ASC7512 ETC2 [List of Unclassifed Manufacturers], ASC7512 Datasheet - Page 20

• Manufacturer Part Number: ASC7512
• Description: DIGITAL TEMPERATURE SENSOR WITH INTEGRATED FAN CONTROL
• Manufacturer: ETC2 [List of Unclassifed Manufacturers]

Fan Register Device Set-Up
The BIOS will follow the following steps to configure the fan registers on the aSC7512. The registers corresponding to each
function are listed. All steps may not be necessary if default values are acceptable. Regardless of all changes made by the
BIOS to the fan limit and parameter registers during configuration, the aSC7512 will continue to operate based on default
values until the START bit (bit 0), in the Ready/Lock/Start/Override register (address 40h), is set. Once the fan mode is
updated, by setting the START bit to 1, the aSC7512 will operate using the values that were set by the BIOS in the fan
control limit and parameter registers (address in the range 5Ch through 6Dh).
© Andigilog, Inc. 2006
1.
2.
[40h] (Optional) Set bit 1 (LOCK) to lock the fan limit and parameter registers.
change in state and locks out further change in critical fan control parameters until power is removed from the aSC7512.
Set Fan Output
Min Speed
or Spin-Up
Time Met?
Set limits and parameters (not necessarily in this order):
•
•
•
•
•
•
•
•
•
[40h] Set bit 0 (START) to update fan control and limit register values and start fan control based on these new
values.
to 100%
[5F-60h] Set PWM frequency for the fan and auto fan control range for each zone.
[62-63h] Set spike smoothing and min/off.
[5Ch] Set the fan spin-up delay.
[75h] Set PWM spin-up mode to terminate after time set in [5Ch]. Value = 00h instead of default 01h.
[5Ch] Match fan with a corresponding thermal zone.
[67-68h] Set the fan temperature limits.
[6A-6Bh] Set the temperature absolute limits.
[64h] Set the PWM minimum duty cycle.
[6Dh] Set the temperature hysteresis values.
No
Output to 100%
Override PWM
Yes
Begin Fan
Spin up
End Fan
Spin Up
Yes
Yes
Yes
Figure 9 Automatic Fan Control Algorithm
based on Auto Fan
Range Algorithm
Set fan speed
Begin Polling
End Polling
AbsLimit?
Output at
Spinning
Temp >=
Temp >=
Limit?
Cycle
Cycle
0%?
Up?
Fan
Fan
No
No
Yes
No
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No
- 20 -
Auto Fan Mode
Min set
Initiated
to 1?
Off /
Yes
(Minimum Speed)
No
(off)
WARNING:
Set Fan Output
Hysteresis?
Temp >=
At 0%?
this is a non-reversible
Output
to 0%
Fan
No
Yes
Yes
August 2006 - 70A05003
No
to auto fan mode
aSC7512
minimum speed
Set fan output