LM96000CIMT National Semiconductor, LM96000CIMT Datasheet - Page 9

• Manufacturer Part Number: LM96000CIMT
• Description: IC,Data Acquisition System,7-CHANNEL,8-BIT,TSSOP,24PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LM96000CIMT

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

2.0 FAN REGISTER DEVICE SET-UP
The BIOS will follow the following steps to configure the fan
registers on the LM96000. The registers corresponding to
each function are listed. All steps may not be necessary if
default values are acceptable. Regardless of all changes
made by the BIOS to the fan limit and parameter registers
during configuration, the LM96000 will continue to operate
based on default values until the START bit (bit 0), in the
Ready/Lock/Start/Override register (address 40h), is set.
Once the fan mode is updated, by setting the START bit to 1,
the LM96000 will operate using the values that were set by
the BIOS in the fan control limit and parameter registers
(adress 5Ch through 6Eh).
1.
Set limits and parameters (not necessarily in this order):
control range.
thermal zone.
– [5F-61h] Set PWM frequencies and auto fan
– [62-63h] Set spike smoothing and min/off.
– [5C-5Eh] Set the fan spin-up delays.
– [5C-5Eh] Match each fan with a corresponding
– [67-69h] Set the fan temperature limits.
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2.
3.
3.0 AUTO FAN CONTROL OPERATING MODE
The LM96000 includes the circuitry for automatic fan control.
In Auto Fan Mode, the LM96000 will automatically adjust the
PWM duty cycle of the PWM outputs. PWM outputs are as-
signed to a thermal zone based on the fan configuration
registers. It is possible to have more than one PWM output
assigned to a thermal zone. For example, PWM outputs 2 and
3, connected to two chassis fans, may both be controlled by
thermal zone 2. At any time, the temperature of a zone ex-
ceeds its absolute limit, all PWM outputs will go to 100% duty
cycle to provide maximum cooling to the system.
[40h] Set bit 0 (START) to update fan control and limit
register values and start fan control based on these new
values.
[40h] Set bit 1 (LOCK) to lock the fan limit and parameter
registers (optional).
– [6A-6Ch] Set the temperature absolute limits.
– [64-66h] Set the PWM minimum duty cycle.
– [6D-6Eh] Set the temperature Hysteresis values.
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