Analog Devices ADT7460 Manual page 43

Table 59. Register 0x62—Enhance Acoustics Register 1 (Power-On Default = 0x00)
Bit Name R /W
<2:0> ACOU R ead/Write
<3> EN1 R ead/Write
<4> SYNC R ead/Write
<5> MIN1 Read/Write
<6> MIN2 Read/Write
<7> MIN3 Read /Write
This register becomes read-only when the Configuration Register 1 lock bit is set to 1. Further attempts to write to this register have no
e ffect.
D escription
T hese bits select the ramp rate applied to the PWM1 output. Instead of PWM1 jumping instantaneously to
i ts newly calculated speed, PWM1 ramps gracefully at the rate determined by these bits. This feature
e nhances the acoustics of the fan being driven by the PWM1 output.
T ime Slot Increase
000 = 1
001 = 2
010 = 3
011 = 5
100 = 8
101 = 12
110 = 24
111 = 48
W hen this bit is 1, acoustic enhancement is enabled on PWM1 output.
S YNC = 1 synchronizes fan speed measurements on TACH2, TACH3, and TACH4 to PWM3. This allows up to
t hree fans to be driven from PWM3 output and their speeds to be measured.
S YNC = 0, only TACH3 and TACH4 are synchronized to PWM3 output.
W hen the ADT7460 is in automatic
or at PWM1 minimum duty cycle when the controlling temperature is below its T
0 = 0 Du % ty Cycle below T
1 = P M1 W Minimum Duty Cycle below T
When the ADT7460 is in automatic fan speed control mode, this bit defines whether PWM2 is off (0% duty
cycle) or at PWM2 minimum duty cycle when the controlling temperature is below its T
value.
0 = 0% Duty Cycle below T
1 = PWM2 Minimu m Duty Cycle below T
When the ADT7 460 is in automatic fan speed control mode, this bit defines whet
c ycle) or at PWM3 minimum duty cycle when the controlling temperatur
value.
0 = 0% Duty Cycle below T
1 = PWM3 Minimum Duty Cycle below T
T ime for 33% to 100%
35 s
17.6 s
18 s
7 s
4.4 s
3 s
1.6 s
0.8 s
fan control mode, this bit
− Hysteresis
MIN
− Hysteresis
MIN
− Hysteresis
MIN
− Hysteresis
MIN
− Hysteresis
MIN
− Hysteresis
MIN
Rev. C | Page 43 of 52
defines whether PWM1 is off (0% duty cycle)
− Hysteresis value.
MIN
MIN
her PWM3 is off (0% duty
e is below its T − Hysteresis
MIN
ADT7460
− Hysteresis