W83627DHG Nuvoton Technology Corporation of America, W83627DHG Datasheet - Page 178

• Manufacturer Part Number: W83627DHG
• Description: IC I/O CONTROLLER 128-QFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83627DHG

• Applications: PC's, PDA's
• Interface: LPC
• Voltage - Supply: 3.3V
• Package / Case: 128-XFQFN
• Mounting Type: Surface Mount
• Pin Count: 128
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.1.2 AC Power Failure Resume
By definition, AC power failure means that the standby power is removed. The power failure resume
control logic of the W83627DHG is used to recover the system to a pre-defined state after AC power
failure. Two control bits at Logical Device A, CR[E4h], bits[6:5] indicate the pre-defined state. The
definition of these two bits is listed in the following table:
Note1. The W83627DHG detects the state before power failure (on or off) through the SUSB# signal and the 3VCC
power. The relation is illustrated in the following two figures.
To ensure that VCC does not fall faster than VSB in various ATX Power Supplies, the W83627DHG adds the
option of “user define mode” for the pre-defined state before AC power failure. BIOS can set the pre-defined state
LOGICAL DEVICE A, CR[E4H],
LOGICAL DEVICE A, CR[E6H]
3VCC
SUSB#
BITS[6:5]
Note 2.
Figure 14.3 The previous state is “on” - 3VCC falls to 2.6V and SUSB# keeps at 2.0V
Figure 14.4 The previous state is “off” - 3VCC falls to 2.6V and SUSB# keeps at 0.8V
3VCC
SUSB#
00
01
10
11
BIT [4]
0
1
System always turns off when it returns from AC power failure
System always turns on when it returns from AC power failure
System turns off / on when it returns from power failure depending
on the state before the power failure. (Please see Note 1)
User defines the state before the power failure. (The previous
state is set at CRE6[4]. Please see Note 2)
-166-
User defines the state to be “on”
User defines the state to be “off”
Publication Release Date: Aug, 22, 2007
DEFINITION
DEFINITION
W83627DHG
Version 1.4