Peripherals
Power Supply System
(PSS)
pwr_req
clk_req
pss_status
pss_control
Power Control Manager
(PCM)
Clock System
(CS)
cs_status
cs_control
Processor
pwr_req
clk_req
PCM Introduction
423
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
Power Control Manager (PCM)
8.1
PCM Introduction
MSP432P4xx family of devices supports several power modes that allow for the optimization of power for
a given application scenario. The power modes can be changed dynamically to cover many different
power profile requirements across many applications. The Power Control Manager (PCM) manages power
requests from different areas of the system and processing the requests in a controlled manner. The PCM
uses all information from the system that may affect the power requirements and adjusts the power as
required, if possible. The Clock System (CS) and the Power Supply System (PSS) settings are the two
primary elements that control the power settings of the device and hence the power consumption of the
device.
8.2
PCM Overview
Several factors determine the power mode setting of the device. This includes existing conditions from the
clock system (CS) settings and the power supply system (PSS) settings. It is possible that a power mode
request cannot be safely entered based on existing conditions in the system. The PCM is an automated
subsystem that adjusts power based on direct power request settings or indirectly based on other
requests in the system. The PCM becomes the main interface between the PSS and CS modules as
shown in
Figure 8-1. Power Control Manager Interaction
The PCM reacts based on events. The most common events are:
•
PCM Control 0 (PCMCTL0) register. This register can be modified directly by the application execution
to request that a particular power mode be entered.
•
Interrupt and wake-up events. Interrupts from low-power modes cause operation to automatically return
to an active mode.
•
Reset events. Reset events cause the power mode to be set back to its default setting.
•
Debug events. Power mode settings are adapted to support debug hardware requirements.
All of these events, regardless of their source, cause a power change request to the PCM. The power
change request is used as an indication that a new power mode setting may be required. The PCM
processes all requests and makes the necessary changes to the system. It may not be possible to fulfill all
requests and the PCM may deny some requests.