Intel 440GX User Manual
Intel
®
440GX AGPset Design Guide
3-23
Design Checklist
Third, if the design currently uses an in-line active gate/buffer on PCIRST# to drive the PCI bus,
consider removal of this gate/buffer entirely. The PIIX4/PIIX4E is designed to drive the entire PCI
bus.
consider removal of this gate/buffer entirely. The PIIX4/PIIX4E is designed to drive the entire PCI
bus.
3.9
ISA Signals
3.10
ISA and X-Bus Signals
•
The PIIX4E will support a maximum of 5 ISA slots.
•
XOE# and XDIR# are connected to the ULTRA I/O device.
•
If internal RTC is used, RTCALE and RTCCS# are no connect or become general purpose
outputs by programming the General Configuration Register(GENCFG) in the Function 0,
offset B0h–B3h.
outputs by programming the General Configuration Register(GENCFG) in the Function 0,
offset B0h–B3h.
•
The LM79 is connected to the X-Bus due to the functionality of the PGCS[1:0]# pins on the
PIIX4E.
PIIX4E.
Table 3-10. Non-PIIX4E PCI Signals
SIGNAL
CONNECTION
ACK64#,
PERR#,
PLOCK#,
REQ64#
(5V PCI environment) 2.7K ohm pull-up resistors to 5V.
(3V PCI environment) 10K ohm pull-up resistors to 3.3V.
PERR# and PLOCK# can be connected together across PCI slots and pulled
up by single resistor.
up by single resistor.
Each REQ64# and ACK64# requires its own pull-up.
GNT[3:0]#
Connected between PCI slots and 82443GX. 8.2K ohm pull-up to VCC3.
IDSEL lines to PCI connectors
100 ohm series resistor recommended per the PCI spec.
SBO#,
SDONE
5.6K ohm pull-up to VCC.
Table 3-11. Non-PIIX4E ISA Signals
SIGNAL
CONNECTION
OSC1
Connected to CK100 through 22 ohm resistor.
RMASTER#
1K ohm pull-up to VCC.