Power Management
15-36
15.3.4.3
Wake-Up Procedure
An interrupt request (not masked) (either to the MPU or to the DSP), a DMA
clock request, or a logical 1 at the TCLB_EN signal exits the idle mode. In
addition, when all internal clocks are stopped (chip-idle mode), the wake-up
procedure can be controlled via the ULPD. The WKUP_MODE bit of the MPU
idle mode entry 1 register (ARM_IDLECT1) defines this wake-up option.
To give the ULPD wake-up control, the WKUP_MODE bit must be cleared to
0 before entering the idle mode.
In the OMAP5910 device, the WKUP_MODE bit is controlled by the MPU in
the MPU idle mode entry 1 register (ARM_IDLECT1). The DSP has no control
of this bit.
When the WKUP_MODE bit value is set to logic 1, a single wake-up condition
(as defined in the following list) initiates a chip wake-up procedure.
1) nIRQ_SET: Upon an interrupt request, the MPU interrupt handler initiates
the restart of the ARM_CK, ARM_INTH_CK, TIPB_CKs, DMA_CK, and
TC_CK clocks (depending on the setting of the MPU idle mode entry 1/2
registers (ARM_IDLECT1/2), peripherals clocks can also restart). If the
idle mode was entered from the SETARM_IDLE bit, then the bit is cleared
to 0.
2) DSP_nIRQ: Upon an interrupt request, the DSP interrupt handler initiates
the restarting of the MPUI clock (if MPUICK_EN is not set to 0), DSP_CK,
DSP_INTH_CK, TC_CK clocks (depending on the setting of the MPU idle
mode entry 1/2 registers (ARM_IDLECT1/2), peripheral clocks can also
restart).
3) TCLB_EN signal: When the internal TCLB_EN signal goes active, the
TC_CK and LB_CK clocks restart. The TC_CK/LB_CK clocks keep
running as long local bus activity occurs.
4) When the system DMA controller receives an asynchronous request from
the traffic controller, DMA_CK/TC_CK/LB_CK and DMA_CK/TC_CK/
LB_CK are enabled to keep running as long as the DMA operates.
5) When the system DMA controller receives a request from the TIPB bridge,
it enables TC_CK/TIPB_CKs/DMA_CK and TC_CK/TIPB_CKs/DMA_CK
to keep running as long as the DMA operates.