ASC7611 ETC2 [List of Unclassifed Manufacturers], ASC7611 Datasheet - Page 24

• Manufacturer Part Number: ASC7611
• Description: HARDWARE MONITOR WITH INTEGRATED FAN CONTROL
• Manufacturer: ETC2 [List of Unclassifed Manufacturers]

Register
Address
Fan Register Device Set-Up
The BIOS will follow the following steps to configure the fan registers on the aSC7611. 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 aSC7611 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 aSC7611 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 75h).
Register 5F-61h: Auto Fan Speed Range, PWM Frequency
In Auto Fan Mode, when the temperature for a zone is above the Temperature Limit (Registers 67-69h) and below its
Absolute Temperature Limit (Registers 6A-6Ch), the speed of a fan assigned to that zone is determined as follows:
When the temperature reaches the Fan Temp Limit for a zone, the PWM output assigned to that zone will be Fan PWM
Minimum. Between Fan Temp Limit and (Fan Temp Limit + Range), the PWM duty cycle will increase linearly according to
the temperature as shown in the figure below. The PWM duty cycle will be 100% at (Fan Temp Limit + Range).
PWM frequency - FRQ[3:0] and HLFRQ
The PWM frequency bits [3:0] determine the PWM frequency for the fan. The aSC7611 has high and low frequency ranges
for the PWM outputs that are controlled by the HLFRQ bit.
PWM Frequency Selection (Default = 0011 ≈ 30 Hz).
© Andigilog, Inc. 2006
5Fh
60h
61h
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 aSC7611.
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.
Read/
Write
R/W
R/W
R/W
[5F-61h] Set PWM frequency for the fan and auto fan control range for each zone.
[62-63h] Set spike smoothing and min/off.
[5C-5Eh] 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.
[67-69h] Set the fan temperature limits.
[6A-6Ch] Set the temperature absolute limits.
[64-66h] Set the PWM minimum duty cycle.
[6D-6Eh] Set the temperature hysteresis values.
Zone 1 Range
Fan1 Frequency
Zone 2 Range/
Fan 2 Frequency
Zone 3 Range/
Fan 3 Frequency
Register Name
(MSB)
RAN3
RAN3
RAN3
Bit 7
RAN2
RAN2
RAN2
Bit 6
www.andigilog.com
RAN1
RAN1
RAN1
Bit 5
- 24 -
RAN0
RAN0
RAN0
Bit 4
HLFRQ
HLFRQ
HLFRQ
Bit 3
WARNING:
FRQ2
FRQ2
FRQ2
Bit 2
FRQ1
FRQ1
FRQ1
Bit 1
this is a non-reversible
October 2006 - 70A05007
(LSB)
FRQ0
FRQ0
FRQ0
Bit 0
aSC7611
Default
Value
C3
C3
C3
Lock
X
X
X