, the DVCC can be easily represent as Equation 1 by using ADC sampling reference without any external components support.

The internal shared reference (1.5 V, 2.0 V, or 2.5 V ) is also internally connected to the built-in DAC of the comparator and SAC (MSP430FR235x devices only) built-in 12-bit DAC as the reference voltage. The source can be selected by setting the specific register configuration of each module For more information, see the MSP430FR4xx and MSP430FR2xx Family User's Guide.

P1.7/UCA0TXD/UCA0SIMO/TB0.2/TDO/OA1+/A7/VREF+ can support a buffered external 1.2-V output when EXTREFEN = 1 in the PMMCTL2 register. ADC channel 7 can also be selected to monitor this voltage. For more information, see the MSP430FR4xx and MSP430FR2xx Family User's Guide.

An additional low-power 1.2-V reference is internally connected to eCOMP0 and eCOMP1. This reference is activated by enabling eCOMP with the channel as threshold source. See Section 5.10.13 for more details.