Fan Control Device with Hardware Monitoring and Acoustic Noise Reduction Features
Datasheet
bit will be set automatically by the EMC6D102 in the Interrupt Status Register 1 (41h). For example,
if the temperature reading from the Remote1- and Remote1+ inputs exceeds the Remote Diode 1 High
Temp register limit setting, Bit[4] D1 of the Interrupt Status Register 1 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 7.6.
Table 7.6 Temperature Limits vs. Register Settings
TEMPERATURE
LIMIT (DEC)
LIMIT (HEX)
-127°c
-127
81h
.
.
.
.
.
.
.
.
.
-50°c
-50
CEh
.
.
.
.
.
.
.
.
.
0°c
0
00h
.
.
.
.
.
.
.
.
.
50°c
50
32h
.
.
.
.
.
.
.
.
.
127°c
127
7Fh
7.2.15
Registers 54-5Bh: Fan Tachometer Low Limit
Register
Address
Read/
Write
Bit 7
Bit 0
Default
Value
Register Name
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
(MSb)
(LSb)
54h
55h
56h
57h
58h
59h
5Ah
5Bh
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Tach1 Minimum LSB
Tach1 Minimum MSB
Tach2 Minimum LSB
Tach2 Minimum MSB
Tach3 Minimum LSB
Tach3 Minimum MSB
Tach4 Minimum LSB
Tach4 Minimum MSB
7
15
7
6
14
6
5
13
5
4
12
4
3
11
3
2
10
2
1
9
1
9
1
9
1
9
0
8
0
8
0
8
0
8
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
15
7
14
6
13
5
12
4
11
3
10
2
15
7
14
6
13
5
12
4
11
3
10
2
15
14
13
12
11
10
Setting the Lock bit has no effect on these registers.
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 high speeds (100% duty cycle), so care should be taken in software to ensure that the
limit is low enough not to cause sporadic alerts. Note that an interrupt status event will be generated
when the tachometer reading is greater than the minimum tachometer limit.
The fan tachometer will not cause a bit to be set in the interrupt status register if the current value in
the associated Current PWM Duty registers is 00h or if the PWM is disabled via the PWM
Configuration Register.
Interrupts will never be generated for a fan if its tachometer minimum is set to FFFFh.
Revision 0.4 (04-05-05)
SMSC EMC6D102
DATA5S8HEET
SMSC [ SMSC CORPORATION ]
