EMC2103-2-AP-TR Standard Microsystems (SMSC), EMC2103-2-AP-TR Datasheet - Page 65

• Manufacturer Part Number: EMC2103-2-AP-TR
• Description: CLOSED LOOP RPM FAN CONTROLLER
• Manufacturer: Standard Microsystems (SMSC)

ADDR
52h
53h
54h
55h
74h
75h
76h
77h
78h
79h
. . .
RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
SMSC EMC2103
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
. . .
The Look Up Table Registers hold the 40 entries of the Look Up Table that controls the drive of the
PWM. As the temperature channels are updated, the measured value for each channel is compared
against the respective entries in the Look Up Table and the associated drive setting is loaded into an
internal shadow register and stored.
The bit weighting for temperature inputs represents °C and is compared against the measured data.
Note that the LUT entry does not include a sign bit. The Look Up Table does not support negative
temperature values and the MSBit should not be set for a temperature input.
Each temperature channel threshold shares the same hysteresis value. When the measured
temperature for any of the channels meets or exceeds the programmed threshold, the drive setting
associated with that threshold is used. The temperature must drop below the threshold minus the
hysteresis value before the drive setting will be set to the previous value.
If the RPM based Fan Speed Control Algorithm is used, the TACH Target is updated after every
conversion. It is always set to the minimum TACH Target that is stored by the Look Up Table. The
PWM duty cycle is updated based on the RPM based Fan Speed Control Algorithm configuration
settings.
If the RPM based Fan Speed Control Algorithm is not used, then the PWM duty cycle is updated after
every conversion. It is set to the maximum duty cycle that is stored by the Look Up Table.
LUT Temp 3
LUT Temp 4
LUT Temp 3
LUT Temp 4
REGISTER
LUT Temp
Hysteresis
LUT Drive
Setting 1
Setting 1
Setting 1
Setting 1
Setting 8
Setting 8
Setting 8
Setting 8
Setting 8
LUT Ext
LUT Ext
LUT Ext
LUT Ext
Diode 1
Diode 2
Diode 1
Diode 2
. . .
RPM /
PWM
Table 6.50 Look Up Table Registers (continued)
. . .
‘0’
‘1’
X
X
X
X
X
X
X
X
X
4096
128
. . .
B7
-
-
-
-
-
-
-
-
-
DATASHEET
2048
. . .
B6
64
64
64
64
64
64
64
64
64
-
65
1024
. . .
B5
32
32
32
32
32
32
32
32
32
-
512
. . .
B4
16
16
16
16
16
16
16
16
16
16
256
. . .
B3
8
8
8
8
8
8
8
8
8
8
128
. . .
B2
4
4
4
4
4
4
4
4
4
4
. . .
B1
64
2
2
2
2
2
2
2
2
2
2
Revision 0.88 (06-30-08)
. . .
B0
32
1
1
1
1
1
1
1
1
1
1
DEFAULT
(127°C)
(127°C)
(127°C)
(127°C)
(127°C)
(127°C)
(127°C)
(127°C)
0Ah
7Fh
7Fh
7Fh
7Fh
92h
7Fh
7Fh
7Fh
7Fh
. . .