EMC6D100-DK SMSC [SMSC Corporation], EMC6D100-DK Datasheet - Page 58

• Manufacturer Part Number: EMC6D100-DK
• Description: ENVIRONMENTAL MONITORING AND CONTROL DEVICE WITH AUTOMATIC FAN CAPABILITY
• Manufacturer: SMSC [SMSC Corporation]

REGISTER
8.24
ADDRESS
SMSC EMC6D100/EMC6D101
6Dh
6Eh
If an absolute limit register set to 80h (-128°c), the safety feature is disabled for the associated zone. That
is, if 80h is written into the Zone x Temp Absolute Limit Register, then regardless of the reading register for
the zone, the fans will not turn on-full based on the absolute temp condition.
Default =100°c=64h.
When any fan is in auto fan mode, then if the temperature in any zone exceeds absolute limit, all fans go
to full, including any in manual mode, except those that are disabled. Therefore, even if a zone is not
associated with a fan, if that zone exceeds absolute, then all fans go to full. In this case, the absolute limit
can be chosen to be 7Fh for those zones that are not associated with a fan, so that the fans won't turn on
unless the temperature hits 127 degrees.
Registers 6D-6Eh: Zone HYSTERESIS Registers
These registers become read only when the Lock bit is set. Any further attempts to write to these registers
shall have no effect.
If the temperature is above Fan Temp Limit, then drops below Fan Temp Limit, the following will occur:
The fan will remain on, at Fan PWM Minimum, until the temperature goes a certain amount below Fan
Temp Limit. That is, when the temperature is less than the temperature limit minus the hysteresis value,
the fan will turn off.
The Hysteresis registers control this amount. See below table for details.
READ/
WRITE
R/W
R/W
Zone 1, Zone 2
Hysteresis
Hysteresis
REGISTER
Zone 3,
NAME
-127°c
-50°c
0°c
50°c
127°c
ABSOLUTE
Table 8.14 - Absolute Limit vs. Register Setting
LIMIT
(MSB)
BIT 7
H1-3
H3-3
DATASHEET
-127
-50
0
50
127
ABS LIMIT (DEC)
BIT 6
H1-2
H3-2
Page 58
BIT 5
H1-1
H3-1
BIT 4
H1-0
H3-0
81h
CEh
00h
32h
7Fh
ABS LIMIT (HEX)
BIT 3
H2-3
RES
Environmental Monitoring and Control Device
BIT 2
H2-2
RES
BIT 1
H2-1
RES
(LSB)
BIT 0
H2-0
RES
Rev. 09-09-04
DEFAULT
Datasheet
VALUE
44h
40h