EMC2103 Standard Microsystems Corporation, EMC2103 Datasheet - Page 59

• Manufacturer Part Number: EMC2103
• Description: Rpm-based Fan Controller with HW Thermal Shutdown
• Manufacturer: Standard Microsystems Corporation

RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
SMSC EMC2103
2
0
0
0
0
1
1
1
1
Bit 7 - 6 - DRIVE_FAIL_CNT[1:0] - Determines how many update cycles are used for the Drive Fail
detection function as shown in
the desired tach target.
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.
Bits 4 - 2 - SPIN_LVL[2:0] - Determines the final drive level that is used by the Spin Up Routine as
shown in
Bit 1 -0 - SPINUP_TIME[1:0] - determines the maximum Spin Time that the Spin Up Routine will run
for (see
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
1
0
0
1
1
‘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.
DRIVE_FAIL_CNT[1:0]
Section
Table
6.40.
SPIN_LVL[2:0]
5.7). If a valid tachometer measurement is not detected before the Spin Time has
Table 6.39 DRIVE_FAIL_CNT[1:0] Bit Decode
1
0
0
1
1
0
0
1
1
0
0
1
0
1
Table
Table 6.40 Spin Level
Table
DATASHEET
6.39. This circuitry determines whether the fan can be driven to
6.41.
59
Disabled - the Drive Fail detection circuitry is
disabled
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
0
0
1
0
1
0
1
0
1
NUMBER OF UPDATE PERIODS
SPIN UP DRIVE LEVEL
60% (default)
Revision 0.85 (01-29-08)
30%
35%
40%
45%
50%
55%
65%