21 / 35 page
- 21 -
© Andigilog, Inc. 2006
www.andigilog.com
August 2006 - 70A05003
aSC7512
Register 5F-60h: Auto Fan Speed Range, PWM Frequency
Register
Address
Read/
Write
Register Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock
5Fh
R/W
Zone 1 Range
Fan1 Frequency
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C3
X
60h
R/W
Zone 2 Range
RAN3
RAN2
RAN1
RAN0
RES
RES
RES
RES
C3
X
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-6Bh), 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 aSC7512 has high and low frequency ranges
for the PWM outputs that are controlled by the HLFRQ bit.
PWM Frequency Selection (Default = 0011 = 30.04 Hz).
HLFRQ
FRQ [2:0]
PWM
Frequency
0
000
10.01 Hz
0
001
15.02 Hz
0
010
23.14 Hz
0
011
30.04 Hz (Default)
0
100
38.16 Hz
0
101
47.06 Hz
0
110
61.38 Hz
0
111
94.12 Hz
1
000
22.5 kHz
1
001
24 kHz
1
010
25.7 kHz
1
011
25.7 kHz
1
100
27.7 kHz
1
101
27.7 kHz
1
110
30 kHz
1
111
30 kHz
Table 9 Register Setting vs PWM Frequency
RAN[3:0]
Linear Control
Range (
°C)
0000
2
0001
2.5
0010
3.33
0011
4
0100
5
0101
6.67
0110
8
0111
10
1000
13.33
1001
16
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
