Power Management
15-37
Clock Generation and System Reset Management
Note:
The internal signals that cause the wake-ups are asynchronous and do not
need a running clock to be activated. When the WKUP_MODE bit value is
a logical 0 and the CHIP_IDLE signal is active, this condition indicates the
entire chip is in deep sleep mode. The combination of one of the above condi-
tions and a CHIP_nWAKEUP request from the ULPD is required to exit the
chip-idle mode. If WKUP_MODE = 1, then the ULPD is not required to exit
the chip-idle mode, only one of the above wake-up conditions.
If the CHIP_IDLE signal is inactive (and at least one of the internal clocks is
running), the CHIP_nWAKEUP signal is disabled and a single wake-up con-
dition (not ULPD controlled) brings the DSP or MPU system out of idle mode.
A global system reset brings the OMAP5910 device out of idle mode, regard-
less of the WAKEUP_MODE bit value, ULPD control, or the interrupt status.
Figure 15–14 illustrates an ULPD-controlled wake-up sequence (assuming
the DSP and the MPU clock domains have the same clock frequency,
CK_REF). The wake-up is initiated from an interrupt to the MPU, whereas the
DSP remains in idle mode.
Figure 15–14. ULPD Controlled Wake-Up Sequences
DSP_CK
TCLB_CK
ARM_CK
ARM_INTH_CK
IRQ_SET
SETARM_IDLE bit
ARMIDLE_REQ
ARMIDLE_ACK
ARMIDLE_INTH
TCIDLE_REQ
TCIDLE_ACK
IRQ or FIQ request
CHIP_IDLE
WKUP_REQ
CHIP_WKUP
DPLL acknowledge delay
ULPD analog delay