EMC2103 Standard Microsystems Corporation, EMC2103 Datasheet - Page 28

• Manufacturer Part Number: EMC2103
• Description: Rpm-based Fan Controller with HW Thermal Shutdown
• Manufacturer: Standard Microsystems Corporation

Revision 0.85 (01-29-08)
5.5.1
M a in ta in F a n D rive
Programming the RPM Based Fan Speed Control Algorithm
The RPM based Fan Speed Control Algorithm powers-up disabled. The following registers control the
algorithm. The EMC2103 fan control registers are pre-loaded with defaults that will work for a wide
variety of fans so only the TACH Target Register is required to set a fan speed. The other fan control
registers can be used to fine-tune the algorithm behavior based on application requirements.
Note that steps 1 - 7 are optional and need only be performed if the default settings do not provide
the desired fan response.
1. Set the Valid TACH Count Register to maximum number of tach counts to indicate the fan is
2. Set the Spin Up Configuration Register to the Spin Up Level and Spin Time desired.
spinning.
R e d u ce F a n D riv e
Figure 5.4 RPM based Fan Speed Control Algorithm
Y e s
Y e s
M e a su re F a n S p e e d
S e t T A C H T a rg e t
N o
R e a d in g =
R e a d in g <
R e q u ire d
S p in U p
T a rg e t?
T a rg e t?
C o u n t
T A C H
T A C H
T A C H
T A C H
?
DATASHEET
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In cre a s e F a n D rive
28
Y e s
N o
RPM-Based Fan Controller with HW Thermal Shutdown
P e rfo rm S p in U p
R o u tin e
R a m p R a te C o n tro l
SMSC EMC2103
Datasheet