EMC2104_11 Datasheet, PDF (94/99 Pages) SMSC Corporation – Dual RPM-Based PWM Fan Controller with Hardware Thermal Shutdown

B.2.1
B.2.2
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B.2.4
Dual RPM-Based PWM Fan Controller with Hardware Thermal Shutdown
Datasheet
Configuration 3 Bit Description
Bit 6 - VIN4_INV = ‘0b’ tells the circuitry that the VIN4 voltage is not inverted and will be asscending
(i.e. a value of 7Fh will represent a larger value than a value of 30h) If used by the LUT, no special
processing needs to be done. This is the default setting.
Bit 5 - VIN3_EN = ‘0b’ tells the circuitry that the VIN3 voltage is not measured. The External Diode 3
pins will measure the External Diode 3 temperature. This is the default setting.
Bit 4 - VIN3_INV = ‘0b’ tells the circuitry that the VIN3 voltage is not inverted. This bit is ignored
because VIN3_EN = ‘0b’. This is the default setting
Bit 3 - VIN2_EN = ‘1b’ tells the circuitry that the External Diode 2 pins (DP2 and DN2) will measure
the VIN2 voltage and will not measure the External Diode 2 temperature. This voltage will automatically
be used by the LUT.
Bit 2 - VIN2_INV = ‘1b’ tells the circuitry that the VIN2 voltage should be inverted. This means that
prior to any limit comparasions (via the high / low limits or the LUT), the measured value will be
subtracted from a value of FFh.
Bit 1 - VIN1_EN = ‘0b’ tells the circuitry that the VIN1 voltage is not measrued. The External Diode 1
pins (DP1 and DN1) will measure the External Diode 1 temperature and will be used by the LUT. This
is the default setting.
Bit 0 - VIN1_INV = ‘0b’ tells the circuitry that the VIN1 voltage is not inverted. This bit is ignored
because VIN1_EN = ‘0b’. This is the defautl setting.
Fan Configuration 1 Bit Description
Bit 7 - EN-ALGO = ‘1b’ tells the circuitry that the FSC alogrithm is active.
Bits 6 - 5 - RANGE[1:0] = ‘01b’ tells the FSC that the expected minimum RPM is 1000. This is the
defautl setting.
Bits 4-3 - EDGES[1:0] = ‘01b’ tells the FSC that the fan is a 2-pole fan generating tach edges per
rotation. This is the defautl setting.
Bits 2 - 0 - UPDATE[2:0] = ‘011b’ tells the FSC to update the fan drive every 400ms. This is the default
setting.
Fan Spin Up Configuration Bit Description
Bits 7-6 - DRIVE_FAIL_CNT[1:0] = ‘00b’ tells the circuitry that the drive fail detection circuitry is not
enabled. This is the default setting.
Bit 5 - NOKICK = ‘0b’ tells the circuitry that if than Spin Up Routine is invoked, it will drive to 100%
duty cycle for 25% of the spin up time. This is the default setting.
Bits 4-2 - SPIN_LVL[2:0] = ‘010b’ tells the circuitry that if the Spin Up Routine is invoked, it should run
at 40% drive.
Bits 1-0 - SPINUP_TIME[1:0] = ‘10b’ tells the circuitry that if the Spin Up Routine is invoked, it will run
at 100% duty cycle for 250ms and at 40% duty cycle for 750ms for a total spin up time of 1s.
LUT Configuration - Bit Description
7 - USE_DTS_F1 = ‘0b’ tells the circuitry that the data in the Pushed Temperature 1 register is in
normal format.
Bit 6 - USE_DTS_F2 = ‘0b’ tells the circuitry that the data in the Pushed Temperature 2 register is in
normal format.
Revision 1.78 (02-28-11)
94
DATASHEET
SMSC EMC2104