SH3100IMTR SEMTECH [Semtech Corporation], SH3100IMTR Datasheet - Page 40

• Manufacturer Part Number: SH3100IMTR
• Description: Supervisory IC with I2C Interface and PWM
• Manufacturer: SEMTECH [Semtech Corporation]

© 2006 Semtech Corp.
POWER MANAGEMENT
Register Descriptions
Register Name MinStartTemp
Register Name DutyCycleStepSize
Register Name ManualPWMDutyCycle
Address(hex): 38
Address(hex): 39
Address(hex): 3A
Bit No.
Bit No.
Bit No.
Bit 7
[7:0]
Bit 7
[7:0]
Bit 7
[1:0]
Description
MinStartTemp
Description
DutyCycleStepSize
Description
ManualPWMDutyCycle[9:8]
Bit 6
Bit 6
Bit 6
(continued)
Bit 5
Bit 5
Bit 5
Description
Description
Description
Bit Value
Bit Value
Bit Value
Bit 4
Bit 4
Bit 4
DutyCycleStepSize
MinStartTemp
40
(R/W) Defines the temperature
at which auto-fan mode starts
to drive the fan
Value Description
This is the ADCCode corresponding to the lowest temperature at
which the automatic fan control mode activates the PWM pin,
and switches on the fan
Code = 163 minus temperature (°C).
In other modes (DeviceCode in the ADCConfig register not equal
to 111), this register has no effect
Default start temperature is 40°C, and the default minimum
duty cycle is 25%
(R/W) The PWM duty cycle
increment for every degree of
rise in the temperature when in
auto-fan-control mode
Value Description
In Auto-fan-control mode (DeviceMode bits in the ADCConfig
register = 111), this is how much the PWM duty cycle
increments for every degree of temperature rise. This
effectively defines the temperature at which the PWM duty cycle
would be 100%, i.e., The fan is on at full speed
DutyCycleStepSize = 768/(MaxTemp – MinTemp)
Default value of 17 gives a maximum temperature of 85°C
(R/W) Sets the PWM duty cycle
when in ‘normal’ mode.
Value Description
The most significant 2 bits of the ManualPWMDutyCycle.
When in normal mode, i.e. DeviceMode bits in the ADCConfig
register set to 000, this defines the duty cycle on the PWM pin.
Duty cycle = ManualPWMDutyCycle/1024
Bit 3
Bit 3
Bit 3
Bit 2
Bit 2
Bit 2
Default Value: 0111 1011
Reset Event: P, W
Default Value: 0001 0001
Reset Event: P, W
Default Value: 0000 0000
Reset Event: P, W
Bit 1
Bit 1
Bit 1
PWMDutyCycle[9:8]
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SH3100
Bit 0
Bit 0
Bit 0