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6.3 Executing Module State Transitions
6.4 IcePick Emulation Support in the PSC
Executing Module State Transitions www.ti.com
The procedure for module state transitions is as follows ( n corresponds to the module number, see
Table 6-1 for the module numbers):
• Wait for the GOSTAT[0] bit in the power domain transition status register (PTSTAT) to clear to 0. You
must wait for any previously initiated transitions to finish before initiating a new transition.
• Set the NEXT bit in the module control n register (MDCTL n) to SwRstDisable (0), SyncReset (1),
Disable (2h), or Enable (3h).
Note: You may set transitions in multiple NEXT bits in multiple MDCTL n in this step.
• This is a special step required for these specific modules. This step is not required for any module that
is not listed. Set the EMURSTIE bit in MDCTL n to 1, if the module you want to transition is any of the
following:
– EMAC
– USB
– ATA
– VLYNQ
– DDR2 memory controller
– Asynchronous EMIF
– McASP
– GPIO
Note: The EMURSTIE bit in MDCTL n is also used for PSC emulation features. The emulation
features are described in Section 6.4 .
• Set the GO[0] bit in the power domain transition command register (PTCMD) to 1 to initiate the
transition(s).
• Wait for the GOSTAT[0] bit in PTSTAT to clear to 0. The module is safely in the new state only after
the GOSTAT[0] bit in PTSTAT is cleared to 0.
• Wait for the STATE bit in the module status n register (MDSTAT n) to change to the required state,
SwRstDisable (0), SyncReset (1), Disable (2h), or Enable (3h), that was set in MDCTL n.
The PSC supports IcePick commands that allow IcePick aware emulation tools to have some control over
the state of power domains and modules.
In particular, the PSC supports the following IcePick emulation commands:
Table 6-3. IcePick Emulation Commands
Power On and
Enable Features Power On and Enable Descriptions Reset Features Reset Descriptions
Inhibit Sleep Allows emulation to prevent software from Assert Reset Allows emulation to assert the
transitioning the power domain out of the on module’s local reset.
state and to prevent software from transitioning
the module out of the enable state
Force Power Allows emulation to force the power domain into Wait Reset Allows emulation to keep local
an on state reset asserted for an extended
period of time after software
initiates local reset de-assert.
Force Active Allows emulation to force the power domain into Block Reset Allows emulation to block
an on state and force the module into the software initiated local and
enable state. module resets.
Power and Sleep Controller (PSC)66 SPRUEP9A – May 2008
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