EVAL-ADM1030 AD [Analog Devices], EVAL-ADM1030 Datasheet - Page 12

• Manufacturer Part Number: EVAL-ADM1030
• Description: Evaluation Board for ACPI Temperature Monitor and PWM Fan Controller
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
EVAL-ADM1030/31
RPM CONTROL MODE
In this method of control the user programs the required RPM
values to the ADM1030/31. Click on the “RPM Feedback
Mode” in the “Mode Select” window of the Control Tab.
1. Enter the required RPM Value in the window.
2. Choose which fan you wish to run at that RPM value.
3. Enter the fan divisor value for that fan.
4. Click on Calculate. The software will calculate Count. This
is the value that has to be written to the ADM1030/31 Tach
High Limit Register to maintain the required speed. See the
datasheet for an explanation of the formulas.
5. Click on “Enable RPM Mode” to place the ADM1030/31 in
RPM Feedback mode.
6. Sometimes after you place a value in the “Enter RPM Mode”
window and click “Calculate” the “Enable RPM Mode” button
does not become active. This is because the Count value is
outside the particular fan’s RPM range. The fan’s RPM range is
determined by the “Fan Divisor Value”.
PWM DUTY CYCLE
In this method the ADM1030/31 is placed under software
control. Fan speed is controlled by programming PWM values
in to the ADM1030/31.
Click on “PWM Duty Cycle Select”
in the “Mode Select” window of the Control Tab.
1. Each fan can be programmed with a duty cycle value of
between 0% and 100%.
2. Choose the required PWM value for each fan, the value
chosen must be on the list in the drop down window as the
ADM1030/31 can only be programmed in 6% increments.
3. Click on “Enable PWM Mode”
4. The fan/s should then either spin up or down to the
programmed value.
TEMPERATURE CONTROL
Temperature control allows the user to heat up the remote
thermal diodes on the ADM1030/31 Evaluation Board. First
choose which diode is to be monitored. Then Click on “Enable
Control”. This causes a current to be switched through the two
large heating resistors behind the remote thermal diodes which
in turn causes the remote thermal diodes to heat up. These
resistors can become very hot so care is required. Do not touch
when there is a current flowing through them. Use the slider to
vary the PWM duty cycle applied to the heating resistors.
Adjusting the slider allows limited control of the temperature of
the heating resistors.
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REV. PrA