EMC2103-2-AP-TR Standard Microsystems (SMSC), EMC2103-2-AP-TR Datasheet - Page 57

• Manufacturer Part Number: EMC2103-2-AP-TR
• Description: CLOSED LOOP RPM FAN CONTROLLER
• Manufacturer: Standard Microsystems (SMSC)

ADDR
43h
RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
SMSC EMC2103
6.23
R/W
R/W
2
0
0
0
0
1
1
1
1
Bit 2-0 - UPDATE - 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 controls the tachometer measurement and advanced features of the
RPM based Fan Speed Control Algorithm.
Bit 6 - EN_RRC - Enables ramp rate control when the fan driver is operated in the Direct Setting mode
or the Direct Setting with LUT mode.
Bit 5 - GLITCH_EN - Disables the low pass glitch filter that removes high frequency noise injected on
the TACH pin.
Bits 4 - 3 - DER_OPT[1:0] - Control some of the advanced options that affect the derivative portion of
the RPM based Fan Speed Control Algorithm as shown in
Fan Configuration 2 Register
Configuration
‘0’ (default) - Ramp rate control is disabled. When the fan driver is operating in Direct Setting mode
or Direct Setting with LUT mode, the PWM setting will instantly transition to the next programmed
setting.
‘1’ - Ramp rate control is enabled. When the fan driver is operating in Direct Setting mode or Direct
Setting with LUT mode, the PWM setting will follow the ramp rate controls as determined by the
Fan Step and Update Time settings. The maximum PWM step is capped at the Fan Step setting
and is updated based on the Update Time as given by
‘0’ - The glitch filter is disabled.
‘1’ (default) - The glitch filter is enabled.
REGISTER
Fan
2
Table
UPDATE[2:0]
6.33.
B7
1
0
0
1
1
0
0
1
1
-
Table 6.34 Fan Configuration 2 Register
RRC
EN_
B6
Table 6.33 Update Time
DATASHEET
GLITCH
_EN
B5
57
0
0
1
0
1
0
1
0
1
DER_OPT [1:0]
B4
B3
Table
Table
6.35. Note that the default derivative
6.33.
ERR_RNG:0]
B2
400ms (default)
UPDATE TIME
B1
1200ms
1600ms
100ms
200ms
300ms
500ms
800ms
Revision 0.88 (06-30-08)
B0
-
DEFAULT
38h