Analog Devices ADT7473 Manual page 67

Table 34. Register 0x63—Enhanced Acoustics Register 2 (Power-On Default = 0x00)
1
Bit Name R/W
<2:0> ACOU Read/write
< 3 > EN3 Read/write
<6:4> ACOU2 Read/write
<7> EN2 Read/write
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.
Table 35. PWM Minimum Duty Cycle Registers
Register Address
0x64
0x65
0x66
Bit Name
<7:0> PWM duty cycle
1 These registers become read-only when the ADT7473 is in automatic fan control mode.
1
Table 36. T Registers
MIN
Register Address
0x67
0x68
0x69
1 These are the T registers for each temperature channel. When the temperature measured exceeds T
MIN
with temperature according to T
RANGE
2
These registers become read-only when the Configuration Register 1 lock bit is set. Any further attempts to write to these registers have no effect.
Description
These bits select the ramp rate applied to the PWM3 output. Instead of PWM3 jumping instantaneously to
its newly calculated speed, PWM3 ramps gracefully at the rate determined by these bits. This effect
enhances the acoustics of the fan being driven by the PWM3 output.
Time Slot Increase
000 = 1
001 = 2
010 = 3
011 = 5
100 = 8
101 = 12
110 = 24
111 = 48
When this bit is 1, acoustic enhancement is enabled on PWM3 output.
These bits select the ramp rate applied to the PWM2 output. Instead of PWM2 jumping instantaneously to
its newly calculated speed, PWM2 ramps gracefully at the rate determined by these bits. This effect
enhances the acoustics of the fans being driven by the PWM2 output.
Time Slot Increase
000 = 1
001 = 2
010 = 3
011 = 5
100 = 8
101 = 12
110 = 24
When this bit is 1, acoustic enhancement is enabled on PWM2 output.
1
R/W Description
Read/write PWM1 minimum duty cycle.
Read/write PWM2 minimum duty cycle.
Read/write PWM3 minimum duty cycle.
R/W 1 Description
Read/write These bits define the PWM
0x00 = 0% duty cycle (fan off).
0x40 = 25% duty cycle.
0x80 = 50% duty cycle.
0xFF = 100% duty cycle (fan full speed).
R/W 2 Description
Read/write Remote 1 temperature T
Read/write Local temperature T
Read/write Remote 2 temperature T
.
Time for 33% to 100%
35 sec
17.6 sec
11.8 sec
7 sec
4.4 sec
3 sec
1.6 sec
0.8 sec
Time for 33% to 100%
35 sec
17.6 sec
11.8 sec
7 sec
4.4 sec
3 sec
1.6 sec
duty cycle for PWMx.
MIN
MIN
MIN
MIN
, the appropriate fan runs at minimum speed and increases
MIN
Rev. 0 | Page 67 of 76
ADT7473
Power-On Default
0x80 (50% duty cycle)
0x80 (50% duty cycle)
0x80 (50% duty cycle)
Power-On Default
0x9A (90°C)
0x9A (90°C)
0x9A (90°C)