Intel 440GX, Design Manual

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Intel
®
440GX AGPset Platform Reference Design
A-4 Intel
®
440GX AGPset Design Guide
Power Connectors Front Panel Jumpers 32
This page shows the system ATX power connector, hardware reset logic, and standard chassis
connectors for the hard disk, power LEDs, and speaker output. Included on this page are the dual-
color LED circuit required to indicate the system state (either ON, OFF, or any of the suspend
states), the 6-pin optional ATX connector, and the Wake-On-LAN header. Note: a CPU Fan Header
is required for the Intel Boxed processor. The dual-color LED circuit is also used to reduce the
voltage going to the power supply fan, thus decreasing its speed and quieting the system.
Pull-up and Pull-down Resistors 34-35
These pages show pull-up and pull-down resistors for PCI signals, PIIX4E, Slot 1(CMOS), ISA,
and AGP signals. Also shown are spare gates.
Decoupling Capacitors 36-37
Decoupling Caps 38
These pages show de-coupling capacitance used in these schematics as well as the voltage dividers
used to provide the GTL reference voltage.
Hardware system manager 39
The LM79 is a hardware system monitor. It monitors voltage regulation, fan RPM and stores POST
codes. The device can be accessed via the X-Bus bus or through the PIIX4E SMBus interface. Note
the voltage level translation circuitry between the 5-Volt LM79 and the rest of the 3.3-Volt SMBus.
Revision History 40
Changes made to the schematics are listed here underneath the revision where they first appeared
and by page number.