EMC2112 Datasheet, PDF (52/65 Pages) SMSC Corporation – RPM-Based Linear Fan Controller with Hardware Thermal Shutdown

RPM-Based Linear Fan Controller with Hardware Thermal Shutdown
Datasheet
Table 6.33 Gain Decode
GAIND OR GAINP OR GAINI [1:0]
1
0
0
0
0
1
1
0
1
1
RESPECTIVE GAIN FACTOR
1x
2x
4x (default)
8x
6.21 Fan Spin Up Configuration Register
Table 6.34 Fan Spin Up Configuration Register
ADDR R/W
REGISTER
B7
B6
B5
B4
B3
B2
46h
R/W
Fan Spin Up DRIVE_FAIL_ NOK
Configuration
CNT [1:0]
ICK
SPIN_LVL[2:0]
B1 B0
SPINUP_
TIME[1:0]
DEFAULT
19h
The Fan Spin Up Configuration Register controls the settings of Spin Up Routine. The Fan Spin Up
Configuration Register is software locked.
Bit 7 - 6 - DRIVE_FAIL_CNT[1:0] - Determines how many update cycles are used for the Drive Fail
detection function as shown in Table 6.35. This circuitry determines whether the fan can be driven to
the desired tach target.
Table 6.35 DRIVE_FAIL_CNT[1:0] Bit Decode
DRIVE_FAIL_CNT[1:0]
1
0
0
0
0
1
1
0
1
1
NUMBER OF UPDATE PERIODS
Disabled - the Drive Fail detection circuitry is disabled
(default)
16 - the Drive Fail detection circuitry will count for 16
update periods
32 - the Drive Fail detection circuitry will count for 32
update periods
64 - the Drive Fail detection circuitry will count for 64
update periods
Bit 5 - NOKICK - Determines if the Spin Up Routine will drive the fan to 100% duty cycle for 1/4 of the
programmed spin up time before driving it at the programmed level.
„ ‘0’ (default) - The Spin Up Routine will drive the fan driver to 100% for 1/4 of the programmed spin
up time before reverting to the programmed spin level.
„ ‘1’ - The Spin Up Routine will not drive the fan driver to 100%. It will set the drive at the
programmed spin level for the entire duration of the programmed spin up time.
Revision 0.88 (11-20-09)
52
DATASHEET
SMSC EMC2112