Environmental Monitoring and Control Device
Datasheet
8.22 Registers 67-69h: Temperature LIMIT
BIT 7
(MSB)
BIT 0
(LSB)
REGISTER
ADDRESS
READ/
WRITE
REGISTER
NAME
DEFAULT
VALUE
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
Zone 1 Fan
67h
68h
69h
R/W
R/W
R/W
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
5Ah
5Ah
5Ah
Temp Limit
Zone 2 Fan
Temp Limit
Zone 3 Fan
Temp Limit
These registers become read only when the Lock bit is set. Any further attempts to write to these registers
shall have no effect.
These are the temperature limits for the individual zones. When the current temperature equals this limit,
the fan will be turned on if it is not already. When the temperature exceeds this limit, the fan speed will be
increased according to the auto fan algorithm based on the setting in the Zone x Range / FANx Frequency
register. Default = 90°C=5Ah
Table 8.13 - Temperature Limit vs. Register Setting
LIMIT
-127°c
LIMIT (DEC)
-127
LIMIT (HEX)
81h
-50
CEh
-50°c
0
00h
32h
7Fh
0°c
50
127
50°c
127°c
8.23 Registers 6A-6Ch: Absolute Temperature Limit
BIT 7
(MSB)
BIT 0
(LSB)
REGISTER
ADDRESS
READ/
WRITE
REGISTER
NAME
DEFAULT
VALUE
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
Zone 1 Temp
6Ah
6Bh
6Ch
R/W
R/W
R/W
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
64h
64h
64h
Absolute Limit
Zone 2 Temp
Absolute Limit
Zone 3 Temp
Absolute Limit
These registers become read only when the Lock bit is set. Any further attempts to write to these registers
shall have no effect.
In Auto Fan mode, if any zone exceeds the temperature set in the Absolute limit register, all PWM outputs
will increase their duty cycle to 100% except those that are disabled via the fan configuration registers.
This is a safety feature that attempts to cool the system if there is a potentially catastrophic thermal event.
SMSC EMC6D100/EMC6D101
Page 57
Rev. 09-09-04
DATASHEET
SMSC [ SMSC CORPORATION ]
