RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
Bit 4 - RPM / PWM - This bit selects the data format for the LUT drive settings.
‘0’ (default) - The Look Up Table drive settings are RPM TACH count values for use by the RPM
based Fan Speed Control Algorithm. The Look Up Table drive settings should be loaded highest
value to lowest value (to coincide with the inversion between TACH counts and actual RPM).
‘1’ - The Look Up Table drive settings are PWM duty cycle values and are used directly. The drive
settings should be loaded lowest value to highest value.
Bit 2 - TEMP3_CFG - Determine the temperature channel that is used for the Temperature 3 inputs to
the Look Up Table. If the External Diode 3 channel is not enabled, then the Temperature 3 inputs are
not used by the Look Up Table.
‘0’ (default) - The External Diode 3 channel is used by the Fan Look Up Table (if enabled).
‘1’ - The data written into the Pushed Temperature 1 Register is used by the Fan Look Up Table.
Bit 0 - TEMP4_CFG - Determine the temperature channel that is used for the Temperature 4 inputs to
the Look Up Table.
‘0’ (default) - The Internal channel is used by the Fan Look Up Table.
‘1’ - The data written into the Pushed Temperature 2 Register is used by the Fan Look Up Table.
6.33
Look Up Table Registers
Table 6.49 Look Up Table Registers
RPM /
PWM
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
‘0’
‘1’
4096
128
2048
64
1024
32
512
16
256
8
128
4
64
2
32
1
LUT Drive
Setting 1
51h
52h
R/W
FBh
LUT Ext
Diode 1
Setting 1
7Fh
(127°C)
R/W
X
X
-
-
64
64
32
32
16
16
8
8
4
4
2
2
1
1
LUT Ext
Diode 2
Setting 1
7Fh
(127°C)
53h
54h
R/W
R/W
LUT Temp 3
Setting 1
7Fh
(127°C)
X
X
-
-
64
64
32
32
16
16
8
8
4
4
2
2
1
1
LUT Temp 4
Setting 1
7Fh
(127°C)
55h
. . .
R/W
. . .
. . .
. . .
‘0’
. . .
4096
128
. . .
2048
64
. . .
1024
32
. . .
512
16
. . .
256
8
. . .
128
4
. . .
64
2
. . .
32
1
. . .
LUT Drive
Setting 8
74h
75h
R/W
R/W
92h
‘1’
LUT Ext
Diode 1
Setting 8
7Fh
(127°C)
X
-
64
32
16
8
4
2
1
LUT Ext
Diode 2
Setting 8
7Fh
(127°C)
76h
77h
R/W
R/W
X
X
-
-
64
64
32
32
16
16
8
8
4
4
2
2
1
1
LUT Temp 3
Setting 8
7Fh
(127°C)
Revision 0.85 (01-29-08)
SMSC EMC2103
DATA6S4HEET
SMSC [ SMSC CORPORATION ]
