SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
6.7
Temperature Limit Registers
Table 6.7 Temperature Data Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Internal Temp
Limit
05h and 0Bh
07h and 0Dh
08h and 0Eh
13h
R/W
-
64
32
16
8
4
2
1
46h (70°C)
External Diode
High Limit MSB
R/W
R/W
R/W
R/W
R/W
R/W
-
-
64
64
32
32
16
16
-
8
8
-
4
4
-
2
2
-
1
1
-
46h (70°C)
00h (0°C)
00h
External Diode
Low Limit MSB
External Diode
High Limit LSB
0.5
0.5
-
0.25
0.25
64
0.125
0.125
32
External Diode
Low Limit LSB
14h
-
-
-
-
-
00h
TCRIT Temp
Limit
19h
16
16
8
8
4
4
2
2
1
1
55h (85°C)
0Ah (10°C)
TCRIT
Hysteresis
21h
-
64
32
The EMC2101 has two 8-bit limit registers, two 11-bit limit registers, and one hysteresis register. The
limits are checked after every temperature conversion.
If the measured temperature for the internal diode exceeds the Internal Temperature limit, then the
INT_HIGH bit is set in the Status Register. It will remain set until the internal temperature drops below
the high limit.
If the measured temperature for the External Diode exceeds the 11-bit External Diode High Limit, or
drops below the 11-bit External Diode Low Limit, then the appropriate status bit will be set. The status
bit will remain set until the temperature is no longer violating the respective limits.
If the External Diode exceeds the TCRIT Temp Limit (even if it does not exceed the External Diode
Temperature Limit), the TCRIT bit will be set in the Status Register.
The TCRIT bit will remain set in the Status Register until the External Diode Temperature drops below
a lower threshold given by equation [2].
TEMP = (TCRIT – TCRITHYS
)
[2]
See Section 6.3 and Section 6.5 for ALERT / TACH pin functionality.
6.8
External Temperature Force Register
Table 6.8 External Diode Force Register
ADDR.
R/W
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
00h
External
Temperature Force
0Ch
Sign
64
32
16
8
4
2
1
SMSC EMC2101
Revision 2.53 (03-13-07)
DATA3S5HEET
SMSC [ SMSC CORPORATION ]
