82801BA Datasheet, PDF (49/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Signal Description
Table 2-18. General Purpose I/O Signals (Continued)
Name
Type
Description
GPIO[5]
GPIO[4:3]
GPIO[2]
GPIO[1:0]
Not implemented.
I
Fixed as Input only. Main power well. Can be used instead as PIRQ[G:F]#.
Not implemented.
I
Fixed as Input only. Main Power Well. Can instead be used for PC/PCI
REQ[A:B]#. GPIO[1] can also alternatively be used for PCI REQ[5]#.
2.19 Power and Ground
Table 2-19. Power and Ground Signals
Name
Vcc3_3
Vcc1_8
V5REF
HUBREF
VccSus3_3
VccSus1_8
V5REF_SUS
VccRTC
VccLAN3_3
(ICH2-M only)
VccLAN1_8
(ICH2-M only)
VBIAS
V_CPU_IO
Vss
Description
3.3V supply for Core well I/O buffers. This power may be shut off in S3, S5 or G3 states.
1.8V supply for Core well logic. This power may be shut off in S3, S5 or G3 states.
Reference for 5V tolerance on Core well inputs. This power may be shut off in S3, S5 or
G3 states.
0.9V reference for the hub interface. This power may be shut off in S3, S5 or G3 states.
3.3V supply for Resume well I/O buffers. This power is not expected to be shut off unless
power is removed.
• 82801BA ICH2: The system is unplugged.
• 82801BAM ICH2-M: The main battery is removed or completely drained and AC
power is not available.
1.8V supply for Resume well logic. This power is not expected to be shut off unless power
is removed.
• 82801BA ICH2: The system is unplugged.
• 82801BAM ICH2-M: The main battery is removed or completely drained and AC
power is not available.
Reference for 5V tolerance on Resume well inputs. This power is not expected to be shut
off unless power is removed.
• 82801BA ICH2: The system is unplugged. Note that V5REF_SUS only affects 5V
tolerance for the USB OC[3:0]# pins and can be connected to VccSUS3_3 if 5V
tolerance on these signals is not required.
• 82801BAM ICH2-M: The main battery is removed or completely drained and AC
power is not available.
3.3V (can drop to 2.0V min. in G3 state) supply for the RTC well. This power is not
expected to be shut off unless the RTC battery is removed or completely drained.
Note: Implementations should not attempt to clear CMOS by using a jumper to pull
VccRTC low. Clearing CMOS in an ICH2-based platform can be done by using a jumper
on RTCRST# or GPI, or using SAFEMODE strap.
3.3V supply for LAN Connect interface buffers. This is a separate power plane that may or
may not be energized in S3–S5 states depending upon the presence or absence of AC
power and network connectivity. This plane must be on in S0 and S1.
1.8V supply for LAN controller logic. This is a separate power plane that may or may not
be energized in S3–S5 states depending upon the presence or absence of AC power and
network connectivity. This plane must be on in S0 and S1.
RTC well bias voltage. The DC reference voltage applied to this pin sets a current that is
mirrored throughout the oscillator and buffer circuitry. See Section 2.20.3.
Powered by the same supply as the processor I/O voltage. This supply is used to drive the
processor interface outputs.
Grounds.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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