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 10KΩ at 25°C. In the Figure 6-1, the thermistor is connected by a serial resistor
with 10KΩ, 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
T
HYST
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.
34
Jan, 2012
V0. 12P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
