In addition to voltage monitoring, voltage rails sequences are also monitored on ACT and SLEEP changes, or on setting SEQ_REC_CTL.REC_START=1.

Sequence Monitoring 1 is a transitional state entered when:

1. ACT transitions 0→1
2. SLEEP transitions 0→1, if ACT=1
3. SLEEP transitions 1→0, if ACT=1
4. Host sets SEQ_REC_CTL.REC_START=1

The first three transitions trigger the same set of actions, with the TPS389006/08-Q1,TPS389R0-Q1 always ending in the ACTIVE state. However, the registers used to log and check the sequencing information are different.

The fourth method to start sequence monitoring (register bit set by the host) gives the flexibility to the host to decide when and where to track a sequence while the external signals are static. This is useful, for example, when software shutdown is initiated using FORCE_SHUTDOWN[1:0].

The following sections describe the actions for the first three cases explicitly for clarity.