Multiple RPM-Based PWM Fan Controller for Five Fans
Datasheet
Table 5.1 EMC2305 Register Set (continued)
REGISTER
NAME
DEFAULT
VALUE
ADDR
R/W
FUNCTION
LOCK
PAGE
Lock Register
EF
R/W
Software Lock
Locks all SWL registers
Revision Registers
00h
SWL
Page 48
Indicates functions determined upon
device power up by external pin states
FCh
R
Product Features
00h
No
Page 48
FDh
FEh
FFh
R
R
R
Product ID
Manufacturer ID
Revision
Stores the unique Product ID
Stores the Manufacturer ID
Revision
34h
5Dh
80h
No
No
No
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Page 49
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During Power-On-Reset (POR), the default values are stored in the registers. A POR is initiated when
power is first applied to the part and the voltage on the VDD supply surpasses the POR level as
specified in the electrical characteristics. Any reads to undefined registers will return 00h. Writes to
undefined registers will not have an effect.
5.1.1
Lock Entries
The Lock Column describes the locking mechanism, if any, used for individual registers. All SWL
registers are Software Locked and therefore made read-only when the LOCK bit is set.
5.2
Configuration Register
Table 5.2 Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
USE_
EXT_
CLK
DR_EXT_
CLK
20h
R/W
Configuration MASK
DIS_TO WD_EN
-
-
-
40h
The Configuration Register controls the basic functionality of the EMC2305. The bits are described
below. The Configuration Register is software locked.
Bit 7 - MASK - Blocks the ALERT# pin from being asserted.
‘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.
Bit 6 - DIS_TO - Disables the SMBus timeout function for the SMBus client (if enabled).
‘0’ - The SMBus timeout function is enabled.
‘1’ (default) - The SMBus timeout function is disabled allowing the device to be fully I2C compliant.
Bit 5 - WD_EN - Enables the Watchdog timer to operate in Continuous Mode (see Section 4.8.2).
‘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 Section 4.8.
SMSC EMC2305
Revision 1.1 (10-12-09)
DATA3S1HEET
SMSC [ SMSC CORPORATION ]
