RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
6.2
Temperature Data Registers
Table 6.2 Temperature data Registers
B6 B5 B4 B3
64 32 16
ADDRESS
REGISTER
B7
B2
B1
B0
DEFAULT
00h
01h
02h
03h
Internal
Diode
Sign
8
8
8
8
4
4
4
4
2
1
1
1
1
00h
External
Diode 1
Sign
Sign
Sign
64
64
64
32
32
32
16
16
16
2
2
2
00h
00h
00h
External
Diode 2
External
Diode 3
The temperature measurement range is from 0°C to +191°C. The data format can be selected between
pure 2’s complement format which displays data from 0°C to +127°C, or in offset 2’s complement
format that displays data over the entire data range. The temperature format is shown below:
Table 6.3 Temperature Data Format
2’S COMPLEMENT FORMAT
BINARY HEX
1000 0000
OFFSET 2’S COMPLEMENT FORMAT
BINARY HEX
1000 0000
TEMPERATURE (°C)
Diode Fault
80h
00h
01h
3Fh
40h
41h
7Fh
7Fh
7Fh
7Fh
80h
C0h
C1h
FFh
00h
01h
3Fh
40h
7Eh
7Fh
<= 0
0000 0000
0000 0001
0011 1111
0100 0000
0100 0001
0111 1111
0111 1111
0111 1111
0111 1111
1100 0000
1100 0001
1111 1111
0000 0000
0000 0001
0011 1111
0100 0000
0111 1110
0111 1111
1
63
64
65
127
128 (Note 6.1)
190
191
Note 6.1 In 2’s complement format, any temperature above +127°C will be displayed as +127°C
If the High Side Fan Driver is active, then self-heating of the large current drive device will affect the
internal temperature reading. Therefore, it is not recommended that the Internal temperature channel
be used to monitor the ambient air temperature.
SMSC EMC2102
Revision 1.95 (10-19-06)
DATA3S3HEET
SMSC [ SMSC CORPORATION ]
