EMC2300-AZC-TR SMSC, EMC2300-AZC-TR Datasheet - Page 31

• Manufacturer Part Number: EMC2300-AZC-TR
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC2300-AZC-TR

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

Fan Control Device with High Frequency PWM and Temperature Monitors
Datasheet
SMSC EMC2300
7.1.3.2
Note: The PWMx Current Duty Cycle register is implemented as two separate registers: a read-only
Auto Fan Control Operating Mode
The
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 Diagram on page
PWM outputs are assigned to a thermal zone based on the PWMx Configuration registers (see
6.9, "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.
EMC2300
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.
implements automatic fan control. In Auto Fan Mode, this device automatically adjusts
When a value is written to this register in manual mode there will be a delay
28). It is possible to have more than one PWM output assigned to a
DATASHEET
31
32).
Revision 0.32 (06-23-08)
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