Environmental Monitoring and Control Device
Datasheet
The range numbers will be used to calculate the slope of the PWM ramp up. For the fractional entries, the
PWM will go on full when the temp reaches the next integer value e.g., for 3.33, PWM will be full on at (min
temp + 4).
8.20 Register 62h, 63h: Min/Off, Spike Smoothing
REGISTER
ADDRESS
READ/
WRITE
REGISTER
NAME
Min/Off, Zone 1
Spike Smoothing
Zone 2, Zone 3
Spike Smoothing
BIT 7
BIT 0
(LSB)
DEFAULT
VALUE
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
(MSB)
OFF3
OFF2
OFF1
RES
ZN1E ZN1-2 ZN1-1 ZN1-0
62h
63h
R/W
R/W
00h
00h
ZN2E
ZN2-2 ZN2-1 ZN2-0 ZN3E ZN3-2 ZN3-1 ZN3-0
These registers become read only when the Lock bit is set. Any further attempts to write to these registers
shall have no effect.
The Off/Min Bits [7:5] specify whether the duty cycle will be 0% or Minimum Fan Duty when the measured
temperature falls below the Temperature LIMIT register setting (see table below). OFF1 applies to fan 1,
OFF2 applies to fan 2, and OFF3 applies to fan 3.
If the Remote1 or Remote2 pins are connected to a processor or chipset, instantaneous temperature
spikes may be sampled by the part. If these spikes are not ignored, the CPU fan (if connected to part) may
turn on prematurely and produce unpleasant noise. For this reason, any zone that is connected to a
chipset or processor should have spike smoothing enabled.
When spike smoothing is enabled, the temperature reading registers still reflect the current value of the
temperature – not the ‘smoothed out’ value.
ZN1E, ZN2E, and ZN3E enable temperature smoothing for zones 1, 2, and 3 respectively.
ZN1-2, ZN1-1, and ZN1-0 control smoothing time for Zone 1
ZN2-2, ZN2-1, and ZN2-0 control smoothing time for Zone 2
ZN3-2, ZN3-1, and ZN3-0 control smoothing time for Zone 3
Spike 'smoothed' with
Temperature spike with
spike smoothing disabled
spike smoothing enabled
FIGURE 8.2 - WHAT EMC6D100/EMC6D101 SEES WITH AND WITHOUT SPIKE SMOOTHING
SMSC EMC6D100/EMC6D101
Page 55
Rev. 09-09-04
DATASHEET
SMSC [ SMSC CORPORATION ]
