2 system power states, 2 system power states -10, Table 5-4. peripherals with pclk gating -10 – Cirrus Logic EP93xx User Manual
Page 136: Shown, Table 5-4
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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
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.
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
-
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