Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
Datasheet
Software uses the information in this register to determine the voltage that the processor is designed
to operate at. With this information, software can then dynamically determine the correct values to
place in the Vccp Low Limit and Vccp High Limit registers.
This register is read only – a write to this register has no effect.
8.2.12
Registers 44-4Dh: Voltage Limit Registers
Table 8.19 Registers 44-4Dh: Voltage Limit Registers
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)
44h
45h
46h
47h
48h
49h
4Ah
4Bh
4Ch
4Dh
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
2.5V Low Limit
2.5V High Limit
Vccp Low Limit
Vccp High Limit
VCC Low Limit
VCC High Limit
5V Low Limit
7
7
7
7
7
7
7
7
7
7
6
6
6
6
6
6
6
6
6
6
5
5
5
5
5
5
5
5
5
5
4
4
4
4
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
00h
FFh
00h
FFh
00h
FFh
00h
FFh
00h
FFh
5V High Limit
12V Low Limit
12V High Limit
Setting the Lock bit has no effect on these registers.
If a voltage input either exceeds the value set in the voltage high limit register or falls below or equals
the value set in the voltage low limit register, the corresponding bit will be set automatically by the
EMC6D103 in the interrupt status registers (41-42h). Voltages are presented in the registers at ¾ full
scale for the nominal voltage, meaning that at nominal voltage, each input will be C0h, as shown in
Table 8.20.
Table 8.20 Voltage Limits vs. Register Setting
REGISTER
SETTING AT
NOMINAL
REGISTER
SETTING AT
MAXIMUM
VOLTAGE
REGISTER
NOMINAL
INPUT VOLTAGE
MAXIMUM
VOLTAGE
MINIMUM
SETTING AT
VOLTAGE
VOLTAGE MINIMUM VOLTAGE
2.5V
Vccp
VCC
5V
2.5V
2.25V
3.3V
5.0V
12.0V
C0h
C0h
C0h
C0h
C0h
3.32V
3.00V
4.38V
6.64V
16.00V
FFh
FFh
FFh
FFh
FFh
0V
0V
0V
0V
0V
00h
00h
00h
00h
00h
12V
SMSC EMC6D103
Revision 0.4 (04-04-05)
DATA6S3HEET
SMSC [ SMSC CORPORATION ]
