SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
As noted in Section 5.2.2.3.1.4, Power Domain and Module States Defined and Section 5.2.2.3.1.5, Executing State Transitions, a particular peripheral's power domain must be enabled before the module is enabled.
Unless there is a system-level reason to perform each function separately, the recommendation is to use the sequence listed in rather than individual sequencing. Even though a single write to the appropriate GO bit starts the power domain and module transition, it is still sequenced such that the memory/logic is certain to turn on before the module is enabled. Thus, there is no ill effect in performing these together.
It is important to know that when a power domain is enabled, all logic/memories for that module are immediately turned on and moved to an active state. This means that there will be a spike in current consumption at that particular time. In other words, di/dt will be affected. To minimize the effect on di/dt of enabling power domains, it is recommended to power up modules one at a time. It is also recommended that all modules be initialized early in the application to avoid a large spike in di/dt during normal operation where the application may already be drawing a substantial amount of current from the supply.