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**Definition of a chip set:
In short it is a set of  chips that allow a system designer to build a
computer.  If we restrict the term  'chip' to that of a microchip then
technically any microcomputer  contains a chip set, even  one based of
7400-series logic alone.

In the context of this document, a chip set is defined as any group of
chips used to implement  an IBM or IBM-compatible PC/XT/AT/386/486/etc
system.

There are 2 main categories that these chips fall into:
1. Direct copies or re-implementations of Intel chips
2. Chip sets sold as a set of chips to implement an IBM-compatible 
   that differ in some way to those used in an IBM system, e.g. not 
   pin compatible.

An  example of  the former  would be  some early  chips built  by VLSI
Technology (at the time known as VTI, to implement a 286:
o  VL82C37A is a: 82C37A DMA controller
o  VL82C59A is a: 82C59A interrupt controller
o  VL82C54A is a: 82C54 timer
o  VL82C612 is a: 74LS612 memory mapper
o  VL82C84A is a: 82284 clock generator and ready interface
o  VL82C88  is a: 82288 bus controller

These are  all direct replacements  for the parts  used in an  IBM AT.
Many companies had compatible versions of these chips.

An early example of the latter is the Chips & Technology NEAT chip set:
o  82C211 CPU/Bus controller, 
o  82C212 Page/Interleave and EMS Memory controller, 
o  82C215 Data/Address buffer 
o  82C206 Integrated Peripherals Controller (IPC).

The description does not map directly to the parts used in the IBM AT.
Later chip sets are often even more integrated sometimes consisting of
just one chip, although two seems to be the most common.

The latter  is generally considered  the definition of a  chip set, and
the former is not generally  considered a chip set per-se. However when
looking  at   the  early  chip sets   this  distinction  can   be  very
slight. Because of this,  sets of chips  meeting the criteria  for (1.)
have been included where possible. 

**'chip set', 'chip-set' or 'chipset'?...
**What's not included:...
**Who made the first chip set?...
**Spelling errors/mistyped words...
**Info needed on:...
**A note on VESA support of 486 chipsets....
**Datasheets:...
*_IBM...
*ACC Micro...
*ALD...
*ALi...
*AMD . . . . . . . [no datasheets, some info]...
*Chips & Technologies...
*Contaq  . . . . . [no datasheets, some info]...
*Efar Microsystems [no datasheets, some info]...
*ETEQ...
*Faraday...
*Forex . . . . . . [List only, no datasheets found]...
*Intel...
**82485       Turbo Cache (and 485Turbocache)                      c90
***Notes:...
***Info:
The 82485 is  a second-level cache controller designed  to improve the
performance  of  Intel486  Microprocessor  systems.  One  82485  cache
controller supports  64K or  128K bytes of  second level  cache memory
that maps  to the  entire 4 Gigabytes  of the  Intel486 microprocessor
address space. The controller  is completely software transparent. One
controller plus SRAMs  provides a 64K or a  128K cache. External EPROM
can  be  cached  yet  remain  write protected.   The  82485  is  fully
compatible  with the  Intel486  microprocessor. All  Intel486 CPU  bus
cycles and timings are supported.

A complete, optional second level  cache controller using the 82485 is
available  as the 485Turbocache  Module from  Intel (data  sheet order
number 240722).

2.0 FUNCTIONAL DESCRIPTION
2.1 Introduction
The 82485 is a single ported, two-way set associative cache controller
designed specifically  to interface with  the Intel486 microprocessor.
The controller supports either a sectored configuration (two lines per
tag) or  a non-sectored configuration  (one line per tag).   The 82485
will directly support a nonsectored  64K data cache or a 128K sectored
data cache.  Both the 64K and  128K configurations are able to map the
entire 4 gigabytes of  the Intel486 microprocessor address space.  The
82485 interfaces directly to  the Intel486 microprocessor.  All Intel-
486 CPU bus cycles and timings are supported.  The 82485 also supports
0 wait  state processor operation  when there is  a cache hit  and has
provisions to support invalidation cycles, BOFF# cycles, and premature
BLAST# terminations.  The controller  is look aside (monitors bus act-
ivity in parallel to the processor) and write through (all writes pro-
pagate to the  system bus), so it supports  the same cache consistency
mechanisms as the  Intel486 CPU.  The controller also  provides a safe
method to cache ROM BIOS through the  use of a write protect pin and a
write protect strapping option.

