emc2105 Standard Microsystems Corp., emc2105 Datasheet - Page 67

• Manufacturer Part Number: emc2105
• Description: Emc2105 Rpm-based High Side Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

RPM-Based High Side Fan Controller with Hardware Thermal Shutdown
Datasheet
APPLICATION NOTE: When the LUT_LOCK bit is set at a logic ‘0’, the fan drive setting will be set at whatever
APPLICATION NOTE: The TACH / DRIVE bit should be set prior to the LUT_LOCK bit being set so that, if the fan
SMSC EMC2105
1
0
0
1
1
Bit 6 - USE_DTS_F2 - This bit determines whether the Pushed Temperature 2 Registers are using
DTS data.
Bit 5 - LUT_LOCK - This bit locks updating the Look Up Table entries and determines whether the look
up table is being used.
Bit 4 - TACH / DRIVEx - This bit selects the data format for the LUT drive settings.
Bits 3-2 - TEMP3_CFG[1:0] - These bits determine the temperature channel that is used for the
Temperature 3 inputs to the Look Up Table as shown in
Bits 1-0 - TEMP4_CFG[1:0] - These bits determine the temperature channel that is used for the
Temperature 4 inputs to the Look Up Table as shown in
TEMP3_CFG [1:0]
‘0’ (default) - The Pushed Temperature 1 registers are not using DTS data. The contents of these
registers are standard 2’s complement temperature data.
‘1’ - The Pushed Temperature 1 registers are loaded with DTS data. The contents of these
registers are automatically subtracted from a fixed value of 100°C before they are compared to the
Look Up Table threshold levels.
‘0’ (default) - The Pushed Temperature 2 registers are not using DTS data. The contents of these
registers are standard 2’s complement temperature data.
‘1’ - The Pushed Temperature 2 registers are loaded with DTS data. The contents of these registers
are automatically subtracted from a fixed value of 100°C before they are compared to the Look Up
Table threshold levels.
‘0’ (default) - The Look Up Table entries can be updated normally. The Look Up Table will not be
used while the Look Up Table entries are unlocked. During this condition, the fan drive output will
not change states regardless of temperature or tachometer variation.
‘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 fan drive output will be updated depending on
the temperature and / or TACH variations.
‘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 fan drive setting values and are used directly. The drive
settings should be loaded lowest value to highest value.
value was last used by the RPM based Fan Speed Control Algorithm or the Look Up Table.
driver is disabled, the output drive is in the proper state.
0
0
1
0
1
Table 6.44 TEMP3_CFG Decode
DATASHEET
67
TEMPERATURE CHANNEL USED
Pushed Temperature 1 (LUT)
TRIP_SET / VIN4 Voltage
External Diode 3 (default)
Table
Table
6.44.
6.45.
Reserved
Revision 1.74 (05-08-08)