Analog Devices ADT7473 Manual page 66

ADT7473
Table 33. Register 0x62—Enhanced Acoustics Register 1 (Power-On Default = 0x00)
1
Bit Name R/W
<2:0> ACOU Read/write
<3> EN1 Read/write
<4> SYNC Read/write
<5> MIN Read/write
<6> MIN Read/write
<7> MIN3 Read/writ
1
This register becomes read-only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to this register have no effect.
Description
These bits select the ramp rate applied to the PWM1 output. Instead of PWM1 jumping instantaneously to
its newly calculated speed, PWM1 ramps gracefully at the rate determined by these bits. This feature
enhances the acoustics of the fan being driven by the PWM1 output.
Time Slot Increase Time for 33% to 100%
000 = 1 35 sec
001 = 2 17.6 sec
010 = 3 11.8 sec
011 = 4 7 sec
100 = 8 4.4 sec
101 = 12 3 sec
110 = 24 1.6 sec
111 = 48 0.8 sec
When this bit is 1, acoustic enhancement is enabled on PWM1 output.
SYNC = 1 synchronizes fan speed measurements on TACH2, TACH3, and TACH4 to PWM3. This allows up to
three fans to be driven from PWM3 output and their speeds to be measured.
SYNC = 0 synchronizes only TACH3 and TACH4 to PWM3 output.
When the ADT7473 is in automatic fan control mode, this bit defines whether PWM1 is off (0% duty cycle) or
at PWM1 minimum duty cycle when the controlling temperature is below its T
0 = 0% duty cycle below T
MIN
1 = PWM1 minimum duty cycle below T
When the ADT7473 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
MIN
1 = PWM 2 minimum duty cycle below T
When the ADT7473 is in automatic fan speed control mode, this bit defines whether PWM3 is off (0% duty
cycle) or at PWM3 minimum duty cycle when the controlling temperature is below its T
value.
0 = 0% duty cycle below T
MIN
1 = PWM3 minimum duty cycle below T
– hysteresis.
– hysteresis.
MIN
– hysteresis.
– hysteresis.
MIN
– hysteresis.
– hysteresis.
MIN
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– hysteresis value.
MIN
– hysteresis
MIN
– hysteresis
MIN