SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 256

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

Rev 0.2 (09-28-04)
(Note 2
INPUT
Register
Address
4.16)
Vccp
VCC
VTR
Vbat
2.5V
12V
5V
4Ah
4Bh
4Ch
4Dh
9Bh
9Ch
9Dh
9Eh
49h
NOMINAL
VOLTAGE
2.25V
12.0V
Read/
Write
3.3V
3.0V
5.0V
3.3V
5.0V
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
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 in the
interrupt status registers (41-42h, 83h). Voltages are presented in the registers at ¾ full scale for the
nominal voltage, meaning that at nominal voltage, each register will read C0h, except for the Vbat
input. Vbat is nominally a 3.0V input that is implemented on a +3.3V (nominal) analog input.
Therefore, the nominal reading for Vbat is AEh.
Note: Vbat will only be monitored when the Vbat Monitoring Enable bit is set to ‘1’. Updating the
Note 24.16 Vbat is a nominal 3.0V input source that has been implemented on a 3.3V analog voltage
Vbat reading register automatically clears the Vbat Monitoring Enable bit.
READING AT
monitoring input.
REGISTER
VOLTAGE
NOMINAL
Register Name
VCC High Limit
VTR High Limit
Vbat High Limit
12V High Limit
VTR Low Limit
Vbat Low Limit
12V Low Limit
5V High Limit
5V Low Limit
C0h
AEh
C0h
C0h
C0h
C0h
C0h
Table 24.5 Voltage Limits vs. Register Setting
MAXIMUM
VOLTAGE
16.00V
4.38V
4.38V
6.64V
3.00V
4.38V
6.64V
DATASHEET
LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
(MSb)
Bit 7
7
7
7
7
7
7
7
7
7
240
Bit 6
6
6
6
6
6
6
6
6
6
READING AT
REGISTER
MAXIMUM
VOLTAGE
FFh
FFh
FFh
FFh
FFh
FFh
FFh
Bit 5
5
5
5
5
5
5
5
5
5
Bit 4
4
4
4
4
4
4
4
4
4
Bit 3
VOLTAGE
MINIMUM
3
3
3
3
3
3
3
3
3
0V
0V
0V
0V
0V
0V
0V
Bit 2
2
2
2
2
2
2
2
2
2
MINIMUM VOLTAGE
Bit 1
1
1
1
1
1
1
1
1
1
READING AT
REGISTER
(LSb)
SMSC SCH311X
Bit 0
0
0
0
0
0
0
0
0
0
00h
00h
00h
00h
00h
00h
00h
Datasheet
Default
Value
FFh
FFh
FFh
FFh
FFh
00h
00h
00h
00h