F71872
6 Function Description
6.1 Power on Strapping Options
The F71872 provides four pins for power on hardware strapping to select functions. There is a form to describe how
to set the functions you want.
Pin No.
1
Symbol
RST_DRV
Value
Description
Pin31/33/34/48/84 will be defined a Open Drain pin. (Default)
Pin31/33/34/48/84 will be defined a Drive pin.
Fan control mode: PWM mode. ( Default)
Fan control mode: Linear mode.
1
0
1
0
1
0
1
0
2
PWM_DC
KBC_EN
121
124
KBC is enabled. (Default)
KBC is disabled.
Config4E_2E
Chip selection in configuration 4E. (Default)
Chip selection in configuration 2E.
6.2 ACPI
The Advanced Configuration and Power Interface (ACPI) is a system for controlling the use of power in a
computer. It lets computer manufacturer and user to determine the computer’s power usage dynamically.
There are three ACPI states that are of primary concern to the system designer and they are designated
S0, S3 and S5. S0 is a full-power state; the computer is being actively used in this state. The other two are
called sleep states and reflect different power consumption when power-down. S3 is a state that the
processor is powered down but the last procedural state is being stored in memory which is still active. S5 is a
state that memory is off and the last procedural state of the processor has been stored to the hard disk. Take
S3 and S5 as comparison, since memory is fast, the computer can quickly come back to full-power state, the
disk is slower than the memory and the computer takes longer time to come back to full-power state. However,
since the memory is off, S5 draws the minimal power comparing to S0 and S3.
It is anticipated that only the following state transitions may happen:
S0→S3, S0→S5, S5→S0, S3→S0 and S3→S5.
Among them, S3→S5 is illegal transition and won’t be allowed by state machine. It is necessary to enter S0
first in order to get to S5 from S3. As for transition S5→S3 will occur only as an immediate state during state
transition from S5→S0. It isn’t allowed in the normal state transition.
14
July, 2007
V0.28P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
