EMC2102-DZK SMSC, EMC2102-DZK Datasheet - Page 44

• Manufacturer Part Number: EMC2102-DZK
• Description: Industrial Temperature Sensors RPM Fan Contrllr
• Manufacturer: SMSC

Specifications of EMC2102-DZK

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 2.02 (05-17-07)
6.17
6.18
6.19
56h
57h
58h
ADDRESS
ADDRESS
ADDRESS
The Valid TACH Count Register stores the maximum TACH count to indicate that the fan is spinning
properly. The value is referenced at the end of the Spin Up Routine to determine if the fan has started
operating and decide if the device needs to retry. See
If the TACH count exceeds the Valid TACH Count Register (indicating that the Fan RPM is below the
threshold set by this count), then a stalled fan is detected. In this condition, the algorithm will
automatically begin its Spin Up Routine.
If a TACH Target Count is set above the Valid TACH Count setting, then that setting will be ignored
and the algorithm will use the current fan drive setting.
The Valid TACH Count Register is software locked.
The TACH Target Register holds the target TACH count that is maintained by the RPM based Fan
Control Algorithm.
If the algorithm is enabled, setting the Fan Target to FFh will immediately disable the High Side Fan
Driver. Setting the Fan Target to any other value will cause the algorithm to invoke the Spin Up Routine
after which it will function normally.
The TACH Reading Register contents describe the current TACH setting of the fan. The data
represents the fan speed as the number of 32.768kHz clock periods that occur for a single revolution
of the fan.
Equation [3]
[4]
measuring 5 edges, with a frequency of 32.768kHz.
Valid TACH Count Register
TACH Target Register
TACH Reading Register
Valid TACH
Count
Fan TACH
shows the simplified translation of TACH Reading Register count to RPM assuming a 2-pole fan,
TACH Target
REGISTER
REGISTER
REGISTER
shows the detailed conversion from TACH measurement (COUNT) to RPM while
2048
B7
2048
Table 6.24 Valid TACH Count Register
2048
Table 6.25 TACH Reading Registers
B7
Table 6.26 TACH Reading Register
B7
1024
B6
1024
1024
B6
B6
DATASHEET
512
B5
512
512
44
B5
B5
256
B4
256
256
B4
B4
RPM-Based Fan Controller with HW Thermal Shutdown
Equation [4]
128
B3
128
128
B3
B3
64
B2
for translating the count to an RPM.
64
64
B2
B2
32
B1
32
32
B1
B1
16
B0
16
16
B0
B0
F5h
SMSC EMC2102
FAh
FFh
DEFAULT
DEFAULT
DEFAULT
Datasheet
Equation