5 82443gx host bridge – Intel 440GX User Manual

Page 70

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Intel

®

440GX AGPset Design Guide

3-10

Design Checklist

3.5

82443GX Host Bridge

3.5.1

82443GX Interface

Table 3-4. 82443GX Connectivity (Sheet 1 of 3)

SIGNAL

CONNECTION

AD#[31:0]

Connected to PCI bus.

ADS#

Connected to CPUs.

AGPREF

Connected to be 0.4 of VCC

3.3

. Can be performed by a voltage divider.

BNR#

Connected to CPUs.

BPRI#

Connected to CPUs.

BREQ0#

Connected to CPUs.

GXPWROK

Connected to PIIX4E PWROK pin.

C/BE[3:0]#

Connected to PCI bus.

FENA

4DIMM Design: Connected to FET-switches as an enable pin.

GCKE

GCKE needs to be disabled for register DIMMS.

GCKE is a NC unless connected to SN74ALVCH16374 16-bit D flip-flop. See
reference schematics for details.

CLKRUN#

If not connected to the PIIX4E, pull down through a 100 ohm resistor at both
82443GX and PIIX4E.

CPURST#

Connected to CPUs and ITP (240 ohm series resistor).

CRESET#

10K ohm pull-up to 3.3V. Controls the mux for the CPU strapping signals.

CSA[5:0]#

Connect to DIMMs; two to each

CSA[7:6]#

Connect CSA[7:6]# to DIMM 3.

CSB[5:0]#

Connect to DIMMs; two to each

CSB[7:6]#

Connect CSB[7:6]# to DIMM 3

DBSY#, DRDY#

Connected to CPUs.

DCLKO

Connected to CKBF. 22 ohm series resistor placed next to 443GX and 47 ohm series
resistor placed next to CKBF.

DCLKWR,
Pin AB22 (NC)

Driven by single clock from CKBF. See Clock section

DEFER#

Connected to CPUs.

DEVSEL#

2.7K ohm pull-up to 5V. Connected to PCI bus.

DQMA[7:0]

Connected to all DIMMs.

DQMB5, DQMB1

4 DIMM: Connected to DIMM2 and DIMM3.

FRAME#

2.7K ohm pull-up to 5V. Connected to PCI bus.

GAD[31:0], GC/
BE[3:0]#

Connected to AGP connector.

GCLKIN

Connected to GCLKOUT through 22 ohm resistor.

GCLKOUT

Connected to AGP connector through 22 ohm series resistor.

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