RPM-Based Fan Controller with Multiple Temperature Zones & Hardware Thermal Shutdown
Datasheet
Table 7.42 DRIVE_FAIL_CNT[1:0] Bit Decode (continued)
DRIVE_FAIL_CNT[1:0]
1
0
NUMBER OF UPDATE PERIODS
32 - the Drive Fail detection circuitry will count for 32
update periods
1
0
64 - the Drive Fail detection circuitry will count for 64
update periods
1
1
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 PWM 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 PWM to 100%. It will set the drive at the programmed
spin level for the entire duration of the programmed spin up time.
Bits 4 - 2 - SPIN_LVL[2:0] - Determines the final drive level that is used by the Spin Up Routine as
shown in Table 7.43, "Spin Level".
Table 7.43 Spin Level
SPIN_LVL[2:0]
2
1
0
SPIN UP DRIVE LEVEL
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
30%
35%
40%
45%
50%
55%
60% (default)
65%
Bit 1 -0 - SPINUP_TIME[1:0] - determines the maximum Spin Time that the Spin Up Routine will run
for (see Section 6.8, "Spin Up Routine"). If a valid tachometer measurement is not detected before the
Spin Time has elapsed, then an interrupt will be generated. When the RPM-based Fan Speed Control
Algorithm is active, the fan driver will attempt to re-start the fan immediately after the end of the last
spin up attempt.
The Spin Time is set as shown in Table 7.44.
SMSC EMC2113
Revision 1.2 (10-08-09)
DATA6S3HEET
SMSC [ SMSC CORPORATION ]
