There are 4 stages from RESET
(Shutdown) to stable Slow Clock.
High level description:
- RESET - Device is in RESET (Shutdown), Slow Clock is inactive.
- HW Boot - Upon exit from RESET (device is enabled), the default setting
initiated by the HW Boot sets the slow clock to LFOSC mode, used for PRCM
functionality.
- SW Boot - After completion of the HW Boot, the HOST MCU performs a SW sequence
to set one of the Slow-Clock functional modes:
- The SW sets M0/M1/M2/M3 Muxs in the correct order and timing for smooth
transition (i.e. no glitches or RTC accuracy penalty) according to the
slow clock mode chosen (see Section 7.3.2.1).
- Operational: Active / Sleep states - After applying the SW Boot settings, the
selected Functional-Mode is remains stable, as long as device is not reset.