ASUS Crosshair VII Hero motherboard has T_in header for 10K thermistor temperature probe. GPIO toggles between 25C (open/low) and 68C (high) temperatures. Triggers BIOS setpoint to ramp fans to user defined level. Motherboard internally has voltage divider with VCC=5V, R1=~12K, R2=(T_in to GND)
How I chose the resistor values was partially trial and error. I assumed R2=10K but measurements at ~27.5C, (2.12V * (R2 + 8950 ohm) = 5.02 * 8950 ohm), calculates out to ~12K.
From thermistor data sheet 2487 ohms = 60C.Voltage divider, T_in = Vcc * R2 / (R1 + R2). T_in ~=1V in order for ADC to think ~2500ohms is present. Measured 1.08V, T_in to Gnd with the resistors I had, HWInfo shows 68C. So I have 10K resistors everywhere except 2.2K for emitter.