EMC6D102-CZC-TR Standard Microsystems (SMSC), EMC6D102-CZC-TR Datasheet - Page 30

• Manufacturer Part Number: EMC6D102-CZC-TR
• Manufacturer: Standard Microsystems (SMSC)

Specifications of EMC6D102-CZC-TR

• Operating Current: 3mA
• Operating Temperature Classification: Commercial
• Package Type: SSOP
• Lead Free Status / Rohs Status: Compliant

Revision 0.4 (09-25-07)
6.1.3.2
Note: The PWMx Current Duty Cycle register is implemented as two separate registers: a read-only
Auto Fan Control Operating Mode
The EMC6D102 implements automatic fan control. In Auto Fan Mode, this device automatically adjusts
the PWM duty cycle of the PWM outputs, according to the flow chart on the following page (see
Figure 6.1 Automatic Fan Control Flow Diagramon page
PWM outputs are assigned to a thermal zone based on the PWMx Configuration registers (see
5.10, "Thermal Zones," on page
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, if the temperature of a zone exceeds its absolute limit, all
PWM outputs go to 100% duty cycle to provide maximum cooling to the system (except those fans
that are disabled or in manual mode).
It is possible to have a single fan controlled by multiple zones, turning on when either zone requires
cooling based on its individual settings.
A VCC POR resets all values to their initial or default states.
If the start bit is one, the Auto Fan Control block will evaluate the temperature in the zones configured
for each Fan in a round robin method. The Auto Fan Control block completely evaluates the zones for
all three fans in a maximum of 0.25sec.
and a write-only.
before the programmed value can be read back by software. The hardware updates the read-
only PWMx Current Duty Cycle register on the beginning of a PWM cycle. If Ramp Rate
Control is disabled, the delay to read back the programmed value will be from 0 seconds to
1/(PWM frequency) seconds. Typically, the delay will be 1/(2*PWM frequency) seconds.
Fan Control Device with Hardware Monitoring and Acoustic Noise Reduction Features
When a value is written to this register in manual mode there will be a delay
27). It is possible to have more than one PWM output assigned to a
DATASHEET
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31).
SMSC EMC6D102
Datasheet
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