Table 3. temperature limits vs register settings, 13 registers 54-5bh: fan tachometer low limit, Functional description – Rainbow Electronics LM96000 User Manual
Page 17
Functional Description
(Continued)
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
50h
R/W
Processor (Zone2)
Low Temp
7
6
5
4
3
2
1
0
81h
51h
R/W
Processor (Zone2)
High Temp
7
6
5
4
3
2
1
0
7Fh
52h
R/W
Processor (Zone3)
Low Temp
7
6
5
4
3
2
1
0
81h
53h
R/W
Processor (Zone3)
High Temp
7
6
5
4
3
2
1
0
7Fh
If an external temperature input or the internal temperature sensor either exceeds the value set in the corresponding high limit
register or falls below the value set in the corresponding low limit register, the corresponding bit will be set automatically by the
LM96000 in the Interrupt Status Register 1 (41h). For example, if the temperature read from the Remote1− and Remote1+ inputs
exceeds the Processor (Zone1) High Temp register limit setting, Interrupt Status Register 1 ZN1 bit will be set. The temperature
limits in these registers are represented as 8 bit, 2’s complement, signed numbers in Celsius, as shown below in Table 3.
Setting the Ready/Lock/Start/Override register Lock bit has no effect on these registers.
TABLE 3. Temperature Limits vs Register Settings
Temperature
Reading (Decimal)
Reading (Hex)
−127˚C
−127
81h
.
.
.
.
.
.
.
.
.
−50˚C
−50
CEh
.
.
.
.
.
.
.
.
.
0˚C
0
00h
.
.
.
.
.
.
.
.
.
50˚C
50
32h
.
.
.
.
.
.
.
.
.
127˚C
127
7Fh
4.13 Registers 54-5Bh: Fan Tachometer Low Limit
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
54h
55h
R/W
R/W
Tach1 Minimum LSB
Tach1 Minimum MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
56h
57h
R/W
R/W
Tach2 Minimum LSB
Tach2 Minimum MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
58h
59h
R/W
R/W
Tach3 Minimum LSB
Tach3 Minimum MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
5Ah
5Bh
R/W
R/W
Tach4 Minimum LSB
Tach4 Minimum MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
The Fan Tachometer Low Limit registers indicate the tachometer reading under which the corresponding bit will be set in the
Interrupt Status Register 2 register. In Auto Fan Control mode, the fan can run at low speeds, so care should be taken in software
LM96000
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