Power Management
15-31
Clock Generation and System Reset Management
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Traffic controller subdomain
The traffic controller clock (TC_CK) is shut off if the MPU and the DSP
DPLLs are in idle mode and there is no DMA transfer. When the clock must
be shut off, the memory interface completes the current memory transac-
tion before notifying the CLKM3 to shut off a clock. The SDRAM is placed
in self-refresh mode before shutting off the SDCLK_EN clock, and there is
no internal local bus activity, as indicated by the internal TCLB_EN
signal.
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MPU peripheral bridge domain
The MPU peripheral bridge clock (TIPB_CK) is shut off if the MPU is in idle
mode and there is no DMA transfer.
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LCD domain
The LCD clock (LCD_CK) is shut off/activated according to the traffic
controller idle mode or forced off with the enable bit.
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MPU MPUI domain
The MPUI clock (API_CK) is shut off if the MPU and the DSP DPLLs are in
idle mode and there is no DMA transfer (when the clock is required to be
shut off, the memory interface completes the current memory transaction
before notifying the CLKM3 to shut off the clock). The MPUI clock can also
be forced off with the enable bit (the MPUI clock can only be shut off by the
enable bit in current implementation).
Note:
To idle the traffic controller, the system software must ensure that the current
transfers are completed and their clock domains are turned off before going
to idle.
The traffic controller clock restarts upon either an MPU or DSP interrupt
request, a DMA request, or activity on the internal buses.
15.3.3.1
DPLL Idle Procedure
In the event that only the input reference clock is needed (that is, only timer/
watchdog are active), then the DPLL can be set to idle mode. This procedure
applies to DPLL. The DPLL clock is stopped if all the domains that use it as a
source are stopped.
Setting the IDLDPLL_ARM bits (in ARM_IDLECT1 register) to logic 1 forces
the corresponding DPLL to enter the idle mode whenever the DPLL output
clocks (CK_GEN1, CK_GEN2, CK_GEN3) are not being used.