Datasheet

6-Channel Intelligent Fan Controller
MAX31785
43
MFR_FAN_LUT (F2h)
The MFR_FAN_LUT command is used to configure the LUT that controls the fan. The fan has an LUT that maps eight
programmable temperature levels to eight programmable fan PWM duty-cycle levels (bit 6 in FAN_CONFIG_1_2 is
zero) or eight programmable target fan speeds (bit 6 in FAN_CONFIG_1_2 is one). The LUT allows a wide variety of
profiles to be used.
USER NOTE: The programmable configuration of MFR_FAN_LUT must be monotonic.
Table 27. MFR_FAN_LUT
TEMPERATURE STEP: Temperature Level Setting
The TEMPERATURE STEP sets the temperature in degrees Celsius and represents a threshold level at which the
device updates the fan PWM duty cycle setting. The 2 data bytes are in DIRECT format. The valid temperature range
depends on the temperature sensor.
Table 28. Valid Temperature Range
BYTE NUMBER WORD NAME MEANING
0-1 TEMP STEP 0 Temperature for step 0.
2-3 SPEED STEP 0 Fan PWM duty cycle or fan speed for step 0.
4-5 TEMP STEP 1 Temperature for step 1.
6-7 SPEED STEP 1 Fan PWM duty cycle or fan speed for step 1.
8-9 TEMP STEP 2 Temperature for step 2.
10-11 SPEED STEP 2 Fan PWM duty cycle or fan speed for step 2.
12-13 TEMP STEP 3 Temperature for step 3.
14-15 SPEED STEP 3 Fan PWM duty cycle or fan speed for step 3.
16-17 TEMP STEP 4 Temperature for step 4.
18-19 SPEED STEP 4 Fan PWM duty cycle or fan speed for step 4.
20-21 TEMP STEP 5 Temperature for step 5.
22-23 SPEED STEP 5 Fan PWM duty cycle or fan speed for step 5.
24-25 TEMP STEP 6 Temperature for step 6.
26-27 SPEED STEP 6 Fan PWM duty cycle or fan speed for step 6.
28-29 TEMP STEP 7 Temperature for step 7.
30-31 SPEED STEP 7 Fan PWM duty cycle or fan speed for step 7.
TEMPERATURE SENSOR VALID RANGE
Page 12: Internal Temp Sensor
-40NC to +85NC
Pages 13 to 16: I
2
C Remote Temp Sensor
-55NC to +125NC
Page 6 to 11: Remote Thermal Diode Temp Sensor
-40NC to +120NC