EMC2302 Standard Microsystems Corp., EMC2302 Datasheet - Page 31

• Manufacturer Part Number: EMC2302
• Description: Rpm-based Pwm Fan Controller
• Manufacturer: Standard Microsystems Corp.

ADDR
33h
43h
Dual RPM-Based PWM Fan Controller
Datasheet
SMSC EMC2302
5.10
0
0
1
1
R/W
R/W
R/W
1
EDGESX[1:0]
2
0
0
0
0
1
1
1
1
Configuration 2
Configuration 2
REGISTER
Bit 2-0 - UPDATEx[2:0] - determines the base time between fan driver updates. The Update Time,
along with the Fan Step Register, is used to control the ramp rate of the drive response to provide a
cleaner transition of the actual fan operation as the desired fan speed changes. The Update Time is
set as shown in
The Fan Configuration 2 register control the tachometer measurement and advanced features of the
RPM-based Fan Speed Control Algorithm.
Fan Configuration 2 Registers
Fan 1
Fan 2
0
1
0
1
0
UPDATEX[2:0]
Table
B7
MINIMUM TACH
-
-
1
0
0
1
1
0
0
1
1
Table 5.12 Minimum Edges for Fan Rotation
Table 5.14 Fan Configuration 2 Registers
5.13.
EDGES
3
5
7
9
RRC1
RRC2
EN_
EN_
B6
Table 5.13 Update Time
DATASHEET
GLITCH_
GLITCH_
1 pole
2 poles (default)
3 poles
4 poles
EN1
EN2
NUMBER OF FAN POLES
B5
31
0
0
1
0
1
0
1
0
1
DER_OPT1 [1:0]
DER_OPT2 [1:0]
B4
B3
MULTIPLIER (BASED ON 2
ERR_RNG1[1:0]
ERR_RNG2[1:0]
400ms (default)
UPDATE TIME
B2
EFFECTIVE TACH
1200ms
1600ms
100ms
200ms
300ms
500ms
800ms
POLE FANS)
Revision 1.2 (03-22-10)
B1
0.5
1.5
1
2
B0
-
-
DEFAULT
28h
28h