The default output voltage and enabling of the regulator during startup sequence is defined by OTP bits.
After start-up the software can change the output voltage with the RANGE and VSEL bits in the SMPSx_VOLTAGE register. The value 0x0 disables the SMPS (OFF).
The operating mode of an SMPSx when the TPS65903x-Q1 device is in ACTIVE mode can be selected in SMPSx_CTRL register with MODE_ACTIVE[1:0].
The operating mode of an SMPSx when the TPS65903x-Q1 device is in SLEEP mode is controlled by MODE_SLEEP[1:0] bit depending on SMPS assignment to NSLEEP and ENABLE1, see Table 6-13.
Soft-start slew rate is fixed (Tramp).
The pulldown discharge resistance for OFF mode is enabled and disabled in the SMPS_PD_CTRL register. By default, discharge is enabled.
SMPS behavior for warm reset (reload default values or keep current values) is defined by the SMPSx_CTRL.WR_S bit.