1°C Triple SMBus Sensor with Resistance Error Correction
Datasheet
4.5
ALERT/THERM2 Output
The ALERT/THERM2 output asserts if an out of limit measurement is detected as described in Section
4.13, "Limit Registers," on page 17. The ALERT/THERM2 pin is an open drain output and requires a
pull up resistor to VDD.The ALERT/THERM2 pin can be used as an SMBALERT#, or may be configured
as a second THERM output.
As described in the SMBus specification, an SMBus slave may inform the SMBus master that it wants
to talk by asserting the SMBALERT# signal. One or more ALERT outputs can be hardwired together
as a wired-or bus to a common input.
The ALERT/THERM2 pin de-asserts when the EMC1033 responds to an alert response address
(ARA=0001 100) sent by the host, and if the out of limit condition no longer exists. It does not reset if
the error condition remains. The ALERT/THERM2 pin can be masked so that it will not assert in the
event of an out of limit temperature measurement, except when it is configured as a second THERM
pin.
Logic
Level
Temp
Temperature High Limit
SMBus ARA
Temperature Low Limit
Logic High
ALERT/THERM2
Time
Figure 4.4 ALERT/THERM2 Response to Temperature Limits Exceeded
The ALERT/THERM2 pin can be configured as a second THERM pin that asserts when the temperature
measurement exceeds the Temperature High Limit value. In this mode, the output will not de-assert
until the temperature drops below the Temperature High Limit minus the THERM Hysteresis value.
4.6
ADDR/THERM Output
The ADDR/THERM output asserts if the temperature measurement exceeds the programmable THERM
limit. It can be used to drive a fan or other fail-safe devices. The ADDR/THERM pin is open drain and
requires a pull up resistor to VDD. The value of this pull up resistor determines the slave address per
Table 1.2 on page 3. The ADDR/THERM pin cannot be masked.
When the ADDR/THERM pin is asserted, it will not de-assert until the temperature drops below the
THERM limit minus the THERM hysteresis value.
Revision 1.1 (01-19-07)
SMSC EMC1033
DATA1S2HEET
SMSC [ SMSC CORPORATION ]
