Multiple RPM-Based PWM Fan Controller for Five Fans
Datasheet
Bit 2 - FAN3_INT_EN - Allows Fan 3 to assert the ALERT# pin if an error condition is detected.
Bit 1 - FAN2_INT_EN - Allows Fan 2 to assert the ALERT# pin if an error condition is detected.
Bit 0 - FAN1_INT_EN - Allows Fan 1 to assert the ALERT# pin if an error condition is detected.
‘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.
5.5
PWM Configuration Registers
Table 5.5 PWM Configuration Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
PWM Polarity
Config
POLARITY
5
POLARITY
4
POLARITY
3
POLARITY
2
POLARITY
1
2Ah
R/W
-
-
-
00h
PWM Output
Config
2Bh
R/W
-
-
-
PWM5_OT
PWM4_OT
PWM3_OT
PWM2_OT
PWM1_OT
00h
The PWM Config registers control the output type and polarity of all PWM outputs.
5.5.1
PWM Polarity Config - 2Ah
Bit 4 - POLARITY5 - Determines the polarity of PWM 5.
Bit 3 - POLARITY4 - Determines the polarity of PWM 4.
Bit 2 - POLARITY3 - Determines the polarity of PWM 3.
Bit 1 - POLARITY2 - Determines the polarity of PWM 2.
Bit 0 - POLARITY1 - Determines the polarity of PWM 1.
‘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.
5.5.2
PWM Output Config - 2Bh
Bit 4 - PWM5_OT - Determines the output type of the PWM 5 driver.
Bit 3 - PWM4_OT - Determines the output type of the of PWM 4 driver.
Bit 2 - PWM3_OT - Determines the output type of the of PWM 3 driver.
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.
‘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.
Revision 1.1 (10-12-09)
SMSC EMC2305
DATA3S4HEET
SMSC [ SMSC CORPORATION ]
