SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 218

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

Rev 0.2 (09-28-04)
Override all PWM
duty cycle except
outputs to 100%
if disabled or in
manual mode
Time Elapsed?
*See PME_STS1 for details.
When in Auto Fan Control Operating Mode the hardware controls the fans directly based on monitoring
of temperature and speed.
To control the fans:
1. Set the minimum temperature that will turn the fans on. This value is programmed in Registers 67h-
2. Set the hysteresis value for the minimum temperature that will turn the fans off. This value will hold
Spin Up
(5C-5E)
No
69h: Zone x Low Temp Limit (Auto Fan Mode Only).
the fans on until the temperature goes a certain amount below the value programmed in the Zone
x Low Temp Limit registers. This value will prevent the fan from oscillating between on and off if
the temperature is around the minimum temperature limit. This value is programmed in Registers
6Dh-6Eh: Zone Hysteresis registers.
Begin Fan Spin-Up
Set Fan Output to
100%
Figure 23.4 Automatic Fan Control Flow Diagram
Yes
Yes
Yes
End Fan Spin Up
Yes
Set fan speed based on
Auto Fan Range
Temp >= Limit
Fan Output
Algorithm*
Temp >=
AbsLimit
(66~68)
(69~6B)
At 0%?
Yes
No
No
Fan Spinning Up?
End Polling Cycle
No
DATASHEET
Begin Polling
LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Cycle
202
No
Auto Fan Mode
Off/Min set to 1?
Set fan to min
Initiated
PWM
(62)
Yes
No
Set Fan Output to
Fan Output
Hyst Temp
Temp >=
(6C~6D)
At 0%?
0%
No
Yes
SMSC SCH311X
Set fan output to
minimum speed.
auto fan mode
(63~65)
No
Datasheet
Yes