System Monitoring and Communication Profile
The input power for the SMAC is provided by a single voltage rail that is distributed throughout the system and delivered to nodes. The power for the SMAC shall default to an “on” state for at least one node in the system when the common power bus is enabled. The power for the remaining SMACs may default to either state depending on the application requirements.
The enable signals for the remaining POLs on the node that power the processing logic are controlled by the SMAC and are attached to network-accessible registers. This allows the system controller to control the majority of the node’s power state directly over the network.
One possible approach for power control is to connect at least two discrete lines that from SMACs on neighboring nodes to the local POLs. These power enable/disable signals should be connected to the POL circuitry in a manner that implements the desired power-on scheme for the application.
POL power conversion is discussed in more detail in the Electrical Specification.