Intel III 450 MHz 80525PY450512 Data Sheet

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In this document, a ‘#’ symbol after a signal name refers to an active low signal. This means that a 
signal is in the active state (based on the name of the signal) when driven to a low level. For 
example, when FLUSH# is low, a flush has been requested. When NMI is high, a nonmaskable 
interrupt has occurred. In the case of signals where the name does not imply an active state but 
describes part of a binary sequence (such as address or data), the ‘#’ symbol implies that the signal 
is inverted. For example, D[3:0] = ‘HLHL’ refers to a hex ‘A’, and D[3:0]# = ‘LHLH’ also refers to 
a hex ‘A’ (H= High logic level, L= Low logic level).

The term “system bus” refers to the interface between the processor, system core logic (a.k.a. the 
AGPset components), and other bus agents. The system bus is a multiprocessing interface to 
processors, memory, and I/O. The term “cache bus” refers to the interface between the processor 
and the L2 cache components (TagRAM and BSRAMs). The cache bus does NOT connect to the 
system bus, and is not visible to other agents on the system bus.

The following terms are used often in this document and are explained here for clarification:

•

 III processor—The entire product including internal components, substrate, cover 

and in S.E.C.C. packaged processors, an extended thermal plate.

•

S.E.C.C.—The processor package technology called “Single Edge Contact Cartridge.”

•

S.E.C.C.2—The follow-on to S.E.C.C. processor package technology. This differs from its 
predecessor in that it has no extended thermal plate, thus reducing thermal resistance.

•

Processor substrate—The FR4 board on which components are mounted inside the S.E.C.C. 
or S.E.C.C.2 packaged processor (with or without components attached).

•

Processor core—The processor’s execution engine.

•

Extended Thermal Plate—This S.E.C.C. package feature is the surface used to attach a 
heatsink or other thermal solution to the processor. 

•

Cover—The plastic casing that covers the backside of the substrate.

•

Latch arms—An S.E.C.C. package feature which can be used as a means for securing the 
processor in a retention mechanism.

•

OLGA - Organic Land Grid Array. This package technology permits attaching the heatsink 
directly to the die.

Additional terms referred to in this and other related documentation:

•

SC242—The 242-contact slot connector (previously referred to as Slot 1 connector) that the 
S.E.C.C. and S.E.C.C.2 plug into, just as the Pentium

®

 Pro processor uses Socket 8.

•

Retention mechanism—A mechanical piece which holds the S.E.C.C. or S.E.C.C.2 packaged 
processor in the SC242 connector.

•

Heatsink support—The support pieces that are mounted on the baseboard to provide added 
support for heatsinks.

•

Keep-out zone—The area on or near an S.E.C.C. or S.E.C.C.2 packaged processor substrate 
that systems designs can not utilize.

•

Keep-in zone—The area of the center of an S.E.C.C. or S.E.C.C.2 packaged processor 
substrate that thermal solutions may utilize.

The L2 cache, TagRAM and BSRAM die, are industry designated names.