emc2104 Standard Microsystems Corp., emc2104 Datasheet - Page 78

• Manufacturer Part Number: emc2104
• Description: Emc2104 Dual Rpm-based Pwm Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

ADDR
B4h
B5h
91h
92h
93h
94h
95h
...
APPLICATION NOTE: For proper operation, the hysteresis must be smaller than the difference between two
Revision 1.74 (05-08-08)
6.34
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
...
LUT2 Voltage
LUT2 Temp 4
LUT 2 Temp
LUT 2 Drive
LUT 2 Drive
REGISTER
LUT2 VIN1
LUT2 VIN2
LUT2 VIN1
3 Setting 1
3 Setting 1
LUT 2 Ext
LUT 2 Ext
LUT 2 Ext
Setting 1
Setting 1
Setting 1
Setting 1
Setting 1
Setting 1
Setting 8
Setting 8
Setting 8
Each temperature (or voltage) 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 fan
drive setting 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 fan drive setting is updated after
every conversion. It is set to the maximum duty cycle that is stored by the Look Up Table.
Look Up Table 2 Registers
Diode 1
Diode 2
Diode 1
...
consecutive thresholds.
TACH /
DRIVE
‘0’
‘1’
‘0’
‘1’
...
X
X
X
X
X
X
X
X
X
Table 6.51 Look Up Table2 Registers
752.9
752.9
752.9
752.9
4096
4096
128
128
B7
...
-
-
-
-
-
376.5
376.5
376.5
376.5
2048
2048
DATASHEET
B6
64
64
64
64
64
64
64
...
Dual RPM-Based PWM Fan Controller with Hardware Thermal Shutdown
78
188.2
188.2
188.2
188.2
1024
1024
B5
32
32
32
32
32
32
32
...
94.12
94.12
94.12
94.12
512
512
B4
16
16
16
16
16
16
16
...
47.06
47.06
47.06
47.06
256
256
B3
...
8
8
8
8
8
8
8
23.53
23.53
23.53
23.53
128
128
B2
...
4
4
4
4
4
4
4
11.76
11.76
11.76
11.76
B1
64
64
...
2
2
2
2
2
2
2
SMSC EMC2104
5.88
5.88
5.88
5.88
B0
32
32
...
1
1
1
1
1
1
1
Datasheet
DEFAULT
(127°C)
(127°C)
(127°C)
(127°C)
(127°C)
(0.4V)
(0.4V)
(0.4V)
(0.4V)
FBh
FBh
7Fh
7Fh
7Fh
7Fh
7Fh
7Fh
7Fh
92h
7Fh
7Fh
...