EMC2302 Standard Microsystems Corp., EMC2302 Datasheet - Page 28

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

ADDR
2Ah
2Bh
ADDR
2Dh
Revision 1.2 (03-22-10)
R/W
R/W
R/W
5.5
5.5.1
5.5.2
5.6
R/W
R/W
PWM Polarity
PWM Output
REGISTER
Config
Config
The PWM Config registers control the output type and polarity of all PWM outputs.
PWM Polarity Config - 2Ah
Bit 1 - POLARITY2 - Determines the polarity of PWM 2.
Bit 0 - POLARITY1 - Determines the polarity of PWM 1.
PWM Output Config - 2Bh
Bit 1 - PWM2_OT - Determines the output type of PWM 2 driver.
Bit 0 - PWM1_OT - Determines the output type of the PWM 1 driver.
The PWM Base Frequency register determines the base frequency that is used with the PWM Divide
register to determine the final PWM frequency. Each PWM frequency is set by the base frequency and
its respective divide ratio (see
Controls the base frequency of PWM drivers 1-3 2
PWM Configuration Registers
PWM Base Frequency Register
REGISTER
PWM Base
Frequency
‘0’ (default) - An error condition on Fan X will not cause the ALERT# pin to be asserted, however
the status registers will be updated normally.
‘1’ - An error condition (Stall, Spin Up, Drive Fail) on Fan X will cause the ALERT# pin to be
asserted.
‘0’ (default) - the Polarity of the PWM driver is normal. A drive setting of 00h will cause the output
to be set at 0% duty cycle and a drive setting of FFh will cause the output to be set at 100% duty
cycle.
‘1’ - The Polarity of the PWM driver is inverted. A drive setting of 00h will cause the output to be
set at 100% duty cycle and a drive setting of FFh will cause the output to be set at 0% duty cycle.
‘0’ (default) - The PWM 1 output is configured as an open drain output.
‘1’ - The PWM 1 output is configured as a push-pull output.
B7
-
-
B7
-
B6
Table 5.6 PWM Base Frequency Register
Table 5.5 PWM Configuration Registers
-
-
B6
-
Section
B5
-
-
DATASHEET
5.8).
B5
-
28
B4
-
-
B4
-
B3
PWM_
-
-
BASE
2_1
B3
PWM_
BASE
Dual RPM-Based PWM Fan Controller
2_0
B2
B2
-
-
PWM_
BASE
POLARITY
PWM2_OT
1_1
B1
B1
2
PWM_
SMSC EMC2302
BASE
1_0
B0
POLARITY
PWM1_OT
Datasheet
B0
1
DEFAULT
00h
DEFAULT
00h
00h