The platform management unit (PMU) in the Zynq UltraScale+ RFSoC device signals power domain changes using the PMU output pins. The Zynq UltraScale+ RFSoC device PMU GPO pins are connected to inputs of the MSP430 system controller via TXS0108E level-shifter U41. The RFSoC U1 bank 501 and MSP430 U42 pin numbers are listed in Table: XCZU28DR U1 to MSP430 Connections .
Through the I2C0 bus RFSoC MIO pins, the PMU has access to the board power controllers and power monitors. See This Figure for more details.
See the Zynq UltraScale+ Device Technical Reference Manual (UG1085) [Ref 3] for more details about the PMU interface.