SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Bit 3 - EXT_LOW - External Diode temperature has fallen below the low limit.
Bit 2 - FAULT - A diode fault has occurred on the External Diode.
Bit 1 - TCRIT - External Diode Temperature has met or exceeded the TCRIT limit.
Bit 0 - TACH - The TACH count has exceeded the TACH Limit.
6.5
Configuration Register
Table 6.4 Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
03h and
09h
FAN_
STANDBY
DIS_
TO
ALT_
TCH
TCRIT
OVRD
R/W
Configuration
MASK
STANDBY
DAC
QUEUE
00h
The configuration register controls the basic functionality of the EMC2101. The bits are described
below:
Bit 7 - MASK - Masks the ALERT / TACH pin functionality when the device is configured as an ALERT
output in Interrupt Mode. This bit is ignored if the ALERT / TACH pin is configured as an ALERT output
in Comparator Mode or if it is configured as a TACH input.
The internal error condition flags are not affected by setting the MASK bit. Therefore, if the MASK bit
is set manually (instead of by reading the Status Register or sending the ARA command), and it is
cleared, the ALERT / TACH pin may be reasserted without any apparent error conditions present. It is
not recommended that the MASK bit be manually set to clear the ALERT / TACH pin.
'0' (default) - The ALERT / TACH pin will be asserted if any bit is set in the Status Register. Once
the pin is asserted, it will remain asserted.
'1' - the ALERT / TACH pin will be masked and will not generate an interrupt. The Status Register
will still be updated normally.
Bit 6- STANDBY - Determines operational mode of the device.
'0' (default) - Operational mode, monitoring temperatures, updating FAN output
'1' - Low power standby mode. In this mode, the Temperature monitor is disabled and the Fan
drivers may be disabled depending on the status of the FAN_STANDBY bit.
Bit 5 - FAN_STANDBY - Determines the operation of the FAN driver when the device is put into low
power standby mode.
'0' (default) - FAN output will remain active when the STANDBY bit is set.
‘1’ - FAN output will be inactive when the STANBDY bit is set. The driver will be set at the default
drive based on the pull-up resistors on the ALERT / TACH pin (see Table 5.1).
Bit 4 - DAC - Determines FAN output mode
'0' (default) - PWM output enabled at FAN pin.
'1' - DAC output enabled at FAN pin.
Bit 3 - DIS_TO - disables the SMBus Time-out functionality.
‘0’ (default) - the SMBus Time-out functionality is enabled and will reset the client block if the clock
is held in a single state for more than 25ms and less than 35ms.
‘1’ - the SMBus Time-out functionality is disabled. The client block will only reset if it receives a
STOP bit.
Bit 2 - ALT_TCH - Determines the functionality of the ALERT / TACH pin.
‘0’ (default) - The ALERT / TACH pin will function as an open drain, active low interrupt.
SMSC EMC2101
Revision 2.53 (03-13-07)
DATA3S3HEET
SMSC [ SMSC CORPORATION ]
