Power Mode Transition Checks
437
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
Power Control Manager (PCM)
8.10 Power Mode Transition Checks
The PCM automatically checks for unsupported power mode transitions.
For active modes, any active mode transition that is not supported causes the active mode transition
invalid flag to be set (AM_INVALID_TR_IFG = 1) and the original AMR settings are retained. When
AM_INVALID_TR_IFG is set, this flag can be cleared by software by setting
CLR_AM_INVALID_TR_IFG = 1. Setting AM_INVALID_TR_IE = 1 enables an NMI/interrupt to be
executed when AM_INVALID_TR_IFG = 1 (see
).
Table 8-4. AM Invalid Transition NMI/interrupt Enable
AM_INVALID_TR_IE
AM_INVALID_TR_IFG
Response
0
0 or 1
None
1
0
None
1
NMI/interrupt
For LPM3 and LPM4 modes, any active to LPM3 or LPM4 mode transition not supported cause the low-
power mode transition invalid flag to be set (LPM_INVALID_TR_IFG = 1) and the original AMR settings
are retained. When LPM_INVALID_TR_IFG is set, this flag can be cleared by software by setting
CLR_LPM_INVALID_TR_IFG = 1. Setting LPM_INVALID_TR_IE = 1 enables a NMI/interrupt to be
executed when LPM_INVALID_TR_IFG = 1. This is summarized in
Table 8-5. LPM Invalid Transition NMI/Interrupt Enable
LPM_INVALID_TR_IE
LPM_INVALID_TR_IFG
Response
0
0 or 1
None
1
0
None
1
NMI/interrupt
8.11 Power Mode Clock Checks
The PCM does not perform any clock frequency or condition checks during any active or LPM0 power
mode transitions. The application must ensure that the system conditions are met before the transition
between these mode transitions.
For transitions to LPM3, LPM4, and LPMx.5 modes, the PCM does perform clock checking. When
entering LPM3, LPM4, and LPMx.5 modes, it is possible that an active clock source is present in the
system in any of the system clocks. This is typically defined as a static clock request. In cases like this,
the application can decide whether to force the LPM3, LPM4, and LPMx.5 entry or not. Forcing LPM3,
LPM4, and LPMx.5 entry in this condition is achieved by setting FORCE_LPM_ENTRY = 1.
defines the static clock request checks that PCM performs for different clocks within the device.
For example: Assume the MSP432P401R and MSP432P401M device is currently operating in
AM_LDO_VCORE0 and has an active clock request on any of the clock lines (ACLK, MCLK, SMCLK, or
HSMCLK). If a request is made to enter any of LPM3, LPM4, or LPMx.5modes, the PCM denies the
request and maintains its setting at AM_LDO_VCORE0 if FORCE_LPM_ENTRY = 0. This ensures that
the active clock can be serviced reliably. The low-power mode invalid clock flag, LPM_INVALID_CLK_IFG
is set. When set, this flag remains set until cleared by software by setting
CLR_LPM_INVALID_CLK_IFG = 1. Setting LPM_INVALID_CLK_IE = 1 enables a NMI/interrupt to be
executed when LPM_INVALID_CLK_IFG = 1. This is summarized in
. The application must
determine the proper action to be taken.
Table 8-6. PCM Static Clock Request Checks
Device
PCM Static Clock Request Checks Performed
for...
MSP432P401R and MSP432P401M
ACLK
MCLK
SMCLK
HSMCLK