F81866A Datasheet, PDF (34/210 Pages) Feature Integration Technology Inc. – 6 UARTs Super IO With 128 Bytes FIFO and Power

F81866A
(1) Monitor Temperature from “thermistor”
The F81866A can connect two thermistors to measure environment temperature or remote
temperature. The specification of thermistor should be considered to (1) β value is 3435K (2)
resistor value is 10K Ω at 25°C. In the Figure 6-1, the thermistor is connected by a serial resistor
with 10K Ω , then connected to VREF.
(2) Monitor Temperature from “thermal diode”
Also, if the CPU, GPU or external circuits provide thermal diode for temperature
measurement, the F81866A is capable to these situations. The build-in reference table is for PNP
2N3906 transistor. In the Figure 6-1, the transistor is directly connected into temperature pins.
Over Temperature Signal (OVT#)
OVT# alert for temperature is shown as figure 6-3. When monitored temperature exceeds
the over-temperature threshold value, OVT# will be asserted until the temperature goes below the
hysteresis temperature.
TOVT
THYST
OVT#
(Level mode)
OVT#
(SMI mode)
Fig 6-3
Temperature PME#
PME# interrupt for temperature is shown as figure 6-4. Temperature exceeding high limit or
going below hysteresis will cause an interrupt if the previous interrupt has been reset by writing
“1” all the interrupt Status Register.
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Jan, 2012
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