RPM-Based Fan Controller with Multiple Temperature Zones & Hardware Thermal Shutdown
Datasheet
‘1’ - The Look Up Table entries are locked and cannot be updated. The Look Up Table is fully active
and will be used based on the loaded values. The PWM output will be updated depending on the
temperature and / or TACH variations.
APPLICATION NOTE: When the LUT_LOCK bit is set at a logic ‘0’, the PWM drive setting will be set at whatever
value was last used by the RPM-based Fan Speed Control Algorithm or the Look Up Table.
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 3 - PUSH1_CFG - Determines whether the PWM Input duty cycle is used instead of the Pushed 1
Temperature data when the TEMP1_CFG bit is set.
‘0’ (default) - The Pushed Temperature 1 register can be written via the SMBus and will hold a
temperature value. The PWM Input Duty cycle is not used.
‘1’ - If the TEMP1_CFG or TEMP3_CFG bit is set, the PWM Input Duty cycle will be used. The
Pushed Temperature 1 register can be written via the SMBus and will hold a temperature value but
will not be used.
APPLICATION NOTE: If the Pushed Temperature 1 data is configured to hold the PWM input duty cycle and is used
in the Look Up Table, then the Look Up Table threshold levels must be programmed in the
same format as the PWM input duty cycle - see Section 7.5 and Section 7.35.
Bit 2 - TEMP1_CFG - Determine the temperature channel that is used for the Temperature 1 inputs to
the Look Up Table.
‘0’ (default) - The External Diode 1 channel is used by the Fan Look Up Table.
‘1’ - Either the data written into the Pushed Temperature 1 Register or the data in the PWM Input
Duty Cycle register is used by the Fan Look Up table as determined by the PUSH1_CFG bit.
Bit 1 - TEMP3_CFG - Determine the temperature channel that is used for the Temperature 3 inputs to
the Look Up Table.
‘0’ (default) - The External Diode 3 channel is used by the Fan Look Up Table (if enabled).
‘1’ - Either the data written into the Pushed Temperature 1 Register or the data in the PWM Input
Duty Cycle register is used by the Fan Look Up table as determined by the PUSH1_CFG bit.
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 diode 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.
7.35
Look Up Table Registers
Table 7.52 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
R/W
FBh
Revision 1.2 (10-08-09)
SMSC EMC2113
DATA6S8HEET
SMSC [ SMSC CORPORATION ]
