EMC2302 Standard Microsystems Corp., EMC2302 Datasheet - Page 26

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

ADDR
24h
25h
26h
27h
Revision 1.2 (03-22-10)
R/W
R-C
R-C
R-C
R-C
5.3
5.3.1
REGISTER
Fan Status
Fail Status
Fan Drive
Fan Spin
Fan Stall
Status
Status
Bit 6 - DIS_TO - Disables the SMBus timeout function for the SMBus client (if enabled).
Bit 5 - WD_EN - Enables the Watchdog timer to operate in Continuous Mode (see
Bit 1 - DR_EXT_CLK - Enables the internal tachometer clock to be driven out on the CLK pin so that
multiple devices can be synced to the same source.
Bit 0 - USE_EXT_CLK - Enables the EMC2302 to use a clock present on the CLK pin as the
tachometer clock. If the DR_EXT_CLK bit is set, then this bit is ignored and the device will use the
internal oscillator.
The Fan Status registers contain the status bits associated with each fan driver.
Fan Status - 24h
The Fan Status register indicates that one or both of the fan drivers has stalled or failed or that the
Watchdog Timer has expired (see
Bit 7 - WATCH - Indicates that the Watchdog Timer has expired. When set, each fan is driven to 100%
duty cycle and will remain at 100% duty cycle until they are programmed. This bit is cleared when it
is read.
Fan Status Registers
‘0’ (default) - The ALERT# pin is unmasked. If any bit in either status register is set, the ALERT#
pins will be asserted (unless individually masked via the Mask Register).
‘1’ - The ALERT# pin is masked and will not be asserted.
‘0’ - The SMBus timeout function is enabled.
‘1’ (default) - The SMBus timeout function is disabled allowing the device to be fully I
‘0’ (default) - The Watchdog timer does not operate continuously. It will function upon power up and
at no other time.
‘1’ - The Watchdog timer operates continuously as described in
‘0’ (default) - The CLK pin acts as a clock input.
‘1’ - The CLK pin acts as a clock output and is a push-pull driver.
‘0’ (default) - The EMC2302 will use its internal oscillator for all Tachometer measurements.
‘1’ - The EMC2302 will use the oscillator presented on the CLK pin for all Tachometer
measurements.
WATCH
B7
-
-
-
B6
-
-
-
-
Table 5.3 Fan Status Registers
Section
DATASHEET
B5
-
-
-
-
26
4.8).
B4
-
-
-
-
B3
-
-
-
-
Dual RPM-Based PWM Fan Controller
DRIVE_
Section
FAIL
B2
-
-
-
4.8.
DRIVE_
STALL
FAN2_
FAN2_
FAN_
FAIL2
SPIN
SPIN
B1
Section
SMSC EMC2302
2
C compliant.
DRIVE_
4.8.2).
FAN1_
FAN1_
STALL
STALL
Datasheet
FAIL1
FAN_
SPIN
B0
DEFAULT
00h
00h
00h
00h