PMM Operation
205
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Power Management Module (PMM)
3.3.5.2
Turning a Power Domain On
A power domain can be turned on by writing the correct key to the LOGICPDPWRCTRL0.LOGICPDONx
or MEMPDPWRCTRL0.MEMPDONx. PMM will automatically restart the clocks to the power domain once
the power is restored if the “automatic clock enable upon wake up” option is selected. If this option is not
selected, the application can turn on clocks to the power domain by clearing the PDCLK_DIS register. The
application must poll the LOGICPDPWRSTATx.DOMAIN_ONx to ensure that the power has been fully
restored before enabling the clocks.
NOTE:
if a power domain is permanently disabled by TI, then the application cannot turn that power
domain back on. No error is generated if the application attempts to do so.
3.3.6 Reset Management
PMM handles the reset sequence for each power domain. When a power domain is turned on from an off
state, the PMM will reset the power domain to ensure that all logic begins in its default reset state.
PMM generates nPORRST (power-on reset), nRST (system reset), nPRST (peripheral reset), and nTRST
(test / debug logic reset) for each domain.
3.3.7 Diagnostic Power State Controller (PSCON)
Each power domain state is controlled by a primary PSCON. There is a second PSCON as well for each
power domain. This is the diagnostic PSCON. All power management inputs to a power domain are
controlled only by the primary PSCON. All power management outputs from the power domain are fed
back to both the primary and the diagnostic PSCON.
The PMM commands both the PSCON identically so that they are always in a lock-step operating mode. A
dedicated compare unit checks the outputs of the two PSCON modules on every cycle.
3.3.8 PSCON Compare Block
The diagnostic compare block can operate in one of four modes:
3.3.8.1
Lock-Step Mode
This is the default mode of operation of the PSCON compare block. The PSCON diagnostic compare
block compares the outputs from the two PSCONs on every cycle. Any mismatch in the PSCON outputs is
indicated as a PSCON compare error. This error signal is mapped to the Error Signaling Module’s (ESM)
Group1 channel 38. The application can define the response to this error.