GMS30C7201 Datasheet, PDF(61/352 Page) Hynix Semiconductor – 60MHz operation frequency Low power consumption

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

GMS30C7201 Datasheet, PDF (61/352 Pages) Hynix Semiconductor – 60MHz operation frequency Low power consumption

◁

PMU & PLL

7.3 Power management states

Run

The system is running normally. All Clocks running (except where gated locally). The SDRAM

controller is performing normal refresh.

SLOW

The CPU is switched into FastBus mode, and hence runs at the BCLK rate (half the FCLK rate).

This is the default mode after exiting SLEEP Mode.

IDLE

In this mode, the PMU becomes the bus master until there is either a fast or normal interrupt for

the CPU, or the peripheral DMA controller requests master-ship of the bus. This will cause the

clocks in the CPU to stop when it attempts an ASB access. Entry to this mode can be caused

by the CPU writing the PMU_IDLE value to the PMU Mode Register when in RUN or SLOW

modes, or a WakeUp signal becoming active when the PMU is SLEEP or DEEP SLEEP modes

SLEEP

In this mode, the SDRAM is put into self-refresh mode, and internal clocks are gated off. This

mode can only be entered from IDLE mode (the PMU bus master must have mastership of the

ASB before this mode can be entered). The PMU must be bus master to ensure that the system

is stopped in a safe state, and is not half way through an SDRAM write (for example). Both the

Video and Communication clocks should be disabled before entering this state.

Usually this state would only be entered briefly, on the way to entering DEEP SLEEP mode.

DEEP SLEEP

In DEEP SLEEP mode, the 3.6864MHz oscillator and the PLL are disabled. This is the lowest

power state available. Only the 32KHz oscillator runs. The real time clock and the PMU are

clocked from this clock. Clocked circuitry in the PMU runs from 4kHz (ie the RTC clock

divided by 8). Everything else is powered down, and SDRAM is in self-refresh mode. This is

the normal system âoffâ mode.

SLEEP and DEEP SLEEP modes are exited either by a user wake-up event (generally pressing

the âOnâ key), or by an RTC wake-up alarm, or by a modem ring indicate event. These interrupt

sources go directly to the PMU.

GMS30C7201 Data Sheet

7-5

▷