6.2.1 OptionalMfgFunction3 Register (0x3D)
Today's computer systems are able to distinguish between different power off states.
For a battery powered system the states S3 (suspend to RAM), S5 (soft off) and G3
(mechanical off) are of particular importance. The main system power is switched off in
all cases, however the system standby power is switched off in the G3 state only.
Of course the system states S3 and S5 provide features such as wake-on-LAN or fast
system resume times. However, for a battery powered system with long standby times it
may be more useful to switch off to the G3 state to minimize power consumption.
Therefore, congatec has defined two bits 'S3' and 'S5' in the smart battery register
OptionalMfgFunction3. These bits are used to signal the SBSM (Smart Battery System
Manager) whether it may additionally switch off the system standby power after the main
system power has been switched off. The following table shows the detailed
OptionalMfgFunction3 register definition:
Bit
Number
Bit
Name
Default
Value
Description
0-7
0xA
Blink warn level [percent]
8
S5
0
Setting this bit to 1 tells the SBSM that it must not switch off the system
standby power because the system is required to stay in the S5 state after
switching off the main system power.
Note: When the SBSM is completely restarted it must reset this bit to its
default value. Usually this bit is set/reset by the system host during the
power-on-self-test (POST) of the system based on CMOS RAM settings.
9
S3
0
Setting this bit to 1 tells the SBSM that it must not switch off the system
standby power because the system is going to enter the S3 state when
switching off the main system power. This bit is set by the system host right
before the system enters the S3 state. The S3 bit must be cleared by the
SBSM when the system resumes from the S3 state, i.e. when main system
power is turned on again.
10
S1
0
This bit indicates that the system is running in a power saving mode. It is
set/reset by the system host when entering/leaving the power saving mode.
11-15
Reserved
Copyright © 2008 congatec AG
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