EMC6D100-DK SMSC [SMSC Corporation], EMC6D100-DK Datasheet - Page 51

• Manufacturer Part Number: EMC6D100-DK
• Description: ENVIRONMENTAL MONITORING AND CONTROL DEVICE WITH AUTOMATIC FAN CAPABILITY
• Manufacturer: SMSC [SMSC Corporation]

Environmental Monitoring and Control Device
Datasheet
8.17
8.18
8.18.1 BITS [7:5] ZONE/MODE
SMSC EMC6D100/EMC6D101
REGISTER
REGISTER
ADDRESS
ADDRESS
5Ah
5Bh
54h
55h
56h
57h
58h
59h
5Ch
5Dh
5Eh
Registers 54-5Bh: Fan Tachometer Low Limit
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 low
speeds, so care should be taken in software to ensure that the limit is low enough not to cause sporadic
alerts.
The fan tachometer will not cause a bit to be set in the interrupt status register if the current value in
Current PWM Duty registers is 00h or if the fan is disabled via the Fan Configuration Register.
Interrupts will never be generated for a fan if its tachometer minimum is set to FFFFh.
These registers become read only when the Lock bit is set. Any further attempts to write to these registers
shall have no effect.
Bits [7:5] of the Fan Configuration registers associate each fan with a temperature sensor. When in Auto
Fan Mode, the fan will be assigned to a zone, and its PWM duty cycle will be adjusted according to the
temperature of that zone. If ‘Hottest’ option is selected (101 or 110), the fan will be controlled by the hottest
of zones 2 and 3, or of zones 1, 2, and 3. If one of these options is selected, the fan is controlled by the
Registers 5C-5Eh: Fan Configuration
READ/
WRITE
WRITE
READ/
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Tach1 Minimum
Tach1 Minimum
Tach2 Minimum
Tach2 Minimum
Tach3 Minimum
Tach3 Minimum
Tach4 Minimum
Tach4 Minimum
Configuration
Configuration
Configuration
REGISTER
REGISTER
NAME
NAME
Fan 1
Fan 2
Fan 3
MSB
MSB
MSB
MSB
LSB
LSB
LSB
LSB
(MSB)
(MSB)
BIT 7
BIT 7
ZON2
ZON2
ZON2
15
15
15
15
7
7
7
7
DATASHEET
BIT 6
BIT 6
ZON1
ZON1
ZON1
14
14
14
14
6
6
6
6
Page 51
BIT 5
BIT 5
ZON0
ZON0
ZON0
13
13
13
13
5
5
5
5
BIT 4
BIT 4
INV
INV
INV
12
12
12
12
4
4
4
4
BIT 3
BIT 3
RES
RES
RES
11
11
11
11
3
3
3
3
BIT 2
BIT 2
SPIN2
SPIN2
SPIN2
10
10
10
10
2
2
2
2
SPIN1
SPIN1
SPIN1
BIT 1
BIT 1
1
9
1
9
1
9
1
9
(LSB)
(LSB)
BIT 0
BIT 0
SPIN0
SPIN0
SPIN0
0
8
0
8
0
8
0
8
Rev. 09-09-04
DEFAULT
DEFAULT
VALUE
VALUE
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
62h
62h
62h