Owner's manual

Table Of Contents
5-10 DS785UM1
Copyright 2007 Cirrus Logic
System Controller
EP93xx User’s Guide
5
5
5
HCLK to the USB Hosts can be gated off as well to further save power. The USH_EN bit in
the "PwrCnt" register serves the purpose.
5.1.6.2 System Power States
The EP93xx has three power states:
Run mode: Normal operation mode.
Halt: ARM Core stops executing instructions.
Standby: Power is on, but only SDRAM self-refresh and the RTC run.
Figure 5-4 illustrates the transitions among power states.
Table 5-4. Peripherals with PCLK Gating
Peripheral
Peripheral/PCLK
on with Enable or
Register Access
PCLK on with
Register Access
Only
PCLK Continuous
UART1 x --
UART2
x --
UART3
x --
KEYPAD -
x -
IRDA
x --
SEC
x --
I
2
S
x --
Watchdog - -
x
TSC - x -
PWM
x --
AAC
x --
SSP
x --
RTC - -
x
GPIO - x -