EMC6D103S-CZC SMSC, EMC6D103S-CZC Datasheet - Page 34

• Manufacturer Part Number: EMC6D103S-CZC
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC6D103S-CZC

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 0.3 (03-01-07)
7.1.3.2
When in manual mode, the current PWM duty cycle registers can be written to adjust the speed of the
fans, when the start bit is set. These registers are not writable when the lock bit is set.
Note: The PWMx Current Duty Cycle register is implemented as two separate registers: a read-only
Auto Fan Control Operating Mode
The EMC6D103 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 7.1 Automatic Fan Control Flow Diagramon page
PWM outputs are assigned to a thermal zone based on the PWMx Configuration registers (see
6.10, "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 High Frequency PWM Support and Hardware Monitoring Features
When a value is written to this register in manual mode there will be a delay
31). It is possible to have more than one PWM output assigned to a
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35).
SMSC EMC6D103
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