ASC7512 ETC2 [List of Unclassifed Manufacturers], ASC7512 Datasheet - Page 25

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

Bit [4] PWM Invert
Bit [4] inverts the PWM output. If set to 0, 100% duty cycle will yield an output that is always high. If set to 1, 100% duty
cycle will yield an output that is always low.
Bit [3] Reserved
Bit [2:0] Spin Up
Bits [2:0] specify the ‘spin up’ time for the fan. When a fan is being started from a stationary state, the PWM output is held at
100% duty cycle for the time specified in the table below before scaling to a lower speed.
The Off/Min Bit 5 specifies whether the duty cycle will be 0% or Minimum Fan Duty when the measured temperature falls
below the Temperature LIMIT register setting (see Table 18 below).
If the Remote pins are connected to a processor or chipset, instantaneous temperature spikes may be sampled by the
aSC7512. Fan speed algorithm has two phases of filtering on temperature zone readings. First, a “No-Spike” value is
created from the current temperature and three previous readings. This is an average of the two remaining values when the
high and low values are removed. This is the temperature used to determine PWM and is always running.
The second phase is a user specified filter and coefficient. This filter determines a smoothed temperature value, Smooth T
by taking the No-Spike T
the previously smoothed temperature. N is a user selectable coefficient, in the range 1 to 8, designated ZN1-2:ZN1-0 for
Zone 1 and ZN2-2:ZN2-0 for Zone 2.
© Andigilog, Inc. 2006
Register
Address
Register 62, 63h: Min/Off, Spike Smoothing
62h
63h
Read/
Write
R/W
R/W
Min/Off,
Zone1 Spike
Smoothing
Zone2 Spike
Smoothing
Register
Name
i
, subtracting the previous smoothed temperature, Smooth T
Fan on Zone 1 auto
Fan on Zone 2 auto
Reserved
Fan always on full
Fan disabled
Fan on Zone 2 auto
Fan controlled by hotter of zones 1 or 2
Fan manually controlled (Test Mode)
(MSB)
ZN2E
Bit 7
RES
Table 16 Fan Spin-Up Register
0 ms
100 ms
250 ms
400 ms
700 ms
1000 ms
2000 ms
4000 ms
Fan Configuration
ZN2-2
Spin Up Time
Bit 6
Table 15 Fan Zone Setting
RES
www.andigilog.com
ZN2-1
Bit 5
OFF
- 25 -
ZN2-0
Bit 4
RES
SPIN[2:0]
000
001
010
011
100
101
110
111
ZN1E
Bit 3
RES
ZN1-2
ZON[2:0]
Bit 2
RES
i-1
000
001
010
011
100
101
110
111
, divided by 2^N and adding that to
ZN1-1
Bit 1
RES
August 2006 - 70A05003
(LSB)
ZN1-0
Bit 0
RES
aSC7512
Default
Value
00
00
Lock
X
X
i
,