The data cache  (Static RAM) resides external to  the 82485. The 82485
provides all  controls for  the SRAMs.  No  external latches  or tran-
ceivers are  required.  The 82485  output buffers support up  to eight
SRAMs.  A  64K cache can be  designed with only  five components; nine
components for a 128K cache.  Two-way set associativity is provided by
dual banked SRAMs. Data parity is supported.

The  82485  can  be  used  to  design  a  custom  second  level  cache
configuration. For an easier system design and higher integration, the
82485M Turbocache  can be used  (see data sheet order  number 240722).
This  module is  a  complete second  level  cache in  one package.  It
consists  of a single  82485 cache  controller and  SRAM to  provide a
complete 64K or 128K second level Intel486 microprocessor second level
cache.

***Versions:...
***Features:...
**82489DX       Advanced Programmable Interrupt Controller    10/12/92...
**82495DX/490DX DX CPU-Cache Chip Set                           <Sep91...
**82495XP/490XP Cache Controller / Cache RAM (for i860)       06/05/91...
**82496/491     Cache Controller / Cache RAM (for P5 Pentium) 03/22/93...
**82497/492   Cache Controller / Cache RAM (for P54 Pentium)    <Nov94...
**82498/493   Cache Controller / Cache RAM (for P54 Pentium)    <Nov94...
**
**Later chipsets (basic spec):
**440 series:...
**450NX  (?)            06/29/98:...
**?????  (Profusion)    c:99...
**800 series...
*Headland/G2...
*HMC (Hulon Microelectronics)...
*Logicstar...
*Motorola...
*OPTi...
*PC CHIPS/Amptron/Atrend/ECS/Elpina/etc...
*SIS...
**85C401/402     ISA 486DX/SX Cache chipset    [no datasheet]        ?
***Notes:...
**85C406/5/411/420/431  EISA 386/486 Chipset   [no datasheet]      c91...
**85C460         ISA 386DX/486 Single Chip     [no datasheet]        ?
**85C461         ISA 386DX/486 Single Chip     [no datasheet]        ?...
**85C471/407     Green PC ISA-VLB 486 Single Chip                  <94...
**85C496/497     486-VIP 486 Green PC VESA/ISA/PCI Chipset         <95...
**85C501/502/503 Pentium/P54C PCI/ISA Chipset                <01/09/95...
**5101/5102/5103 Pentium/P54C PCI/ISA Chipset                <04/02/95...
**5120           Pentium PCI/ISA Chipset (Mobile)            <01/28/97...
**5501/5502/5503 Pentium/P54C PCI/ISA Chipset                <04/02/95...
**5511/5512/5513 Pentium PCI/ISA                             <06/14/95...
**5571           (Trinity) Pentium PCI/ISA Chipset (75MHz)   <12/09/96...
**5581/5582      (Jessie)  Pentium PCI/ISA Chipset (75MHz)   <04/15/97...
**5591/5592/5595 (David)   Pentium PCI A.G.P. Chipset        <01/09/98...
**5596/5513      (Genesis) Pentium PCI Chipset               <03/26/96...
**5597/5598      (Jedi)    Pentium PCI/ISA Chipset           <04/15/97...
**530/5595       (Sinbad) Host, PCI, 3D Graphics & Mem. Ctrl.<11/10/98...
**540            (Spartan) Super7 2D/3D Ultra-AGP Single C.S.<11/30/99...
**55x            SoC (System-on-chip)                        <03/14/02...
**
**Support chips:
**85C206     Integrated Peripheral Controller [no datasheet]         ?...
**5595       Pentium PCI System I/O                          <12/24/97...
**950        LPC I/O                                         <07/16/99...
**Other:...
**PII/III/Pro...
**Athlon etc...
*Symphony...
*TI (Texas Instruments)...
*UMC...
*Unresearched:...
*VIA...
*VLSI...
*Western Digital...
*Winbond...
*ZyMOS...
*General Sources:...

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