ADT7470_15 Datasheet, PDF (34/40 Pages) Analog Devices – Temperature Sensor Hub and Fan Controller

ADT7470
Data Sheet
Table 38. Register 0x69. PWM3/PWM4 Configuration Register (Power-On Default = 0x00).
Bit Name
Read/Write
Description
[0]
N/A
Set to 0 (default).
[1]
N/A
Set to 0 (default).
[2]
N/A
Set to 0 (default).
[3]
N/A
Set to 0 (default).
[4] INV4
Read/Write
Setting this bit to 1 inverts the PWM4 output. Default = 0
[5] INV3
Read/Write
Setting this bit to 1 inverts the PWM3 output. Default = 0
[6] BHVR4
Read/Write
This bit assigns fan behavior for PWM4 output.
0 = manual fan control mode (PWM duty cycle controlled in software).
1 = (automatic fan control mode.
[7] BHVR3
Read/Write
This bit assigns fan behavior for PWM3 output.
0 = manual fan control mode (PWM duty cycle controlled in software).
1 = automatic fan control mode.
Table 39. Register 0x6A to Register 0x6D. PWMMIN Duty Cycle Registers (Power-On Default = 0x80 (50% Duty Cycle).
Register Address
Read/Write
Description
0x6A
Read/Write
PWM1 min duty cycle.
0x6B
Read/Write
PWM2 min duty cycle.
0x6C
Read/Write
PWM3 min duty cycle.
0x6D
Read/Write
PWM4 min duty cycle.
Table 40. PWMMIN Duty Cycle Registers Detailed Description
Bit Name
Read/Write
Description
[7:0] PWM Duty Cycle Read/Write
These bits define the PWNMIN duty cycle for PWMx (x = 1 to 4).
0x00 = 0% duty cycle (fan off ).
0x40 = 25% duty cycle.
0x80 = 50% duty cycle.
0xFF = 100% PMW max duty cycle (full fan speed).
Table 41. Register 0x6E to Register 0x71. TMIN Registers (Power-On Default = 0x5A (90°C)).
Register Address
Read/Write
Description
0x6E
Read/Write
Temperature 1 TMIN.
0x6F
Read/Write
Temperature 2 TMIN.
0x70
Read/Write
Temperature 3 TMIN.
0x71
Read/Write
Temperature 4 TMIN.
Table 41 shows the TMIN registers for each thermal zone. When the temperature measured exceeds TMIN, the appropriate fan runs at
minimum speed (PWMMIN). They increase to maximum speed (PWMMAX) at TMIN + 20°C.
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