82801DB Datasheet, PDF (59/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

Intel^® ICH4 Power Planes and Pin States
3.4
Output and I/O Signals Planes and States
Table 3-4 shows the power plane associated with the output and I/O signals, as well as the state at
various times. Within the table, the following terms are used:
“High-Z”
Tri-state. ICH4 not driving the signal high or low.
“High”
ICH4 is driving the signal to a logic ‘1’
“Low”
ICH4 is driving the signal to a logic ‘0’
“Defined”
Driven to a level that is defined by the function (will be high or low)
“Undefined”
ICH4 is driving the signal, but the value is indeterminate.
“Running”
Clock is toggling or signal is transitioning because function not stopping
“Off”
The power plane is off, so ICH4 is not driving
Note that the signal levels are the same in S4 and S5.
Table 3-4. Power Plane and States for Output and I/O Signal (Sheet 1 of 4)
Signal Name
Power
Plane
During
PCIRST#⁴ /
RSMRST#^5,7
Immediately
after
PCIRST#⁴ /
RSMRST#⁵
S1
S3
PCI Bus
AD[31:0]
Main I/O
High-Z
Undefined
Defined
Off
C/BE#[3:0]
Main I/O
High-Z
Undefined
Defined
Off
DEVSEL#
Main I/O
High-Z
High-Z
High-Z
Off
FRAME#
Main I/O
High-Z
High-Z
High-Z
Off
GNT[0:4]#
Main I/O
High
High
High
Off
GNT[A:B]#
Main I/O
High-Z with
Internal Pull-
Up
High
High
Off
IRDY#, TRDY#
Main I/O
High-Z
High-Z
High-Z
Off
PAR
Main I/O
High-Z
Undefined
Defined
Off
PCIRST#
Resume I/O
Low
High
High
Low
PERR#
Main I/O
High-Z
High-Z
High-Z
Off
PLOCK#
Main I/O
High-Z
High-Z
High-Z
Off
STOP#
Main I/O
High-Z
High-Z
High-Z
Off
S4/S5
Off
Off
Off
Off
Off
Off
Off
Off
Low
Off
Off
Off
Intel^® 82801DB ICH4 Datasheet
59